ST150 Nuclear Lab Station SPECTECH - TEL
Contents
1. SPECTECH ST150 Nuclear Lab Station Operating and Service Manual April 1996 Page 1 Model ST150 Nuclear Lab Station The ST150 Nuclear Lab Station provides a self contained unit that includes a versatile timer counter GM tube sample stand and an 11 piece absorber set The unit comes complete with a serial interface to either Macintosh or IBM compatible personal computers High voltage is fully variable from 0 to 800 volts The supply is fully regulated and controlled by the processor for digital accuracy and readout on the display Extra large LED s are used for the digital display for clear visual readout under widely differing ambient light conditions with leading zero suppression for clarity Classroom demonstrations and nuclear experiments may now be run directly from an IBM PC or Apple Macintosh compatible computers using the on line serial DATALINK built into the ST150 and the NUCLAB emulation software Counting functions may be initiated from the ST150 or the computer The software supplied produces computer screen displays of all functions including analog and digital emulation of a ratemeter Real time data is automatically transferred to the computer and stored in spreadsheet compatible files Data analysis and graphical presentation are now possible using many common spreadsheet programs bringing new techniques to Nuclear Science education An AC to DC line converter is supplied for continuous ben2. ST 150 COUNTER Size Number Rev A1 G1500 3 Date 3 22 96 Drawn by R S S Filename ST150 S01 Sheet 1 of 1 Reference Designator Part Comp Description Qnty R38 R42 A1001 Res 1 00K 1 2 R34 A4221 RES 4 22K 1 1 R11 R14 R15 R16 R17 R18 R19 AAI00 Res 10 7 R25 R28 AAI01 RES 100 2 R37 AAI02 RES 1K 1 R29 R39 AA103 RES 10K 2 R32 R41 AAI04 RES 100K 2 R20 R22 R31 AA105 RES 1M 3 R4 AA563 RES 56K 1 R24 AA182 RES 1 8K 1 R1 AARO Res 1 1 R8 R9 R10 AA202 RES 2K 3 R26 R33 R35 R36 AnA226 RES 22M 4 R30 AA302 RES 3K 1 R23 AMT3 RES 47K 1 R2 R3 R4 R5 R6 R7 A410 RES 51 6 R2AR3AR4AR5AR6AR7A AA512 RES 5 1K 10 R12 R13 R21 R27 R45 A2513 RES 51K 1 C29 CB102 CAP 001UF 1 C27 CB103 CAP 01UF 1 C15 C16 CB470 CAP 47PF 2 C2 C3 C4 C5 C6 C7 C8 C9 C10 CC104 CAP 1UF Mono 15 C11 C12C13C18 C26 C28 C17 C19 C20 C22 C23 C24 CD103 CAP O1UF 6 C21 CD470 CAP 47PF 1 C1 C30 C31 CNI00 CAP 10UF 35V 3 C14 CNIOR CAP 1UF 25 1 D1 D2 D3 D4 D5 D6 DA004 Diode 1N4004 6 D7 D8 D9 DA008 Diode 1N4148 3 LED1 LED2 LED3 DLOO1 LED HLMP4700 3 11 12 18 14 15 16 DLO02 LED LR1720R P 6 CM EC001 Conn DE9P m 1 Ji EC007 Power Jack ST350 1 Che EC018 Conn DE9P f 1 si ES005 Switch SPST 1 Ti LX001 XFormer HV 1 Man 150 Operation Manual 1 MC002 Charger 9v 115v 1 R43 PA103 POT 10K Timmer 1 RAB 11 ST150 Absorber holder 1 Q8 TA001 Trans MPSA64
3. 0 200 400 600 800 1000 High Voltage Page 7 Resolving Time Geiger Mueller tubes exhibit dead time effects due to the recombination time of the internal gas ions after the occurrence of an ionizing event The actual dead time depends on several factors including the active volume and shape of the detector and can range from a few microseconds for miniature tubes to over 1000 microseconds for large volume devices When making absolute measurements it is important to compensate for dead time losses at higher counting rates If the resolving time of the detector is known the true counting rate may be calculated from the measured rate using the following expression n m 1 mt where n is the true counting rate m the measured rate and t the detector resolving time If the detector resolving time is unknown it may be determined experimentally using two radioactive sources Maintaining constant counting geometry is important throughout the experiment A special source split into two halves is available for making the measurement but good results may be obtained by careful positioning of two standard check sources With the high voltage correctly set for the GM tube position the two sources a b side by side to obtain a count rate of at least 10 000 CPM Accurately record the countrate as R a b Remove source b and record the count rate as Ria Carefully replace source b to its original position remove source a and record the
4. 1 Q1 Q2 08 04 05 06 Q7 TA003 Trans 2N3906 7 Spectrum Techniques Inc 106 Union Valley Road Oak Ridge TN 37830 USA Tel 865 482 9937 Fax 865 483 0473 support spectrumtechniques com www spectrumtechniques com
