Home

X-Ray Radiation Safety Manual

1. lonizing radiation does have enough energy to remove gt Note electrons from neutral atoms lonizing radiation is of Gamma Ray Tracer XRF concern due to its potential to alter the chemical TI s Alpha Particle devices emit structure of living cells These changes can alter or 2 only X rays impair the normal functions of a cell Sufficient ee amounts of ionizing radiation can cause hair loss blood Sg DEENEN changes and varying degrees of illness t y There are four basic types of ionizing radiation emitted from different Kry parts of the atom zs m Types of lonizing Radiation and e Alpha particles Their Sources e Beta Particles e Gamma rays or X rays e Neutron Particles The penetrating power for each of the four basic radiations varies significantly e alpha X SEN SN particle B e beta particle gamma aU fei or X rays o paper body metal concrete The Penetrating Power of Radiation 030 0011 01 0 8 X Ray Radiation Safety Manual BRUKER Bruker Elemental Alpha particles gt Have a large mass consisting of two protons and two neutrons gt Have a positive charge and are emitted from the nucleus gt lonize by stripping away electrons from other atoms with its positive charge Range Due to their large mass and charge alpha particles will only travel about one to two inches in air This also limits its penetrating ability Shieldin Mo
2. Precise biased inaccurate Precise unbiased accurate Figure 2 Illustration of Precision Accuracy and Bias Gaussian Distribution Physicists have verified that the X ray fluorescence process is truly random The statistical law that describes random processes is the Poisson distribution law Because the Poisson distribution law approximates the normal Gaussian i e bell shape distribution as a limit the mathematical descriptions applicable to the Gaussian distribution or normal law are used The illustration shows the relationship between the normal curve and the standard deviation Standard Deviation The standard deviation SD is the most commonly used of several indices of the precision or error in XRF data The SD indicates the reliability of a measurement or a set of of total area under Frequency of measured value M 3 2 4 D 1 42 3 Standard deviation SD Normal distribution approximates Possion Distribution Laws measurements If N is the sum of all X rays recorded counts during a specified interval of time the Standard Deviation is Standard Deviation SD N or AN 030 0011 01 0 37 X Ray Radiation Safety Manual BRUKER Bruker Elemental The standard deviation may be written in fractional form as SD VN 1 1 N JNJN AN N Multiplying the fraction by 100 will give the standard deviation in percent It is important to note that the precision of measur
3. Plane of NS Pa sample Surface E 100 cm Side View Top View Radiation Profile of the Tracer SD Table 1 Table 2 Reading Reading Reading Reading A bkgnd G bkgnd A bkgnd G bkgnd B bkgnd H bkgnd B bkgnd H bkgnd C bkgnd l bkgnd C bkgnd I bkgnd D bkgnd J bkgnd D 10 urem hr J 25 urem hr E bkgnd K bkgnd E bkgnd K bkgnd F bkgnd L bkgnd F bkgnd L bkgnd 40kV 20pA with Duplex 2205 15kV 9 60pA with AI2024 Sample Sample Dose rates for the Tracer SD normal operation configuration All other locations on side top bottom and back of the analyzer are background bkgnd Readings taken with a Bicron Model RSO 50E low energy ion chamber survey instrument Reference distances were measured from the effective center of the detector to the surface of the analyzer The indicated readings were the maximum noted for the distances and locations Each reading was taken over a one minute period with the analyzer operating at its respective settings Table 1 shows the results at 40 kV and 20 uA the maximum voltage at the highest current available at that voltage with the titanium aluminum filter in place Table 2 shows the results at 15 kV and 60 pA without a filter NOTE The L line of the silver target in the X ray tube produces X rays of 3keV This accounts for the higher emission in the open beam without the Ti AI filter in place Dose rates will vary based on current energy sample
4. X Ray Radiation Safety Manual BRUKER Bruker Elemental e Individual sensitivity to ionizing radiation developing embryo fetus is the most sensitive children are the second most vulnerable theelderly are more sensitive than middle aged adults youngto middle aged adults are the least sensitive Prenatal Exposure A developing embryo fetus is the most sensitive to ionizing radiation because of its rapidly dividing cells While no inheritable effects from radiation have yet been recorded there have been effects seen in some children exposed to radiation while in the womb Possible effects include e Slower growth e Impaired mental development e Childhood cancer Some of the children from Hiroshima and Nagasaki exposed to radiation while in the womb were born with low birth weights and mental retardation While it has been suggested that such exposures may also increase the risk of childhood cancer this has not yet been proven It is believed that only doses exceeding 15 000 mrem significantly increase this risk It should be stressed that many different physical and chemical factors can harm an unborn child Alcohol exposure to lead and prolonged exposure in hot tubs are just a few of the more publicized dangers to fetal development See page 21 for more discussion on pregnancy and exposure Putting Risks in Perspective Acceptance of any risk is a very personal matter and requires that a person make informed judgm
5. C of the analyte has not changed This can cause an error in the estimated concentration due to matrix effects unless corrected for during calibration or with a spectrum analysis algorithm The Bruker Elemental XRF analyzer s unique spectrum analysis algorithm corrects for such interferences and effects by monitoring the X ray intensity from the interfering element and applying correction factors derived during calibration 030 0011 01 0 35 X Ray Radiation Safety Manual BRUKER Bruker Elemental Data Reduction Errors in XRF Analysis There are different reasons for errors and uncertainties in XRF analysis Some uncertainties are introduced by the randomness of fluorescent events i e the emission of X rays from the sample is random but predictable Similarly the detection of X rays is also a random but predictable event Systematic and Random Errors All errors may be classified as either systematic errors or random errors The effect of systematic errors can be minimized by careful procedures and use of proper calibration constants Even without systematic errors a set of measurements under supposedly identical conditions will yield values with some variation when the variations are considered from a statistical probability viewpoint The results of the measurements can be expressed with an assigned probability of error the error is expressed as follows Error E Measured value M True value T In reality the True
6. X rays emitted from electrons during electron shell transfers Fail Safe Design A design in which any reasonably anticipated failure of an indicator or safety component will cause the equipment to fail in a mode such that personnel are safe from exposure to radiation e g a light indicating X RAY ON fails the production of X rays shall be prevented lon An atom that has lost or gained an electron lon Pair A free electron and positively charged atom lonization The process of removing electrons from the shells of neutral atoms lonizing Radiation Radiation that has enough energy to remove electrons from neutral atoms Isotope Atoms of the same element that have a different number of neutrons in the nucleus Non ionizing Radiation Radiation that does not have enough energy to remove electrons from neutral atoms Normal Operation Operation under conditions suitable for collecting data as recommended by manufacturer including shielding and barriers Primary Beam In the context of X ray fluorescence measurements the primary beam is the ionizing radiation from an X ray tube that is directed through an aperture in the radiation source housing Radiation The energy in transit in form of electromagnetic waves or particles Radiation Generating Machine A device that generates X rays by accelerating electrons which strike an anode Radiation Source An X ray tube or radioactive isotope Radiation Source Housing That portion
7. analyzer into another jurisdiction contact the appropriate authority in that jurisdiction for their particular requirements This Radiation Safety Operator Training manual is for use by operators of the Bruker Elemental handheld XRF analyzers This manual contains three sections 1 Radiation Safety begins on page 4 2 Theory of XRF Operation begins on page 30 3 Specific Bruker Elemental XRF analyzer requirements begins on page 42 The first two sections contain generic theory and safety issues while section three discusses the specifics of the Tracer XRF analyzer For detailed information about the S1 Sorter and S1 Turbo see the instrument s User Guide Recipients of Bruker Elemental XRF analyzers which contain an X ray tube which differ from radioactive sourced analyzers may be subject to X ray protection requirements established by government agencies General Information Bruker Elemental Bruker AXS Handheld Inc DBA Bruker Elemental manufactures XRF analyzers that contain an X ray tube They are registered with the U S FDA Center for Devices and Radiological Health Each purchased analyzer which contains an X ray tube is provided with specific safety requirements All Bruker Elemental XRF analyzers should be operated only by individuals who have completed an approved radiation safety training program Damage to a Bruker Elemental XRF analyzer may cause unnecessary radiation exposure If a Bruker Elemental XR
8. 55 790 7 899 173 Tantalum 67 416 57532 8 146 74 Tungsten 69 525 59 318 8 398 75 Rhenium 71 676 61 140 8 653 76 Osmium 73 871 63 001 8 912 7 7 Iridium 76 111 64 896 O5 78 Platinum 78 395 66 832 9 442 79 Gold 80 725 68 804 ONIS 80 Mercury 83 102 70 819 9 989 81 Thallium 85 530 72 872 10 269 82 Lead 88 005 74 969 10 552 83 Bismuth 90 526 77 108 10 839 84 Polonium 93 105 79 290 11 131 85 Astatine 95 730 81 520 11 427 86 Radon 98 404 83 780 11 727 87 Francium 101 137 86 100 12 031 88 Radium 103 922 88 470 12 340 89 Actinium 106 755 90 884 12 652 90 Thorium 109 651 93 350 12 969 gii Protactinium 112 601 95 868 SE 92 Uranium 115 606 98 439 13 615 030 0011 01 0 52 X Ray Radiation Safety Manual BRUKER Bruker Elemental Appendix B Radiation Profile Normal Condition The radiation profile of the Tracer SD shown in the following diagram reflects the conditions during normal operation with a sufficiently thick sample to contain the main X ray beam These readings show the radiation background around the instrument in all directions These values were obtained using a Bicron Low Energy Micro Rem ion chamber and indicate that the dose rate at 10 cm from any accessible surface was lower than 5 0 uSv hr less than 500 urem hr Beam Line Background 100 em EE Background b L Plane of Sample Surface Background dech Background Background A 3 d 10cm Ee Background A d 30cm y
9. Spectrum This figure shows an X ray spectrum which corresponds to the X ray lines as recorded by the Bruker Elemental XRF analyzer The actual spectrum is the sum of the overlapping pulse height distributions During calibration element channel ranges for each element are recorded Counts par and stored The width of these channel channel ranges are approximately equal to 1 FWHM and centered on the maximum peak Each range is selected for each peak based on the recorded readings for each element s standard The sensor gain is normally adjusted so that the useful spectral range excludes the first 10 and the last 10 channels on a 2048 channel analyzer 030 0011 01 0 Counts per channel Bruker Elemental Fluorescent Peaks Compton backscatter cu 7n peak A Background tail e lt t Mean pulse height 3 Energy or pulse height Maximum La FWHM A Half maximum channel 4 Channel 3 Zn Channel 2 Cu Channel 1 Fe Compton scatter Channel 39 X Ray Radiation Safety Manual BRUKER Bruker Elemental Calculation of Net Intensities Some peaks in an accumulated spectrum are distorted to some degree by spectral interference due to background and or overlap Background Background interference arises from gamma ray or X ray backscatter and the low energy tail associated with each peak This background Background tail interference is
