Chemical Instrumentation S. Z. LEWIN, N e w York University, Washington Square, New York 3, N. Y.
-a-
feature
T h i s series of articles presents a suruey of the basic principles, characteristics, and limitations of those instruments which find important apThe emphasis is on commercially available plications i n chemical wmlc. eqzcipn~ent,and approximate prices are quded to show the order of magnitude of cost of the various types of design and construction.
13. Nuclear Radiation Nucleor-Chicago Corp. An extensive line of nuclear radiation instrumentation, a8 u-ell as radioactive sources and standards, labeled compounds, detectors, and training kits, is manufnctured by the Nuclear-Chicago Corporation, Des Plaines, Illinois. This rompany's instruments run the gamut from small survey meters to a. subcritical training reactor, and are currently in nidespread use. Survey Meters. Tho line of partable, battery-powered, radiation survey instruments includes a count-rzte meter employing Geiger-Miiller tuhe detectors (Model 2612M for general heta-gamma survey work, with a Model D50 thin glass-wall G.M. tube, $255; Model 2612P for al~lso surveying for alphas and neak betas, with a. Model D35 thin mica endwindow tuhe, $295). The circuit uses two hearing-aid type vacuum tubes, a 25microampere read-out metor, crystal earphones, and a 900." stabilized audio oseilliator high-voltage supply for the G.M. tube. The battery complement consists of two 1.5-v flashlight, type cells, and two 67.5-volt portable radio type cells. The ranges are 0.2, 2.0, and 20 mr/hr full scale, and the accuracy is +lo%. A calibrated reference source is mounted on the instrument ease, and the output signal ran be recxlibrated as oitcn as desired by means of s. screwdriver adjustment accessible to the user. This basic instrument is also available in a modified form designed for use with epecial detector probes for alpha and neutron survey work (Model 2112P, with Model AP4 alpha probe, $445; Model 2112P\', with Model DN3 neutron probe, 8670). The counGrate meter cirouit is modified to adjust the time constants to t,he eharaoteristics of the probes, and a transistorized high-voltage supply based upon three 1.3-v mercury batteries and two 67-v batteries is employed to provide the probe voltage. The alpha probe consists of an unsealed air proportional chamber with an active a r m of 75 cm2 and a window (of rubber hydrochloride, Aquadag-coated to minimize sbatitio charge effects) thickness of ca. 0.7 mg/am2; mountcd on the hark of this chamber is a transistor amplifier uith n gain of 100, whieh raises the signal due to the alpha pulses from its initial value of
0 0025 v to the 0.25 v necemary to trigger the caunGmte meter circuit This probe will detect as little as 2 alphas/cm2/min. The neutron probe rontains s, brasswall counter, s/a-m. in diameter and 3.5-in. in active length, filled with B-10 enriched BFa. When thermal neutrons interact with B-10 nuclei, the following t r a n s formation occurs: n
+ B-10
-
Li-7
+ cr
The alphas generated in the probe chamber produce an ionization current, and are detected by the type of circuitry described above far the alpha probe. For the detection of fast neutrons, the prohe is supplied with a removable, 1-in. thick, paraffin shield with an outer liner of cadmium. When this moderator is in place, slow neutrons (i.e., those with energies below the cadmium resonance a t 0.176 ev) are absorbed by the cadmium liner; the more energetic neutrons pass through this shield and enter the paraffin moderator, where they are slowed down to thermal energies before entering the counter tube. The neutron prohe is insensitive to gamma radiation intensities as great as 50 r/br. A survey instrument is also available which contains two neutron probes, one for thermal neutrons and a second, in a wax block surrounded by cadmium, for fast neutrons (Model 2715 Nemo, $1350). The range is 10 to lo4 neutrons/ema/sec, and is read-out on a single, logarithmic meter scale. Survey instruments for the monitoring of fairly high field intensities and which are designed with a pistol grip, so that the unit can be aimed a t the area to be sur-
consist of a main body cont&ing the power supply, amplifier, and read-out meter, and a detachable ionization chamber unit. An example of this type of instrument is shown in Figure 34. The ionization current generated by the radiation field is preamplified in a feedbackstabilized electrometer cirouit which is sealed into the ionization chamber housing, and further amplified in the main body of the instrument. Model 2586 ($365) is supplied with a 500-e~cylindrical ionieation chamber, and is suitable for m e a s
Figure 34. A "Cutie-Pie" gun-type portable survey meter (Model 2586 of Nucleor-Chicogal. The sensor is a detorhable sylindricol ionization chamber with sealed-in electrometer preamplifier. The body of the instrument contains the power supply, amplifier, read-out meter, and pistol grip.
