User Manual
Contents
1. g p gR52_ AHU10 cse39V TIOA 8 8 _ 8 a C UU X X cas 5 m N T 20 8 0 5 Sana D RS9 R57 2 6 37 2 Q5A R47 R49 R44 lt 25 c34 Fa SN CD uA U3A 04 0144 0 2 R35 3 J 15 A 20 U1A C31 8 2 33 gt 18 R25A ces OSC Gage ae eee um R37 202 R33 C32 CAIN 822. CNV C k 38690709 _ AQ ihe Lhe gt air the ake _ 518 osasi 15 o4 eb ob eb abe ole 918 gts Ses fat ATs u Sire STs 32019 9 i x fox ay 2 1 3 8 5 2 3 lt 1 55 S 2 2 arin oa 8 AVTASIO EZTI i 1802205 081 898N 915 lo 2 sive HES p roua 6 3 asa a LS 855 7 39 21 oy vein
3. 28 WING 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 REM 500 INSTRUCTION MANUAL DESIGN QUAN J J2 J4 TP1 2 1 1 ay N H N H lt O XO lt 1 gt Q gt Q S 22 IN ox O NS LS i gt SN PART NO CHR26G ND
4. z z Jen Nph 3 olal 848 3 a 1148 1 lt gt 25 823218 ade 558 2 8 8 0 GEN SY nggal vy 3 z a 1531 ete WNT 1504 Wy pao 5 AR 258 ay n z L 40132130 OL er lt 1 27 A ole 3104 2253 158 5 1 NN9IS OL93130 OL 795 M o t0 TF na WHBINA o g D 2 sio 555 7 za s ante Ps tdl 2 1 15990 35 REM 500 INSTRUCTION MANUAL
5. hse Se 12 CALIBRATION MODE 13 CALIBRATING 16 RADIOACTIVE MATERIAL INSIDE DETECTOR 18 XIX MAINTENANCE MODE 19 CIRCUIT DESCRIPTION 20 ELECTRONIC ADJUSTMENTS 23 XXII TROUBLE SHOOTING 5 25 QUALITY 56 26 XXIV PARTS LIST ee ae A Re a ee 27 XXV PARTS LOCATION AND SCHEMATICS 31 REM 500 INSTRUCTION MANUAL ii SPECIFICATIONS MECHANICAL DETECTOR OPERATIONAL Size 12 L x 4 5 W 4 5 H excluding handle handle extends height to 6 25 Weight 5 165 2 oz including alkaline batteries External Controls 5 pushbutton switches for POWER ON OFF MODE AL TERNATE RESET and LIGHT Internal Controls Cal and Reset pushbutton Coarse Contrast Pole Zero High Voltage and LLD trimpots Type Sealed Spherical TE Proportional Counter Rossi Type 2 1 4 ID Wall Material A150 Conducting Tissue Equivalent plastic Wall Thickness 0 12 cm 144 mg cm Aluminum can 065 Filling Gas Propane gas 2 micron Internal Source Less than 1 uCi Cm244 Readout Alphanumeric 2 line x 16 character LCD Range Autoranging from 001 mREM h to 999 REM and 001 mRAD h to 999 RAD h rate and 001
6. L 4 5403120902 WOW was 1 SPOJDJOJD LU U 210 sioyl9Dpdpo 210 04 T 000 L a SPDADJOIIW 34D 540 48 558 92 1 ot uss zeeen Tsou te ge SuuuO Ul 8 0151894 V els 2 310 gt T 136 011 838 7 lz Nesen 202 S gt XW ce TER gp tee w Ts sp eee T 258 4 aan 555 238 VO SSR x 555 15 2 853 AlddNS AH 2 ays 2 2526 26 4 2 4 Be ge a rde SoH ase 8 gt won z lt T o ges pes 225 m 2 27 ols 2 asso 87 an WNO NA so aLa 1 se 1 Sys 8 5 20 avegercg 122 8 ven 235 2 8 gt 918 A e Te 04990802 201 5 gt g amp ob 1 5 378 828 5 w 5 51258 ge 855 19 888 823 1 1 5 4 mee aN er a 2
7. JNEXT from the Rate display This display is continually updated The upper left shows the time that the MCA has been run ning It displays the time in HRS MIN SEC and will go as high as 18 hrs 12 min 15 seconds before it rolls over to zero and continues to count up again The OCT upper right corner shows the number of events that have been counted the NEXT RST RUN came as in the integrate range The buttons are relabeled with the names Figure 3 MCA is stopped Shown in the display The abbreviations stands for CHECK and Right button is marked turns on and off the source inside the detector Push it once to turn on RUN 00 00 00 source Push it again and the source will turn off If the MCA is not run ning then there is no visual indication that the source 15 on or off NEXT CK NEXT RST STP will return to normal rate display RST Resets the MCA by clearing all the channels time and counts RUN and are the same button When running Note the MCA is stopped the button says RUN indicating that pushing it will how right button has changed to STP start it running If the MCA is running the button says indicating that pushing it will stop it All of these operations are duplicated in the RS 232 serial link See the fol lowing section on SERIAL COMMUNICATIONS section for more details on this link REM 500 INSTRUCTION MANUAL 10 XIV SERIAL COMMUN
8. 1 1 a gt 5 w w a dus r 13 208 prian Saw 8 0 4 aay 5 on 8 n f 5 740 9119 s a 48 QL e aHa er 35 1 55 th i I 238 5 A W 15 4 9119 zn 4 uzyu 365 an F L 98 59 s oR NY OHYLNS 53 Fe 5 ven van
9. eee 2 skg red s 815 3 els ols 4 s et x 88 3 9 _ 2 258 21114 ezn E ES 599 12 a 5 g a 4 u on e azin 59 weg 599701 sin 366 ce 1 mM HA vo 3 ASIMIALYO ssajun lt 210 03 NP OHYLNS gt SPDADJOIDIL B4D S10 190dD9 49 0009 8 Sas weep 20 AVS IO _ 21 Ul 510351894 a n NZ OHy NS 53103 y 8 een NPQOHPLNS NZ OH NS i lt FZ 20 sen vane 1 2 ms 111141 13638 340 5 44410 0000 2 OL 5 E ES A ee r
10. 19 23 lt 18 19 37 23 ne 34 REM 500 INSTRUCTION MANUAL SCHEMATICS SOTVNV 21 V Add 100 1 Te ol elu _ OLLWINSHOS eee ee epo l 38260709 wool YESH ova b a 5 ss un
11. 232 4 000 2 3 6864 2 LEXAN 6 32 x 5 8 6 10 32 x 1 2 6 32 x 3 8 6 32 1 6 32 x 1 6 32 x 1 4 6 Int Star 6 32 x 3 4 FF DESCRIPTION Connector Connector Connector Elect romagnet Connector Connector Connector FET FET FET FET FET FET Resistor Resistor Resistor Resistor Potentiometer Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor network Resistor network Switch tiny Switch tiny Switch Switch Switch Switch Switch Switch Stake Stake Stake Microprocessor 8 bit Octal D F F EPROM RAM 1K x 8 Op Amp LCD alphanumeric Quad AND Quad Nor gate Hex inverter 3 to 8 Decoder Dual Flip Flop Voltage Detector Hex Inverter 5 V Regulator T0220 PIA Interface EEPROM Volt Converter Volt Converter UART Volt Conv RS232 Crystal Crystal HANDLE Top Plate Switch Panel Shield Analog Bd WINDOW GASKET SWITCH DIGITAL CIRCUIT BD CIRCUIT BD ANALOG PCB FRONT PANEL LCD DISPLAY Cable Ribbon Cable Ribbon Cable Ribbon Screw Pan Phil PS Washer Nylon Screw Pan Phil PS Screw Set SS Spacer Angle Spacer Hex Screw PAN PH PS Lockwasher Spacer Angle MFG CW Ind Molex Molex Magnet Sal CW Ind Molex CW Ind Panasonic CTS CTS Panasonic Panasonic Panasonic Panasonic Pa
12. pane CHAN CNTS chan 2 256 for channels is derived from smoothing of values ranges from 1 to 24 8 K is the Calibration Factor If you wish a different QF then please consult HPI The RAD display is thus the same as the REM except for the Quality factors The average quality factor can be derived by dividing the REM reading by the RAD reading REM 500 INSTRUCTION MANUAL 12 2 DETECTOR The detector is a spherical tissue equivalent proportional counter which measures the absorbed dose in LET actually P Y spectra It is based upon the design orig inated by Rossi using a spiral grid over the electrode for uniform collection char acteristics The detector is housed in an aluminum shell which serves as a vacuum tight hous ing The housing is filled with propane gas which allows the spherical detector to simulate small tissue volumes of approximately 2 micron diameter An internal Cm244 alpha source is mounted to allow the alpha particles to tra verse the diameter of the sphere in the CHECK mode The energy deposited by the alpha particle is considered to be 90 Ke V u Therefore by adjusting the system to place the peak into channel 90 the pulse height of the interactions will corre spond to the energy deposition Ke V u When the instrument is placed in a neutron field the interactions with the neu trons will cause a recoil proton to traverse a portion of the
13. 15 C16 C17 C18 C19 C20 C21 C22 C23 C24 C25 C26 C27 C28 C29 01 02 4 05 06 D07 D08 50KX 00KX 681X 20 0K 0 2000 511 2 7 OOKX 000 299 10M 00 00 00 0K 01 15 300KX 00 Sous gt gt XO O XO VO WO 5 828 OR 00 0K 500 072 072 ND 072 ND 072 ND 072 ND 072 ND LO64CN LO62CP D4066NCN DCO804LCN M393N D4013BCN 11 CD4098 3852 CM7556IPD TLC27 LCP 4094 P106 12 5 581 4 7 10 21RD747 21RD722 1 1 14 lt lt lt lt lt lt lt DW104 DW104 00 10 3 10 DW104 DW104 DW104 DW104 DW104 DW104 DW104 DW104 DW104 7M16 7M16 7M16 7M16 7M16 581 47 16 2180710 21RD710 581 10M 581 10M 581 10M 581 10M 1N4148PH 1N4002G 1N4148PH 1N4148PH 1N4148PH 1N4148PH 1N5817 1N5817 I GQGQGGGGGGWHEGGG 0101010101 OO 1 1 Sos Oooo MOX 300 1000M DW104M lt lt 5 9 9 9 9 9K 9 9 9 9 44 44 44 44 44 44 1064 1062 066 080 LM 393 4013 4098 LM 385 CL766 TLC271 CD4094 1 1 1 1 1 1 1 1 Piezo 47 pF
14. OPERATIONS AND REPAIR MANUAL MODEL REM 500 NEUTRON SURVEY METER INCLUDES SECTION ON MCA OPTION September 1998 Revision A The REM 500 contains a small check source Please read the section on Radioactive material health physics instruments 330 D South Kellogg Ave Goleta CA 93117 Tel 1 805 967 8422 REM 500 INSTRUCTION MANUAL TABLE OF CONTENTS SPECIFICATIONS ege hee eh vs kusi pa SE W ER SE L INTRODUCTION 1 STARTED 1 MODES 2 TV CHANGE L 66 Oa pun Be 3 V BUTETONS fess isi a Q a Gel Sd 5 VI OVERFLOW AND RADIATION LEVELS 6 VIL SHOCK Se eal b 2 hee ed Gs 7 VITELOW BATTERY 2S aus ate ayay ee ee 7 BATTERY REPLACEMENT gt eraco es ee ee 7 Xe FAILURES t esa Ee as Me Oe 8 STATISTICS AND 5 8 MODE wis 3 SS pu DS 8 MULTICHANNEL ANALYZER MODE 9 XIV SERIAL 6 10 PRINCIPAL OF OPERATION 11 ELECTRONICS SOFTWARE 11 2 DETECTOR