10. The basic unit of each element is the atom which is very small but has all the chemical characteristics of that element There are approximately 110 principle elements Some of the most common elements are shown in the table to the right Most matter does not exist in pure elemental form but rather in chemical combinations called molecules The Molecule The molecule is the basic unit of a chemical combination A molecule is formed when two or more atoms combine to create a material with its own distinctive properties Atoms combine according to definite rules Structure of the Atom The atom consists of two main parts the nucleus and the electron shells The nucleus is the center of the atom and contains neutrons and protons which make up almost all of the mass of the atom Element Oxygen Sodium Carbon C Copper Cu Hydrogen H lodine Chlorine Cl Sulfur S H20 Water Salt NaCl Alcohol C H OH Quartz SiO Common Molecules The electron cloud surrounds the nucleus and is composed of electrons that are in constant motion For convenience scientists draw the electrons in plain orbits and they visualize electrons as occurring in shells surrounding the nucleus The Electron Electrons orbit the nucleus in certain energy states electron shells in relation to the nucleus They have a very small mass
11. by workers to measure the radiation exposure to the extremities This device records a measured dose that is used as an individual s legal occupational extremity exposure 030 0011 01 0 23 X Ray Radiation Safety Manual BRUKER Bruker Elemental Reducing Exposure ALARA Concept While dose limits and administrative control levels already ensure very low radiation doses it is possible to reduce these exposures even more The main goal of the ALARA program is to reduce ionizing radiation doses to a level that is As Low As Reasonably Achievable ALARA ALARA is designed to prevent unnecessary exposures to employees the public and to protect the environment It is the responsibility of all workers managers and safety personnel to ensure that radiation doses are maintained ALARA There are three basic practices to maintain external radiation ALARA e Time e Distance e Shielding Time The first method of reducing exposure is to limit the amount of time spent in a radioactive area the shorter the time of exposure the lower the amount of exposure The effect of time on radiation could be stated as Dose Dose Rate x Time This means the less time you are exposed to ionizing radiation the smaller the dose you will receive Example If 1 hour of time in an area results in 100 mrem of radiation then 1 2 an hour results in 50 mrem 1 4 an hour would yield 25 mrem and so on Distance The second method for red
12. cells make up tissues which in turn make up the body s organs Some cells are more resistant to viruses poisons and physical damage than others The most sensitive cells are those that are rapidly dividing such as those in a fetus Radiation damage may depend on both resistance and level of activity during exposure Acute and Chronic Doses of Radiation All radiation if received in sufficient quantities can damage living tissue The key lies in how much and how quickly a radiation dose is received Doses of radiation fall into one of two categories acute or chronic Acute Dose An acute dose is a large dose of radiation received in a short period of time that results in physical reactions due to massive cell damage acute effects The body can t replace or repair cells fast enough to undo the damage right away so the individual may remain ill for a long period of time Acute doses of radiation can result in reduced blood count and hair loss Recorded whole body doses of 10 000 25 000 mrem have resulted only in slight blood changes with no other apparent effects Radiation Sickness Radiation sickness occurs at acute doses greater than 100 000 mrem Radiation therapy patients often experience it as a side effect of high level exposures to singular areas Radiation sickness may cause nausea from cell damage to the intestinal lining and additional symptoms such as fatigue vomiting increased temperature and reduced white blood cell
13. compared to the neutron and proton i e approximately 2000 times less mass Electrons are negatively charged The protons in the nucleus are positively charged When the negative charge of the electrons is equal to the positive charge of the nucleus the two cancel each other and the atom is said to be electrically neutral If the two charges become unequal the atom is said to have a net electrical charge either positive or negative and is called an ion Generally this is because an outer electron shell has gained or lost an electron 030 0011 01 0 30 X Ray Radiation Safety Manual BRUKER Bruker Elemental Atoms combine chemically in predictable proportion according to each element s pattern of electrons The orbital electrons especially the outermost are the controls of chemical reactions The Nucleus The Nucleus is composed of protons and neutrons that are held very close together by powerful nuclear forces Protons and neutrons are approximately equal in mass and together they make up almost the entire mass of the atom The charge of the proton is equal in size but opposite in polarity to that of the electron Therefore the number of protons in the nucleus must be balanced by an equal number of electrons surrounding the nucleus in order to make the atom electrically neutral Neutrons on the other hand have no electrical charge and are present in all atomic nuclei except hydrogen this does not include deute
14. count Acute Dose to the Whole Body Recovery from an acute dose to the whole body may require a number of months Whole body doses of 500 000 mrem or more may result in damage too great for the body to recover from Example Thirty firefighters at the Chernobyl facility lost their lives as a result of severe burns and acute radiation doses exceeding 800 000 mrem Only extreme cases as mentioned above result in doses so high that recovery is unlikely Acute Dose to Part of the Body Acute dose to a part of the body most commonly occur in industry use of X ray machines and often involve exposure of extremities e g hand fingers Sufficient radiation doses may result in loss of the exposed body 030 0011 01 0 16 X Ray Radiation Safety Manual BRUKER Bruker Elemental part The prevention of acute doses to part of the body is one of the most important reasons for proper training of personnel Chronic Dose A chronic dose is a small amount of radiation received continually over a long period of time such as the dose of radiation we receive from natural background sources every day Chronic Dose vs Acute The body tolerates chronic doses better than acute doses because e Only a small number of cells need repair at any one time e The body has more time to replace dead or non working cells with new ones e Radical physical changes do not occur as with acute doses Genetic Effects Genetic effects involve changes
15. ideem M M 18 Radiation DOSE LIMITS usce ener ERE terea etie een teet sane e pne x he AO tense E eene paar eR Yee 20 Whole BOOY e 20 ades ee 20 dg 20 Organs or Tissues excluding lens of the eye and the skin sese 20 Lens oh the EY Oss ode rate esce tacens tede Eege 21 Declared Pregnant Worker embryo fetus essere enne nennen nnne 21 Measuring RAG ALON wissccevissccecevastcccavacccccuvencacdusseccecdvanscdcussvececunviaccdusssccdcusssicccacuvecccuavvitdduaueccecdevscdeadancees 22 Measuring Devices cicer br oen bim nete adiit enges Ee 22 lonizatiorChambB eese roca eer crate eaaa ede qct peo etra t EE a unu ge duo ap RERNA ec FREE Ee Ne ERR 22 030 0011 01 0 iii X Ray Radiation Safety Manual Ed mm Bruker Elemental The Geiger Mueller Tube eese esent entrent enne nn sienne se senta nnne nnas 22 Th Pocket Dositrieter orte e eee ente eei treu ere e inue e 22 Thermoluminescence Devices TLDs and Optically Simulated Luminescence Dosimeter OSL 23 Boi lrccm E 23 Reducing Exposure ALARA Concept 24 Uu 24 Bc ees 24 eil el TEE
16. in chromosomes or direct irradiation of the fetus Effects can be somatic cancer tumors etc and may be heritable passed on to offspring Somatic Effects Somatic effects apply directly to the person exposed where damage has occurred to the genetic material of a cell that could eventually change it to a cancer cell The chance of this occurring at occupational doses is very low Heritable Effects This effect applies to the offspring of the individual exposed where damage has occurred to genetic material that doesn t affect the person exposed but will be passed on to offspring To date only plants and animals have exhibited signs of heritable effects from radiation This data includes the 77 000 children born to the survivors of Hiroshima and Nagasaki The studies performed followed three generations which included these children their children and their grandchildren Biological Damage Factors Biological damage factors are those factors which directly determine how much damage living tissue receives from radiation exposure and include e Total dose the larger the dose the greater the biological effects e Dose rate the faster the dose is received the less time for the cell to repair e Type of radiation the more energy deposited the greater the effect e Area exposed the more body area exposed the greater the biological effects e Cell sensitivity rapidly dividing cells are the most vulnerable 030 0011 01 0 17
17. is pulled the infrared sensor is engaged and the push button safety switch has been depressed the red light will be activated indicating the generation of X rays If the red light bulb is burned out or has been removed X rays will not be generated e Communication for newer Tracers all SD Models and the Sorter model The analyzer must be connected to a computer device and communications established to turn X rays on e Count Rate for newer Tracers all SD Models and the Sorter Model Immediately after X rays are turned on the analyzer s software tests to ensure that sufficient X rays are detected in order to conclude a sample is present In addition to the safety circuit described above the small palm top computer will display a small red radiation symbol 4 when X rays are being generated and the computer is accumulating the data vacuum port infrared proximity sensor communications clip on window 1 e protector red lamp examination yellow lamp indicates window indicates power X ray production E Operator Primary Tl Power Power Key Eet Lock Safety Interlock Features 030 0011 01 0 46 X Ray Radiation Safety Manual BRUKER Bruker Elemental XRF Analyzer Safety Signs The Bruker Elemental Tracer XRF analyzers have warning signs as described below Voies den ameet DO NOT EXPOSE ANY PART TO BE OPERATED BY AUTHORIZED PERSONNEL ONLY OF BODY TO THE BEAM C
18. target collimator and windows 030 0011 01 0 53 Cox BROKER X Ray Radiation Safety Manual Bruker Elemental Appendix C Tracer XRF Instrument PDA Lock amp Plunger PDA Cradle ge Window Protector infrared proximity sensor e P gt Filter screw Tracer Ill SD Trigger only examination Remote Control Eyelet for Wrist Port or Shoulder Strap Figure 3 Profile of the Tracer SD Vacuum Port Communications Power E Key Lock Yellow Lamp Red Lamp indicates power indicates X rays Figure 4 Tracer Control Panel 030 0011 01 0 54 X Ray Radiation Safety Manual Bruker Elemental Appendix DSurvey Meters Operation and Maintenance Introduction Survey meters are often used to determine radiation fields around instruments that use a radioactive source or use an X ray tube The ones that will be discussed here are the hand held variety of rate meters that detect X rays and gamma rays note some can measure X rays and gamma rays and also measure beta particles Here are some of the survey meters on the market Picking the Right Survey Instrument for the X ray Tube Excited XRF Instrument Bruker Elemental s X ray tube instruments typically produce X rays with energy less than 45 kV The specific maximum voltage and current settings for your instrument are listed on the plate attached to the bottom of the instrument Checking the Survey Instrument before Operation As with all meas
19. the frequency of the X ray waves and is inversely proportional to their wavelength An X ray of energy of 12 39 keV has a wavelength of about 1 Angstrom One Angstrom is 1x10 cm Appendix A lists the energies and relative intensities of the main characteristic X ray lines in most of the elements detectable with the Bruker Elemental XRF analyzers An X ray source can excite characteristic X rays only if the source energy is greater than the absorption edge energy for the particular electron orbit group e g K absorption edge and L absorption edge of the element The absorption edge energy is somewhat greater than the corresponding fluorescent energy For any element the K absorption edge energy is approximately equal to the sum of the K L and M fluorescent energies and the L absorption edge energy is approximately equal to the sum of the L and M fluorescent energies Note The K line energies for a given element are the most energetic If the K lines are excited then the L lines of the same element will also be excited in cascade but the L lines are always of a much lower about one seventh energy Simplified X ray Spectrum Example shows characteristic lines of the element peaks Fluorescent Peaks I Fe and Compton scattered Counts per 1 Compt unit pulse KN X rays The dotted curves height Electronic Lo iy indicate how the detector I D D Y I e spreads the lines as it l i I converts the X ray q