5. TSV to indicate a Tab Separated Value file format This format allows the collected data to be directly imported into most speadsheets with the run number voltage count elapsed time and time of day information correctly separated into columns File Presets View Help 9 38 57 am Elapsed Time 30 Voltage 500 Count 430 Runs 10 In the event of a breakdown in the communication between the ST150 and the computer the link may be reestablished if possible by choosing Serial Relink from the Presets menu If this fails to reestablish communications try powering down both the ST150 and the computer to fully reset the serial port sw1 VAL C2 ci oS o2 oo VAL J1 R24 1 8k R29 4 7K C26 01 C27 01 WP1 R1 5V LM555CHC 1 Vlg 2 5V R39 10K MAX232 C2 C2 a U1 LM7805CTB C1 10uF GND 10uF C31 5V P2 5V C2 C3 C4 C5 C6 C7 C8 C9 1 1 1 1 1 1 1 GND 2 START 3 2 STOP 3 2 HV 3 2 TIME 3 2 3 2 3 C19 C20 01 1KV 01 1KV WP7 T1 S1 1 QO Di D2 A K A K WP9 1N4004 1N4004 K S2 1 VAL Q C22 1N4004 01 1KV A 5V R32 GND 100K C Q8 C 5 1K D8 D9 eo a7 R37 1N914 1N914 E MPSA64 R41 2N3906 CH 5V E 8 we TH CTS 15 bie Lae CNT 14 5 HV 13 0 Par P33 INTI P13 TIME 12 INTL 3 P32 INTO P12 TXD 11 2 1 P31TXD P11 RE P30 RXD P10 2 P27 A15 PO7 AD7 2 P26 A14 POG ADE S seid se P2513 POS ADS S F
6. count rate of source b as Rip The resolving time is given by R a R b R a b 2R a R b The resolving time of the ST150 Nuclear Lab Station is very short and is not a significant factor compared to that of the GM tube Page 8 Applications The ST150 may be used for a variety of applications some of which are listed below Surface contamination measurement Plotting a GM plateau Radiation background measurement Natural radioactivity GM resolving time Detector efficiency Radiation absorption studies Backscattering Inverse square law Isotope half life Radiation properties Counting statistics Page 9 Maintenance CAUTION Dangerous voltages can exist inside the ST150 from the high voltage power supply Before removing the cover ensure the instrument is in the OFF position and the high voltage is set to zero Only qualified technicians should attempt any repairs Your ST150 has been built with care using quality parts and should not require any routine service In the unlikely event of a malfunction the unit may be returned to the factory for repair We will gladly supply a cost estimate if the warranty period has expired A complete list of parts is included for your convenience Please contact our customer service department for pricing and availability In many instances substitute parts may be used providing they meet or exceed the original specifications Page 10 NucLab Nuclear Lab Statio
7. Lab Station Help On Help How To Run a Plateau Automatic Counting Manual Counting Operating the ST 150 Commands File menu commands Mode menu commands Presets menu commands View menu commands COUNT STOP Several different VIEW modes are possible including analog ratemeter and digital counter timer with CPM or CPS selection When counting is stopped on the ST150 either by pressing STOP or by reaching a preset time the latest count data will be transferred to the computer If a count is interrupted by clicking the STOP icon on the NucLab screen the data will be not transferred This allows a count to be interrupted and restarted without being saved on the computer To force a count to be saved as a legitimate data run press the Insert Ins key From the Presets pull down menu a number of automated data runs may be invoked by choosing Set Preset Runs After the number of desired runs is entered pressing the COUNT button on the ST150 or clicking the Count icon from the software will initiate the first count When the preset time is reached the data will be transferred to the computer the elapsed time and counter will be cleared and the next count interval will begin This process continues until Page 12 the number of entered runs have completed When all of the desired data has been collected the data may be saved to a spreadsheet compatible text file by choosing the Save selection from the File menu The extension defaults to