15. 22 pF 100 BS SS Re E O 1 41 41 4 4 4 N4148 N4002 N4148 N4148 N4148 N4148 Schott Schott nm nm ohm ohm ohm ohm ohm ohm ohm re 4 Z 5 BE 50 lt lt lt lt 00 ohm 1 4 7 uF 10V V lt lt lt lt lt lt lt lt lt lt lt lt lt lt lt P 99 99 99 cO Alkaline DC DC DC DC DESCRIPTION Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Pot 3 4 Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Transformer Stake test Stake test Stake test Stake test Stake test Stake test Quad op amp Dual op amp Switch qua A D Conv 8 Dual Compar Dual D Flip 2 5 V Refer Dual Timer Op amp Shift Regis Battery Buzzer Capacitor Capacitor Capacitor Capacitor Capacitor Capacitor Capacitor Capacitor Capacitor Capacitor Capacitor Capacitor Capacitor Capacitor Capacitor Capacitor Capacitor Capacitor Capacitor Capacitor Capacitor Capacitor Cap
16. 233 248 QF 37 165 233 248 QF 40 OF 166 234 248 QF 42 168 QF 234 QF 248 QF 45 315 QF 170 80 QF 235 3145 248 210 47 171 235 248 50 172 236 248 52 173 236 248 54 QF 174 238 248 57 20 176 85 238 150 248 215 58 177 OF 238 QF 248 QF 61 178 QF 239 248 QF 62 QF 179 QF 239 248 QF 64 182 240 QF 248 QF 67 25 QF 183 90 240 155 248 220 69 184 240 QF 248 72 186 QF 241 QF 248 73 187 241 QF 248 75 188 243 248 78 30 QF 189 95 243 160 248 225 80 191 243 QF 248 QF 82 QF 192 QF 244 QF 248 84 193 244 248 QF 87 QF 194 QF 244 QF 248 QF 88 335 QF 196 200 QF 245 3165 QF 248 230 QF 90 QF 197 QF 245 QF 248 QF 93 198 245 248 94 199 246 248 97 200 246 QF 248 99 40 QF 202 105 246 170 248 235 QF 100 QF 202 QF 246 _ 103 203 248 i 105 QF 204 QF 248 OF 248 106 QF 205 QF 248 OF 248 109 45 207 110 24
17. REM 500 INSTRUCTION MANUAL 16 XVII CALIBRATING THE INSTRUMENT The instrument is easily calibrated There are two stages to the calibration The first is to adjust the high voltage so the channel numbers correspond to known The second stage 18 to expose the instrument to a calibrated neutron source to set the overall sensitivity of the instrument REQUIRED Calibrated neutron source Both stages use the calibrate mode Please read the previous section on how to en ter in the calibrate mode The first stage of the calibration is the adjustment of the high voltage This is accomplished by 1 Enter the Calibrate mode You will be in the High Voltage Adjust display See section XVI for instructions on how to enter the Calibrate Mode 2 Wait about 15 to 30 seconds for the high voltage to stabilize 3 Push RST button to restart the peak calculations 4 Wait 30 seconds to 1 minute for the peak to stabilize 5 We want the peak to be in channel 90 If it is not in channel 90 then it is neces sary to change the high voltage If the peak is below channel 90 then it is neces sary to raise the high voltage and if it is above channel 90 it is necessary to lower the high voltage You should set it to channel 90 3 channels Raising the High Voltage Factor by 1 will raise the peak about 1 2 channel Repeat steps 2 3 4 and 5 over until the peak is on channel 90 3 channels When you are satisfied with the reading
18. 4 6 32 x 3 8 6 32 x 3 8 4 40 x 1 4 0 32 x 1 4 26 pin 26 pin 26 pin 26 pin 26 pin 26 pin 4 pin 42 26 conductor 6 long 10 26 conductor 10 long conductor 3 long DESCRIP Spacer Screw Screw Spacer Spacer Lockwas Nut He Screw Spacer Spacer O ring Screw Spacer Screw TION Rnd Pan PH PS Pan PH PS Nylon Rnd her Int Star x PS Pan PH PS Button Hex Rubber Pan PH PS Rnd Pan Nylon Nut Nylon Bracket Bottom Magnet Bracket Cover Preamp Gasket Ball Pl Ssrew Lockwas Screw Spacer Screw Nut He Nut He Lockwas Screw Screw Screw Screw Nut He Lockwas Spacer Washer Screw Cable Screw Screw Screw Socket Socket Socket Socket Socket Socket Box Battery top Box Battery Bottom Batt End Plate Bottom Battery Cover Can Housing Top Preamp PCB Detector Detector Elect romagnet ungers Thumbscrew Cap Pan PH PS her Int Star Pan PH PS Hex SHCS SS Battery Contact x PS x PS her Int Star Pan Sealing CS PH 100deg 55 Set SS x PS her Int Star Hex PS Set SS SIP Pan PH PS Pan PH PS PHCS SS Connector Connector Connector Connector Connector Connector Terminal Housing Pins for housing Cable Cable Cable Ribbon Ribbon Ribbon MFG Jo Jo Jo Jo Jo nnson nnson nnson nnson
19. VDC Capacitor mono Thomson REM1 00 581 UDW104M 41 21 550 Capacitor mono Thomson REM1 00 581 UDW104M 1 uF 50 VDC Capacitor mono Thomson 1 00 581 UDW104M 550 VBC Capacitor mono Thomson 1 00 581 33 10 33 uF 10 VDC Capacitor tant Thomson 1 00 581 UDW104M 1 uF 50 VDC Capacitor mono Thomson 1 00 581 UDW104M 1 uF 50 VDC Capacitor mono Thomson REM1 00 581 33M10 33 uF 10 VDC Capacitor tant Thomson 1 00 581 10 10 0 uF 10 VDC Capacitor tant Thomson 1 00 581 10 10 0 uF 10 VDC Capacitor tant Thomson REM1 00 1N4148PH N4148 Diode Philips REM1 00 1N4148PH N4148 Diode Philips REM1 00 1N5812 N5812 Diode HP REM1 00 1N5812 N5812 Diode HP REM1 00 FR107 ND Fast Rec 1000 VDC Diode DI REM1 00 CHS10G ND 0 Pin HDR 1 1 Connector CW Ind 1 00 WM1105 093 Terminal Molex REM1 00 WM1105 093 Terminal Molex REM1 00 CHS26G ND 26 5 Connector CW 1 00 CHR10G ND 0 Pin RA Connector MT CW Indust REM1 00 2N4416A 2N4416 FET GE 1 00 2N4416A 2N4416 FET GE 1 00 4250 2N4450 Transistor National 1 00 VN10KM N PWR FET Siliconix 1 00 VN10KM N PWR FET Siliconix REM1 00 MOX 300 1000M 000 ohm 5 Resistor Victoreen 1 600 MOX 300 250M 250M 5 Resistor Victoreen REM1 00 MOX 300 1000M 000 ohm 5 Resistor Victoreen REM1 00 MOX 300 1000M 000 5 Resistor Victoreen REM1 00 299 10M 2 ea 10M 5 1 8W Resistor REM1 00 47 5 47 5 1 Resistor REM1 00 2 00KX 2 00 1 Resi
20. a reasonable accurate reading the number of counts needs to be at least 10 It should preferably be around 100 and for more accurate analysis it should be around 1000 This is the reason for the different time constants In high radiation areas the time constant may be any setting but the lower TC of 10 sec would probably be sufficient if the counts are high enough Obviously as the radiation level decreases the time constant should be increased to 30 or 60 sec onds to give more time to accumulate counts to obtain better statistics The inte grate range can be used for any radiation level but it is really ideal when looking at very low levels CHECK MODE The Check mode of operation is used to determine the quality of the detector and to check the operation of the instrument It can be used as an operational check To get in to the Check mode from normal operation push MODE 1 Inside detector is a small Curium alpha source When Check mode the curium source radiates a small stream of alphas across the center LFTPK RT NEXT Wao 090 100 4 of the detector These events simulate a neutron event in channel 90 of the instrument In the Check mode the instrument operates as a multichannel analyzer and dis plays the peak PK channel number as well as the left LFT and right RT half max channel numbers It updates the display every second Pushing the ALT but ton will reset the MC
21. instrument on Keep holding the LOCATION OF CAL PUSHBUTTON ALT button down letting it go even for a mi The Cal Pushbutton is located on the right hand side of the instru crosecond will enter normal operation In ment on the display board To access it remove the four screws on the top plate Be careful of the wires The Pushbutton is pushed from 10 seconds the Calibrate Mode will be dis above played If this does not work then instru ment has been programmed to not enter the Calibrate Mode from the front panel and it will be necessary to open the case and enter the mode by method 1 The first display is the High Voltage Adjust display This display allows you to change the high voltage which changes the peak If the peak is below 90 PK 090 HF 130 then raising the high voltage will raise the peak Likewise if the peak is UP DN SAVE RST above 90 lowering the high voltage will lower the peak The top line This is the first display of shows the peak PK followed by the High Voltage Factor HVF The 51 disp i High Voltage Factor is proportional to the high voltage It is displayed in Although the display does not Stead of the actual high voltage Raising it will raise the high voltage and show any down arrows indicat conversely lowering it will lower the high voltage ing the keys they are assumed to be there In this mode all of
22. its operation and use ll GETTING STARTED The instrument is very easy to use There are only 5 controls across the top of the instrument All of the controls are push buttons To turn the instrument on push the ON OFF button The instrument will first do a self test and wait until it stabilizes The countdown shows how much longer to wait and also shows that the instrument is functioning REM 500 10 SELF TEST TURN ON DISPLAY When the instrument is finished with the opening display it goes into nor mal operation It may show a small amount of radiation on the first display You will notice in the upper right hand corner a countdown of seconds When it gets to zero it displays the next reading and then recycles The lower left of the display shows the time constant in seconds The lower right shows the number of counts acquired during the time constant period 000 mREM h 9 10 Changing from to is very easy just push ALT button Each time it is pressed it changes from RAD to or from ON OFF MODE ALT RESET LIGHT REM to RAD It just alternates back and forth between If you having difficulty seeing display because you are in dim light pushing the LIGHT button will turn on the display backlight for 15 seconds FRONT PANEL To freeze the display push the RESET button The word HOLD will appear in the upper right hand corner of the display The readin
