S.E. International INSPECTUSB
Contents
1. shows various indicators according to the mode setting function s being performed and battery condition as shown below A X1000 B Total H Set C Hourglass TOTAL X1000 SE cs Fr URS Measurement D Radiation Symbol ER ol DT Ab I TY Di CPM DEM a E Battery E af jai Mery lj mi R hr J Numeric Display F Isotope Icons 835 Si Y90 Cs187 P32 C14 1310080 ALPHA NU Aam OON RECQRD Ne RANGE Full K RANGE Full G Menu L Recording M On Off Indicators Figure 1 e X1000 A appears when the numeric display is to be multiplied by 1000 e TOTAL B appears when the Inspector is in Total Counts Total Timer mode e An hourglass C appears to the left of the numeric display during a timed count e A Radiation Symbol D appears to the left of the numeric display when the Alert mode is activated e A Battery Icon E appears to the left of the numeric display indicating low battery voltage e The Isotope Icons F identify the user selected isotope efficiency for calculating activity See Chapter 9 Built in Isotope Efficiencies e MENU G appears upon entering the menu e SET H appears when you are setting the timer the numeric display shows the timed period instead of the current radiation level and while adjusting settings in the Utility and Alarm Menus e The current unit of measurement I CPM CPS mR hr uSv hr Bq or DPM is displayed to the right of the numeric display e T2. O 0OWOWWdWNNNNNN ererr rPrRO O 11 11 11 12 12 12 12 13 13 13 13 13 13 13 14 14 14 14 14 15 15 The X Axis The Y Axis Observer USB Meter Screen Enable Alarm Zero Units Echo Display Averaging Time Chapter 8 Observer USB Calibration Software General Discussion of Calibration Pulse Calibration Efficiency Calibration Exposure Rate Calibration Chapter 9 Built in Isotope Efficiencies Built in Isotope Efficiencies Decay Selecting a Built In Isotope Efficiency Selecting Between DPM and Bq Chapter 10 Troubleshooting Chapter 11 Basics of Taking Measurements How to Detect Background Radiation How To Survey a Surface How to Perform a General Survey How to Determine Alpha Beta or Gamma source Radiation Measurement Units Converting CPM to mR hr Chapter 12 Glossary of Common Terms Background Radiation CPM counts per minute lon lonization lonizing Radiation Radiation Radionuclide Decay Half life Chapter 13 Accessories Xtreme Boot Wipe Test Plate Stand Appendix A Technical Specifications Appendix B Limited Warranty Calibration Database Application 15 15 15 15 15 15 15 16 16 16 17 19 20 20 20 20 20 21 22 22 22 22 23 24 24 25 25 25 25 25 25 25 25 25 25 26 26 26 26 27 28 29 Chapter 1 Introduction The Inspector is a health and safety instrument that is optimized to detect low levels of radiation It mea
3. as the nucleus of a helium atom Positively charged particles emitted from the nucleus Alpha particles are relatively large and very heavy Due to this strong positive charge and large mass an alpha particle cannot penetrate far into any material It generally can travel no more than 1 to 3 inches in air before stopping and can be stopped by a piece of paper 13 Chapter 7 Observer USB Software The Observer USB reads in Total Counts CPM CPS uR hr mR hr uSv hr and has the ability to collect log the data received calibrate the unit and echo the readings collected on a PC The data is displayed on a graph as well as a digital on screen meter and can be saved or printed in various ways including a spreadsheet format The dwell count time can be adjusted for each point on the graph You can also set the length of time for the count The on screen display in the software has adjustable settings as well as a settable alarm Installing the Observer USB Software To use the Observer USB Software with your unit you will first need to install the software prior to connecting your instrument to the computer You can download a copy at seintl com software After the software has completed downloading double click on the installer and follow the on screen prompts Once the software is installed and started the detector will be automatically detected and identified once the unit is connected via USB Connect to The Inspector Ensure that you
4. have installed the Observer USB Software before connecting the Inspector The USB port is a mini B type jack located on the side of the Inspector above the Output Figure 2 9 To connect the Inspector power on your detector plug the cable into the USB jack and connect the other end to the USB port on your computer Note If the battery icon is on after plugging in your unit to the USB cable connected to the PC turn the unit off and then on again and the USB Observer will launch Once the unit is connected the Observer Software will launch and open a window for the instrument with a serial number displayed in the upper left corner of the title bar Anew window will open for each detector connected The software may reset in high static electrical environments Bm me r Preferences pe jee Input tee g The alarm settings auto save chart feature and the e grid settings for datalogging frequency and units of a measurement can be adjusted in View gt Preferences E menu x Using the Data Logging Feature You must set the time and date on the Inspector prior um teya um Nm eaw vo ro urn Wem wya umge N Deeg Et Cm Da Goa COT Mite Klinge amy Gage Ghas et wma i mm to collecting data We recommend the clock be set mR h u rn prior to collecting data to ensure a correct time and 0 01 1 a EEE nn date in your collected data If you exceed that amount u nn of time after setting the time and date you will need toe ren un to r
5. the Utility Menu 21 Chapter 11 Basics of Taking Measurements The Inspector will not detect neutron microwave RF radio frequency laser infrared or ultraviolet radiation All of our instruments are most accurate for Cesium 137 and isotopes of similar energies Some isotopes detected relatively well by most Geiger counters are Cobalt 60 Technicium 99M Phosphorous 32 Strontium 90 and many forms of Radium Plutonium Uranium and Thorium Some forms of radiation are very difficult or impossible for a Geiger tube to detect Tritium for example is a by product of a nuclear reactor and is used in research The beta emissions from Tritium are so weak that there are very few instruments that are capable of detecting it More sophisticated equipment is needed for the measurement of environmental samples such as radioactivity in milk produce soil etc unless you are looking for gross contamination The radiation from some isotopes can cause a Geiger tube to overexcite and indicate a higher level of radiation than is actually present Americium 241 is an example of this phenomenon Americium 241 is used in some smoke detectors and many different types of industrial density and flow meters Unless you know exactly what you are measuring and understand the limitations of detection instruments it is possible to draw misleading conclusions from your readings We design our instruments to detect the broadest range of ionizing radiation poss
6. the numeric reading by 1000 to get the complete radiation level For details see Taking a Timed Count in Chapter 3 Off On Audio Switch Figure 2 3 Audio The Inspector is on and makes a clicking sound for each radiation event detected On The Inspector is operating but the audio is off Off The Inspector is not operating 7 Tube Center Indicator 2 Mode Switch 10 USB Port 3 On Off Audio Switch 9 Output Jack The Backlight The LCD has a backlight that can be activated for the default 10 seconds by pressing the button The duration time of the backlight can be changed with the software If the duration time has been changed you can restore the default time of 10 seconds in the utility menu See Utility Menu in Chapter 3 for more information on using the utility menu Set Button Figure 3 5 The Set button is used to set the Alert or Timer in 5 Set Button m Center Indicator normal operating mode and to select items in the Utility Menu See Chapter 3 Using the Alert Taking a Timed Count and Utility Menu and Buttons Figure 3 6 The and buttons are used to adjust the numeric display for timed counts alert settings and to make selections in the utility menu The Detector CAUTION The mica surface of the Geiger tube is fragile and should be handled with care Be careful not to let anything penetrate the screen 6 Plus amp Minus Buttons Figure 3 The Inspector uses a two inch t