8. ME again HIGH VOLTAGE The high voltage setting on the GM tube may be set by pressing the H V button The current setting will be displayed The high voltage may be adjusted in 20 volt increments using the UP DOWN buttons between 0 and 800 volts To return to count display mode press H V again Page 5 Operation Basic operation of the model ST150 Radiation Counter is straightforward and intuitive First set the high voltage to the recommended value for the GM tube using the H V and UP DOWN buttons If no other presets are required press H V again to return to the count display mode Operation may now be controlled with the START and STOP buttons Pressing TIME will display the acquisition time in seconds To count for a preset time press the TIME button and enter the required counting time in seconds using the UP DOWN buttons Once set the preset time will remain unchanged unless the UP DOWN buttons are pressed again Start the count with the COUNT button The count may be stopped before the preset time is reached by pressing the STOP button Once the preset time is reached the counter will stop accumulating data At this point it is only necessary to press COUNT to restart the next cycle as the preset will automatically be restored and the count register reset to zero If the ST150 is linked to a computer running the NUCLAB software data will be automatically transferred to the computer whenever a count stops either by reaching t
9. apter Specify 110 120 220 240 VAC at time of order 10 in W x 7 5 in H x 6 2 in D ST150 Nuclear Lab PC emulation DOS program runs with or without Windows on most IBM compatible PC s Requires EGA or better graphics capability Optional Macintosh software runs under Multi Finder under System 6 0 and later and also runs under System 7 x All software provides real time display of simulated analog or digital ratemeter in CPM or CPS count elapsed time preset time high voltage setting acquisition time and run number Data is saved to spreadsheet compatible files Bi directional control offers computer control of count start stop and data transfer Page 3 Operation Page 3 CAUTION The detector window is extremely thin and fragile If broken it cannot be repaired and will not be covered under the warranty Never allow objects to touch the window General The ST150 Radiation Counter may only be operated with the AC adapter provided or with one of identical specifications The sample holder provides six positions with 1 cm separation between each for placement of radioactive sources and absorbers 11 absorbers are provided for use in radiation absorption experiments Absorbers may be placed in empty sample holder slots between the source and the detector Detectors Geiger Mueller tubes produce electrical pulses when ionizing radiation events occur within their sensitive volume For proper operation these detecto
10. chtop operation Warranty Spectrum Techniques warrants products of our manufacture against defects in workmanship or material for a period of one year from date of shipment We will repair or replace at our option any instrument that is deemed to be defective during this period This warranty fully covers all replacement parts and labor The instrument must be returned to our factory prepaid and we in turn will pay the cost of return shipping This warranty does not cover damage caused by mishandling or misuse GM tubes with broken windows are specifically excluded from this warranty Accessory items not manufactured by Spectrum Techniques but supplied as part of our systems will be subject to the original manufacturers warranty Specifications Input High voltage Display Modes Data Link Absorbers Sample holder Power Dimensions Software supplied Page 2 Built in Geiger Mueller tube 15 mm diameter 1 5 2 mg cm window 500V operating 150V plateau 0 to 800 volts digitally selectable in 20 volt increments 6 decade LED in numerals Displays counts time and high voltage Count for preset time set and view preset time and set and view high voltage 0 800v DB 9 male connector accepts RS 232 serial cable to IBM PC compatible and DB 9 female accepts DIN cable for Macintosh computers 11 piece set 6 7400 mg cm 6 position 1cm spacing Input 9 volt DC at 5 00mA from AC ad
11. he preset time or pressing the STOP button If however the count is stopped by remote control from the computer the data is NOT automatically transferred This allows a single run in a multiple run experiment to be repeated before it is stored Page 6 GM Plateau The correct operating voltage for the Geiger Mueller tube may be determined experimentally using a small radioactive source such as Cs 137 or Co 60 A properly functioning tube will exhibit a plateau effect where the counting rate remains nearly constant over a range of applied voltage Place the radioactive source close to the window of the GM probe and slowly increase the high voltage until radiation events just begin to be detected Now increase the voltage in 20 volt steps recording the counting rate at each increment The rate should remain fairly constant over a range of voltage and then increase rapidly as the high voltage is further raised indicating that the tube is entering the breakdown region Do not continue to operate the tube in this breakdown condition but reduce the high voltage and make a plot of the counting rate versus the applied voltage The recommended operating voltage may now be determined as the center of the plateau region In the example below note that the plateau extends from approximately 350V to 600V A reasonable operating voltage in this case would be 500V GM Plateau 6000 5000 4000 3000 Counts 2000 1000 0