wing beta or gamma. radiation up to 2500 mr/hr. In order to m a s u r e higher intensities with the s m e circuitry, it is necessary to reduce the volume of the ionization chamber, so that the detector current remains within the limits imposed by the charact,eristics of the electrometer tube. Thus, Model 2586P ($395) is supplied with a 5-ce ionization chamber, and it can be used for radiation intensities up to 250 r/hr. Also t~vailahle is the Model 25868 ($475) whieh is supplied wit,h tu-o interchangeable chambers; one gives instantaneous dose rate information, and the other provides integrated (i.e., tobal accumulated) dose measurements. Ratemetem. A ratemeter (or, eount-rate meter) does not diRer in principle from a survey meter; i t is common practice among instrument mmufacturers to employ the designation "survey meter" for instruments whieh are portable and of limited accuracy (probable error=tlO %, or more), and to designate as "ratemeters" the nonportahle, more elaborate inst,mments intended for use a t the laboratory bench. Such ratemeters are widely used lor monitoring the radiation level at a working area, for ohecking radioactive contamination on hands or apparatus, for mapping out the diatrihution of radionctivity in s. region, and for conducting rapid, moderate-precision assays of ores, solutions, and other samples. The Xuclear-Chicago Model 1613A "Classmaster" Radioactivity Demanstrator (6195) is an inexpensive ratemeter with a numher of accessories specificslly designed for use in classroom demonstrations of some of the properties of beta and gamma radiation. The radiation intensity being sensed by the Geiger-Miiller tube is presented as a. meter deflection; to enhance the utility of this instrument for the classroom, a neon lamp mounted on the front panel flashes a t a rate proportional t o the rate of pulsing of the G.M. Volume 38, Number 7, July 1961
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A457
tube, and thus provides a second form of visual read-out. Simultaneously, s built-
in speaker produces audible clicks at the (Continuedon page A4601
DETECTOR
-7-
COUNTS
I THYRATRON \,
I
SPEAKER
AVERAGING ClRCUlT
It
HIGH V O L T A G E SUPPLY
-
L O W VOLTAGE SUPPLY
4
t
SELECTOR
METE-
Figure 35. Block diagram of lhe circuitry contained in the Nuclear-Chicago Model 161 3 A Clorrmorter radioactivity monitor. The dircriminotor posses 0.25 volt pvlres to the thyrotron tube amplifier, which presents reshaped pulses for three different sirnultoneour types of read-out. The meter con read either counts per minute or voltoge, depending upon the position of the selector switch.
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same pulsing rate tto provide a third form of read-out. A block diagram of the elertronie eirouitry of this instrunlent is given ia given in Figure 35. The Model 1619A "Lalitron" ($325) is a more prpeisr instnzment designed primarily for monitoring watk .4 highvoltage supply that is continuously variable from 600 v to 2150 v is provided, and the amne meter that servps for read-out, of thc counting rate can be employed by means of a selector switch to measure the voltage that is being applied to the G.M. tube. The 0.25." pulses from the G.M. tube are reshaped in a flip-flop (univibcrtor) circuit and fed to the inbegrating (caparitor storage) circuit. A loudspeaker with adjustable volume eontrol provid~sa simult,aneous aural indication of radiation intensity. A connector is provided s t the rear of the chassis for the attachment of any l-milliampere recorder, so that a continuoup record of radiation intensity ran lhe obtained as a function of time or of loention of the probe. The Model 1620RS Analytical Count, Rate Meter ($675) is intended t o provide the maximum preri~iorr possible with a ratemeter rend-out, i . ~ . ,to keep all errors and nonlineerities below the precisian of reading of the output meter. The main problem in constructing a precision ratemeter lies in the necessity of insuring that the same charge is fed to the integrating capacitor for every primary pulse, regardleas of the