7. time remove the battery to avoid battery corrosion inside the battery compartment 5 Do not place the unit inside a microwave oven as it can damage the unit and or the microwave This instrument is for detecting ionizing radiation such as alpha beta gamma and x rays It will not detect non ionizing radiation such as microwave and radio emissions 6 Do not place any objects that may puncture the mica end window of the detector near the detector 12 Chapter 6 Basics of Radiation and Its Measurement lonizing Radiation lonizing radiation changes the structure of individual atoms by ionizing them The ions produced in turn ionize more atoms Substances that produce ionizing radiation are called radioactive Radioactivity is a natural phenomenon Nuclear reactions take place continuously on the sun and all other stars The emitted radiation travels through space and a small fraction reaches the Earth Natural sources of ionizing radiation also exist in people and in the ground The most common sources of ground radiation are uranium and its decay products Types of lonizing Radiation X Rays X rays are man made radiation produced by bombarding a metallic target with electrons at a high speed in a vacuum X rays are electromagnetic radiation of the same nature as light waves and radio waves but at extremely short wavelength less than 0 1 billionth of a centimeter They are also called photons The energy of X rays are millions of times gre
8. when DONE is displayed The Inspector will continue with the normal start up routine Options Options dLoG UNIT EFF AVEr CLOC dEF VEr USE donE 10 Function Data Logging The logging interval can be set in the USB Observer Software Unit of Measurement Efficiency Averaging Clock We recommend the clock be set prior to collecting data to ensure a correct time and date in your collected data Default Settings Does not change calibration Version Use specific isotope efficiency Done Comments Turns on or off the data logging feature for storing collected readings in the internal memory Default is 10 minutes Selects between mR hr and CPM or uSv hr and CPS Displays the efficiency for the pre pro grammed isotopes built into the Inspector Turns Auto Averaging on and off Sets the internal clock for use with the data logging feature Set the unit to the default settings Alarm off Auto Averaging on mR hr amp CPM recording off clears and resets isotopes and backlight time and exits the Utility Menu Displays the firmware version If surveying a known isotope select from the list of isotopes efficiencies to display activity in Bg or DPM Press the SET button when done is dis played to exit the menu and begin taking readings Setting the Internal Clock It is necessary to set the internal clock to properly time stamp the data collection on your device We
9. with a duration of approximately 3 3 to 5V peak to peak square wave No high voltage is connected to this test point 2 Power on the instrument 3 Connect the instrument to the PC running Observer USB using the USB cable An application window for the attached instrument should open within a few seconds 4 Go to View gt Cal Panel menu of The Observer USB Software to access the Calibration Screen 5 Record the currently displayed dead time Default is 1 8E 4 seconds 6 Change the dead time to 0 and click the Update Settings button After a second or two the instrument should beep to acknowledge that the new setting has been received stored and applied Setting the dead time to 0 seconds causes the device to not apply any dead time correction at all so the display should report the true input pulse rate 7 Run the pulse generator at several different rates to span the range of the instrument For the Inspector the maximum working input pulse rate should be about 367 000 CPM 6 123 Hz Verify that the value reported by the instrument is within 10 of the input value in all cases 8 Change the dead time back to the setting recorded in Step 5 16 Efficiency Calibration The Inspector can be used beyond simple detection of contamination and can also be used to determine the activity of any beta or alpha emitting isotopes present Efficiency is the ratio of events detected by the instrument to the number of decays of the
10. 37 but also serve as excellent indicators for many other sources of ionizing radiation Gamma and x rays are measured in milliroentgens per hour mR hr microsieverts uSv hr or millisieverts mSv hr Alpha and beta are measured in counts per minute CPM or counts per second CPS The window of the GM tube is very thin mica This mica window is protected by a screen Some levels of alpha low energy beta gamma and x rays that cannot penetrate the plastic case or the side ofthe tube can be sensed through the window Try not to touch the instrument to any suspected radioactive substance Although some beta and most gamma radiation can go through protective gear try to avoid skin contamination and ingestion When you leave a radioactive area remove any protective outerwear and dispose of it properly If you think you have been contaminated as an additional precaution shower and consult a physician How to Determine Alpha Beta or Gamma source To determine whether the radiation detected is alpha beta or gamma hold the instrument toward the source Alpha If there is no indication through the back of the case the side of the tube position the window close to but not touching the source If there is an indication it is alpha beta or low energy gamma If a sheet of paper placed between the window and the source stops the indication it is most likely alpha To avoid particles falling into the instrument do not hold the source abov
11. AL NUMBER ADDRESS DATE PLACED IN SERVICE a EMAIL STATE ZIP amp COUNTRY PHONE NUMBER Or fill out the form online at http seintl com calibrations 29
12. Hg gt a TERNATI Ly L rei else Inspector OPERATION Se S E International Inc P O Box 39 436 Farm Rd Summertown TN 38483 USA 1 800 293 5759 931 964 3561 Fax 1 931 964 3564 www seintl com radiationinfo seintl com Contents Chapter 1 Introduction How The Inspector Detects Radiation Precautions Chapter 2 Features The LCD Display Indicators The Switches Mode Switch Off On Audio Switch The Backlight Set Button and Buttons The Detector The Input Output Ports Chapter 3 Operation Starting the Inspector Units of Measurement Display Update Maximum level Response Time Autoaveraging Autoranging Operating in Dose Rate Modes Operating in Timer Mode Taking a Timed Count Using Dose Rate Modes While Timer is On Using The Alert Utility Menu Options Setting the Internal Clock Interfacing with an External Device Chapter 4 Common Procedures Establishing the Background Count Environmental Area Monitoring Checking for Surface Contamination Chapter 5 Maintenance Calibration General Maintenance Tips Chapter 6 Basics of Radiation and Its Measurement lonizing Radiation Types of lonizing Radiation X Rays Gamma Rays Beta Radiation Alpha Particles Chapter 7 Observer USB Software Installing the Observer USB Software Connect to The Inspector Preferences Using the Data Logging Feature Show Grid Observer USB Chart Screen 2 w w ooooovumuuvuPr_ PrP gt gt WO
13. ake up to 30 seconds to stabilize For details see Autoranging in this chapter CPM CPS and Total counts are the most direct methods of measurement mR hr and uSv hr are calculated using a conversion factor optimized for Cesium 137 This mode is less accurate for radionuclides other than Cs 137 unless you have calibrated the Inspector for the specific radionuclide you are surveying The most immediate indicators of the radiation level are the audio and count light Operating in Timer Mode When the mode is set to Total Counts Total Timer the numeric display is updated every second and totaling starts Taking a Timed Count The Inspector can give you a total count for a timed period from 1 minute to 24 hours The default setting is 10 minutes A timed total count is useful for determining the average counts per minute over a longer period of time The number of counts detected by the Inspector varies from minute to minute due to the random nature of radioactivity When a count is taken over a longer period the average count per minute is more accurate Taking an average allows you to detect low level contamination or differences in background radiation due to altitude or soil mineral content For example if one 10 minute average is 1 count per minute higher than another 10 minute average the increase is likely due to normal variation But over 12 hours a 1 count per minute increase over the 12 hour background average may be statisticall