12. n Software for IBM PC Compatibles Your ST150 Radiation Counter is supplied with a computer communication and control software package named NUCLAB Command and data are transferred via the standard RS 232C serial port and require connection to the computer s COM 1 or COM 2 port NUCLAB allows counting control of the ST150 from either the front panel buttons or the computer system To run NucLab insert the program disk supplied into drive A type A NUCLAB and the following screen will appear File Presets View Help Select COM port Select the appropriate COM port and continue The COUNT and STOP controls on the ST150 front panel are repeated on the main NucLab screen and will remotely control those operations on the unit Other features of the software are invoked from their selection within the menu system Features and menu selections are made by clicking on the selection with a mouse or by pressing the key corresponding to the underlined character in the selection Page 11 NucLab contains an on screen help menu for guidance through the basic operations The Help system provides hypertext allowing topics to be quickly accessed To invoke the Help system choose Help Contents from the Help menu bar selection Click on any highlighted text to see an explanation of the feature Highlighted text may also be selected by pressing TAB until the desired selection is indicated File Presets View 9 50 50 am Help ST 150 Nuclear
13. ore Pz4Al2 PosaD4 FE Ai 3 P23 A11 P03 AD3 38 a Zl P2210 Poz aD2 FT Ama 52 P21 A9 POt AD1 3 P20 A8 POO ADO PSEN 29 ALE 30 PSE 31 GND 9 18 19 x1 12MHz 47 47 C15 C16 anD C17 01 1KV D3 D4 D5 A K A K A K 1N4004 1N4004 1N4004 C23 C24 01 1KV 01 1KV 10K GND 1 00K LR1 R2 720R DS6 STOP START SA3 SA2 SA1 SAO AD7 AD6 ADS AD4 AD3 AD2 AD1 ADO C14 1UF R34 U10 C MC3405P 2N3906 5V AO Al A2 A3 A4 A5 A6 A7 AB8 AB9 AB10 5V ABTI AB12 ALE ADO AD1 AD2 AD3 AD4 AD5 AD6 AD7 Al WR GND LR1720R 74LS373 13 SN74LS32N 10 8 9 ADO AD1 AD2 AD3 AD4 AD5 AD6 AD7 3 3M R26 R33 22M R38 C28 R46 74LS374 GND 2N3906 11 12 13 15 16 17 18 19 LR1720R 2N3906 U2 D se 74LS04 WR SN74LS32N 2 3 1 A0 9 ADO ADO AD1 AD1 AD2 AD2 AD3 AD3 AD4 AD4 AD5 ADS AD6 AD6 AD7 AD7 2 AO 5 Al 6 A2 9 A3 12 A4 15 A5 16 A6 19 A7 U2 F D gt O 12 74LS04 2 TLED 5 6 9 12 15 16 19 C21 47pF 1KV 47K D7 1N914 TB1 SIG GND GM 15 13 12 GND 11 ADO 10 a Ts AD2 T4 Ar TLC7524CN LR1720R LR1720R LR1720R 2N3906 51 5V DS3 DS1 74LS04 U2 B 74LS04 U2 C 74LS04 74HC374 5V 100 74LS04 D EE GG O OS Changed R22 22M gt gt 3 3M 5 2 02 Added R22A lt 5 1M gt 5 2 02
14. rs should be run at a predetermined operating voltage specified by the manufacturer or derived empirically To improve sensitivity to alpha and beta particle radiation many GM tubes have extremely thin entrance windows which require considerable care in handling Do not allow any object to come in contact with the GM tube mounted in the top of the sample holder T h e ST150 includes a fully adjustable high voltage power supply to cover a wide range of applications The high voltage level may be displayed on the digital readout by pressing the H V button once Adjustments to the high voltage may then be made in 20 volt increments using the UP DOWN buttons To return to count display mode press H V again Page 4 Operating Modes and Controls COUNT This is the normal operating mode where the display registers the number of radiation events detected by the GM tube Before starting a count a preset time may be entered using the TIME and UP DOWN buttons To begin the count interval press the COUNT button Any existing count and elapsed time will be automatically cleared If a preset time has been entered the unit will count until the preset time is reached STOP This button will stop the current count TIME If the operator wishes to count radiation events for a predetermined time a preset time may be entered by pressing TIME and entering the required counting time in seconds using the UP DOWN buttons To return to count display mode press TI
Download Pdf Manuals
Related Search