size, shape or duration of the pulae, and independent of variations in the charseteristics of components and vacuum tubes, or of fluctuations in the supply voltage. The degree of sophistication of t h e circuitry needed to achieve this result is illustrated by the block diagram of the Model 1620 given in Figure 36. The lower half of the diagram represents the power supply. When the instrument is turned on, a 3 k e c delay switch ( K - I ) prevents the high-voltage from being applied to the high-voltago rectifier until any transient overshoots have dipd sway and the tube8 have warmed up. The upper half of the dingram shows the ratemotor circuits. The input pulses, a-hich must exceed a n~inimumvoltage that is gonerally chosen ns 0.25 v because this is the size of the pulse usually produced in a. G.M. tuhe detector, but which can he set for any value in the range 0.1 to 1.0 v, are fed into amplifier and pulse-shaping circuits, and finally to the storage (integrating) circuit. The voltage built up on the storage capacitor is amplified by a dc feedback amplifier (V-6), in which the output is fed hack t o the input through the time constant, RC-delay, circuit (not shown). The ~mplifieroutput is read out by means of a vacuum tube voltmeter (VTVIW), and simultaneously by a loudspeaker. The bask cirouit error in this instrument is less than 10.25y0; the over-all error is determined by the D'Arsonval meter movement and is about f2y0of the meter reading. The loudspeaker system which is incorporabed for aural monitoring has the unique feature of giving a. tone that varies in pitch in proportion to the eounb ingrate. The frequency of the oscillstar, V-8, iis cont.rolled by the Vl'VA'nl output,. A distinct change can be detected aurally (Continued on page A4621
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Figure 36. Block diogrom of the circuitry of the Nuclear-Chicago Model 1 6 2 0 Analytical Count Rote Meter. Lower half of diagram ,hour the power supply sections; upper half shows the ornplifler, puke$hoper, m d read-out circuitry.
for very small changes in tho counting rate. Connect,ions nrr also pravidod for sbtaching this ratemeter ont,~,ut to pithcr a 1-milliampere direct deflection recorder, or a 10-millivolt potentiometer recorder. The most recent developments in this line of ratrmrtrrs comprise t w o units that, are part of this rompsny's so-railed "Logic" scrim of instruments; this series
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consists of a nurnher of modular units whirh can be assembled into a variety oi integrated counting and spectrometry systems. The I\Zodd 8:150 Linear Ratemeter (51085) is s. precision instrument which will aerept inpubs from any G..\I., porportional, or scintillation detector. The ranges are from 300 up to 10' cpm (Continiced on page 11464)
fu to ti: cc 0,
T (91 or ra
Pi ra of soale deflection by means of the "Decades Full Scale" select,or switch. The "CPM Suppressed'' switch permits lo2, 10", 10" 106 or 108 cpm t o be selected as the lowor limit of count rate shown on t h e meter movement. The "+I00 Volt 1)isc." control is a. ten-turn variable potentiometer by means of which the discriminator level can he set with precision to any voltage between +5 and +100v. Seale~s. This manufacturer produces a variety of scalers t h a t include binary, hinzry-decimal,. glow transfer, and beamswitching sealmg stages. The instru-
A464 / lournal of Chemical Education
Figure 38. Precision generol-purpose radiomctivity measuring instrumentotion o f NuclearChicago featuring in-line numeric01 read-out. The charsir shown are, from the boltom: o preamplifier (the m o l l vnit ot the left), o bare vnit Iconloining cooling fan blowertl, a high voltage power supply unit, a scaler unit, and o timer unit.
ments in culrent production are sum-
(Confini~edon page A.487)
Table 2.
Model
Type of sesline
-
161A Binary
Nuclear-Chicago Scalers
Soale factor 25fi
151A Binary-Decimal
2 decades
181B Binsry-Decimal
:I decades
183B Binary
Resolving High Input time voltage sensitivitv" fmicrosec) . . suoolv , .. fv) . . Price
.