20. you understand radiation we ll start by briefly discussing the composition of matter The physical world is composed of key materials called elements The basic unit of every element is the atom Although microscopic each atom has all the chemical characteristics of its element All substances or materials are made from atoms of different elements combined together in specific patterns That is why atoms are called the basic building blocks of matter Example Oxygen and hydrogen are two very common elements If we combine one atom of oxygen and two atoms of hydrogen the result is a molecule of H20 or water 030 0011 01 0 4 X Ray Radiation Safety Manual se Parts of the Atom Bruker Elemental Just as all things are composed of atoms atoms are made up of three basic particles protons neutrons and electrons Together these particles determine the properties electrical charge and stability of an atom Protons Neutrons VV ON ON WV Electrons D gt gt Are found in the nucleus of the atom Have a positive electrical charge Determine the atomic number of the element therefore if the number of protons in the nucleus changes the element changes Are found in the nucleus of the atom Have no electrical charge Help determine the stability of the nucleus Are in the nucleus of every atom except Hydrogen H 1 Atoms of the same element have the same number of protons but can have a diff
21. 0 367 9252 1 098 32 Germanium 11 103 9 886 1 188 33 Arsenic 11 867 10 544 1 282 34 Selenium 12 658 11 222 1 379 35 Bromine 13 474 11 924 1 480 36 Krypton 14 326 12 649 1 586 37 Rubidium 15 200 133395 1 694 38 Strontium 16 105 14 165 1 807 39 Yttrium 17 038 14 958 1 923 40 Zirconium 17 998 15 775 2 042 41 Niobium 18 986 16 615 2 166 42 Molybdenum 20 000 17 479 2 293 43 Technetium 21 044 18 367 2 424 44 Ruthenium 22 117 19 279 2 559 45 Rhodium 23 220 20 216 2 697 46 Palladium 24 350 21 177 2 839 47 Silver 25 514 22 163 2 984 48 Cadmium 26 711 23 174 3 134 49 Indium 27 940 24 210 3 287 50 Tin 29 200 25 271 3 444 5i Antimony 30 491 26 359 3 605 52 Tellurium 31 814 27 472 3 769 53 lodine 33 169 28 612 3 938 54 Xenon 34 561 29 779 4 110 55 Cesium 35 985 30 973 4 287 56 Barium 37 441 32 194 4 466 57 Lanthanum 38 931 33 440 4 651 58 Cerium 40 443 34 720 4 840 59 Praseodymium 1199A 36 026 5 034 60 Neodymium 43 569 37 361 5 230 61 Promethium 45 184 38 725 5 433 030 0011 01 0 51 X Ray Radiation Safety Manual C BR KER v Bruker Elemental Atomic Element K Absorption K Shell L Shell Number 62 Samarium 46 834 40 118 5 636 63 Europium 48 519 41 542 5 846 64 Gadolinium 50 239 42 996 6 057 65 Terbium 51 996 44 482 6 273 66 Dysprosium 53 789 45 998 6 495 67 Holmium 55 618 47 547 6 720 68 Erbium 57 486 49 128 6 949 69 Thulium 59 390 50 742 7 180 70 Ytterbium 61 332 52 389 7 416 Ge Lutetium 63 314 54 070 7 656 72 Hafnium 65 351
22. 0x the operator should multiply the result on the display by 10 and likewise the 100x scale means you multiply the result by 100 A ways start your measurements on the 100x scale If the needle barely deflects then switch the scale to 10x if that is not sensitive enough then switch to the 1x Be as gentle with the detector of the instrument as possible sudden motions may make the instrument register counts that aren t there When surveying move the detector slowly over the areas you want to survey If you come across an area that makes the needle deflect to the top of the scale move the detector away quickly and change to a less sensitive scale With proper care and maintenance these instruments will last for many years so take good care of your survey equipment 030 0011 01 0 56 X Ray Radiation Safety Manual Bruker Elemental Contact Us This manual contains proprietary information which is protected by copyrights All rights reserved No part of this manual may be photocopied reproduced or translated to another language without prior written consent of Bruker Elemental Refer to the LICENSE NOTICE for complete list of terms and conditions ActiveSync Excel and Windows and trademarks of Microsoft Corporation and are protected by their respective copyrights The information in this manual was correct at the time of printing and supersedes previously published material However Bruker Elemental continues to imp
23. 25 License Registration Requirements ccccccsssecesscecsececssecesseecssseccssececaeecessecesseeecaueceseeceseeceaeeeeaaeeesees 27 Bruker Elemental X ray Tube XRF Anahyzer eene 27 Transportation Reguirementzs nennen nnnnnnaninan inani nas ih as isas isis is aiiaas asas aeiae iE 28 Section 2 Theory Of XRF Operation e eeee eese eene eene eene nennen nennen nenne nannte nannten 29 What ISX RP E M 30 Review The Composition of Matter nnne enne nnns nenne nnnn nasse nennen asas asse ni an 30 The ET TE 30 vetri 30 Mun O 30 ele rote Detur edet entonces dpi E 31 Nuclear Stability e E SeeN 31 X ray Ee E 31 a PU CHE et 31 The Proce ss of X ray Fluorescence cetero teca retorica ho od toe Lai Eg 32 Bruker Elemental XRF Instruments ANEN 33 Characteristic CN 33 X ray Line Interference oie eet eterni n ER Nee eeh REENEN ENEE 34 Scattered X rays Compton NEEN 34 Intensity Concentration Relation 34 Dattal certe 36 Selen EE 36 Systematic and Random Errors ccccscssssscecececsesennececececesseseaeaeceessceeesaeaecececssesseaeaeceeecuseeseeaeeeeeeesees 36 Accuracy Precision ANG TEE 36 030 0011 01 0 iv X Ray Radiation Safety Manual Ed mm Bruker Elemental PEOCISIOLT s e
24. 5 microcurie Am 241 plastic source disk half life 432 years This source is placed into a mount on a test bed fixture mounts would be placed at a few distances from the source for the probe to fit in a few cm from the source When the instrument is first received the user records the typical reading at each probe mount locations After that the instrument should read the same reading at each calibration check Using a Survey Meter While there is variation between instruments and from one probe type to another most of the instruments operate in a similar way Some probe types have a cover that the operator must remove to measure beta particles and install when measuring X or gamma rays Some displays are analog a white display with a needle that bounces back and forth and some are digital Some display their answer in counts per minute some in mRem hr some in Roentgens hr and others in Sv hr Some instruments give you the ability to average the reading and some can incorporate alarm sounds Read the instrument user manual to understand how to operate and interpret the measurements provided by the instrument One thing that is fairly common among the instruments is that there are usually 3 or 4 scales of measurement e g 1x 10x and 100x These scales allow the user to measure a large range of radiation levels from a source If the scale is set to the 1x the operator should multiply the result on the display by 1 If the scale is set to 1
25. AUTION Sign located on the rear of the WARNING Sign located near the analyzer nosepiece of the analyzer oe X e WARNING HIGH INTENSITY X RAYS DO NOT EXPOSE ANY PART OF BODY TO THE BEAM WARNING Sign located on the window label WARNING Sign located on clip on window protector CAUTION RADIATION GENERATING MACHINE For safe operation see User Manual The receipt possession use and transfer of this device are subject to registration as required by the users state MODEL TRACER SD C ZA Device S N MFG Date This device contains a 40 kV 60uA X ray tube E us In case of emergency service or repair contact BRUKER AXS Handheld Inc 1 509 783 9850 415 North Quay St Ste 1 Kennewick WA 99338 USA DC 15V 3A MAX This label shall be maintained on the device in legible condition Example of Manufacturers regulatory plate located underneath analyzer 030 0011 01 0 47 X Ray Radiation Safety Manual Bruker Elemental Radiation Safety Tips for Using the XRF Analyzer All Bruker Elemental Tracer analyzer operators should follow minimum safety requirements discussed below When handled properly the amount of radiation exposure received from the Bruker Elemental Tracer XRF Analyzer will be negligible However the following safety tips are provided to help ensure safe and responsible use e Do not allow anyone other than trained and certified personnel to operate
26. C BR KER C 030 0011 01 0 Bruker Elemental X Ray Radiation Safety Manual for Operator Training Bruker Elemental Hand held XRF Analyzers X Ray Radiation Safety Manual BRUKER Bruker Elemental Table of Contents Important Notes to Hand Held XRF Analyzer Customers esses eene enne enne nnns 1 General INOA E 1 Responsibilities of the Customer c cccccsssccessenceceeseececeeseneecseseeeecesseeeecseseesecseseeaecseseaecesseeaeceeseaaecseeeaaees 2 Section E IER 3 What RETTEN E 4 THE Composition of Matters uscire t Ree od EAEE RR Re E EN dee eu BRE ERR eS EAR RURS 4 Parts Of tTHE ALOMM onerar enoii 5 Neel 5 KEE de EE 5 lte EE 5 Structure OF THE ATOM E 5 VIe 5 Sg E 6 Electrical Charge of the e EE 6 The Stability Of th tege 6 Radiation Terminology c ccccccccsssssssececececessessesecececsceesesaeaeeececesseseeaeeeseeesessesaeaeceeecssessesaaaeceseesseeseasaeeeeeens 7 Kee RAGIACION E 8 Nonsionizing RadiatiOri uiii ice pottea cernere cox eese reae eE a eet nana AE KAAK eE aE ae Roe eds 8 l ni ine Radiatio WEE 8 el We El de 9 Beta Particles TEE 9 Gamma Rays and pc m 10 Nurses 10 Units of Measuring Radiation esses ener enn snnt nens en nnne sene n nennen nnn 11 PROG IES CM DEE 11 Rad Radiation Absorbed Dose 11 nim 11 Radiation Quality FaCtOF oett eot docens inert
27. ER 47 Radiation Safety Tips for Using the XRF Analyzer ccccccsccccesssscecessececsesaececsesaececessaececeesaeeeeeesaeeeeeeaaes 48 In Case of Emergencies itr ee ete eie EE EE 49 Ville teleib EE 49 Major Damage ce rite Macatee etos ee eege e doa 49 LOSS or THE eene iinei P M 49 PAPO IGE S mmt A 50 Appendix A X ray Critical Absorption Energies in key 51 030 0011 01 0 V X Ray Radiation Safety Manual se Bruker Elemental Appendix B Radiation Profile Normal Condition ve sccsccscsssescnccscescesuescscensensoseneassscuseodesenspenstansernctessd 53 Appendix C Tracer iu I L 54 Appendix D Survey Meters Operation and Maintenance eene 55 Contact Eeer 57 030 0011 01 0 vi X Ray Radiation Safety Manual Bruker Elemental Important Notes to Hand Held XRF Analyzer Customers gt Note Governing agencies regulate the use of X ray generating devices such as XRF analyzers through a set of regulations Actual regulations for all XRF analyzers vary by locale gt Note Bruker Elemental as used throughout this manual refers specifically to the device manufacturer Bruker Elemental Bruker AXS Handheld Inc DBA Bruker Elemental gt Note Governing agencies may require registration and or licensing A fee payment may be required If you are planning to transport a Bruker Elemental XRF
28. F analyzer is damaged such that radiation shielding damage is suspected a Bruker Elemental service representative should be contacted immediately at 509 783 9850 If any hardware items are damaged even if the instrument remains operable contact a Bruker Elemental service representative for additional information Tampering with any Bruker Elemental XRF analyzer component except to replace the batteries or to remove the hand held computer where applicable voids the warranty and violates the mode of operation In such cases harm or serious injury may result 030 0011 01 0 X Ray Radiation Safety Manual Ed mm Bruker Elemental Responsibilities of the Customer Contact the appropriate regulatory authority to determine if registration or licensing requirements apply Comply with all instructions and labels provided with the XRF Do not remove labels Removal of labels will void the warranty Test an XRF device for correct operation of the ON OFF mechanism every six months and keep records of the test results If the instrument fails either test call Bruker Elemental immediately for instructions and return of the instrument for repair Do not abandon any XRF instrument Maintain a record of the XRF instrument use and any service to shielding and or containment mechanisms for two years or until the ownership of the instrument is transferred or until the instrument is decommissioned Report any possible damage to shielding or