14. ater than that of light and radio waves Because of this high energy level X rays penetrate a variety of materials including body tissue Electromagnetic radiation photons of higher frequency and energy than visible and ultraviolet light X rays are photons emitted by interactions involving orbital electrons rather than atomic nuclei X rays and gamma rays have the same basic characteristics The only difference between them is their source of origin Gamma Rays Gamma rays are almost identical to X rays Gamma rays generally have a shorter wavelength than X rays Gamma rays are very penetrating and thick lead shielding is generally required to stop them Short wavelength electromagnetic radiation higher in frequency and energy than visible and ultraviolet light Gamma rays are emitted from the nucleus of an atom These high energy photons are much more penetrating than alpha and beta particles Beta Radiation Beta radiation A beta particle consists of a negatively charged electron emitted from an atom It has more mass and less energy than a gamma ray so it doesn t penetrate matter as deeply as gamma and X rays Beta particles have a mass and charge equal to that of an electron They are very light particles about 2 000 times less mass than a proton and have a charge of 1 A few millimeters of aluminum will stop most beta particles Alpha Particles Alpha radiation is a particle that consists of two protons and two neutrons the same
15. blem Display works but no counts are registered Reading is high but another instrument has a normal read ing in the same location Instrument has false high reading Instrument has false high reading or OVERRANGE Display is blank There is wrong or no time and date stamp on my collected data Possible Cause defective Geiger tube or bad cable possible contamination moisture photosensitivity continuous discharge electromagnetic field no battery dead battery poor battery connection defective LCD Internal Clock has reset The instrument has been powered off for 120 hours Action look through the window to check the mica surface of the tube if it is wrin kled or a break is visible replace it scan the Inspector with another instrument You may need to replace the rubber strips on back of the Inspector circuit board may be wet dry the in strument in a warm dry place if it still has a problem it requires service remove from direct sunlight and ultra violet sources ifthe high count drops the mica window coating may have washed off the Geiger tube due to getting wet the tube will need to be replaced replace the Geiger tube move the instrument away from possi ble sources of electromagnetic or radio frequency radiation install anew 9 volt battery if count light and audio work the LCD may need to be replaced Reset the clock to the current time using the Observer Software or
16. by 10 If you re taking a 24 hour background count then divide the total by 1440 the number of minutes in a 24 hour period to get your Counts Per Minute background level The longer you take a timed count the more statistically accurate your reading will be You will then subtract that amount from the readings of your sample Appendix B Limited Warranty WARRANTOR S E International Inc P O Box 39 436 Farm Road Summertown TN 38483 0039 USA 931 964 3561 ELEMENTS OF WARRANTY S E International Inc warrants for one year all materials and craftsmanship in this product to be free from all defects with only the limitations set out below WARRANTY DURATION The warranty shall terminate and be of no further effect one year after the original date of purchase of the product or at the time the product is a damaged or not maintained as is reasonable or necessary b modified c repaired by someone other than the warrantor for a defect or malfunction covered by this Warranty d contaminated with radioactive materials or e used in a manner or purpose for which the instrument was not intended or contrary to S E International Inc s written instructions This warranty does not apply to any product subjected to corrosive elements misuse abuse or neglect STATEMENT OF REMEDY In the event that the product does not conform to the warranty at any time while this warranty is effective the Warrantor will repair the defect and return t
17. ces may go through several stages of decay before they change into a stable or non ionizing form For example U 238 has 14 different stages of decay before it stabilizes An element may have several forms or isotopes A radioactive isotope of an element may be called a radioisotope However the more correct term is radionuclide Selecting a Built In Isotope Efficiency Enter the Utility Menu and scroll to the USE menu item and press SET on the end panel of the unit to select the isotope efficiency you want to use for your survey For example if you know you are surveying lodine 131 then you would select 1131 from the menu Once you have selected the cooresponding isotope press the SET button to select it Press SET again to begin normal operation of the Inspector You can select from any of the following isotope efficiencies built into the Inspector Sulfur S 35 Strontium Sr y 90 Cesium Cs 137 Phosphorus P 32 Carbon C 14 lodine I 131 Cobalt Co 60 and Alpha Selecting Between DPM and Bq Enter the Utility Menu and scroll to the UNIT menu item and press SET on the end panel of the unit to change the units of measurement between DPM when mR hr and CPM are selected and Bq when uSv hr and CPS are selected 20 Chapter 10 Troubleshooting The Inspector is a highly reliable instrument If it does not seem to be working properly look through the following chart to see if you can identify the problem Pro
18. con are displayed Use the and buttons to adjust the display to the desired level 3 Press the SET button once to retain the setting in memory and activate the alert The ALERT icon radiation symbol is now displayed to indicate the unit is operating in the Alert mode To deactivate the Alert mode press and briefly hold the SET button again The ALERT icon is no longer displayed To use the previous alert setting press the set button twice Now the alert mode is on indicated by the radiation symbol on the display Utility Menu The Utility Menu allows the user to change default settings for several operating parameters Once a setting is changed it remains in effect unless they are changed through the Utility Menu or The USB Observer Software 1 To activate the Utility Menu hold down the button on the end panel while turning the instrument on The display will show the MENU icon Release the button and donE will appear along with the MENU icon 2 Scroll through the menu by pushing the or buttons 3 To select an option push the SET button and the SET icon is displayed 4 Use the or buttons to toggle between choices and press the SET button to enter the new value The instrument will continue to operate in the Utility Menu mode and the display will show DONE and MENU To adjust another Utility Menu option repeat the above steps 5 To exit the Utility Menu at any time press the SET button again
19. d response at any radiation level by using the Utility Menu detailed in Chapter 3 Refer to the following table After 30 second start up The reading will be based if instrument is detecting on an average of the previous lt 100 CPS 30 seconds lt 6000 CPM or lt 1 75 mR hr 100 200 CPS 6 seconds 6000 12 000 CPM or 1 75 3 6 mR hr gt 200 CPS 3 seconds fast response gt 12 000 CPM or gt 3 6 mR hr Autoranging When radiation levels increase in some modes over certain preset levels the Inspector uses autoranging automatically changing to the X1000 scale While in CPM or Total Counts Total Timer mode whenever X1000 is shown above the numeric display multiply the displayed reading by 1000 to determine the radiation level mR hr uSv hr and CPS are not applicable Mode Ranges as they are displayed CPM 0 to 2 999 CPM gt 9 999 X1000 10 000 10 000 CPM to 350 230 000 PM Total Count 0 9 999 counts gt 9 999 Total Timer X1000 10 00 10 000 to 9999 9 999 000 counts Operating in Dose Rate Modes Caution Be sure there is no obstruction between the detector window and the source being monitored surveyed Avoid making measurements with the GM window facing the sun as it could affect your readings When the mode switch is set to mR hr and CPM or uSv hr and CPS the numeric display is updated every 3 seconds unless you are using the Timer mode At low count rates significant changes in the radiation level displayed can t