23. lines of 5 digits This is the counts for each channel The counts are from 0 to 65534 65535 is the maximum count even if the counts are more than this There 18 overflow indication other that keeping the count at the maximum value next is a line of counts and time counts are in HEX and are total counts of all channels This is 6 hex digits The time is in HR MIN SEC This line is the same as sent every second when the MCA is running XV PRINCIPAL OF OPERATION The Instrument is basically a 256 channel multichannel analyzer or MCA with a dedicated program coupled to a Tissue Equivalent Rossi type spherical propor tional counter 1 ELECTRONICS SOFTWARE In normal operation the instrument gathers the pulses from the detector measures their height counts them and stores them according to their height and then cal culates the correct REM or RAD Every 10 seconds it goes through this routine and every 10 second interval is separate In the rate mode it uses 1 3 or 6 de pending on the TC of these 10 second intervals for the total value In the integrate mode it just sums the results of each 10 second calculation Thus every 10 second operation is the same regardless of the mode or the time constant The display is derived from the formulas For a 10 second integration period where TC for 10 sec 3 to 30 sec 6 for 60 sec and 360 for integrate 63 CHAN x CNTS chanx QF REM K x 256
24. sphere The neutron collides with a nucleus and is scattered with a loss of energy which appears as the kinetic energy of the recoil nucleus In tissue elastic scattering is the dominant neutron interaction in the energy interval 10 KeV to 10 MeV 1 the sum of the ki netic energies of the participating particles remains constant before and after the interaction The average neutron energy loss will be one half for a collision with a hydrogen atom In interactions of neutrons with energies below 10 KeV a recoil proton in tissue no longer has sufficient velocity to ionize matter and will not be efficiently de tected The lowest detection level for the instrument is set at channel 5 Pulses be low this value are considered to be gamma ray interactions or spurious noise pulses For neutrons with energies above 10 MeV inelastic scattering and nuclear interac tions become important For these high energy events the spherical detector re produces the energy loses that would occur in a single tissue cell from such high energy interactions LET distributions from neutron fields interacting with tissue have been studied extensively Proton recoils from neutrons of energy 10 KeV to 1 MeV have a maximum LET of about 85 90 KeV u This maximum LET occurs near peak of the Bragg Curve The LET of proton recoils from neutrons with energies above 1 MeV gradually decreased in such a manner that at a neutron energy of 20 MeV the LET has decreased to 5 K
25. the Time Constant or TC and the display contrast Pushing the buttons un der each one changes the corresponding item For example pushing the 104 button would change the TC from 10 to 30 Pushing the DISPL but ton would change the contrast 1 level moves you to the next dis play as shown below LEVEL 3 MENU This is the Check menu that only allows you to go into the check or MCA mode Pushing the button changes into the Check menu Pushing the button if installed changes into the MCA menu The 14 button returns you normal operation MCA will show only if the MCA option is installed CHECK MENU This is the Check menu The numbers under the LFT PK and RT will be calculated the numbers shown are Just for reference See the Check sec tion for an explanation of Check returns you to normal LFTPK RT NEXT 080 090 100 4 tion A detailed discussion of the function of each key 15 discussed in the Buttons section 00 00 00 0CT MCA MENU This is the Multichannel or MCA menu This mode allows the instrument to gather data and then download the data to a computer on an RS232 serial link The remote computer can also control the operation of the MCA See the MCA section for a complete explanation of the MCA LNEXT returns you to normal operation REM 500 INSTRUCTION MANUAL 5 V BUTTONS There are 5 buttons on the front of the instrumen
26. whose LCDLED end now goes toward VBAT because of pullup resistor R14 This turns on 1 on the display board which turns on the LCD lamp Pin 24 and PA4 Pin 25 are not used and are pulled up using RN2 PAS Pin 26 controls the CS or Chip select input on the EEPROM PA6 Pin 27 controls the SK or clock input on the EEPROM Pin 28 controls the DI or Data Input line of the EEPROM PBO Pin 29 receives the DO or Data Output line from the EEPROM PB1 Pin 30 is the input from the CAL switch on the front panel PB2 Pin 31 is the input from the low battery detector 12 PB3 Pin 32 is the input from the LIGHT switch on the front panel PB4 Pin 33 is the input from the RESET switch on the front panel PBS Pin 34 is the input from the ALT switch on the front panel PB6 Pin 35 is the input from the MODE switch on the front panel All the switches are normally high because of pullup resistor network RN2 The four pushbuttons S3 4 5 amp 6 are all also connected to D3 4 5 amp 6 When any of the pushbuttons are pushed it grounds RSTC through the diode RSTC is an interrupt input to the microprocessor REM 500 INSTRUCTION MANUAL 22 Pin 37 is the LSB of the R 2R ladder network used to generate the voltages for the LCD contrast 1 Pin 38 16 bit 1 of the R 2R ladder network used to generate the voltages for the LCD contrast PC2 Pin 39 is bit 2 of the R 2R ladder network used to generate the voltag
27. 0 33 uF 10 VDC Capacitor tant Thomson 1 00 581 10 10 0 uF 10 Capacitor tant Thomson REM1 00 581 10M10 0 uF 10 VDC Capacitor tant Thomson REM1 00 P3102 001 uF 50 VDC Capacitor film Pansasonic 1 00 P3103 01 uF 50 VDC Capacitor film Panasonic REM1 00 P310 00 pF 50 VDC Capacitor film Panasonic REM1 00 P3103 01 uF 50 VDC Capacitor film Panasonic REM1 00 P310 00 pF 50 VDC Capacitor film Panasonic REM1 00 P3104 1 uF 50 VDC Capacitor film Panasonic REM1 00 581 UDW104M 1 uF 50 VDC Capacitor mono Thomson 1 00 581 UDW104M 1 uF 50 VDC Capacitor mono Thomson REM1 00 21RD722 22 pF 50 VDC Capacitor mono 1 00 2180710 0 pF 50 VDC Capacitor mono REM1 00 581 0 2102 001 uF 50 VDC Capacitor film Thomson 1 00 681 680 pF 50 VDC Capacitor film anasonic 1 00 21RD610 00 pF 50 VDC Capacitor mono 1 00 581 UEZ103K 1 01 UF 150 VDC Capacitor mono Thomson REM1 00 581 UEZ102K 001 uF 50 VDC Capacitor mono Thomson 1 00 581 UEZ102K 001 uF 50 VDC Capacitor mono Thomson 1 00 21RD610 00 pF 50 VDC Capacitor mono 1 00 581 47 16 47 uF 16 VDC Capacitor tant Thomson 1 00 581 UEZ102K 001 uF 50 VDC Capacitor mono Thomson 1 00 6103 01 uF 600 VDC Capacitor film Panasonic REM1 00 581 33M10 33 uF 10 VDC Capacitor film Thomson 1 00 581 UDW104M 1 uF 50 VDC Capacitor mono Thomson 1 00 581 UDW104M 50 VDC Capacitor mono Thomson 1 00 581 UDW104M 1 uF 50
28. 100 but it is adjusted differently for each instrument CALIBRATE FACTOR dis play is for changing the over Ty this mode all of the buttons except the ON OFF button are redefined MODE button becomes JUP and the ALT button becomes JDN They work by raising and lowering the Calibration Factor Each time the LUP is pushed it raises the factor by 1 Each time the J DN is pushed it lowers the factor by 1 Holding the buttons down will do nothing To raise the fac tor by 10 it is necessary to push the LUP button 10 times The RESET button becomes SAVE button and will put the new Calibration Factor into the permanent memory of the instrument and then go to the Calibra tion Select display Until this button is pushed the calibration factor is not changed inside the instrument Turning the instrument off and on will restore the original value After setting the calibration factor to the correct value in the dis play push SAVE The LIGHT button becomes JUP button or Preset button This presets all the permanent values into the instrument It sets the Calibration factor to 100 the time constant to 10 seconds the display to the middle of its con trast range the high voltage to its nominal value and the Calibration Select to ON enabling the front panel calibrate button Push it to set all these values to these levels CALIBRATE SELECT The next menu that will appear after pushing is the Calibrate