29. a result of the imperfect detection process and its magnitude is proportional to the peak causing it Spectral Overlap 2 39 Spectral Overlap occurs when two peaks are not completely resolved The degree of overlap depends on the energy separation of the peaks compared with the detector and spectrometer resolution at that energy The superior resolution of most Bruker Elemental instrumentation compared to that of proportional counters and scintillation type detectors permits a more accurate resolution of peaks and background from elements of an adjacent channel2 Cu Channel 3 Zn atomic number minimizing the amount of overlap or interference Eliminating Background and Overlap After spectral accumulation the first stage of spectrum analysis is the mathematical elimination of background and peak overlap These calculations are made during instrument calibration using spectra taken from reference standards standard reference materials or site specific standards The net pulse counts net intensities in each element channel or window are related to the elemental concentrations The subtraction of background and overlap causes an increase in the statistical error on the net intensity The larger the degree of overlap and the smaller the measured peak compared to background the greater the risk of relative statistical error on the net intensity Calculating Concentrations After obtaining net X ray intensities the next step in spectrum a
30. adiation primarily is considered an external hazard due to its range and penetrating ability 030 0011 01 0 10 X Ray Radiation Safety Manual BRUKER Bruker Elemental Units of Measuring Radiation The absorption of radiation into the body or anything else depends upon two things the type of radiation involved and the amount of radiation energy received The units for measuring radiation are the roentgen rad and rem Roentgen A roentgen is named after Wilhelm Roentgen the discoverer of X rays A roentgen is a unit of exposure dose that measures X rays or gamma rays in terms of the ions or electrons produced in dry air at 0 C and one atmosphere equal to the amount of radiation producing one electrostatic unit of positive or negative charge per cubic centimeter of air Rad Radiation Absorbed Dose A rad is e A unit for measuring the amount of radiation energy absorbed by a material i e dose e Defined for any material e g 100 ergs g e Applied to all types of radiation e Notrelated to biological effects of radiation in the body e 1 0 Rad 1000 millirad mrad e The Gray Gy is the System International SI unit for absorbed energy e 1 0 Rad 0 01 Gy 1 0 Gy 100 rad Rem Actual biological damage depends upon the concentration as well as the amount of radiation energy deposited in the body The rem is used to quantify overall doses of radiation their ability to cause damage and their dose equiva
31. ands or portions of the body in the beam path 030 0011 01 0 45 X Ray Radiation Safety Manual BRUKER Bruker Elemental Safety Logic Circuit Warning Lights and Warning Labels The Bruker Elemental Tracer XRF analyzers have been designed with a Failsafe Safety Circuit to prevent operation of the analyzer The safety system for the Tracer analyzer consists of two failsafe lights a key lock a trigger to activate X rays and an infrared sensor The S1 Sorter and S1 Turbo do not require a key lock these analyzers require passwords The function of each of the seven safety features is described below e Primary Power Safety Keylock a key lock is employed to control power to all components The key lock must be turned on before any other actions can be initiated e Yellow High Voltage On Failsafe Warning Light when the key lock is turned on the yellow light is activated to indicate there is voltage to the power supply If the bulb has failed or has been removed the safety circuit will not permit the application voltage to the power supply e Operator Trigger Interlock when the trigger is pulled X rays are generated if the rest of the safety circuit has been satisfied e Infrared Proximity Safety Sensor The infrared proximity safety sensor located on the nose aperture end of the Tracer analyzer will not permit X rays to be generated unless covered by a solid object e Red X ray On Failsafe Warning Light when the trigger
32. anger to the operator or others APPLICATIONS e Alloy grade identification and quantitative chemistry analysis e Pollutant Metals in Soil EPA RCRA metals e Coating thickness QA S Throughout this section the Bruker Elemental XRF analyzer will be referred to as the Tracer analyzer 030 0011 01 0 42 X Ray Radiation Safety Manual Bruker Elemental Radiation from the XRF Analyzer Radiation Scatter Radiation scatter is produced whenever an absorbing material is directly irradiated from a nearby source The spectrum displays the scatter from the main excitation source X ray tube as well as the radiation produced through the XRF process This spectrum represents the X rays that reach the detector X rays produced through fluorescence are randomly distributed in all directions Scattering however is not uniform and is dependent on the sample being tested the energy of the radiation and other factors The X ray tube within the Tracer XRF analyzer is used to irradiate a chosen material at very close range with a narrow collimated beam The X rays from the tube excite the atoms of the material which then produce K or L shell X rays These fluorescent X rays the main beam and scattered radiation can be contained inside the instrument if the sample is sufficiently dense and thick e g a U S quarter is sufficient to effectively contain the radiation to inside the instrument in contrast a plastic lid is not sufficient to co
33. any loss or theft of the instrument to the appropriate authority Transfer the instrument only to persons specifically authorized to receive it and report any transfer to the appropriate regulatory authority normally 15 to 30 days following the purchase if required Report the transfer of the instrument to Bruker Elemental at 509 783 9850 030 0011 01 0 2 Cc X Ray Radiation Safety Manual BRUKER Bruker Elemental Section 1 Radiation Safety 030 0011 01 0 3 X Ray Radiation Safety Manual BRUKER Bruker Elemental What is Radiation The term radiation is used with all forms of energy light X rays radar microwaves and more However for the purpose of this manual radiation refers to invisible waves or particles of energy from radioactive sources or X ray tubes High levels of radiation may pose a danger to living tissue because they have the potential to damage and or alter the chemical structure of cells This could result in various levels of illness ranging from mild to severe This section provides a basic understanding of radiation characteristics This should help in preventing unnecessary radiation exposure to Bruker Elemental customers users and staff while using the Bruker Elemental XRF analyzers The concepts have been simplified to give a cursory picture of what radiation is and how it applies to the manufacturing staff and operators of Bruker Elemental XRF analyzers The Composition of Matter To help
34. ation utilizes a bulk rhenium or silver target with a separate window The X ray tube is potted with a high voltage HV potting material that provides shielding for X ray radiation HV insulation and protection against physical shock and environmental conditions The X ray tube is shielded to reduce stray X ray radiation to background levels The Tracer X ray beam is produced when electrons are accelerated and strike the bulk metal e g silver rhenium target inside the X ray tube Some of the X rays produced at the metal target are transmitted through the X ray tube port and form the main X ray beam The majority of the X rays produced inside the tube is not directed towards the X ray port and must be contained inside the tube instrument with proper shielding See the Radiation Profile Section page 45 for discussion of the radiation profile measurements 030 0011 01 0 44 X Ray Radiation Safety Manual BRUKER Bruker Elemental Tracer Analyzer Radiation Profile The measurements recorded on the radiation profile in Appendix B were obtained using the Bicron lon Chamber for radiation profiles specific to your device consult your User Guide The Geiger Muller GM counter was used for qualitative measurements since it operates in a more sensitive range and utilizes a much smaller detector However the readings using the ion chamber range from 2 3 times higher than the GM readings Note Dose rates will vary depending upon current energ
35. d perhaps most important method of reducing exposure is shielding Shielding is generally considered to be the most effective method of reducing radiation exposure and consists of using a material to absorb or scatter the radiation emitted from a source before it reaches an individual As stated earlier different materials are more effective against certain types of radiation than others The shielding ability of a material also depends on its density or the weight of a material per unit of volume Example A cubic foot of lead is heavier than the same volume of concrete and so it would also be a better shield against x rays 030 0011 01 0 25 X Ray Radiation Safety Manual uu E Bruker Elemental Although shielding may provide the best protection from radiation exposure there are still several precautions to keep in mind when using Bruker Elemental XRF devices e Persons outside the shadow cast by the shield are not necessarily 10096 protected Note All persons not directly involved in operating the XRF should be kept at least three feet away e Awallor partition may not be a safe shield for persons on the other side Note The operator should make sure that there is no one on the other side of the wall e Scattered radiation may bounce around corners and reach an individual whether directly in line with the test location or not 030 0011 01 0 26 X Ray Radiation Safety Manual BRUKER Bruker Elemental License Regis
36. deoocc itecto uidere cedes recited hh eed cA cbe dec sscteastsadereetssoceasesageeteyssoteasesshes 36 IDE 36 Gaussian Distribution tei Eee teres oett ade nee edax Rove Ue eg Ree SER EE CINE REX SER ETE DEERE 37 Standard rure 37 Reducing ROESER ee 38 X ray Detectie EE 38 Counting StatlsStiCS oer t Eae eege epe dead inns 38 Spectrum Accurmulatlor cotto ceo etti teo te vcdcbes ronde tactus ise sere bets sede etadiec ug ette ERR 39 ei lege dg 39 TNE SPECON EE 39 Calculation of TS dl ue nn A0 BACK gue E A0 Spectral OVE at ege geesde ees AAE EEA NEEE A EEN EE 40 Eliminating Background and Overlap cccccssssscecccecessesssaeceeeceessseeeaeeeeecssessesaeaeeeeeesseeseaeaeeeeeeeseesegs 40 Calculating e elle ele gie CT 40 Section 3 Specific XRF User Requirements ee eese eese e eee eene eene enne enne nennen ntn nnne 41 Handheld XRF Analyzer Applications cccccsessceceeecessesssaeceeececseseeaaecesecsseesesaeaeeeeeceseesesasaeeeesesseeseaaeas 42 Radiation from the XRF Analyzer ccccccesssscecesssececeesececsesseeccsesaeeecsesaeeecsesaeeecsesaeeecsesaeeecsesaeeecsesaeeeessaas 43 EK ET TEE 43 Ee TEE 43 Handheld XRF Analyzer Safety Design 44 Tracer Analyzer Radiation Profile 45 Safety Logic Circuit Warning Lights and Warning Labels cccccscssscecececesseseaeeeeeesseesesteaeeeeeesseesees 46 KEI
37. e ruens deed e o desee Haeo eeu eegene 11 Dose Eduivalence somete MEI UE ME 12 Dose and Dose Rate etr rte Abee te a UE etae eec sic eme acie e Faber Der Fel gone 12 030 0011 01 0 ii X Ray Radiation Safety Manual Ed mm Bruker Elemental SOUPCES OF RACIAtlON EE 12 NatUral SOUTCES EE 12 ET EE E Wl 14 Average Occupational DOSES cccsccccccccsssssessscecececesseseseeeeececssseseaaeseeeeecesseseaaeseeeessessesaaaeseeeeseneees 15 Slide KEE 15 Biological Effects of Radiation eessssssssssiseseeeesesee eene nnns nnne nnn nana sies eser tira nasa asse rania eiie 16 Cell EELER 16 Acute and Chronic Doses of Radiation esses senes tenete tentent entente ntes en sensn 16 ACUTE E E 16 Radiation SiCKn ss 2 ccsicee M m 16 Acute Dose to the Whole Body 16 Acute Dose to Part of the Body o tee eee rite dee AE Deae dence 16 euenire C E 17 Chronic DOSE vs ACUte oer Ret otii ne EE er hn eet ai EE Ee rU ee a 17 GENETIC Ce 17 SOMAtIG Ee 17 Heritable Effects tee bee ie eoo c tee beo e ede eec cbe vencer Deoa 17 Biological Damage Factors rite rite ere nieto ek haad eda regu ESAO ut eain re EE RR ae eda 17 Prenatal EXDOSUFe iem eere te eege eroe eset dee eet dee E set deese 18 Putting Risks in Perspective 5 oe s eec stet n eec auae pde ase ABest 18 Risk Setee
