UNCLASSIFIED AUTOMATIC SAMPLE CHANGER UNCLASSIFIED GENERALS E LECTRIC K) metadc HW HANFORD ATOMIC PRODUCTS OPERATION COPY NO.

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1 HW AEC RESEARCH AND DEVELOPMENT REPORT NSTRUMENTATON COPY NO. AUTOMATC SAMPLE CHANGER BY M. O. RANKN AND R. A. HARVEY HANFORD LABORATORES OPERATON JANUARY 3, 1957 K) 1957 HANFORD ATOMC PRODUCTS OPERATON RCHLAND, WASHNGTON GENERALS E LECTRC metadc AEC-GE RCHLAND. WASH,

2 LEGAL NOTCE Ths report was prepared as an account of Government sponsored work. nor the Commsson, nor any person actng on behalf of the Commsson: Nether the Unted States, A. Makes any warranty or representaton, express or mpled, wth respect to the accuracy, completeness, or usefulness of the nformaton contaned n ths report, or that the use of any nformaton, apparatus, method, or process dsclosed n ths report may not nfrnge prvately owned rghts; or B. Assumes any labltes wth respect to the use of, or for damages resultng from the use of any nformaton, apparatus, method, or process dsclosed n ths report. As used n the above, "person actng on behalf of the Commsson" ncludes any employee or contractor of the Commsson to the extent that such employee or contractor prepares, handles or dstrbutes, or provdes access to, any nformaton pursuant to hs employment or contract wth the Commsson.

3 HW nstrumentaton (TD-4500, 12th Ed.) AUTOMATC SAMPLE CHANGER By M. 0. Rankn and R. A. Harvey Radaton Protecton nstruments Research and Development Physcs and nstruments Research and Development Operaton January 3, 1957 HANFORD ATOMC PRODUCTS OPERATON RCHLAND, WASHNGTON Work performed under Contract No. W Eng-52 between the Atomc Energy Commsson and General Electrc Company Prnted by/for the U. S. Atomc Energy Commsson Prnted n USA. Prce 20 cents. Avalable from the Offce of Techncal Servces U. S. Department of Commerce Washngton 25, D. C.

4 -2- HW NTERNAL DSTRBUTON Copy Number E. D. Clayton J. E. Faulkner P. F. Gast R. A. Harvey M. O. Rankn D. L. Red H. A. Trebes 300 Fles Record Center Extra

5 -3- HW AUTOMATC SAMPLE CHANGER NTRODUCTON Radochemcal control work at Hanford requres that samples contanng trace amounts of radoactve sotopes be counted daly to determne the amount and knd of sotope present. Each sample s prepared on a stanless steel sample dsh, mounted on an alumnum holder, and manually placed under a mca-wndow G M tube for countng. The sample s counted for a fxed tme, removed, and all data are recorded by hand. Many samples requre countng several tmes wth fxed tme ntervals between each countng perod to obtan necessary nformaton for decay curve data. Background counts for varous predetermned tmes are requred perodcally. To determne GM tube characterstcs, a certan number of counts must be made on a known sample durng a gven perod. An automatc sample changer was developed to ncrease the number of samples that can be handled and elmnate many routne manual operatons. REQUREMENTS The automatc sample changer, to replace the present manual methods, must meet the followng requrements: dependable contnuous operaton, smooth handlng of each sample, capacty of ffty 2-1/2'' x 3-1/2'' x 1/16'' sample holders, and versatle enough to obtan routne sample, decay curve, background, and tube characterstc data. The nstrument must record all nformaton from the scaler and the wrtten materal on the sample holder. SUMMARY An automatc sample changer was developed to ncrease the number of samples that can be handled daly by elmnatng many of the operatons now done manually. When the nstrument s n operaton, t wll only be