29. 2 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 023 023 023 023 023 023 023 023 023 023 023 023 023 023 023 023 023 023 023 023 023 023 REM 500 INSTRUCTION MANUAL DESIGN QUAN PART NO M23 M24 M25 M26 M27 M28 M29 M30 M3 M32 M33 M34 M35 M36 M37 0 M02 M03 M04 M05 M06 M07 M08 M09 M10 M11 M12 M13 M14 M15 M17 M18 M19 M20 M21 M22 M23 M24 M25 M26 M27 M28 M29 M30 M31 M32 M33 M34 M35 M36 M37 M38 P1 P2 P3 P4 P5 P6 P7 7 1 W2 W3 4 4 4 4 4 4 4 5 5 2 2 Q Q2 OY Q O S gt gt IN G J246 J230 313 1437 014 REM1 026 J178 J168 REM1 005 REM1 006 REM1 011 REM1 010 REM1 008 REM1 013 REM1 014 REM1 009 REM1 003 REM1 0041 REM1 LET REM1 028 99 600 9 REM1 028 S 6 32 x 1 4 313 6487 020 REM1 025 4 CKC26G ND CKC26G ND CKC26G ND CKC26G ND CKC10G ND CKC10G ND WM2002 WM2200 R025 ND R020 ND R025 ND TYPE 6 32 7 8 6 32 1 8 2 56 3 8 4 1 8 6 x 7 16 2 2 56 6 32 x 3 4 Nylon 6 32 x 1 2 1 8 x 18 6 32 x 3 8 6 x 1 8 4 40 x 1 2 4 40 Neoprene 12VDC 6 6 32 x 1 4 6 6 32 x 1 4 6 32 x 3 8 6 32 x 3 8 6 32 0 32 10 6 32 x 1 4 4 40 x 1 2 0 32 x 1 2 0 32 x 5 16 4 40 4 4 40 x 5 8
30. 785 x 1000 which is 67785000 UREM h which is 67 785 if the instrument was in the rate mode reading REM In the MCA mode the serial link allows complete control of the MCA The instru ment must be in the MCA mode for this link to function The commands are sin gle characters except for the D command and are as follows RESET This will reset the MCA and all data time and channels This is the same as pushing the RST button 5 STOP This will stop the MCA This is the same as pushing the STP button GO This will start the MCA This is the same as pushing the RUN button C CHECK This will turn on the check source in the detector if the source is off and turn it off if it is on This is the same as pushing the CK button D This will dump the channel data on the serial port A character is needed after the D to actually send the data i e it needs two characters to dump the data a D followed by any character The instrument automatically stops before dumping the data In addition when the instrument is running in MCA mode it will send the follow ing line every second 6 hex digits of counts followed by the time in HR MIN SEC These values are the same values as shown on the display except the counts are in hex REM 500 INSTRUCTION MANUAL 11 DATA DUMP OF CHANNELS Sending D followed by another character when the instrument 15 in the MCA mode will dump the data from the channels Data record 18 as follows 256
31. 8 175 110 208 248 113 208 248 QF 114 209 248 116 210 248 QF 118 50 212 115 248 180 Ore ewes QF 120 QF 212 248 121 213 248 OF 248 124 QF 214 248 OF 248 126 QF 215 QF 248 OF 248 QF 127 355 QF 215 120 QF 248 3185 129 QF 217 QF 248 QF 248 QF 131 QF 218 QF 248 ey QF 132 QF 219 248 02228 135 219 248 One das QF 136 60 220 125 QF 248 90 Orn us QF 139 QF 222 QF 248 4 QF 140 QF 222 QF 248 QF 142 223 QF 248 QF 144 QF 224 248 QF 145 65 QF 224 130 QF 248 195 01 C02 C03 c04 05 C06 07 C08 C10 12 13 14 CIS C16 18 19 C20 C21 C22 C23 C24 C25 C26 C27 C28 C22 C30 C32 G33 C34 C35 C36 REM 500 INSTRUCTION MANUAL 27 DESIGN QUAN PART NO TYPE DESCRIPTION MFG DRAWING 212 5315 47K 47 pF 600 VDC Capacitor film Xicon 1 00 581 33 16 33 uF 10 VDC Capacitor tant Thomson 1 00 6473 047 600 VDC Capacitor film Panasonic REM1 00 EF6473 047 600 VDC Capacitor film Panasonic REM1 00 232 1000 005 5 pF 50 VDC Capacitor slv mica REM1 00 581 33 10 33 uF 10 VDC Capacitor tant Thomson 1 00 581 33 1
32. 8 9 2 Y R39 USA o 7 5 gt x 8 2255 s 21 z cah 8 R38 5 R29 RIGA G J4A 24 CBA gt 45400 C POLE ZERO RIZ 0 17 2 2 U8 TPIA U4A TP2A TT cno Ll tpg 597 ANALOG BOARD UE 112 2019 2 2 011 C22 o I y O 5 3 RTG 188 Cy 03 3 817 6 21 2 23 113 09 U7 us 111 WIG Lt C184 R22 RI8JP2 JPI 16 04 29 03 0 C17 5 9 3 2 0 02 N 02 D 5 S 9 R3 06 89 8 RIS 5 RI RE 019 R7 vt 0150 8240 me RZ 20 R24 5 2602 5 7 R10 5 2 1 REV 5 REM 500 020 2 gt 2 gt 2 5 S 8 5 X A lt ot 25 20 gt REV HA 5 gt FWT HPI REM 500 020 REV A REM 500 021 5 gt 58 57 56 55 54 S LU RISA R7A 815 BZ1 D R14 gt 2 2 RIA DISPLAY BOARD 2 REM 500 INSTRUCTION MANUAL PARTS LOCATION TOP SECTION 32 REM 500 INSTRUCTION MANUAL 33 PARTS LOCATION BOTTOM SECTION 20 1 14 20 8 20
33. A data and restart the acquisition If the display remains on channel 0 or 1 this indicates that the instrument is not functioning properly Try tapping on the side of the detector to free the shutter that shields the alpha source The peak channel indicates the calibration of the instrument and the left and right half max channels indicate the quality of the detector The peak should be within REM 500 INSTRUCTION MANUAL 9 15 channels of 90 Each channel away from 90 is an error of about 1 5 if the Cal ibration Factor remains unchanged If it is out of this range then the high voltage needs to be adjusted as described in the Calibration Mode section VI The spread of the channels RIGHT LEFT should be no more than 50 channels If the spread is more than this then the detector needs to be returned to the factory for refilling Leave this mode by pushing NEXT If the rate display reads a high number after leaving Check mode then the magnet actuated shutter that shields the alpha source may be stuck Just tapping the side of the detector should free the shutter There is also an additional Check mode in the Multichannel Analyzer section that allows dumping all the channels See that section for a description of the Check mode MULTICHANNEL ANALYZER MODE 00 00 00 This mode is only available if the MCA option has been installed Figure 3 shows the Multichannel Analyzer MCA display The MCA mode can be reached by pushing MODE
34. CTION MANUAL 19 XIX MAINTENANCE MODE Maintenance Mode 18 used for electronic checkout To get into Maintenance Mode Hold down the MODE and RESET keys while turning the instrument on If the instrument has failed see below In the Maintenance Mode the 3 digits in the upper left of the display are the channel number of the pulse height This ranges from 000 to 255 The next three digits are the contents of the pulse counter Every time a new count is received the counter increments by The next item is either the letter H or L This is the comparator that checks the condition of the battery If it is L it indicates a good battery if it is H it indicates a bad battery The Last item is the number of the last switch that was pushed The switch numbers are 1 MODE 2 ALT 3 RESET 4 LIGHT and 5 CAL button 090 000 ADC CLR MAINTENANCE MODE The buttons are redefined and their abbreviations are show on line 2 The MODE button becomes the or MAGNET button The ALT button becomes the JADC button The RESET button is the JCLR or CLEAR button and the LIGHT button remains the LIGHT button The action of each of these buttons is defined below Turns on the Magnet attached to the outside of the detector This causes the internal alpha source to irradiate the detector simulating neutron events with an average energy that should be in channel 90 The electronics can be tested with these signals The Displ
35. E modes it will not show low battery in LEVEL 1 2 3 or CHECK In the MCA mode the upper right corner will flash when the batteries are low The light uses the most power If the batteries just check good turning on the light may make them check bad This is the reason the instrument when first turned on checks the batteries with the light on When the batteries are low it is a good idea not to use the light IX BATTERY REPLACEMENT The Rem 500 uses 6 C cells either carbon zinc or alkaline The alkaline will of course last longer The current drain is less than 40 mA with the light off To change the batteries remove the four screws on the end of the case that hold on the small cover The batteries should fall out Use the sticker on the inside of the REM 500 INSTRUCTION MANUAL 8 box as a guideline for inserting them The batteries on left hand side go in caps first and those on the right go in with their caps out Do not ship the instrument with batteries because it may turn on in shipment X FAILURE The instrument self checks itself at turn on If it detects a failure it will display FAILURE in the display If this occurs the instrument cannot be used See the Maintenance Mode section for repair procedures STATISTICS AND COUNTS The display shows the number of counts that the instrument has received for that reading in the lower right hand corner For valid statistics the number of counts is important To achieve