38. effects for a given dose Extremities are less sensitive than internal organs because they do not contain critical organs That is why the annual dose limit for extremities is higher than for a whole body exposure that irradiates the internal organs Your employer may have additional guidelines and set administrative control levels which you will need to be aware of to do your job safely and efficiently Whole Body The whole body is measured from the top of the head to just below the elbow and just below the knee The whole body occupational radiation dose limit in the U S is 5 rems 5 000 mrems per year This limit is based upon the total sum of both external and internal exposures Extremities Extremities refer to the hands arms below the elbows feet and legs below the knees In the U S the occupational radiation dose limit for the extremities is 50 rems per year Skin The occupational radiation dose limit for the skin is 50 rems per year Organs or Tissues excluding lens of the eye and the skin The occupational radiation dose limit for organs and tissues is 50 rems per year 030 0011 01 0 20 X Ray Radiation Safety Manual Edi Bruker Elemental Lens of the Eye The occupational radiation dose limit for the lens of the eye is 15 rems per year Declared Pregnant Worker embryo fetus A female radiation worker may inform her supervisor in writing of her pregnancy at which time she becomes a Declared Pregna
39. electrons the charge is positive e Negative Charge If an atom has more electrons than protons the charge is negative e Neutral No Charge If an atom has an equal number of protons and electrons it is neutral or has no net electrical charge The process of removing electrons from a neutral atom is called ionization Atoms that develop a positive or negative charge gain or lose electrons are called jons When an electrically neutral atom loses an electron that electron and the now positively charged atom are called an ion pair The Stability of the Atom The concept of stability of an atom is related to the structure and the behavior of the nucleus e Every stable atom has a nucleus with a specific combination of neutrons and protons e Any other combination or neutrons and protons results in a nucleus that has too much energy to remain stable e Unstable atoms try to become stable by releasing excess energy in the form of particles or waves radiation The process of unstable atoms releasing excess energy is called radioactivity or radioactive decay 030 0011 01 0 6 X Ray Radiation Safety Manual BRUKER Bruker Elemental Radiation Terminology Before examining the subject of radiation in more detail there are several important terms to be reviewed and understood Bremsstrahlung The X rays or braking radiation produced by the deceleration of electrons namely in an X ray tube Characteristic X rays
40. ely charged particles and gamma radiation gt Increases in intensity at higher altitudes because there is less atmospheric shielding gt The average dose received by the general public from cosmic radiation is approximately 28 mrem per year Example The population of Denver Colorado receives twice the radiation exposure from cosmic rays as people living at sea level Terrestrial Radiation Internal Sources There are natural sources of radiation in the soil rocks building materials and drinking water Some of the contributors to these sources include naturally radioactive elements such as radium uranium and thorium Many areas have elevated levels of terrestrial radiation due to increased concentrations of Uranium or Thorium in the soil The average dose received by the general public from terrestrial radiation is about 28 mrem per year The food we eat and the water we drink all contain some trace amount of natural radioactive materials These naturally occurring radioactive isotopes include Na 24 C 14 Ar 41 and K 40 Most of our internal exposure comes from K 40 There are four ways to receive internal exposure e Breathing e Swallowing ingestion e Absorption through the skin e Wounds breaks in the skin The average dose received by the general public from internal sources is about 40 mrem per year Examples of Internal Exposure 1 Inhalation of radon or dust from other radioactive materials 2 P
41. ement may be computed even though the count is measured only over a single interval of time As the total number of counts increases an increase in measurement time the uncertainty in the result decreases 95 5 of a group of repeat measurements will be within two standard deviations of the mean or a single result with an error reported as two standard deviations would have a confidence of 95 5 Reducing Error To reduce the error standard deviation by one half the count rate must be increased by a factor of four Other things being equal this could be accomplished by increasing the measurement time by a factor of four X ray Detection The X ray detection process involves the following steps 1 Absorption of the X ray photon by the detector 2 Conversion to a charge pulse of size N electronic charges where N is proportional to the X ray energy E 3 Linear amplification of the charge pulse so that its height in volts is proportional to X ray energy By this means each X ray photon is detected sequentially Counting Statistics The detected X ray spectrum is affected by the random nature of XRF events The total number of X rays N measured in a given time interval has an associated statistical error approximately equal to the square root of the number of X rays observed This is because the X rays are emitted from the source in random fashion and in turn the atoms in the sample are excited in random fashion Example If the to
42. ents weighing benefits against potential hazards Risk Comparison The following summarizes the risks of radiation exposure e The risks of low levels of radiation exposure are still unknown e Since ionizing radiation can damage chromosomes of a cell incomplete repair may result in the development of cancerous cells e There have been no observed increases of cancer among individuals exposed to occupational levels of ionizing radiation Using other occupational risks and hazards as guidelines nearly all scientific studies have concluded the risks of occupational radiation doses are acceptable by comparison 030 0011 01 0 18 X Ray Radiation Safety Manual 5e BR KER Bruker Elemental Occupation Estimated Activity Estimated Days Lost Days Lost Mining Quarrying 328 Cigarette smoking 2250 Construction 302 25 Overweight 1100 Agriculture 277 Accidents all types 435 Transportation Utilities 164 Alcohol consumption U S avg 365 Radiation dose of 5 rem per yr for 30 years 150 Driving a motor vehicle 207 All industry 74 Medical X rays U S avg 6 Government 55 1 rem Occupational Exposure 1 Service 47 1 rem per year for 30 years 30 Manufacturing 43 Note based on US data only Trade 30 No matter what you do there is always some risk associated with it For every risk there is some benefit so as the worker you must weigh these risks and determine if the risk i
43. erent number of neutrons Are found orbiting around the nucleus at set energy levels or shells K and L shells are important in X ray fluorescence Have a negative electrical charge Determine chemical properties of an atom Have very little mass Structure of the Atom The design or atomic structure of the atom has two main parts the nucleus and the electron shells that surround the nucleus Nucleus z 030 0011 01 0 WV WW ON Is the center of an atom Is composed of protons and neutrons Produces a positive electrical field Makes up nearly the entire mass of the atom X Ray Radiation Safety Manual BRUKER Bruker Elemental Electrons Circle the nucleus of an atom in a prescribed orbit Have a specific number of electrons Produce a negative electrical field VV ON ON Are the principle controls in chemical reactions The protons and neutrons that form the nucleus are bound tightly together by powerful nuclear forces Electrons are held in orbit by their electromagnetic attraction to the protons When these ratios become unbalanced the electrical charge and stability of the atom are affected Electrical Charge of the Atom The ratio of protons and electrons determine whether the atom has a positive negative or neutral electrical charge The term jon is used to define atoms or groups of atoms that have a positive or negative electrical charge e Positive Charge If an atom has more protons than
44. he electron shells or from an X ray generating machine gt lonize atoms by interacting with electrons Range Because gamma and X rays have no charge or mass they are highly penetrating and can travel quite far Range in air can easily reach several hundred feet Shieldin Gamma and X rays are best shielded by use of dense materials such as concrete lead or steel Hazard Due to their range and penetrating ability gamma and X ray radiation primarily are considered an external hazard Neutron Particles gt Create radiation when neutrons are ejected from the nucleus of an atom gt Are produced during the normal operation of a nuclear reactor or particle accelerator as well as the natural decay process of some radioactive elements gt Can split atoms by colliding with their nuclei forming two or more unstable atoms This is called fission These atoms then may cause ionization as they try to become stable gt Can also be absorbed by some atoms captured without causing fission occasionally resulting in the creation of a radioactive atom dependent on the absorber This is called fusion Range Since neutrons have no electrical charge they have a high penetrating ability and require thick shielding material to stop Range in air can be several hundred feet Shieldin The best materials to shield against neutron radiation are those with high hydrogen content water concrete or plastic Hazard Neutron r
45. in question C Weight fraction of the element H Matrix Absorption coefficient The practical implications of the above equation are e The stronger the source and more efficient the sensor to sample geometry the larger the signal N e The longer the measurement time the larger the signal N e tis helpful to place the sensor against the sample at a direct angle so as to minimize errors due to variation of k defined above e Achangein the source aperture shutter partially open changes k e Source decay reduction in lo must be corrected for if when it becomes significant e Theexcitation cross section T i e the efficiency of excitation varies with atomic number of the element and with source energy A rule of thumb is that the closer the element s absorption energy is to the source energy the higher the excitation cross section the further away the two energies are the lower the efficiency of excitation The matrix absorption coefficient is the sum of the X ray absorption coefficient of all the elements in the sample It is primarily the cause of what is known as matrix effects 030 0011 01 0 34 X Ray Radiation Safety Manual BRUKER Bruker Elemental Suppose a second element has a much higher or lower X ray absorption coefficient than the rest of the sample If that element s concentration varies it will change the value of H and so change for the target element i e the analyte even though the concentration
46. ld eight electrons e The M shell can hold 18 electrons e The N shell can hold 32 electrons Example The sodium atom contains 11 electrons two in the K shell eight in the L Shell and a single electron in the M shell 030 0011 01 0 31 X Ray Radiation Safety Manual Bruker Elemental The inner electrons are more tightly bound and require much more energy to displace them from their normal levels As a result a photon of much higher energy is emitted when the atom returns to its normal state after the displacement of an inner electron The displacement of the inner electrons gives rise to the emissions of X rays The Process of X ray Fluorescence X rays from the Bruker Elemental XRF analyzers bombard the atoms of the target sample Some of the generated photons collide with K and L shell electrons of the sample dislodging them from their orbits This leaves a vacant space in the K L shell which is immediately filled by any electron from the L M or N M or N shell This is accompanied by a decrease in the atom s energy and an X ray photon is emitted with energy equal to this decrease Since the energy change is uniquely defined for atoms of a given element it is possible to predict definite frequencies for the emitted X rays This means that when electrons are dislodged from atoms the emitted X rays are always identical These X rays are analyzed with an X ray detector and the quantity of K shell and o