6 -4- HW necessary for the operator to load the samples nto a rack and select the mode of operaton desred. Background counts for varous predetermned tmes and data for decay curves are obtaned automatcally. For each sample the count, duraton of count, date, tme, sample number, and other wrtten data are recorded wth a 35 mm camera to provde a permanent record. EQUPMENT DESCRPTON The overall system, completely mounted on a castored steel table, comprses three prncpal sectons; namely, the electromechancal, the countng, and the recordng sectons. The electromechancal system utlzes a servo system for ndexng and a motor drven slde for handlng the samples. The countng secton utlzes a commercal scaler(1) whch provdes for manual, pre-set count, prey-set tme, and count-tme operaton. The recordng secton employs a 35 mm, automatc camera(2) wth a 36 mm, f/3. 5, Wray "Supar" anastgmat lens n a calbrated mount, and a 24-volt power supply. OPERATON The sample changer was desgned to be easly adaptable to the present methods used n the radochemcal control laboratory. t wll handle the alumnum sample holders now used n the countng room. Routne samples are delvered to the laboratory daly and are loaded nto the sample rack of the automatc sample changer. Each sample s removed from the rack by the motor drven slde, pushed nto the lead pg, counted for a predetermned tme or count, and returned to the rack. Then the servo system ndexes the rack one poston and the next sample s nserted automatcally nto the pg for countng. (1) Nuclear nstrument and Chemcal Corporaton; Model 192X Ultrascaler. (2) D. Schackman and Sons; Mark.

7 -5- HW Selected samples are counted several tmes wth fxed tme- ntervals between each countng perod to obtan decay rate data necessary for plottng decay curves. A maxmum of 50 of these selected samples may be loaded nto the sample changer. The rack of samples can be returned to the number one poston after 10, 20, 30, or 50 samples have been counted, the number of whch s determned by the poston of the selector swtch on the front panel. The length of tme between the successve countngs of a partcular sample s determned by the number of samples to be counted and by the length of tme of the countng perod. Background counts are requred perodcally and may be obtaned by nsertng blank plates whch wll be counted for the same length of tme as each of the samples. To obtan longer background counts for mproved accuracy, a specal background plate whch actuates a swtch that nterrupts current flow to the tmer motor can be nserted nto the rack. Ths plate must be manually removed to end the countng perod. After a new mca-wndow tube s nstalled, t s necessary that a known sample be counted several tmes to nsure that the tube and assocated countng equpment are operatng satsfactorly. Ths operaton may be accomplshed automatcally by nsertng the known sample n the rack at the ndexed poston and turnng off the power to the servo ndexng unt. The complete system, shown schematcally n Fgure 1 and pctorally n Fgures 5 and 6, s comprsed of three prncpal sectons; namely, the electromechancal, the countng, and the recordng sectons. The Electromechancal System The electromechancal secton ncludes the servo system, motor drven slde, gear box, assocated swtches and relays, and the drve motor. A complete crcut dagram s shown n Fgure 3.

8 -6- HW After ffty prepared samples are loaded nto the rack, placed n the automatc sample changer and the nstrument s energzed, the motor drven slde pushes one sample nto the lead pg for countng. As the sample s wthdrawn, each of the sequentally operated shaft cam swtches close. Swtch number 4 (Fgure 1) energzes the col of the camera that records all data, number 3 closes and resets the scaler, and number 1 energzes the col of the steppng relay. The rack of samples s ndexed and another sample s pushed nto the lead pg. Swtch number 2 starts the countng cycle and s held closed by the cam untl the countng of the sample s completed. ndexng of the samples s accomplshed wth a servo system. The balancng potentometer, balancng motor, and sample rack are connected through a gear tran. When the steppng swtch s advanced to the new poston, the voltage dfference between the trmmng potentometer for that poston and the balancng potentometer s amplfed n the servo amplfer. The amplfed sgnal drves the balancng motor untl the voltage of the balancng potentometer and the trmmng potentometer are equal. When these voltages are equal, the rack s ndexed at the new poston. Safety Devces Three safety devces are ncorporated to protect dfferent portons of the system. When the nstrument s ndexng, a. porton of the sgnal to the servo motor operates a relay whose contacts opensand de-energze the drve motor crcut. When the rack s returnng to poston 1, swtch number 6 prevents the motor from operatng untl the rack s ndexed. These features prevent the slde from beng pushed nto the rack except when t s n an ndexed poston. A sprng loaded clutch protects the drve motor aganst overloadng. f the clutch becomes dsengaged, a phosphor bronze clp whch brdges the clutch s released and touches a brass stop. Usng ths stop and motor shaft as ground, a 6 volt relay s energzed whose contacts stop the drve motor.