36. ICATIONS There 15 RS 232 Seriallink built into the 500 for communications with a terminal or computer It is only available if the MCA mode is installed The link not only allows the user remote control of the MCA but also dumps the data on command One end of the RS 232 Cable plugs into the top of the REM 500 next to the handle The other end plugs into the 25 pin RS 232 COM port of a Personal Computer or a terminal The computer or terminal should be set to 9600 baud no parity 8 data bits 1 stop bit The serial link allows communications with both the normal rate and integrate displays and with the MCA When the instrument is in the normal rate or integrate mode sending a to REM 500 will turn on the data link The instrument will respond with an and will send out the radiation level every time it updates the display The level is the same as the display This is every 10 seconds in the integrate mode and when the time reaches 0 in the rate display To turn it off turn the instrument off The data that is transmitted is 5 dig its of radiation level followed by an exponent The basic units are UREM uRAD uREM h and uRAD h or nSv h and nGy h depending the mode the instrument is in and are the same as the display The exponent is the power of 10 that the reading should be multiplied by Thus 12567 0 would be 12567 x 10 0 which is 12567 uREM h 12 567 mREM h and 67785 3 would be 67785 x 10E3 which is 67
37. K Turns on the check source and checks for the peak channel number from this operation See section on Check LEVEL 3 Changes from level 3 to normal operation NOTE To reach Check from normal operation push MODE CHECK CHECK JNEXT Changes to normal operation same as level 3 NEXT NOTE To reach MCA from normal operation push MODE NEXT Changes to normal operation same as level 3 VI OVERFLOW AND HIGH RADIATION LEVELS High level radiation over 100 REM h or 10 RAD h may give poor results This depends on the average quality factor of the radiation The instrument does not have any dead time correction and consequently while the software is capable of going up to 999 REM h the detector and electronics may not be The dead time associated with each pulse is about 60 uS The instrument works by acquiring each pulse measuring its height and then adding one to one of the 256 channels that correspond to its height It is a classic multichannel analyzer Every 10 sec onds the instrument calculates the raw REM and RAD data and resets all 256 channels to zero and starts acquiring the data again There are several problems with this approach The first is that each channel can only store 65536 counts The second is that the higher channels contribute much more to the radiation level than do the lower channels because of their higher quality factor C
38. MATERIAL INSIDE DETECTOR The sealed detector contains 1 microcurie 20 Curium 244 check source The source material is deposited on the end of a 063 dia stainless steel rod and has a gold flashing over it to secure the source material It is necessary for you to in clude this source material on your radioactive materials license If it is necessary to ship the instrument it should have a statement as to the type of radioactive material Cm244 and the amount 1 microcurie It should also in clude the following statement in the box so it is the first thing seen when the box is opened No special packaging material is required other than the normal 2 pack ing material on all sides and a sturdy cardboard box FROM ADDRESS This package conforms to the conditions and limitations specified in 49 CFR 173 421 for Excepted Radioactive Material Limited Quantities N O S UN 2910 and also IATA section 5 7 27 This is to certify that this package conforms to all packaging requirements of the U S Department of Transportation and the International Aid Transport Associa tion rules and regulations regarding the shipment of Radioactive Materials Limited Quantities The radiation level on the surface of this package is less than 0 5 mR hr No other labels required NAME SIGNATURE TITLE The above form serves only as a guideline Your requirements may change de pending on government regulations REM 500 INSTRU
39. Select dis play The top line will tell you the current status of the instrument If it dis FRONT PANEL ON plays Front Panel On it means that you will be able to get into the Calibrate ON OFF SAVE Mode from the front panel Front Panel Off means that you must open the CALIBRATE SELECT Snclosure to get into the Calibrate Mode Pushing the LON or LOFF but turns the front panel calibra ton will change the status of the Calibrate Select You can see the change tion button owand on the first line Pushing SAVE will save this and return to normal oper ation REM 500 INSTRUCTION MANUAL 15 To summarize If you want convenience of getting into the calibrate mode without opening the case and are not concerned with security of the calibrate number then push YES and then If you do not want anyone to be able to enter the calibrate mode without having to open the case then push LOFF and SAVE SI UNITS SELECT The next menu that will appear after pushing the calibrate select is the SI Units Select display The choice is either for SI units or REM RAD units This will effect the units in the rate and integrate displays and in the download SI data Pushing 4SI will put the instrument the SI Units mode Pushing SI UNITS SELECT chooses the will put the instrument in the Rem Rad units mode Pushing the the units for the displays Rad Reni oe Su Gy are the result in no change choices
40. WM4204 WM4205 1 CHR26G ND WM2002 CHS26G ND VN10KM VN10KM VN10KM VN10KM VN10KM VN10KM OOKX 36C24 49 9KX 49 9 49 9 OOKX OOKX OOKX OOKX OOKX 49 9KX 29MF250 1 5M 499KX 20 5MQ 390KQ 3 3 0 770 101 R100K 770 101 R10K 80375 80375 80365 80365 80365 80365 80365 80365 V1072 ND V1072 ND V1072 ND NSC800N 31 MM74HC574N UM6116 3L TLC271CP SSM2160MYB G 74 08 74 02 74 04 MM74HC138N MM74HC74AN CL7665CPA 511 4069 LM2931T 5 0 5 810 3 93 46 CL7660SCPA CL7660SCPA 5 2691 1 24 232 080 CTX049 1 007 015 1 004 1 002 1 002 1 0021 1 018 1 025 2 1 025 3 1 025 1 23 23 23 00 23 23 23 354K ND 2181 353K ND 1093 1032 18 26 HDR 4 Pin SIP HDR 7 Pin SIP HDR 12 26 HDR 4 Pin SIP 26 ST HDR PWR PWR PWR PWR PWR OOK 5 M 5 OOK 5 00 0K 1 20 K 1 6mm 49 9 1 49 9 1 49 9 1 00 0K 00 0K 00 0K 00 0K 00 0K OK 5 49 9 1 0 sores n 0 n 16 x 2 w bklt LED 74 08 74 02 74 04 74HC138 74 74 ICL7665 4069 LM 2931 NSC810 93C46 ICL7660 ICL7660 8 2691
41. acitor Capacitor Capacitor Capacitor Capacitor Capacitor Capacitor Diode Diode Diode Diode Diode Diode Diode Diode ect point point point point point point d bit ator Flop Mono Multivibrator ence ter tant mono mono mono mono mono tant tant mono mono mono mono mono mono mono mono mono tant tant tant tant tant tant mono mono tant tant tant tant MFG Victoreen Panasonic HPI Vector Vector Vector Vector Vector Vector TI TL National National National National SGS National Harris TI Panasonic GPE Thompson rhompson rhompson rhompson rhompson rhompson rhompson rhompson rhompson rhompson rhompson rhompson rhompson rhompson rhompson rhompson rhompson rhompson rhompson rhomnpson rhompson TEIE F Oe ae Pe PTE TI Ps a TA rhompson rhompson rhompson rhompson hilips en Inst hilips hilips hilips hilips Dio Inc Dio Inc rg rg rg rg Q g DRAI 13 UJ U 123 UJ D 127 23 23 12 233 127 23 73 23 23 12 23 23 23 23 12 233 123 23 23 23 23 23 23 23 23 23 02 23 123 23 23 13 23 13 23 73 13 23 13 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 13 23 23 23 23 23 23 03 23 2323 23 23 23 23 23 23 23 23 03 23 03 23
42. ay should also show the counts although the peak energy is hard to see because of the number of counts Turn the magnet off by pushing After is pushed software constantly resets the ADC portion of the circuit It puts a constant pulse on pin 2 U4 and on pin 13 and on pin 10 U6B Turn it off by pushing JCLR This button clears all the parameters set by the other buttons It turns on the interrupts and the timer It turns off the magnet the ADC reset signal and the beeper LIGHT The light is turned on whenever this button is pushed and turned off by pushing CLR This button sends an out the serial port if the serial port is in stalled It also turns off the interrupt and timer CAL This turns on the beeper Pushing JCLR turns it off If the EEPROM has failed the instrument will display a dim FAILURE If this is the case then it is necessary to replace the EEPROM U16 on the Digital Board After replacing it enter the Maintenance Mode and push LIGHT at the failure in dication This will program the EEPROM with default values Then turn the in strument on and off again to resume normal operation The instrument will need to be recalibrated because the Calibration Factor is in the EEPROM REM 500 INSTRUCTION MANUAL 20 XX CIRCUIT DESCRIPTION The electronic circuit is broken down into two main sections the analog and the digital circuits Each circuit has two printed circuit boards asso