47. left in an unattended analyzer Always store the instrument in a secure location when not in use Storage of the key in a separate location is recommended in order to avoid unauthorized usage e During transport to and from the field store the instrument in a cool dry location i e in the trunk of a car rather than in the back seat Blue Ice can be used to cool the XRF instruments during hot conditions 030 0011 01 0 48 X Ray Radiation Safety Manual BRUKER Bruker Elemental In Case of Emergencies The X ray emission from the X ray tube used in a Bruker Elemental Tracer Handheld XRF analyzer could be harmful to a person if the analyzer is operated without the appropriate training If a Bruker Elemental analyzer is lost or stolen notify the local regulatory agency as soon as possible The owner operator can locate emergency call numbers from the emergency call list provided by Bruker Elemental with each analyzer The first action to take in the event of an accident with the Bruker Elemental XRF system is to turn off the device and remove the battery pack Then follow the steps below Minor Damage If any hardware item appears to be damaged even if the system remains operable immediately contact the Bruker Elemental RSO at 509 783 9850 for advice Use of a damaged analyzer may lead to unnecessary radiation exposure and or inaccurate measurements Major Damage If the analyzer is severely damaged immediately contact Bruker Ele
48. lence e Isa unit for measuring dose equivalence e sthe most commonly used unit of radiation exposure measure e Pertains directly to humans e Takes into account the effects of energy absorbed dose in humans the biological effect of different types of radiation in the body and any other factors For gamma and X ray radiation all of these factors are equivalent so that for these purposes a rad and a rem are numerically equal e Sievert is the SI unit for dose equivalence e 1rem 1000 millirem mrem e 1rem O 01 Sievert Sv and 1Sv 100 rem Radiation Quality Factor Quality Factor QF is a numerical value given to each type of radiation based on its potential to produce biological damage 030 0011 01 0 11 X Ray Radiation Safety Manual Edi Bruker Elemental Quality Factors for the various types of radiation are X ray Gamma ray beta 1 Neutron Fast 10 Alpha 20 Dose Equivalence The rem is used to determine dose equivalence and is equal to the dose in rads times a Quality Factor or rem rad x Quality Factor Example A worker at a nuclear power plant is involved in a clean up operation and receives a 0 17 rad dose of neutron radiation Neutron radiation has a QF of 10 which results in a dose of 1 7 rems 0 17 rad x 10 QF 1 7 rems Dose and Dose Rate Dose is the amount of radiation received during Example any exposure 1 Dose rate dose time mrem hr Dose Rate is the rate at which you
49. mental and the appropriate regulatory agency in your local jurisdiction or country Care must be taken to ensure that personnel near the device are not exposed to unshielded X rays that still may be generated i e the safety logic circuit is not functional Quickly remove the battery pack to stop all X ray production Loss or Theft In the case of a stolen device notify the appropriate regulatory agency in which the device is being utilized In addition immediately contact the police and the Bruker Elemental RSO Take the following precautions to minimize the chance of loss or theft e Never leave the analyzer unattended when in use e When not in use always keep the device in its shipping container and store it in a locked vehicle or in a secured area e Keep the key separate from the analyzer e Maintain records to keep track of all instruments owned and the operators assigned to use them and where they were used 030 0011 01 0 49 X Ray Radiation Safety Manual BRUKER Bruker Elemental Appendices 030 0011 01 0 50 X Ray Radiation Safety Manual S Bruker Elemental Appendix A X ray Critical Absorption Energies in keV Atomic Element K Absorption K Shell L Shell Number 23 Vanadium 5 465 4 952 0 511 24 Chromium 5 989 5 415 0 573 25 Manganese 6 539 5 899 0 637 26 Iron 2 112 6 404 0 705 27 Cobalt 7709 6 930 0 776 28 Nickel 8 333 7 478 0 852 Do Copper 8 979 8 048 0 930 30 Zinc 9 659 8 639 1 012 31 Gallium 1
50. must verify that the new recipient is authorized to receive the analyzer No verification is required when returning it to Bruker Elemental the original manufacturer There are no special Department of Transportation DOT interstate travel and shipping regulations for a Bruker Elemental X ray tube XRF analyzer The analyzer may be shipped using any means Care should be taken if flying it is recommended that the device be checked through due to possible concerns about the X ray unit in the main cabin The owner should ensure compliance with all requirements of the jurisdiction where the X ray tube XRF is to be used In order to prevent inadvertant exposure of a member of the public and in case the X ray tube XRF analyzer is lost or stolen the key if so equipped should be maintained and shipped separately Passwords for S1 TURBO and S1 SORTERS should be protected 030 0011 01 0 28 Cc X Ray Radiation Safety Manual BRUKER Bruker Elemental Section 2 Theory of XRF Operation 030 0011 01 0 29 X Ray Radiation Safety Manual What Is XRF Bruker Elemental XRF stands for X Ray Fluorescence It is the process used by Bruker Elemental XRF analyzers to detect various elements in a matrix Before exploring the specifics of XRF we ll review some of the important concepts covered in Section One Radiation Safety Review The Composition of Matter As we learned our world is made up of fundamental materials called elements
51. nalysis is to convert the net intensities to element concentrations This is done by a patented mathematical process algorithm using empirical coefficients and linear and or polynomial multi parameter regressions Calibration is achieved by measuring known samples that are of the same type material but not necessarily the same physical form as the unknown samples In order to calibrate the instrument a suite of samples i e site specific or standard reference materials of the same type as the unknown must be measured to acquire the net intensities The element concentrations of the reference samples must be independently known at least as accurately as the accuracy expected of the subsequent XRF analysis The slope and intercept coefficients for each element are then calculated from the known values The calculations are performed by the Bruker Elemental microprocessor 030 0011 01 0 40 Cc X Ray Radiation Safety Manual BRUKER Bruker Elemental Section 3 Specific XRF User Requirements 030 0011 01 0 41 X Ray Radiation Safety Manual Bruker Elemental Handheld XRF Analyzer Applications The Bruker Elemental XRF analyzer has been registered with the U S Department of Health and Human Services Food and Drug Administration Center for Devices and Radiological Health for sale and use for the applications listed below When safety procedures identified in subsequent sections are followed the use of this analyzer presents no d
52. nalyzer Safety Design The Bruker Elemental Tracer XRF analyzers employ a miniature X ray tube instead of a radioactive source to generate the X rays The general construction and the safety features described in this manual are the same for all Tracer models Bruker Elemental has voluntarily designed the hand held X ray tube analyzer to conform to ANSI N43 3 and the 21 CFR 1020 40 safety requirements for cabinet X rays systems with the exception of providing a totally enclosed beam Extensive safety circuit requirements including switches and failsafe lights have been incorporated This was done even though in paragraph A applicability of 21 CFR 1020 40 states The provisions of this section are not applicable to systems which are designed exclusively for microscopic examination of material e g X ray diffraction spectroscopic and electron microscope equipment or to systems for intentional exposure of humans to X rays See the Tracer Safety Logic Circuit section page 46 for discussion on the warning lights failsafe features and labeling that has been incorporated to provide a high level of protection to the operator The Bruker Elemental Tracers are small 5 Ib X ray fluorescence XRF analyzers used as an analytical X ray product system It employs a 1 watt miniature lt 15 mm diameter and lt 75 mm long X ray tube operated with an acceleration voltage range of 10 to 45 kV and a current range of 1 100 pA The standard tube configur
53. nt Worker The employer must then provide the option of a mutually agreeable assignment of work tasks without loss of pay or promotional opportunity such that further radiation exposure will not exceed the dose limits for the embryo fetus The radiation dose limit from occupational sources for the embryo fetus of a Declared Pregnant Worker is 500 mrem during the entire gestation Efforts should be made to avoid doses exceeding 50 mrem per month 030 0011 01 0 21 X Ray Radiation Safety Manual BRUKER Bruker Elemental Measuring Radiation Since we cannot detect radiation through our senses some regulating agencies require special devices for personnel operating an XRF in order to monitor and record the operator s exposure These devices are commonly referred to as dosimeters and the use of them for monitoring is called dosimetry The following information applies directly to personnel using the Bruker Elemental XRF analyzers in locales that require dosimetry e Wear an appropriate dosimeter that can record low energy photon radiation e Dosimeters wear period of three months may be used contact your local Radiation control agency e Each dosimeter will be assigned to a particular person and is not to be used by anyone else Measuring Devices Several devices are employed for measurement of radiation doses including ionization chambers Geiger Mueller tubes pocket dosimeters thermoluminescence devices TLD s opticall
54. ntain the main beam The main beam is much stronger than the fluorescence or scattered radiation and should be avoided therefore knowledge of the possible location of the main beam is important Backscatter The handheld XRF analyzer generates spectrum data by analyzing the specific X ray energies that get back to the detector Because the X rays travel in all directions it is possible for an X ray to miss the detector and be scattered in the direction of the operator This is referred to as backscatter Although the Tracer analyzer is specifically designed to limit backscatter reaching the operator there is always the possibility that a small number of X rays may scatter beyond the detector In the case of light or thin samples that do not contain the main beam the main beam may then be scattered back towards the operator In this case a shield around the sample should be used To ensure safe operation of the system it is vital that the operator understands the radiation field The radiation profile shown in Appendix B illustrates the radiation field for the Tracer analyzer The Radiation Profile section page 45 contains measurements of the radiation field The profile should be studied carefully by anyone who operates the Bruker Elemental Tracer analyzer in order to better understand and apply the practices of ALARA using time distance and shielding 030 0011 01 0 43 X Ray Radiation Safety Manual Bruker Elemental Handheld XRF A
55. of an X ray fluorescence XRF system which contains the X ray tube or radioactive isotope Radioactive Material Any material or substance that has unstable atoms that are emitting radiation System Barrier That portion of an area that clearly defines the transition from a controlled area to a radiation area and provides the necessary shielding to limit the dose rate in the controlled area during normal operation X ray Generator That portion of an X ray system that provides the accelerating voltage and current for the X ray tube X ray System Apparatus for generating and using ionizing radiation including all X ray accessory apparatus such as accelerating voltage and current for the X ray tube and any needed shielding 030 0011 01 0 7 X Ray Radiation Safety Manual BRUKER Bruker Elemental Types of Radiation Radiation consists of invisible waves or particles of energy that if received in too large a quantity can have an adverse health effect on humans There are two distinct types of radiation non ionizing and ionizing Non ionizing Radiation Non ionizing radiation does not have the energy necessary to ionize an atom i e to remove electrons from neutral atoms Sources of non ionizing radiation include light microwaves power lines and radar Although this type of radiation can cause biological damage such as sunburn it is generally considered less hazardous than ionizing radiation lonizing Radiation