20. e the window Beta Place a piece of aluminum about 1 8 inch 3 mm thick between the instrument and the source If the indication stops decreases or changes it is most likely beta radiation Most common isotopes emit both beta and gamma radiation This is why the indication would decrease or change but not stop The non occupational dose limits set by the government is 100 mR above background annually It is up to the individual to decide what a safe radiation level is It will be different depending on the individual and their knowledge of radiation and its affects Radiation levels will vary according to location and circumstances As an example if your background level is 25 CPM counts per minute where you live when you fly in an airplane at 30 000 feet your rate meter may measure 200 CPM 2 mR for 2 to 5 hours That is 8 times your normal background radiation on the ground but it is only for a limited amount of time When measuring radiation in an emergency response situation it is good to have something to compare your readings to Taking a background radiation level reading in your area before a radiation event will help you determine if you have an elevated level of radiation and whether or not to stay in that location Background radiation is naturally occurring radiation that is always present It includes high energy gamma rays from the sun and outer space and alpha beta gamma radiation emitted from elements in the earth Using a
21. eed a PC running Observer USB and a Gamma calibration range Procedure 1 Power on the instrument 2 Connect the instrument to the PC running Observer USB using the USB cable An application window for the attached instrument should open within a few seconds 3 Display the calibration panel by clicking View Cal Panel 4 Record the displayed values for Dead Time and Sensitivity 5 Begin checking the instrument s Sensitivity Place the instrument in a relatively low field approximately 5 mR hr and allow it 30 seconds or so to stabilize 6 If the indicated response is off by more than 3 at this level adjust the Sensitivity to a lower value if the instrument is reading too low or to a higher value if the instrument is reading too high After changing the value on the Calibration Panel click the Update Settings button After a second or two the instrument will beep to indicate that the new value has been received 7 Repeat Step 5 as needed to bring the instrument indication as close as possible to the true value 8 Next expose the instrument to a field near the top of its range of 100 mR hr Allow the reading to stabilize for at least 30 seconds In the preferences tab you can adjust the time in the gird to show a selected average count 9 If the indicated response is off by more than 10 adjust the Dead Time to a lower value if the instrument reading is too low or to a higher value if the instrument reading is too high After c
22. entgens 10 uSv hr 1 milliroentgen hr Curie is the amount of radioactive material that decays at the rate of 37 billion disintegrations per second approximately the decay rate of one gram of radium Microcuries millionths of a curie and picocuries trillionths of a curie are also often used as units of measurement Becquerel Bq is defined as the activity of a quantity of radioactive material in which one nucleus decays per second 1 dps one disintegration per second Converting CPM to mR hr cpm i sensitivity Sensitivity is expressed in cpm per mR hr Counts Per Minute for every milliroentgen the GM tube can detect referenced to Cs 137 Mathematically the cpm units cancel each other out leaving mR hr as shown below pn N aig cpm 1 mR hr For example if you have collected 200 CPM with the Radiation Alert Inspector which has a typical gamma sen sitivity of 3340 com per mR hr you would divide the 200 cpm by the 3340 cpm per mR hr sensitivity The com cancels out and you are left with 200 3340 mR hr 0 0599 mR hr 200 cpm cpm 3340 mR hr 0 0599 mR hr 24 Chapter 12 Glossary of Common Terms Background Radiation Naturally occurring radiation is always present it includes high energy gamma rays and particles from the sun and outer space and alpha beta and gamma radiation emitted from elements in the earth CPM counts per minute The unit of measurement usually used to measure alpha and beta radiation
23. eset the clock to the current time and date In addition to being able to set the time via the utility menu the internal clock of the Inspector can be set to the time on the PC you are using by clicking Functions gt Synchronize Inspector to PC Clock The Inspector will beep twice once synchronization has completed The update will be recorded in the on board memory if the recording feature is on See Chapter 3 Operation Utility Menu for information on activating the recording feature If the recording feature on the Inspector is activated and the internal clock is set then the collected data can be retrieved from the unit s internal memory by selecting Functions gt Retrieve Memory Data is stored ina text delimited file which can be opened in your preferred spreadsheet software The default data logging frequency is 10 minutes You can change the value in the Cal Panel of the Observer USB Software 14 Show Grid a nn The Show Grid check box displays the data collected in the grid The grid displays an ongoing collection of data based on the user selectable settings in the View gt Preferences gt Grid Settings dialog box For example if the grid setting is 60 seconds a new data point will appear on the grid every minute Observer USB Chart Screen The Observer USB Chart Screen displays a chart of the data currently collected by the attached instrument The X Axis The X axis consists of the time and date stamp of the readi
24. g the Background Count Normal background radiation levels vary at different locations different times even in different areas of the same room To accurately interpret the readings you get on the Inspector it is good to establish the normal background radiation count rate for each area you plan to monitor You can do this by taking a timed count For more information on using the timer see Taking a Timed Count in Chapter 3 A 10 minute average is moderately accurate You can repeat it several times and compare the results to establish accuracy To establish a more accurate average take a 1 hour timed count If you need to determine whether there is prior contamination take averages in several locations and compare the averages Environmental Area Monitoring You can keep the Inspector in CPM or mR hr mode whenever you want to monitor the ambient radiation and look at it from time to time to check for elevated readings If you suspect an increase in ambient radiation use the timer and take a 5 or 10 minute count and compare the average to your average background count If you suspect an increase that is too small to detect with a short timed reading you can take a longer count for example 6 12 or 24 hours 11 Checking for Surface Contamination To check a surface hold the detector window close to the surface and read the count rate wait 30 seconds or until the reading has stabilized If you want to find out if a surface is slight
25. hanging the value on the Calibration Panel click the Update Settings button After a second or two the instrument will beep twice to indicate that the new value has been received 10 Repeat step 9 as needed to bring the instrument s indication within 10 of the true value 11 Once the values for Sensitivity and Dead Time have been verified to be correct expose the instrument to a series of values spanning the range of the instrument All indications should be within 10 of the true value 19 Chapter 9 Built in Isotope Efficiencies Built in Isotope Efficiencies The Inspector has a number of built in efficiencies for specific isotopes If you know the isotope being surveyed then you can select one of the pre programmed isotope efficiencies to calculate the activity of your known source The activity DPM and Bq is different from the rates of exposure mR hr uSv hr CPM and CPS Activity is the number of disintegrations of a radioactive substance in a given unit of time which is specific to the isotope being detected The efficiencies programmed into the Inspector USB are based on the geometry of our wipe test plate which places samples 1cm from the end window of the detector Caution Do not use the built in efficiencies unless you are surveying a known isotope as doing so will give you inaccurate results Decay When an atom emits an alpha or beta particle or a gamma ray it becomes a different type of atom Radioactive substan