43. ciated with it DIGITAL CIRCUIT The digital circuit comprises the Digital Circuit Board and the Display Board Both are shown on schematic REM1 002 POWER SUPPLY The instrument is powered by 6 C cells The negative side of the batteries is switched to turn the instrument on and off U13 forms an alternate action set reset flip flop that is controlled by the front panel on off switch The output of this flip flop turns on Q5 which grounds the negative side of the battery to turn the in strument on U13 is always powered on but its current drain when the instrument is off is only a couple of microamps The battery power goes to a 3 terminal regulator U14 which has a low drop out voltage Its output is 5V U17 and U18 form a voltage converter that changes the 5V into 5V 8V and 8 V U12B is a low battery detector used to reset sys tem when the battery voltage drops too low When the battery voltage gets to 5 4V it puts the system into reset This causes the display to go dim because the NSC810 outputs turn into inputs and the contrast is changed The other half of U12 U12B is the low battery detector It switches at about 6V MICROPROCESSOR The microprocessor U1 is an NSC800 and uses the Z80 instruction set It is sup ported by the address latch U2 EPROM U3 RAM U4 address decoder U10 and various other gates U7 U8 U9 and U11 The oscillator X1 R2 C2 and oscillates at 4 0 MHz It is the timebase for the inst
44. eV u Carbon atom recoils from neutron interactions show an increasing LET with in creasing neutron energy such that with incident neutron energy of 20 MeV a car bon recoil will exhibit an LET of over 400 KeV u REM 500 INSTRUCTION MANUAL 13 The detector measures the LET from all neutron interactions that are important for radiobiological studies ICRP has developed radiation protection standards to evaluate the quality factors which are applied to the pulse heights produced in the detector and processed by the associated electronics XVI CALIBRATION MODE The Calibration Mode is used to change the overall sensitivity of the instrument change it to SI units and to adjust the high voltage It was setup and calibrated at the factory but can be easily changed The Calibration mode lets you change the Calibration Factor which changes all readings the same integrate and rate REM and RAD and it also lets you change the high voltage which increases or de creases the channel number of the peak in the check mode Getting into the Calibration Mode be accomplished two ways Method 1 is to turn the instrument off then push down the cal pushbutton inside the instrument lo cated on the display circuit board and hold it down while turning on the instrument The Calibrate Mode will be immediately visible showing the High Voltage Adjust display as shown below Method 2 is to turn the instru ment off Hold down the ALT button and turn the
45. es for the LCD contrast Pin 1 is the MSB of the R 2R ladder network used to generate the voltages for the LCD contrast Pin 2 and 5 Pin 5 are not used and are pulled up by RN2 DISPLAY The LCD display is U6 It has a contrast input that is controlled by U5 and the R 2R ladder network U7 thru R13 This is the digital control of the contrast R5 is the coarse set for the contrast EEPROM The EEPROM holds 128 bytes of data even when the power is off Only 7 bytes are used SERIAL PORT U19 and U20 comprise the serial port U19 is the UART and U20 is the voltage drivers for RS 232 The UART has its own crystal X2 ANALOG CIRCUIT The analog circuit is on two circuit boards the Preamp and the Analog Circuit Board They are shown in schematic REM1 001 HIGH VOLTAGE POWER SUPPLY The supply output for the detector is around 500V U9A is an oscillator which produces a 2 usec pulse every 4 msec This drives U9B which expands the pulse width and turns it on and off depending on the output of U10 The output of U9 drives Q5 which in turn drives T1 This is a step up transformer Its secondary is rectified by D5 and filtered by R46 C31 and in the preamp by C4 C3 and RS The high voltage is measured by resistor divider R47 and R48 and R49 U10 com pares this voltage to that set by R51 the high voltage control and the DAC and turns on and off the oscillator in U9B to regulate the voltage R4 and R2 are a volta
46. g is REM 500 INSTRUCTION MANUAL 2 ON OFF MODE ALT RESET LIGHT now frozen Pushing the RESET button again will reset the instrument and put it back into normal operation To change from the rate mode of operation to integrate mode just push MODE button twice To get back to the RATE mode again push the MODE but ton twice Switching back and forth between rate and integrate is very easy just push the MODE button twice The integrate mode has a slightly different display The Integrate time 15 shown lower left counts that have been acquired remain on the lower right The upper FRONT PANEL right is blank The ALT RESET and LIGHT buttons work in this mode just like the rate mode You have now run the instrument through its basic operation More areas of the instrument are discussed in the following sections Remember you cannot hurt the instrument if you push the wrong button at the wrong time Turning it on and off will restore it to normal operation II MODES OF OPERATION There are three main modes of operation rate integrate and Multichannel Ana lyzer if installed Rate and integrate are discussed here See the Multichannel Analyzer section for a description of that mode In addition there is a Check mode which is discussed in the Check Mode section Each mode can be identified by the arrangement of the display See the MCA mode section for a description of the Multichannel Analy
47. ge divider to provide the helix in the detector with the correct voltage The DAC allows the high voltage to be adjusted by the front panel and consists of the REM 500 INSTRUCTION MANUAL 23 ladder network R56 to R71 The shift register U11 shifts and latches the serial data from the microprocessor to the ladder network PREAMP The high gain charge sensitive preamp uses a low noise 2N4416 as the input FET 2 provides bias for 1 18 an impedance converter and 04 is the output buffer Feedback 18 by R15 and the small amount of stray capacitance across it 15 the feedback capacitor The output of the preamp is a series of ramps The input pulse drives the output positive and then the signal slowly decays back toward ground is an input for an external pulsar POST AMPLIFIERS R17 is the pole zero control U1 s four amplifiers shape the pulses for use by the ADC R28x sets the gain MCA U5 a voltage comparator and a flip flop start the ADC conversion USA de tects the peak above the Low Level Discriminator LLD The signal then is am plified by U2A and U2B They form a closed loop to charge capacitor C22 to the peak value of the input pulse The output of U2A drives the input of the Analog to Digital Converter U4 U7 times the conversion U3A and U3D reset the peak catcher The reference voltage of 2 5V for the ADC is set by U8 R32 sets the Low Level Discriminator below which the pulses will not initiate a convers
48. hannel 10 has a quality factor of 3 2 while channel 230 has a quality factor of 24 8 The RAD ranges have no quality factor These three items REM 500 INSTRUCTION MANUAL 7 dead time maximum counts channel and different quality factors lead us to sev eral guidelines 1 At 10 000 counts in 10 seconds the instrument will loose 1 of the counts and response will start to fall off above this amount 3 If the REM h range is overrange then suspect RAD h range has dead time losses 4 If you have to use the instrument in high radiation levels then correct for dead time losses Vil SHOCK The instrument has some sensitivity to shock Banging the case or the detector could result in spurious counts A sharp rap on the detector with a pencil will in deed produce spurious counts Just hold the instrument with the handle and don t bang it against anything while making measurements Vill LOW BATTERY When first turned on the instrument turns on the light and checks the status of the battery If it has less than 10 hours remaining it will show LOW BATTERY in the display If the batteries are too poor to turn the instrument on the display will re main dim During normal operation the instrument continually checks the status of the bat teries If it sees that there are only 10 hours remaining then the instrument will flash LBAT in the upper right hand corner of the display every 13 seconds This is only in the RATE and INTEGRAT
49. ion The microprocessor after processing the signal resets the ADC by J4 10 ELECTRONIC ADJUSTMENTS There are 4 electronic adjustments All controls are independent and do not need to be done in any order they were factory set and do not usually need adjustment Replacing the detector would necessitate adjusting the Pole Zero the high volt age and doing a calibration HIGH VOLTAGE The High Voltage control is on the bottom right of the Analog Circuit Board Set the High Voltage Factor in the High Voltage Adjust display of the Calibrate mode to 130 Exit the Calibrate mode Enter the Check mode and look at the peak un der the Check Mode Adjust the high voltage until the peak is on channel 90 2 channels REM 500 INSTRUCTION MANUAL 24 CONTRAST The Coarse Contrast control on the lower right hand side of the Digital Board ad Justs the contrast of the display The Contrast adjust from the front panel fine tunes this value To set the pot 1 Turn the instrument on press MODE then NEXT to get into the display change mode Push the LDISPL button 20 times The contrast will get dark then Jump to light and get dark again There are 12 steps in the adjustment and every time the LDISPL pushbutton is pushed it changes the level 1 step 2 Adjust the Coarse Contrast control until it seems that the 12 steps are in the middle of the range of the display The lightest display should be just visible LLD The LLD on the upper lef