9 -7- HW Two seres cadmum sulfde photocells, one located on each sde of the rack of samples, are shelded from the lght when the motor drven slde moves nto the lead pg. The resultng resstance ncrease n these cells causes a second relay to de-energze whch has contacts n the sgnal lead of the servo motor and prevents the system from ndexng. Countng Secton The countng secton conssts of a mca-wndow GM tube and the scaler. The varous modes of operatons of the scaler whch may be selected nclude predetermned tme, predetermned count, and predetermned tme-count. The automatc tmer, used to select the predetermned tme, s contnously adjustable from 0 to 60 mnutes n mnmum ncrements of three seconds. The pre-set count selector knob s adjustable for 10, 100, or 1000 regster counts. Scalng factors of 4, 10, 40, 100, 400, and 1000 are avalable n the scaler. By combnng the operaton of these swtches a wde range of pre-set counts s avalable. Recordng Secton The recordng secton utlzes a 35 mm, 150 exposure, automatc camera wth a 36 mm, f/3. 5 lens, two 4 x 5 mrrors, and auxlary lghts. The flm s advanced by a sprng motor whch s wound each tme the camera s loaded and the shutter s trggered electrcally wth a 24 v d-c power supply. A wrng dagram s shown n Fgure 4. Data recorded on the flm nclude the date, tme of day, tme of count, predetermned tme or count settng, count, sample number, wrtten nformaton on the sample dsh, and all swtch postons on the face of the scaler. The wrtten nformaton on the sample dsh s reflected nto a vertcal plane by two 4 x 5 mrrors. Data from a test sample are shown n Fgure 2.

10 -8- HW A 300-watt flood lamp and a 60-watt bulb are used for auxlary lghtng. An exposure tme of 1/25 second s used to photograph data on the movng sample plate clearly. An aperture openng of f/3. 5 provdes the correct amount of lght and a suffcent depth of feld to photograph all data. Recorded data for any group of samples can be removed from the camera at any tme. After developng the flm by a standard photographc process, the results can be nterpreted and read out by usng a vewer. Each roll of flm may be fled for future reference. Operatng Sequence The operatng sequence for a routne sample s as follows: A. Manual. Load 50 samples n ther alumnum holders nto the rack.. nsert the rack nto the Automatc Sample Changer. The rack wll seat at an ndexed poston determned by the poston of the steppng swtch.. Energze the nstrument. V. Advance the steppng swtch to the number 1 poston by movng the selector swtch to 10 and manually operatng Swtch No. 1 untl the steppng relay automatcally moves to poston 1. B. Automatc. The slde and sample are pushed nto the lead pg after the rack s ndexed. A. Mcroswtch number 2 s held closed by cam.. 1. The tmer s energzed. 2. The drve motor relay contacts open thus stoppng the motor. 3. The count cycle s started n scaler.

11 -9- HW The Count Perod ends as determned by the tmer settng. A. The tmer s tmed out. B. The drve motor relay contacts close and start motor agan.. The slde and sample are wthdrawn from the lead pg. A. Swtch number 2 opens. 1. The tmer s de-energzed and reset. B. Swtch number 4 s momentarly closed. 1. The col n the camera s energzed. C. Swtch number 3 s momentarly closed. 1. The scaler s reset to zero. D. Swtch number 1 s momentarly closed. 1. The steppng swtch s advanced one poston. a. The unbalanced voltage between balancng potentometer and trmmng potentometer s used as nput sgnal to the balance unt. b. The amplfed output sgnal from the balance unt drves the balancng motor. 1. The drve motor relay contacts open thus stoppng the motor. c. The balancng potentometer s drven untl t reaches the same voltage as the trmmng potentometer. 1. The drve motor relay contacts close and start the motor agan. V.. Start for a new cycle automatcally.

12 -10- HW CONCLUSON The chef functon of the automatc sample changer s to count samples for a pre-set tme automatcally. However, the nstrument s versatle and can be used n a varety of ways. Any group of samples may be counted for a predetermned tme, a predetermned count, combnaton of predetermned tme and count, or manually. ACKNOWLEDGEMENT The authors gratefully acknowledge the assstance of W. G. Spear n testng the electronc system of the nstrument descrbed. M. O. Rankn R. A. Harv

13 -11- HW Trmmng Potentometer Power Supply Camera Drve [Clutch C Gear GCams_ BMotoro Box Cams Swtches -H Steppng Swtch Slde Balancng Motor o- CDS Servo Amplfer CDS Potentometer Lead M W Pg Scaler s FGURE 1 SAMPLE CHANGER BLOCK DAGRAM ACC-GE RCHLAND WN

14 -12- HW FGURE 2 PHOTOGRAPH SHOWNG RECORDED DATA, USUALLY READ FROM NEGATVES AEC-GE NCHLAND. WN.