26. he average count is in counts per minute To convert to mR hr for Cesium 137 divide by 3340 Move the Mode switch to one of the dose rate modes to return to normal operation If you move the Mode switch to one of the dose rate modes while the Inspector is taking a timed count the timed count will continue 8 To reset the timer to take another timed count press the SET button to set the time for another count 9 Press the SET button a second time and the Inspector will start totaling the counts it registers and the numeric display is updated each time a count is registered Using Dose Rate Modes While Timer is On Dose rate modes can be used while the timer is on In any dose rate mode the hour glass indicator will continue to flash during a timed period At the end of the timed period the hour glass will remain continuously on and the Inspector will beep 3 times and repeat 3 times The timed count can be displayed by returning to the Timer mode from other modes Using The Alert The Alert can be set in dose or rate modes When using Utility Menu option UNITS to switch units of measurement the alert will retain the user selected alarm level Once the alert threshold is reached the beeper will sound and the ALARM icon will flash until the alert is deactivated or the radiation level drops below the set alert threshold 1 To set the Alert press the SET button on the end panel The ALERT icon radiation symbol and the SET i
27. he Numeric Display J shows the current radiation level in the unit specified by the mode switch setting e RANGE Full K appears when the radiation present exceeds the upper detection limit of the Inspector e RECORDING L appears when the Inspector is logging data to the internal memory e On Off M indicates that a feature is on or off in the utility menu e Alarm N indicates that an alarm threshold has been met and that the alarm has been triggered The Switches The Inspector has 2 switches on the front and 3 buttons on the end panel Each switch has 3 settings which are described below Mode Switch Figure 2 2 mR hr uSv hr The numeric display shows the current radiation level in milliroentgens per hour or when SI units are used in microsieverts per hour e In mR hr mode The Inspector displays the radiation level from 001 to 100 e In uSv hr mode The Inspector displays the radiation level from 01 to 1000 See Utility Menu in Chapter 3 for details on how to switch between modes CPM CPS In CPM the display shows the current radiation level in counts per minute from 0 to 350 000 When using SI units the display shows the radiation level in counts per second from 0 to 5000 When X1000 is shown on the display multiply the numeric reading by 1000 to get the complete radiation level Total Counts Total Timer The display shows the accumulated total of counts from 1 to 9 999 000 When X1000 is shown on the display multiply
28. he instrument to you prepaid without charge for parts or labor NOTE While the product will be remedied under this warranty without charge this warranty does not cover or provide for the reimbursement or payment of incidental or consequential damages arising from the use of or the inability to use this product The liability of the company arising out of the supplying of this instrument or its use whether on warranties or otherwise shall not in any case exceed the cost of correcting defects in the instrument and after the said one year 90 days on the tube period all such liability shall terminate Any implied warranty is limited to the duration of the written warranty PROCEDURE FOR OBTAINING PERFORMANCE OF WARRANTY In the event that the product does not conform to this warranty please write or call to the address above S E International Inc will not accept contaminated instruments for calibration or repair under warranty or otherwise NOTE Before using this instrument the user must determine the suitability of the product for his or her intended use 28 Calibration Database Application Please fill out this form and send it back to us if you would like to be notified of the NIST calibration renewal for your instrument to S E International Inc P O Box 39 436 Farm Rd Summertown TN 38483 1 800 293 5759 931 964 3561 Fax 1 931 964 3564 www seintl com radiationinfo seintl com NAME MODEL NAME COMPANY SERI
29. hin window Geiger tube commonly called a pancake tube The screen on the back of the Inspector is called the window Figure 4 1 It allows alpha and low energy beta and gamma 1 Geiger Mueller Window radiation which cannot get through the plastic case to penetrate the mica surface of the tube The small radiation symbol on the front label indicates the center of the Geiger tube Figure 2 7 Inspector ce The Input Output Ports The Output Port Figure 2 9 The Output port allows you to interface the Inspector to a computer data logger or other device The USB Port Figure 2 10 The USB Port above the Output jack allows you to interface the Inspector to a PC for use with the Observer Software For details see Chapter 7 Observer Software 2 Battery Compartment Figure 4 Chapter 3 Operation Starting the Inspector Before starting the Inspector install a standard 9 volt alkaline battery in the battery compartment located in the lower rear Figure 4 Note Place the battery against the bottom wall and make sure the wires are placed along the side of the battery and not under it To start the Inspector set the mode switch to the mode you want and set the bottom switch to On or Audio The Inspector then begins a 6 second system check All indicators and numbers are displayed After the system check the radiation level is displayed in the selected mode Approximately 30 seconds after you start the Inspector a sh
30. ible and still be affordable The full spectrum of ionizing radiation cannot be measured by one single instrument Everyone agrees that radioactive materials can be dangerous We encourage you to seek out other sources of information How to Detect Background Radiation To see what the background radiation is in your area simply turn the instrument on and after the 30 second start up beep the general background radiation will be displayed How To Survey a Surface When surveying a surface such as a counter top you will need to hold the Inspector about 1 2 centimeters from the surface while moving the unit horizontally across the survey area at a rate of 2 inches per second How to Perform a General Survey A general survey would be used to find a potential source For example if you are looking for a potential source in a pile of scrap the Inspector will typically detect about 2 feet into a pile It is easier to find a source when the Inspector is set to Fast Response mode However even ifthe Inspector is in Auto Averaging mode the audio clicks that indicate a count should be a sufficient indicator if a potential source is present To find the source slowly move the Inspector in the direction of the higher readings or clicks until the potential source is found 22 Geiger counters can detect the four main types of ionizing radiation alpha beta gamma and x rays Some detect only gamma and x rays Our instruments are calibrated to Cesium 1
31. ing d in tough environments such as 1st Responders _ PigilertepQ Mining and HAZMAT crews Made of a RoHS De compliant TPE rubber the case also offers superior grip and drop protection When using the pancake detector a protective door opens on the back of the case exposing the end window of the GM for alpha detection Wipe Test Plate The stainless steel WipeTest Plate slides easily onto the Inspector positioning the depression and wipe directly in front of the GM tube window at a fixed distance of 1 centimeter The WipeTest plate is removable for general surveying patent 5 936 246 Many of the customers using the Inspector Wipe Test Plate also use it as a Beta Shield for the 2 inch GM detector patent 5 936 246 Stand Whether you need to perform area monitoring or scan your hands and items for contamination the STAND offers a convenient way for the instrument to STAND vertically while leaving your hands free for other tasks The STAND is made from electro polished stainless steel Double stick adhesive strips can be used to mount the STAND in a permanent location 26 Appendix A Technical Specifications Detector Internal Halogen quenched uncompensated GM tube with thin mica window 1 4 2 0 mg cm2 areal density Effective diameter of window is 45 mm 1 77 in Radiation symbol on front label and end panel marks the center of the detector Averaging Periods Display updates every 3 seconds At low background leve