50. mREM to 999 REM and 001 mRAD to 999 RAD integrate SI units of Sv and Gy are also selectable Multi Channel Analyzer 256 Channel 65535 counts channel RS 232 se rial link can control MCA operation Temperature Dependence less than 15 from 15 to 45 C Humidity Response Less than 10 change from 0 to 95 RH non condensing Neutron Energy Response 70 KeV to 20 MeV Gamma Response Less than 1 at 1 RAD h Warm Up Time 15 seconds Battery Life 100 hours 6 ea alkaline C cells Serial RS232 link In Rate and Integrate mode sends radiation level on com mand In MCA mode dumps MCA raw channel data count time total counts and Instrument Calibration Factor Baud rate is 9600 Available if the MCA option is installed REM 500 INSTRUCTION MANUAL iii PLEASE NOTE All of the descriptions and examples throughout the manual use the units of Rem and Rad Si units of Sv and Gy are also available To select the Si units please re fer to the Calibration section This manual covers the REM 500 with or without the MCA option To check if the MCA option is installed look on the front panel If the panel contains a jack on the lower right for a connector then the MCA option has been installed REM 500 INSTRUCTION MANUAL 1 I INTRODUCTION The Rem 500 is a Neutron Survey Meter that reads in both REM RADS It is a small light portable instrument that is at home both in the field and in the lab This manual describes
51. naconic Panasonic Panasonic Panasonic Vector Vector Vector National National TL SHELLY National National National National National Maxim SGS National National ICT Harris Harris Signetics Maxim CTS CTS Amatom 9 Keystone FF JOHNSON Keystone 29 DRAWING 23 03 13 23 UJ D 17 23 23 12 233 127 233 U 23 23 13 23 23 23 23 12 233 13 23 73 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 73 23 23 23 23 23 23 23 23 23 23 UJ 23 23 23 23 23 23 23 23 23 23 23 23 U LU 23 23 23 23 23 23 23 23 23 23 23 03 LU U 23 23 23 23 23 23 23 23 J J J J U 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 002 00
52. nnson APM Hexsel EF Johnson HPI CW CW CW CW CW CW Molex Molex OKI OKI OKI 30 DRAWING 23 07 13 23 12 13 23 23 23 12 23 123 23 23 23 23 13 23 23 23 23 13 23 23 23 23 23 23 23 23 73 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 73 23 23 23 23 23 23 23 03 23 23 23 23 13 tJ J 023 023 023 023 023 023 023 023 023 023 023 023 023 023 023 024 024 024 024 024 024 024 024 024 024 024 024 024 024 024 024 024 024 024 024 024 024 024 024 024 024 024 024 024 024 024 024 024 024 024 024 024 025 025 025 025 025 025 025 025 025 025 3025 REM 500 INSTRUCTION MANUAL XXV PARTS LOCATIONS AND SCHEMATICS PARTS LOCATION CIRCUIT BOARD
53. on NOTE To reach LEVEL 1 from normal operation push MODE LEVEL 1 Puts the instrument into the Integrate mode LEVEL 1 Puts the instrument into the Rate mode LEVEL 1 Changes from level 1 to level 2 NOTE To reach LEVEL 2 from normal operation push MODE LEVEL 2 Changes the Time constant of the instrument for the Rate mode Each time it is pressed it changes to the next time constant There are three time constants 10 30 and 60 seconds This is the time the instrument will gather data before presenting it on the screen The upper right hand corner of the rate display will show the time remaining in this time constant i e before updating The in strument will remember the time constant when it is turned off The next time it is REM 500 INSTRUCTION MANUAL 6 turned on it will have the same time constant If it is set to 60 seconds and turned off the next time it is turned on it will still be 60 seconds LEVEL 2 Changes the contrast of the display There are 12 levels of contrast Each push of the L DISPL button will change the contrast by one level When the contrast reaches the maximum it jumps to the minimum Just keep pushing the button until the contrast looks correct When the instrument is turned off it remembers the contrast setting LEVEL 2 Changes from level 2 to level 3 NOTE To reach LEVEL 3 from normal operation push MODE NEXT NEXT LEVEL 3 CHEC
54. push the SAVE button This will save the val ues and change the display to the Calibrate Adjust display Exit the calibration displays by pushing JSAVE SAVE and This completes the high voltage adjustment stage The next stage is to check and if necessary adjust the overall sensitivity of the instrument 1 Using the calibrated neutron source expose the instrument to a known quantity of radiation It is desirable to expose it in the integrate range for a period of time sufficient to accumulate at least 1000 counts 2 Calculate the correction factor for the instrument CORRECTION FACTOR DESIRED LEVEL READING 3 Enter the Calibration Mode See the Calibration Mode section for a description of how to get into this mode Bypass the High Voltage Adjust display by pushing SAVE You are now in the Calibration Adjust display REM 500 INSTRUCTION MANUAL 17 4 Multiply the Calibration Factor in the display by the correction factor to obtain a new Calibration Factor 5 Set the new calibration factor in the instrument by using the and JDN but tons When the value is correct push the 15 button Exit the Calibration mode by pushing and LOK 6 Repeat step 1 to 5 until the instrument reads correctly Steps 2 to 5 correct the instrument Calibration Factor to match the reading 1 if the reading it 10 low then you need to raise the correction factor by 10 REM 500 INSTRUCTION MANUAL 18 XVIII RADIOACTIVE
55. ru ment ADC CONTROL The ADC is memory mapped just like all the other peripherals Reading it activates the output of U9C LOCATION OF HIGH VOLTAGE CONTROL The High Voltage Control is located on the left hand side of the in strument on the analog board To access it remove the four screws on the top plate Be careful of the wires Turning the control clock wise raises the peak turning it counter clockwise lowers it and this controls the signal ADC RESET This is the only signal that resets the ADC When a conversion is ready it signals the system through the INTR line REM 500 INSTRUCTION MANUAL 21 IN OUT The In Out ports for the system are in the NSC810 015 This chip has an I O RAM and atimer The RAM is used for the stack the timer is used to generate the 1 second heartbeat from TO out This goes to the NMI input on the microproces sor The various ports are used as follows PAO Pin 21 controls the electromagnet L1 on the side of the detector To turn on L1 Pin 21 U15 goes high This turns on the gate of Q2 Q2 brings the P2 4 end of 1 1 to ground turning it on The other side of L1 goes to unregulated battery volt age VBAT PA1 Pin 22 controls the buzzer in the same way that the electromagnet is con trolled 2 Pin 23 controls the front panel backlight To turn on the light Pin 23 015 goes high It is normally low This turns off Q4
56. stor 1 00 0 0 0 15 Resistor REM1 00 0 0 0 15 Resistor REM1 00 0 0 0 ohm 1 Resistor REM1 00 00 00 1 Resistor 1 00 0 0 0 15 Resistor REM1 00 00 0 ohm 5 Resistor 1 00 00 0 ohm 5 Resistor REM1 00 MOX 300 1000 000 5 Resistor Victoreen REM1 00 CEG14 Pot 3 8 top Panasonic REM1 00 4 99KX 4 99K 1 Resistor 1 00 2 00 2 00 15 Resistor REM1 00 0 0 0 ohm 1 Resistor REM1 00 00 0 1 Resistor REM1 00 562 562 1 Resistor REM1 00 00 0 1 Resistor REM1 00 00 0 1 Resistor 1 00 562 562 1 Resistor REM1 00 00 0 1 Resistor REM1 00 00 0 ohm 1 Resistor REM1 00 0 1 Resistor 1 00 CEG15 00 K Pot 3 8 top Panasonic REM1 00 1 51 1 55 Resistor REM1 00 00 0 ohm 1 Resistor REM1 00 00 0 ohm 1 Resistor 1 00 01815 00 K Pot 3 8 top Panasonic REM1 00 00 1 Resistor 1 00 REM 500 INSTRUCTION MANUAL DESIGN QUAN PART NO R34 R35 R36 R37 R38 R39 R40 R41 R42 R43 R44 R45 R46 R47 R48 R49 R50 R51 R52 R53 R54 R55 R56 R57 R58 R59 R60 R61 R62 R63 R64 R65 R66 R67 R68 R69 R70 R7 2 4 6 00 002 003 004 005 006 007 008 009 010 011 B1 21 01 02 04 05 C06 07 08 09 C10 C11 C12 C13 C14
57. t There operation is described below ON OFF Turns the instrument and off If the instrument is on pushing it will turn it off If it is off pushing it will turn it on MODE Selects the various modes and displays Pushing it twice will switch be tween rate and integrate and vice a versa Pushing it once will enter the menu of Level 1 ALT ALT is for ALTERNATE which selects between REM and RAD If the in strument is reading in REM pushing the ALT will switch ON OFF MODE ALT RESET LIGHT to RAD If the instrument is reading in RAD pushing it will change to REM When in the Rate mode switching between and RAD will reset data even if the strument is on hold This is not true for Integrate FRONT PANEL range If the instrument is on hold then switching be tween RAD and REM will not reset the data RESET Puts the instrument in either a Hold mode or resets it The first push of the button holds the data The display will show HOLD in the upper right hand corner to let you know that the instrument is in hold Pushing the button again will reset the instrument and it will resume normal operation If the instrument is on HOLD and in the integrate range the ALT button will change between RAD and REM on the same data without resetting the instrument LIGHT Turns on the light for 16 seconds If you are in the various menu s push ing the light will keep it on until you go back to normal operati