15 )ovac 3 AMP FUSE HW V RH-1 3 AMP FUSE RC - RD-1 V AC V COUNT S3-C 53-8 S3-A TRANSFORMER COUNT COUNT COUNT "10O FL AMENT? 110 VAC S3-D 0 O R O - SGMA 6V W la W S mf 27 2 J Q RE- cr u jr 600V RA RE-2 RE-3 RE-4 RE-5 RE-6 RE-7 RE-8 MCROFLEX TMER CONTACT OPEN WHEN TMED OUT W W O 2 H BODNE MOTOR 27060V H ~ U x Q W 0 z J W 1w450 cr H COUNT O O ~ LL COUNT COUNT COUNT AUTOMATC ELEC CO. 100SO 120 VAC. O V U O MCROFLEX TMER MOTOR RE REMOTE U Y 2 Q R-D W J AUTOMATC ELEC. CO. V AC RELAY 1000 _ W cr 5BOURNES nU WH A m NHAARALLEL t 600 loonloo V 0000V00 COUNT/ LOC. N SCALER CLOSED WHEH CLOSED MCROFLEX S TMED 0 THEN..TMED OAF MCROSWTCH CAM OPERATED MSe2 o 16 H AT 50 REMOTE RD- U CHOKE H-AT6SO RG-1 RG 41 QOZZ W -45 MECHANCAL GROUND WHEN CLUTCH S 190n r 40 'tdscharged 400V 16 H AT 50 JO O ~ W Z P110 VAC N SC NC MCROSWTCH 5 N LEAD PG OPENED BY BGRD PLATE 0 O O R-E ma CHOKE 2300 c Boa, / xc craus MCROSWTCH CAM OPERATED MSf3 AUTOMATC ELEC. CO V AC.25f RESET LOC.N SCALER RESET REMOTE TOGG -LE SWTCH ALER N 6V FROM RF- RF-2 RF-3 RF-4 RF-5 RF-7 RF-6 RF-8 TRANSFCALMER VAC S4-D Z S4-A 4 RESET N a- BROWN BALANCNG MOTOR CADMUM SULPHDE CELLS (2) SERES RB SGMA PAL 800 CPS RELAY RB- 0 LO FTRP Cn r a RESET RESET RESET RECTFER FEDERAL 2OOma 10O6A Z NTERUPTER CONTACTS S4-C 30 Cf) 4 POLE 4 POSTONS 3 RANKS S4-B m OK f W W 16 mf 450V DAGRAM SHOWS SWTCHES N PRESENT SCALER RH 3 10OV -0.1L / CAMERA TOPOWER SUPPLY STEPPNG W mf AUTO. ELEC. CO. RELAY byOV AC C7 Z a R-C P LOT LGHT( > 27 St > 1W M COL RH -2 o-2 RH N a 2709 w M CROSW TCH *CAM OPERATED MCROSWTCH RE9 SCALER 0-S CP RACK OPERATED CLOSED ONLY ON POSTON +.- RF9 WPERS TO STEPP ND SWTCH CONTACTS MODFCATONS BRONEECTRN BALANCE UNT 4 5 ~ PLOT LGHT TOGGLE " 6 vvv - SWTCH TURN HELLPOT 2752 W TOGGLE SWTCH 10 W, FEDERAL A 200 MA RECTFER mf 450V. 1 68K 70 K DAGRAM SHOWS CHANGES N COMMERCAL SCALER FGURE 3 AEC-GE RCHLAND. WN. CRCUT DAGRAM

16 UNC LASSFED HW Trans - Rect- 2 A former fer Slow Blo 50 Mfd 50V 110 V from Scaler 3.9 K R-J Plot Lght Push M. S. Operated Button By Relay J Cam Operated Mcro- Swtch A B C Camera Socket A B 4)C Flm ndcator Swtch Shutter ndcator Swtch Camera Shutter Solenod --a1 FGURE 4 WRNG DAGRAM FOR AUTOMATC CAMERA AEC-GE RCHLAND. WN UNC LASSF ED

17 -15- HW wry FGURE 5 COMPLE TE SYSTEM N OPERA TON AEC-GE RCHLAND. WN.

18 z F L.' V 3 r 0 6 'y 4 - skk 'p z 1 FGURE 6 w tl RACK AND NDEXNG MECHANSM

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