32. is clicked the averaging of the collected counts starts over Units Echo Display When Echo Display is checked the meter screen will mirror the display of your Inspector and the Units dropdown box selects the unit of measurement displayed on the y axis of the chart screen When Echo Display is not checked the meter screen will not mirror the display of your Inspector You can select your own averaging time and the Units dropdown box selects the unit of measurement displayed on both the y axis of the chart screen and the meter screen Averaging Time The Averaging Time selects the amount of time in which the previous readings are averaged for a more accurate display of the collected counts The longer the averaging time the more accurate your reading Shorter averaging times allow significant changes to be seen more quickly 15 Chapter 8 Observer USB Calibration Software General Discussion of Calibration In order to have confidence in the measurements taken with a radiation detection instrument a calibration must be performed The calibration compares the response of the instrument to known values and the instrument is adjusted if needed to bring all indications within the range of the instrument to within 10 of the true values Generally radiation detection instruments should be calibrated annually CAUTION Errors can occur when using low level sources or background for calibrating In the Calibration mode the smallest inc
33. ledge receiving the updated settings 17 Procedure Metric Units 18 1 Attach the Wipe Test Plate and power on the Inspector Make sure the Inspector is in Total Timer Total Timer mode displaying COUNTS Place the Inspector in the location where the efficiency calibration will be performed and take a count of at least 10 minutes Multiply the acquisition time by 60 to convert it from minutes to seconds Divide the total number counts by the acquisition time in seconds to calculate the background counting rate RB in cps Record this value Center the first source to be used into the Wipe Test Holder and take a count of at least 1 minute Divide the total number of counts by the counting time in seconds to calculate the gross count rate gcps or RG Calculate the efficiency using the following equation Where Eff Re Ra Eff is instrument efficiency in counts per disintegration A RG is the gross count rate in counts per second cps RB is the background count rate in cps A is the activity of the source in disintegrations per second dps or becquerels Bq 5 Repeat Steps 3 and 4 for additional radionuclides 6 If you would like to record efficiency values in the Inspector s memory for any of the supported 8 9 radionuclides S 35 Sr Y 90 Cs 137 P 32 C 14 I 131 Co 60 ALPHA continue with the following steps Connect the Inspector to the PC running Observer USB using the USB cable An app
34. lication window for the Inspector should open within a few seconds Display the control panel by clicking View Cal Panel Enter the updated efficiencies in the appropriate fields 10 If you would like the Inspector to display in activity units i e DPM for a specific source instead of the count rate CPM select it from the Applied Isotope dropdown box Otherwise leave as None cpm cps 11 When all relevant values have been updated click the Update Settings button After a second or two the Inspector should beep to acknowledge receiving the updated settings Exposure Rate Calibration An exposure rate calibration correlates the number of counts in a given time to the exposure rate present in that field This is in many ways similar to efficiency but we refer to it in this case as gamma sensitivity Although it is possible to express this value in several different units the Inspector uses a formula of CPM mR hr counts per minute per milliroentgen per hour The instrument is placed in gamma radiation fields of different but known intensities that span the working range of the instrument and the settings are adjusted if needed such that all measurements are within 10 of the true value The relevant settings include both the sensitivity and the dead time The gamma field is usually generated by a relatively strong Cs 137 source Exposure rates are calculated to the center of the detector s volume Requirements You willn
35. lon An atomic particle atom or molecule that has acquired an electrical charge either positive or negative by gaining or losing electrons lonization The process by which neutral atoms of molecules are divided into pairs of oppositely charged particles known as ions lonizing Radiation Radiation capable of producing ionization by breaking up atoms or molecules into charged particles called ions Radiation The emission and propagation of energy through space or through matter in the form of particles or waves Radionuclide The naturally occurring or artificially produced radioactive form of an element Decay When an atom emits an alpha or beta particle or a gamma ray it becomes a different type of atom Radioactive substances may go through several stages of decay before they change into a stable or non ionizing form For example U 238 has 14 different stages of decay before it stabilizes An element may have several forms or isotopes A radioactive isotope of an element may be called a radioisotope However the more correct term is radionuclide Half life Each radionuclide has a characteristic half life which is the time required for half of a quantity of the material to decay 25 Chapter 13 Accessories Xtreme Boot The Xtreme boot offers maximum performance in a lightweight rugged solution for using Radiation 200 T Alert products in the field The Xtreme boot is designed specifically for individuals operat
36. ls the update is the average for the past 30 second time period The timed period for the average decreases as the radiation level increases Operating Range mR hr 001 1uR to 100 CPM 0 to 350 000 End Window uSv hr 01to 1000 CPS 0 to 5000 __ENERGYRESPONSE 9V Total Counts Total Timer 1 to 9 999 000 counts Ma ain Accuracy Cs137 ees Lik mR hr 10 typical NIST 15 max O to 100 N S 2p uSv hr 10 typical NIST 15 max 01 1000 o CPM 10 typical NIST 15 max 0 to 350 000 10 10 10 10 Energy Sensitivity PHOTON ENERGY keV Detects Alpha down to 2 MeV Detects Beta down to 16 MeV typical detection efficiency at 1 MeV is approx 25 Detects Gamma down to 10 KeV through the end window 3340 CPM mR hr Cs1 Smallest detectable level for 112 is 02 uCi at contact Display 4 digit liquid crystal display with indicators Display updates every 3 seconds Alert Set Range mR hr 001 50 and CPM 1 160 000 70db 1m Pulsating beeper sounds the alert Adjustable alert levels are used for mR hr CPM and uSv hr CPS Alarm will sound when in Timer Mode when set alarm threshold is reached Count Light Red LED flashes with each radiation event Audio Indicator Internally mounted beeper can be switched off for silent operation Outputs Dual miniature jack drives CMOS or TTL devices a
37. ly radioactive take a timed count or a longer accumulated count Chapter 5 Maintenance The Inspector requires regular calibration and careful handling to assure good measurements Use the following guidelines to maintain the instrument properly Calibration We recommend that the Inspector be calibrated annually or as often as your regulations require The best way to calibrate is using a calibrated source at a calibration lab However if no source is available it is possible to calibrate electronically using the calibration software See Chapter 8 for more information The standard by which the Inspector is calibrated is Cesium 137 A certified calibration source should be used To calibrate the Inspector for another radionuclide use a calibrated source for that radionuclide or the appropriate conversion factor referenced to Cs 137 CAUTION Errors can occur when using low level sources or background for calibrating In the Calibration mode the smallest increment which can be adjusted is 010 If you would like more information about source calibrations please contact us at 1 800 293 5759 or go to seintl com services General Maintenance Tips 1 Do not get the instrument wet 2 Be sure to store the meter in a location without direct sunlight as sunlight can damage the end window of the detector over time 3 Be sure to store the unit inside the carrying case when not in use 4 If you are planning to store the unit for a long