58. t of the Analog Board is set with a voltmeter 1 Attach a voltmeter negative lead to Test Point 5 Attach the positive lead to Test Point Adjust the LLD SET control until the voltmeter reads 158 milli volts 2 This adjustment can be checked with a mercury pulsar connected between TP1 and ground TP5 Enter maintenance mode and adjust the pulsar to channel 10 Then slowly lower the pulsar and note the lowest channel that is displayed on the left of the display Raise the level back to around channel 10 and slowly lower it again Do this a couple of times to check the lowest channel number It should be channel 5 If it is a higher number then lower the LLD slightly and try it again POLE ZERO The Pole Zero is on the upper left of the Analog Board Connect an oscilloscope between ground 5 and pin 1 of U1 Enter the Maintenance Mode and turn on the magnet Adjust the Pole Zero control fully CCW Then adjust the control until the bottom of each pulse is even with the baseline of all the pulses REM 500 INSTRUCTION MANUAL 25 XXII TROUBLE SHOOTING NOTES 1 A mercury pulsar can be used to test the instrument It connects to and ground TP5 on the Analog Board 2 Pressing the CAL button the front panel after the unit is turned on will termi nate the 15 second self check at power up This is useful for testing the instrument especially if you have to turn it on and off many times 3 If the instrument does no
59. t work and there is power to the chips then turn the in strument off short pin 1 and 2 of the NSC810 and turn power back on This will cause the program to send out a pulse train on pin of the NSC810 If this occurs then the microprocessor is working You can disconnect the following to see if it works US LCD display U4 RAM U19 UART U20 U16 012 05 U11 and U8 The pulse does not need any of these If they are removed and it works then try putting them in and see if the pulses are still there 4 If there is no display then try changing the contrast It may be that the contrast is too light The coarse contrast may also need changing 5 The two circuit boards hinge on one side Undo the two screws on the side op posite the hinges on each board and they will open like a fan REM 500 INSTRUCTION MANUAL XXIII QUALITY FACTORS Quality Factors for each channel as pre programmed into the REM 500 MCA VS1 0 10 QF QF 10 QF QF 10 QF QF 10 CHAN CHAN CHAN CHAN QF 4 QF 147 QF 225 QF 248 QF 7 QF 149 OF 226 248 11 151 226 248 14 152 228 248 17 55 QF 153 70 228 3135 248 200 20 156 229 248 QF 25 QF 157 229 248 QF 27 158 230 QF 248 QF 30 160 230 QF 248 32 10 QF 162 75 231 140 QF 248 205 QF 35 163
60. the buttons except the ON OFF button are redefined The MODE button becomes the JUP and the ALT button becomes the They work by raising and lowering the high voltage factor which raises and lowers the high voltage To increase the high voltage factor push and hold down REM 500 INSTRUCTION MANUAL 14 the JUP button The High Voltage Factor will increase by every second The button works in the same way except that it lowers the High Voltage Factor To raise the factor 10 it is necessary to hold down the JUP button for about 10 seconds The RESET button becomes the SAVE button and will put the new High Volt age Factor into the permanent memory of the instrument and then go to the Cali bration Factor display Until this button is pushed the High Voltage Factor is not changed inside the instrument Turning the instrument off and on will restore the original value After setting the High Voltage Factor to the correct value in the display push SAVE The LIGHT button becomes the RST button or reset but ton This resets the peak values and starts the peak calculations all over again For the proper setting of this adjustment see the following section on Calibration The Calibration Factor display is the next display The number in the upper left hand is the Calibration Factor It is the number that needs to be changed to 100 CALIBRATE increase or decrease the sensitivity of the instrument It s nominal value is UP DN SAVE P
61. v ery 10 seconds The radiation level autoranging from 001 mREM to 999 0ct REM is shown on the upper left If the instrument is reading RADS then it will show between 001 mRAD and 999 RAD It indicates over range INTEGRATE DISPLAY showing REM or RAD if reading in RADS in the display The lower left shows the time of integration It displays the time in HRS MIN SEC and will go as high as 18 hrs 12 min and 15 seconds before it re sets to zero It updates every second The lower right hand corner shows the num ber of events that have been counted When the HOLD button is pushed the instrument recalculates the level for that second then updates the display and shows HOLD in the upper right hand corner Switching between REM and RAD when on hold using the ALT button will show the two levels If the battery is bad the word LBAT will flash in the upper right hand corner The instrument will continue to gather data until it is reset IV CHANGE MODE NEXT Soft Keys are shown with an arrow The change mode allows adjustment of the display contrast and time constant it is also a way into the Check mode There are five levels of displays that can be shown besides the rate and integrate displays We have named them level 1 level 2 level 3 check and MCA You may have noticed level 1 when you switched between the rate and integrate modes On these displays the meaning of the keys are changed The new meaning is sho
62. wn on the display with arrows pointing to the corresponding key The keys that are re defined in all except the MCA mode are the three middle keys The LIGHT key is not changed except in the MCA mode The ON OFF key is not changed The five levels are shown below To get to level 1 push the MODE key once To get to level 2 just push the key To get to level 3 just push the NEXT key again and to get back to normal operation just push key again If you are in the Check display pushing NEXT will get you back to normal opera tion The same is also true for the MCA mode Pushing the NEXT key repeat edly will always get you back to normal operation REM 500 INSTRUCTION MANUAL 4 LEVEL 1 MENU INT RATE NEXT This 18 the display for the Level 1 menu if the instrument was the Inte grate mode when the MODE button was pushed You will note that the new definition of the MODE button is RATE If the instrument was in the RATE mode when MODE button was pushed then the display would look like the next example This change of definition of the key 16 the way it is possible to switch between the Rate and Integrate mode just by pushing the mode button twice To exit this menu push either the INT or RATE and you will be back in normal operation NEXT moves you to the next display as shown be low LEVEL 2 MENU RATE INT NEXT This is the display for the LEVEL 2 MENU It allows adjustment of two items
63. zer RATE MODE 000 MREM h 9 Figure shows the RATE display When first turned on the instruments is in this mode The integrate mode can be reached by pushing MODE twice from the Rate mode 10sec TC Oct FIGURE 1 The radiation level autoranging from 001 mREM h to 999 REM h is RATE DISPLAY shown on the upper left If the instrument is reading RADS then it will show between 001 mRAD h and 999 RAD h It indicates over range by showing gt 1K gt 1K RAD h if reading in RADS in the display The lower left shows the current time constant The instrument gathers data for the time constant period then displays it The upper right hand corner of the dis play shows the time remaining in this period There are 3 Time Constant settings 10 30 or 60 seconds The number in the upper right corner of the display shows the time remaining in this time constant period Each reading is completely sepa rate from any other reading The lower right hand corner shows the number of events that have been counted during this period When the HOLD button is pushed the word HOLD will ap REM 500 INSTRUCTION MANUAL 3 pear in the upper right corner of the display If the battery is bad the word LBAT will flash in the same place INTEGRATE MODE 000 mREM 00 00 10 FIGURE 2 Figure 2 shows the Integrate display The Integrate display can be reached by pushing twice from the RATE display The display is updated e
Download Pdf Manuals
Related Search