56. of static electricity which it stores like a condenser As radiation passes through the chamber the charge is reduced in proportion to the amount of radiation received and the indicator moves towards a neutral position A dosimeter that has been exposed to radiation must be periodically recharged or zeroed 030 0011 01 0 22 X Ray Radiation Safety Manual Ed Bruker Elemental Thermoluminescence Devices TLDs and Optically Simulated Luminescence Dosimeter OSL TLDs and OSL are devices that use crystals which can store free electrons when exposed to ionizing radiation These electrons remain trapped until the crystals are read by a special reader or processor using heat TLD or light OSL When this occurs the electrons are released and the crystals produce light The intensity of the light can be measured and related directly to the amount of radiation received Thermoluminescent materials useful as dosimeters include lithium fluoride lithium borate calcium fluoride calcium sulfate and aluminum oxide Dosimeters There are two common types of dosimeters whole body and extremity Whole Body Dosimeter A TLD or OSL whole body dosimeter is used to measure both shallow and deep penetrating radiation doses It is normally worn between the neck and waist This device records a measured dose that is used as an individual s legal occupational exposure Finger Ring A finger ring is a TLD in the shape of a ring which is worn
57. otassium 40 in bananas 3 Water containing traces of uranium radium or thorium 4 Handling of a specified radioactive material without protective gear or with an unhealed cut 030 0011 01 0 13 X Ray Radiation Safety Manual Edid Bruker Elemental Radon RADIOACTIVE gt Comes from the radioactive decay of radium which is naturally present in scil gt sagas which can travel through soil and collect in basements or other areas of the home gt Emits alpha radiation Because alpha radiation cannot penetrate the dead layer of skin on your body it presents a hazard only if taken into the body gt Is the largest contributor of natural occurring radiation Radonandits decay products are present in the air When inhaled they can cause a dose to the lung Man made Sources In addition to natural background radiation some exposure comes from man made sources that are part of our everyday lives These sources account for approximately 65 mrem per year of the average annual radiation dose The four major sources of man made radiation exposures are Medical radiation approximately 53 mrem per year Consumer products approximately 10 mrem per year Industrial uses less than 3 mrem per year Atmospheric testing of nuclear weapons less than 1 mrem per year Medical Radiation Medical radiation involves exposure from medical procedures such as X rays chest dental etc CAT scans and radio
58. r L shell X rays detected will be proportional to the number of atoms of the particular element or elements present in the sample Ejects electron from K or L shell Incident Ps Wii Photon The incident photon is either transmitted scattered or absorbed If absorbedatKorL shell the electron is ejected if energy of incident photon binding energy of K or L Electron Shells z Sr 5 Replacement electrons fill vacancy in K or L shell by atomic E transition emitting a characteristic X ray in the process X ray excited Figure 1 Simplified X ray Fluorescence of an Atom production used for XRF 030 0011 01 0 32 X Ray Radiation Safety Manual BRUKER Bruker Elemental Bruker Elemental XRF Instruments Now that we have an understanding of X ray fluorescence we ll look at how it applies to the Bruker Elemental XRF analyzers Characteristic X rays When X ray or gamma radiation from the XRF instruments X ray tube source excites the atoms in the sample the atoms release fluorescent X rays The energy level of each fluorescent X ray is characteristic of the element excited As a result one can tell what elements are present based on the energies of the X rays emitted Bruker Elemental XRF instruments detect and determine the fluorescent X rays energies produced The figure below illustrates a simplified X ray spectrum The unit of energy is the kilo electron volt keV X ray energy is proportional to
59. receive the 2 Dose dose rate x time mrem dose Sources of Radiation We live in a radioactive world and always have As human beings we have evolved in the presence of ionizing radiation from natural background radiation Whether or not a person is working with radioactive materials no one can completely avoid exposure to radiation We are continually exposed to sources of radiation from our environment both natural and man made The average person in the U S receives about 360 millirem mrem of radiation per year The average annual radiation dose in the state of Colorado is 450 500 mrem per year Natural Sources Most of our radiation exposure comes from natural sources about 300 mrem per year In fact most of the world s population will be exposed to more ionizing radiation from natural sources than they will ever receive on the job There are several sources of natural background radiation The radiation from these sources is exactly the same as that from man made sources The four major sources of natural radiation include e Cosmic Radiation e Terrestrial Radiation sources in the earth s crust e Sources sources in the human body such as K 40 e g eating bananas also referred to as internal Sources 030 0011 01 0 12 X Ray Radiation Safety Manual e BRUKER UV Bruker Elemental e Radon Uranium and Thorium Cosmic Radiation gt Comes from the sun and outer space gt Is composed of positiv
60. rium and tritium which are isotopes of hydrogen Nuclear Stability For each stable atom the nucleus exists in definite combinations or ratios of protons and neutrons Any combination or ratio other than that which defines stability results in an unstable nucleus In the process of reaching stability the nucleus emits one or more types of particles of energy called alpha beta gamma rays or neutrons This emission is called radiation X ray Emissions X rays and gamma rays are both electromagnetic radiations i e photons The distinction is that gamma rays are produced and emitted from the nucleus while X rays are produced and emitted from the electron energy changes For an X ray tube the X rays are produced by Bremsstrahlung as accelerated electrons interact with the target material How XRF Works X ray fluorescence XRF is the production of X rays in the electron orbits To understand this process we need to understand how electrons are arranged in complex atoms see Figure 1 In atoms with many electrons the electrons are arranged in concentric shells at increasing distances from the nucleus These shells are labeled K L M N etc the K shell being closest to the nucleus the L shell the next closest and so on Atoms in the balanced state non excited have a definite number of electrons in each shell Each shell has a maximum number of electrons it can accommodate e The K shell can hold two electrons e TheLshell can ho
61. rove products and reserves the rights to change specifications equipment and maintenance procedures at any time without notice Bruker Elemental products are covered by U S and foreign patents issued and pending Copyright 2008 2010 Bruker AXS Handheld Inc DBA Bruker Elemental For product information sales service and technical support e n North America call 1 509 783 9850 or Fax 1 509 735 9696 e Email us hhinfo bruker elemental net Worldwide visit http www bruker axs com to find contacts in your area 030 0011 01 0 57
62. s worth the benefit lonizing radiation is the drawback of many beneficial materials services and products that we use every day By learning to respect and work safely around radiation we can limit our exposure and continue to enjoy the benefits it provides 030 0011 01 0 19 X Ray Radiation Safety Manual Bruker Elemental Radiation Dose Limits To minimize the risks from the potential biological effects of radiation the state health departments Nuclear Regulatory Commission NRC and other agencies have established radiation dose limits for occupational workers The limits apply to those working under the provisions of a specific license or registration The limits described below have been developed based on information and guidance from the Environmental Protection Agency EPA the National Council of Radiation Protection NCRP the International Commission on Radiological Protection ICRP and the Biological Effects of lonizing Radiation BEIR Committee Note Radiation Dose Limits Exposure to someone in the general public from a licensed device must not exceed 100 mrem per year For an XRF analyzer which uses an X ray Tube as the source of X rays the requirement on dose limits for the operators are established by local governing agencies In most instances the dose limits will be similar to those established by the NRC In general the larger the area of the body that is exposed the greater the biological
63. st alpha particles will be stopped by a piece of paper several centimeters of air or the outer layer i e dead layer of the skin Hazard Due to limited range and penetration ability alpha particles are not considered an external radiation hazard However since it can deposit large amounts of concentrated energy in small volumes of body tissue if inhaled or ingested alpha radiation is a potential internal hazard Beta Particles gt Havea small mass and a negative charge similar to an electron gt Are emitted from the nucleus of an atom gt lonize other atoms by pushing electrons out of their orbits with their negative charge Range Small mass and a negative charge give the beta particle a range of about 10 feet in air The negative charge limits penetrating ability Shieldin Most beta particles can be stopped by a few millimeters of plastic glass or metal foil depending on the density of the material Hazard Although beta particles have a fairly short range they are still considered an external radiation hazard particularly to the skin and eyes If ingested or inhaled beta radiation may pose a hazard to internal tissues 030 0011 01 0 9 X Ray Radiation Safety Manual BRUKER Bruker Elemental Gamma Rays and X rays gt Are electromagnetic waves or photons of pure energy that have no mass or electrical charge gt Are identical except that gamma rays come from the nucleus while X rays come from t
64. tal accumulated count number in the target element s fluorescent peak is 100 then the statistical error would span from roughly 80 to 120 or 20 of the actual average number of random counts If the total count were 1 million the statistical error would span from 998 000 to 1 002 000 or 0 2 of the actual average number of counts so that the precision with 1 million counts is 100 times better than with 100 counts 030 0011 01 0 38 X Ray Radiation Safety Manual Spectrum Accumulation During a count period the photons being emitted from a sample are detected and sorted into one of a maximum of 2048 channels or increments according to their energy The total number of counts in each Counts per unit pulse height channel during the count period are translated into a spectrum where the Y axis is the number of counts pulse height and the X axis is the energy recorded The figure shows a schematic of the X ray fluorescent lines and scattered peaks with the corresponding Electronic Noise detected peaks dotted superimposed are shown in the figure Spectral Resolution Recorded X rays of the same energy taken over a period of time form a Gaussian i e bell shape peak The resolution of the spectrometer i e analyzer is defined as the full width at half maximum FWHM of the peak The resolution of the Bruker Elemental XRF analyzer system is somewhat dependent on the energy level being measured The
65. the Bruker Elemental Tracer XRF analyzer e Be aware of the direction that the X rays travel when the red light is on and avoid placing any part of your body e g eyes hands near the X ray port to stabilize the instrument during operation see the Radiation Profile Section page 45 Wor measurement information e WARNING No one but the operator s should be allowed to be closer than 3 feet from the Tracer particularly the beam port Ignoring this warning could result in unnecessary exposure e Never hold sample up to the X ray port for analysis by hand hold instrument to sample e Pregnant women who use the XRF device should be aware that improper handling or improper use of the instrument could result in radiation exposure which may be harmful to a developing fetus e The infrared IR sensor located on the nosepiece is designed to prevent the emission of X rays from the X ray port without a solid object being in direct contact with the nosepiece e WARNING The operator should never defeat the IR sensor in order to bi pass this part of the safety circuit Defeating this safety feature could result in over exposure of the operator e If required by a local regulatory agency wear an appropriate dosimetry e The operator is responsible for the security of the analyzer When in use the device should be in the operator s possession at all times i e either in direct sight or a secure area The key if so equipped should not be