38. microwave oven It cannot measure microwaves and you may damage it or the oven e This instrument may be sensitive to and may not operate properly in radio frequency microwave electrostatic and electromagnetic fields e If you do not expect to use the Inspector for longer than one month remove the battery to avoid damage from battery corrosion Change the battery promptly when the battery indicator appears on the display e CAUTION When using the unit at altitudes higher than 8000 feet 2438 4 meters it is possible that the tube window can rupture CAUTION High Voltage Inside unit Do Not Open Unit CAUTION Do not place any object through screen Window is fragile Chapter 2 Features The Inspector measures alpha beta gamma and x ray radiation It is optimized to detect small changes in radiation levels and to have high sensitivity to many common radionuclides For more information see Appendix A Sensitivity to Common Radionuclides This chapter briefly describes the Inspector s functions For more information on how to use the Inspector see Chapter 3 Operation The Inspector counts ionizing events and displays the results on the liquid crystal display LCD You control which unit of measurement is shown by using the mode switch Whenever the Inspector is operating the red count light flashes each time a count an ionizing event is detected Figure 2 8 The LCD Display Figure 2 1 The LCD liquid crystal display Figure 1
39. nd counts to computer or datalogger USB for use with Observer USB Software for PCs Anti Saturation Meter will hold at OVER RANGE in fields as high as 100 times the maximum reading Power Requirements One 9 volt alkaline battery Battery life is approx 2000 hours at normal background Temperature Range 102C to 50 C 142F to 122 F Weight Inspector 273 g 9 6 oz without battery Size 150 x 80 x 30 mm 5 9 x 3 1 x 1 2 in Includes Carrying Case Certification of Conformance Observer USB Software Options Xtreme Boot Wipe Test Plate amp Stand Limited Warranty 1 year limited warranty 27 How can use the Inspector USB to detect radiation in food and water A Geiger counter is a Yes or no and how much type of detector They cannot determine the distribution of the incident radiation energy so they cannot identify which potential isotopes are present To identify specific isotopes a radiation spectrum analyzer with a sensitive enough scintillation detector for the application would be necessary Geiger counters are ideal for basic screening especially if you do long timed counts and in most instances will give you an indication regarding foods that are significantly contaminated When using a Geiger counter to test food you should take into consideration that the meter is likely missing a bit ofthe radiation This is due to the shielding of the radiation by the density of food and the limitations posed by the detection range
40. ng collected and will adjust automatically to display all of the data collected unless the Scroll check box is selected If the Scroll check box is selected the X axis will display the latest readings collected in the minute s time frame selected next to the Scroll check box For example if 2 minutes is selected in the Scroll time then the chart will display the latest 2 minutes of data collected The most recent data collected will be shown on the right side of the graph The Y Axis The Y axis displays the unit of measurement for the reading displayed and will automatically adjust to display the highest reading collected tpm ord Sere Ks Se sRrsetax g HAt Inspector 000000 E Observer USB Meter Screen Eemien EmetianmHei The Observer USB Meter Screen simulates a digital meter to display the readings collected by the detector 0 008 mR h enable Alarm This will enable the alarm that is built into the software Once the radiation levels go back below the set level of the alarm the averaging 10 Units om ke alarm will stop unless you have checked Latch Alarm When the Latch Alarm is checked the alarm will continue to go off until the reset button is pressed This is a USB Observer Software alarm only not the alarm on the unit itself V Echo Inspector Display Enable Alarm at Latch Alarm O3 Reset G2 Zero When the Zero
41. ofthe meter Alpha radiation can be detected on the food s surface but can be blocked if there is internal contamination You can better test food by grinding it into a paste and taking a timed count This may give an indication that you have contamination in your food though it will not qualify what type of radiation may be present in the sample Water and food can also be a shield for radiation so unless there is gamma radiation our instruments are not the most ideal without a little processing of the material in question beta and alpha will not move very far in water and will be shielded by it You can take a sample of the water and run it through a filter and test the filter or you can evaporate it down and test the swipe on an Inspector USB witha Wipe Test Plate however the URSA II with the appropriate detector would be much more efficient for this application but scintillation based instruments are more expensive than the handheld GM based alternatives Regardless most of the higher energy betas and gamma radiation that falls within the sensitivity of the detector will be measured It is important to remember to establish a background count prior to surveying your samples To do this use your Inspector in the Timed Count mode and take a background count of at least 10 minutes Then divide the total counts displayed on the unit by the number of minutes of your count For instance if you take a 10 minute timed count divide the total counts
42. ort beep indicates that enough information has been collected to ensure statistical validity Units of Measurement The Inspector is designed for use of conventional units milliroentgens per hour mR hr and counts per minute CPM or SI units microsieverts per hour uSv hr and counts per second CPS To switch between conventional or SI units choose UNITS in the Utility Menu For details see Utility Menu in Chapter 3 Display Update In the dose rate and count modes the numeric display is updated every 3 seconds In Timer mode the numeric display is updated every second Maximum level When the maximum level for the current mode is reached the Inspector beeps for 3 seconds pauses for 3 seconds and repeats that pattern Also the RANGE Full icon is displayed and the numerical values displayed will show OVER instead of the specific rate The beeping pattern and the flashing display continue until the level decreases or the Inspector is turned off Response Time Autoaveraging When the radiation level is less than 6 000 CPM the reading in any of the dose rate modes is based on the radiation detected in the previous 30 seconds In order to give a quicker response to changes when the radiation level exceeds 6 000 CPM in any 30 second period the reading is based on the previous 6 seconds When the radiation level exceeds 12 000 CPM in any 30 second period the reading is based on the previous 3 seconds Note You can choose the 3 secon
43. particular isotope The units are therefore counts per disintegration of c d Since efficiencies are generally somewhat less than one they are often multiplied by 100 and expressed as a percentage However the Observer USB software requires that values not be entered as percentages Since efficiency varies based on the energy and abundance of the particular isotope being measured it is best to determine efficiency for the specific isotope s for which the activity is to be determined The efficiency is also affected by the size of the source and the source to detector distance To achieve consistency efficiencies should be determined using a point source which means a source with an area significantly smaller than the detector entrance window at a fixed distance from the detector face which must be specified but 1 cm will be assumed to be the standard Requirements You willneed a PC running Observer USB Calibration sources an Inspector Wipe Test Plate or other constant geometry source holder to maintain sources 1 cm from the detector entrance window Procedure American Units 1 Attach the Wipe Test Plate to the Inspector Ensure the Inspector is in Total Counts Total Timer mode displaying COUNTS 2 Place the Inspector in the location where the efficiency calibration will be performed and take a count of at least 10 minutes Divide the total number counts by the acquisition time in minutes to calculate the background counting