66. therapy The typical dose received from a single chest X ray is about 10 mrem per exposure Radioactive sources used in medicine for diagnosis and therapy result in an annual average dose to the general population of 14 mrem The average dose received by the general public from all medical procedures is about 53 mrem per year Consumer Products These include such products as e TVs Building materials Combustible fuels Smoke detectors Camera lenses Welding rods 030 0011 01 0 14 X Ray Radiation Safety Manual Edi m Bruker Elemental The total average dose received by the general public from all these products is about 10 mrem per year Industrial uses Industrial uses include X ray generating machines used to test all sorts of welds material integrity bore holes and to perform microscopic analyses of materials The average dose received by the general public from industrial uses is less than 1 mrem per year Atmospheric testing of nuclear weapons The testing of nuclear weapons during the 1950s and early 1960s resulted in fallout of radioactive materials This practice is now banned by most nations The average dose received by the general public from residual fallout is approximately 1 mrem per year mrem per f Exposure Exposure Source Occupation year mrem per year Radon in homes 200 Airline flight crewmember 1000 Medical exposures 53 Nuclear power plant
67. tration Requirements Bruker Elemental X ray Tube XRF Analyzer The owner operator of the Bruker Elemental X ray tube XRF analyzer may be subject to registration with the appropriate regulatory agency The owner operator should Contact the appropriate authority where the analyzer is to be used about regulatory requirements Never remove labels from the analyzer Comply with all instructions and labels provided with the device Store the analyzer in a safe place where it is unlikely to be stolen or removed accidentally If so equipped keep the key separate from the analyzer If a password is required for operation keep the password protected Maintain records of the storage removal and transport of the analyzer Know its whereabouts at all times Monitor operator s compliance with safe use practices Use dosimetry where required Report to the appropriate regulatory agency any damage to the shielding and any loss or theft of the analyzer Sell or transfer the analyzer only to persons registered to receive it Notification of your local regulatory agency may be required for the transfer or disposal of the X ray unit 030 0011 01 0 27 X Ray Radiation Safety Manual BRUKER Bruker Elemental Transportation Requirements Bruker Elemental X ray Tube XRF Analyzer An owner operator of a Bruker Elemental X ray tube XRF analyzer may transfer custody of the analyzer to authorized license registration individuals only The owner
68. uanta to M electrical pulses resolution Energy or pulse height 030 0011 01 0 33 X Ray Radiation Safety Manual BRUKER Bruker Elemental X ray Line Interference X ray lines from different elements if present in the sample can be very close in energy and therefore interfere by giving an overlapped spectrum peak Sometimes the spectral overlaps interference are caused by the K line of one element having energy close to the L line of another element or the Compton backscatter peak may interfere with a peak from an element Scattered X rays Compton X rays and or Gamma rays from the source are scattered from the sample by two mechanisms coherent scattering no energy loss and Compton Scattering small energy loss Compton Scattering is the process whereby a single high energy photon produces a photon of lower energy by interaction with the materials in the sample Background and source noise are other common terms used to describe gamma ray backscatter Intensity Concentration Relation The X ray intensity size of spectrum peaks is directly proportional to the concentration of the elements in the sample 1 N t k lo T C H Where X ray Intensity counts per second N Net count after background and overlap subtractions t Measurement time seconds k Geometrical constant sensor sample geometry lo Source strength photons per second steradian T Excitation cross section for the element
69. ucing exposure is by maintaining the maximum possible distance from the radiation source to the operator or member of the public The principle of distance is that the exposure rate is reduced as the distance from the source is increased as distance is increased the amount of radiation received is reduced This method can best be expressed by the Inverse Square Law The inverse square law states that doubling the distance from a point source reduces the dose rate intensity to 1 4 of the original Tripling the distance reduces the dose rate to 1 9 of its original value 030 0011 01 0 24 X Ray Radiation Safety Manual Ed Bruker Elemental Expressed mathematically C x D4 Dj 1 Variables C the intensity dose rate of the radiation source D the distance at which C was measured D the actual distance from the source the new level of intensity at distance D from the source Example If the intensity C of a point source is 100 mrem hr at one foot D then at two feet Dz it would be 25 mrem hr I C 100 mrem hr Di 1foot D2 2 feet I 25 mrem hr x Di D2 100 x 1 2 100 4 25 mrem hr I The inverse square law does not apply to sources of greater than a 10 1 ratio distance source size or to the radiation fields produced from multiple sources ORIGINAL 1 4 1 9 DOSE ORIGINAL ORIGINAL RATE DOSE DOSE RATE RATE The Inverse Square Law Shielding The third an
70. uring devices it is important to first verify that it is operating within specifications before using the survey meter to check the Tracer instrument The following should be checked on a typical Survey meter e Batteries Typically there is a built in voltmeter in the instrument There should be a setting on the display of the instrument to check the batteries Turn a dial to the Battery position and the needle on the display will deflect If the needle is in the Good range your battery is OK to use If not replace it before attempting to make a measurement e High Voltage Some probes on survey meters need to have a bias voltage applied to the detector Some survey meters allow you to check that voltage This is usually done by turning the dial to the High 030 0011 01 0 55 X Ray Radiation Safety Manual Bruker Elemental Voltage position and the needle will deflect If the instrument is working properly the needle will deflect to a certain small range noted on the display If it is not in that range and the batteries are good discontinue the use of the instrument and return it to the manufacturer for repair e Calibration check Usually a survey meter must be calibrated once a year at the instrument vendor s factory In general the calibration of the instrument does not have to be checked at every use however it is a good idea to check it every one to two weeks Most users buy a small radioactive check source e g a
71. value T can never be determined with certainty In the real world the best approximation of the True value is the arithmetic mean of a number of measurements but only if systematic type errors can be corrected or reduced to a negligible value The error or deviation in terms of measurable quantities may be expressed as Deviation D Measured value M Arithmetic mean S Accuracy Precision and Bias The magnitude of the Deviation D is the measure of the reproducibility or precision of the measurements There is a great deal of confusion about the use of terms precision accuracy and bias in physical measurements For the measurement to be accurate it must be both precise and unbiased See Figure 2 for an illustration of the relationship between precise accurate and bias Precision Precision is a measure of the agreement among a group of individual measurements Precision is strongly influenced by random decay calibration substrate matrix effects and measurement time Bias Bias is influenced primarily by systematic errors such as voltage changes a lack of an adequate number of calibration standards or wrong calibration constants that introduce constant errors into the data Example A set of measurements can be precise the measurement values agree with one another but still not be accurate close to the true value 030 0011 01 0 36 X Ray Radiation Safety Manual 5e BR KER LL Bruker Elemental
72. worker 700 Terrestrial radiation 30 Grand central station worker 120 Cosmic radiation 30 Medical personnel 70 Round trip US by air 5 DOE DOE contractors 44 Building materials 3 6 Worldwide fallout lt 1 Natural gas range 0 2 Smoke detectors 0 0001 Siqnificant Doses The general public is exposed daily to small amounts of radiation However there are four major groups of people that have been exposed in the past to significant levels of radiation Because of this we know much about ionizing radiation and its biological effects on the body These four major groups include e The earliest radiation workers such as radiologists who received large doses of radiation before biological effects were recognized Since then safety standards have been developed to protect such employees e The more than 100 000 people who survived the atomic bombs dropped on Hiroshima and Nagasaki It is estimated these survivors received radiation doses in excess of 50 000 mrem e Those involved in radiation accidents like Chernobyl thirty firefighters received acute doses in excess of 800 000 mrem e People who have received radiation therapy for cancer This is the largest group of people to receive significant doses of radiation 030 0011 01 0 15 X Ray Radiation Safety Manual BRUKER Bruker Elemental Biological Effects of Radiation Cell Sensitivity The human body is composed of over 50 000 billion living cells Groups of these
73. y sample target collimator and windows As shown in Appendix B the Tracer SD analyzer was operated at approximately 20 uA and 40 kV as well as 60 pA and 15 kV under the standard operating conditions expected during the profile measurement Turbo models would operate under similar settings whereas the Sorter and Tracer IIIV would be set at about 1 10 the current setting of the Tracer SD Distances recorded i e 10 30 amp 100 cm were measured from the surface of the analyzer to the effective center of the ion chamber The analyzer was operated as it would be in normal use with a sample When there is no sample in front of the aperture the safety circuit turns the X rays off however if the X rays were capable of being on when no sample is present an intensity of approximately half a rem hour would be expected at 5 cm 2 inches when the unit is run at 40KeV and 2uA with the standard TiAl 25um 300um filter These settings of 40KeV and 2pA with the standard TiAl 251m 300jum filter are similar to those used in the Sorter model The intensities have been estimated from results of tests done on the original Tracers and are given here as rough estimates of the main beam s intensity When following the appropriate operating instructions for the instrument operators should not receive any appreciable radiation dose from the instruments during normal use Note that the highest dose rates are close to the beam end of the device Avoid placing h
74. y stimulated luminescence dosimeters OSL and film badges It is the responsibility of your Radiation Safety Officer RSO or Radiation Protection Officer RPO to specify and acquire the dosimetry device or devices specified by your regulatory body for each individual and to specify any other measuring devices to be used See Appendix D for survey meter information and operation lonization Chamber The lonization Chamber is the simplest type of detector for measuring radiation It consists of a cylindrical chamber filled with air and a wire running through its center length with a voltage applied between the wire and outside cylinder When radiation passes through the chamber ion pairs are extracted and build up a charge This charge is used as a measure of the exposure received This measurement is not highly efficient 30 4096 efficiency is typical as some radiation may pass through the chamber without creating enough ion pairs for proper measurement The Geiger Mueller Tube The Geiger Mueller GM Tube is very similar to the ion chamber but is much more sensitive The voltage of its static charge is so high that even a very small number of ion pairs will cause it to discharge A GM tube can detect and measure very small amounts of beta or gamma radiation The Pocket Dosimeter The Pocket Dosimeter is also a specialized version of the ionization chamber It is basically a quartz fiber electroscope The chamber is given a single charge

X-Ray Radiation Safety Manual

Contents

Download Pdf Manuals

Related Search

Related Contents