44. rate RB in CPM Record this value 3 Center the first source to be used into the Wipe Test Holder and take a count of at least 1 minute Divide the total number of counts by the counting time in minutes to calculate the gross count rate gcpm or RG 4 Calculate the efficiency using the following equation Where Re Rp Eff is instrument efficiency in counts per disintegration Ao RG is the gross count rate in counts per minute cpm RB is the background count rate in com A is the activity of the source in disintegrations per minute dpm Eff 5 Repeat Steps 3 and 4 for additional radionuclides 6 If you would like to record efficiency values in the Inspector s memory for any of the supported radionuclides S 35 Sr Y 90 Cs 137 P 32 C 14 I 131 Co 60 ALPHA continue with the following steps 7 Connect the Inspector to the PC running Observer USB using the USB cable An application window for the Inspector should open within a few seconds 8 Display the control panel by clicking View Cal Panel 9 Enter the updated efficiencies in the appropriate fields 10 If you would like the Inspector to display in activity units i e DPM for a specific source instead of the count rate CPM select it from the Applied Isotope dropdown box Otherwise leave as None cpm cps 11 When all relevant values have been updated click the Update Settings button After a second or two the Inspector should beep twice to acknow
45. rate meter you can determine your normal background radiation levels Gamma and X Rays If there is an indication of radioactivity it is most likely gamma or high energy beta Low energy gamma and x rays 10 40 keV cannot penetrate the side of the GM tube but may be detected through the window If you perform the alpha beta test above and there is no change or only a very slight change in the indication the source is emitting primarily gamma radiation 23 Radiation Measurement Units Several different units are used to measure radiation exposure and dosage Roentgen is the amount of X radiation or gamma radiation that produces one electrostatic unit of charge in one cc of dry air at 0 Cand 760 mm of mercury atmospheric pressure One thousand milliroentgen 1 000 mR 1R The Inspector displays in milliroentgens per hour mR hr Rad is the unit of exposure to ionizing radiation equal to an energy of 100 ergs per gram of irradiated material This is approximately equal to 1 07 roentgen Rem is the dosage received from exposure to a rad It is the number of rads multiplied by the quality factor of the particular source of radiation The rem and millirem are the most commonly used measurement units of radiation dose in the U S 1 rem 1 rad Sievert is the standard international measurement of dose One sievert is equivalent to one hundred rems A microsievert uSv is one millionth of a sievert A unit of dose equivalent 1 Sv 100 ro
46. recommend the clock be set prior to collecting data to ensure a correct time and date in your collected data The unit will beep three times on start up ifthe clock has been reset To set the internal clock enter into the utility menu select CLOC and press set 1 The seconds are displayed Use the and buttons to select the seconds for the clock and press SET to select your choice 2 The time will be displayed The minutes will flash while using the and buttons to select the desired minutes and press SET You will then select the hour and press SET again 3 The date will be displayed First set the day and press SET Then select the month and press SET 4 The year will be displayed Select the appropriate year and press SET You will now see done displayed in the Utility Menu You can now select another item in the Utility Menu or press SET to enter into the normal function of the Inspector Interfacing with an External Device The USB jack on the left side of the Inspector provides an interface for use with the USB Observer Software Figure 2 10 You can use it to record the counts on a computer download the recorded data and calibrate the instrument For details see Chapter 7 Observer Software Chapter 4 Common Procedures The following sections give instructions for several commonly used procedures With any procedure the user must determine the suitability of the instrument or procedure for that application Establishin
47. rement which can be adjusted is 010 Pulse Calibration Since GM based instruments are essentially pulse counters it must be verified that the number of counts reported equals the number of counts input This should be demonstrated for both count rates and total counts The issue is confused somewhat with the addition of dead time compensation where the number of counts in any given second is adjusted upward to account for pulses lost during the time the detector is busy recharging from a pulse Requirements Calibration Panel Serial Number 000002 DeadTime sec 1 140E 04 Sensitivity cpm per mR h 3340 Applied Isotope Efficiencies counts per disintegration c 14 0 0291 S 35 0 0317 Cs 137 0 2078 P 32 0 2200 Co 60 0 1400 Sr Y 90 0 2274 I 131 0 0600 Alpha 0 0420 Update Settings Units American mR h cpm dpm Metric uSv h cps Bq Alarm cpm 334 Preset Counting Time 10 Use Datalogging Datalogging Interval min 10 Circular Buffer Clear Memory Backlight On Time 10 Contrast Darker Lighter V Auto Averaging All calibration factors must be entered using the Observer USB software You will need a PC running Observer USB and a Pulse generator Procedure 1 With the instrument powered off remove the back of the unit and attach a pulse generator to the unlabeled test point immediately to the left of U2 Pulses must be positive
48. sures alpha beta gamma and x ray radiation ionizing radiation only Its applications include e Detecting and measuring surface contamination e Monitoring possible radiation exposure while working with radionuclides e Screening for environmental contamination e Detecting noble gases and other low energy radionuclides How The Inspector Detects Radiation The Inspector uses a Geiger Mueller tube to detect radiation The Geiger tube generates a pulse of electrical current each time radiation passes through the halogen quenched tube and causes ionization Each pulse is electronically detected and registers as a count The Inspector displays the counts in the mode you choose The number of counts detected by the Inspector varies from moment to moment due to the random nature of radioactivity A reading is expressed more accurately as an average over time and the average is more accurate over a longer time period For details see Operating in Timer Mode in Chapter 3 Precautions To keep the Inspector in good condition handle it with care and observe the following precautions e CAUTION Never touch the Inspector to a surface that may be contaminated You may contaminate the instrument e Do not leave the Inspector in temperatures over 100 F 38 C or in direct sunlight for extended periods of time e Do not get the Inspector wet Water can damage the circuitry and the mica surface of the Geiger tube e Do not put the Inspector in a
49. y significant You can end a timed count by pressing the SET button while the remaining time is displayed To take a timed count follow these steps 1 With the Inspector operating set the Mode switch to Total Counts Total Timer The display shows 0 and Total in the upper left portion of the display Press the SET button on the end panel to set the time for your count You will see the hourglass and the most recent timing period used The first time you use the timer the setting is 00 10 ten minutes Use the and buttons to set the timing period The timed period can be for 1 to 10 minutes in one minute increments for 10 to 110 minutes in 10 minute increments or for 2 to 24 hours in 1 hour increments Press the SET button The Inspector starts totaling the counts it registers and the numeric display is updated each time a count is registered The hourglass indicator flashes during the timed period During the counting period if you want to see how many minutes remain press and briefly hold the SET button The display counts down from the time setting in hours and minutes to zero For example if the display shows 00 21 then 21 minutes remain At the end of the timed period the Inspector beeps 3 times and repeats the beeping 3 times The number displayed is the total count and the hourglass will stop flashing To find the average dose rate for the timed period divide the total by the number of minutes T
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