0.25~ 5
l or 5 by
251;
l86A Binary-Decimal
3 decades
I
192B Binary-Decimal
4 decades
I
202
6 or 10decades (the 4 decades of the
Rinary-Decimal
82.50 Rmm-witching
the scaler) 6 decades
marized in Table 11. The sealer roadouts arc in most cases by means of neon glow lamps within the waling stages, and by digital register for counts exceeding the highest scaling factor. I n the case of the Model 8250 sealer (see Figure 38), which is a member of the new "Logic" series of instruments, the rend-out is by the so-called in-line numerical presentation. This form of read-out is illustrated on the instrumontation shown in Figures 38, 40, and 41. Each of the decade sealing
50(t
1mvto 2.0 v
1
002to5 1 v negative 5tolOOv positive
selector switch
$
675
3000 5002.500 50Cb 5M10 5005000 50s 5000
none
tubes is a. "Nixie" tube (trademark of Burroughs Corp.), which is a. type of glawtransfer tube (see earlier discussion oi this type of component) in which the various position8 and configurations of the gaseous discharge are so shaped as to form sequentially the s ~ r i e sof numerala from zero through nine. Sample Handling Systems. Among the complete counting systems ollered by (Continued on p q e A4881
Volume 38, Number 7, July 7 96 7
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Figure 39. Conrtrvction of the paper strip feeder "red with the Nuclear-Chicago Model ClOOA Collimator slit selector is shown a t left. Acligroph I1 chrornotogrom ,canner.
this menufacturcr in an automatic lawbarkground system employing s, flow gas detector and a cosmic ray guard detector in an anticoincidence circuit, an automatic sample changer holding up to 35 samples, and a printer which makes a record of each sample number and the time required to reach a preselected total count (Model C115 System, without sealer t ~ n dprinter, 54125; lZlodel C l l l R Printing Timer,
$770). Bn automatic sample changer for up to 49 gamma-emitting specimens is based upon a ~cintillation ud-detector into which the samples are lowered (Model
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C120, $2495). A sample handling system for liquid scintillation counting of r e a k heba emitters, such as C-14 or H-3, includes a tnmperature-rh;rrt recorder. Thc spectrometer circuitry is design~rlso bhst the input signals in the two eham~clsmay he? added or subtracted, as desirrd, or the two channels may he rcnd out separately. The- print-out speed is 4 channels per second. Gamma ray spectrometers are gaining 1rspidl2-in popular it^., 1argel.v because of the iart that scintillation detection is capaide of greater sensitivity, reprodueibilit?-, and specificity than any of the other detection techniques. The nprrtramctcr permits the maximum use to he made of the iniorrnation potentially prrsent in t h r output of the scintillation dctwtor. Alan, ~rintillstion detectors can Iht. eonlhintrl in various ways, e.g., in pal; nllrl as ellon-n in Figure 44, which are not ~mwtical for eleetricnl puke detectors (:is distinguished from thrae, which :trr nptieal l~ulscsmsors).
algebra of the binary nurobcr rystcm, thc total nunher of pulses fed to w givon loration on the memory core can he mad out, a t any subsrquent time by determining the states of magnctiaatian of the various ferrite discs. This stored digital informstion is read out dir~otlyon tho printcr, and is also oonverted hack to an analog form for presentation on the face of an oscilloscope ( C R T = cathode ray tube)
Radiation Instrument Development Laboratory
.I complete linc of detectors, sourers, m ~ drlwtronic gear for radiation moasnrement is also available from Radiation Inetrummt Uevelopmcnt Laboratory, Sorthlake, Illinois. This manufacturer has specialized prinripally in the production of clcctranic gear for laboratory mensurements, as distinguished franr, e.g., survey mrters and pcrsannel dosimeters. The instruments currently in productiorl include representatives of the t y p e of polver supplies, amplifiers, rate(Confintiedon page A476)
netic core mamory unit, analog-t,o-digital ronversion, cathode ray tube display, and prmter rnrd-out.
Radiation Counter Laboratories
CATHODE FOLLOIL.
Figure 42.
Block diagram of the Victoreen Model ET-l Flight-+Time
metem, scalers, low-level collrlting ~ y d e r m , pulse height analyzers, and spectrometers already described above in connection with other manufacturer's products. An interesting feature of several R.I.D.L. scalers is the numerical read-out, indicator illnstmted in Figuro 45. I n t,his case, a convent,ional dccimnl sealing stage is employed, and the tobal number of pulses received determines which of thc ten lamps will be lit a t any moment. The lamp that is on projects an image of of its associated numeral onto a viewing screen. This gives a larger visual presentation than is commonly used on decimal scalers. R.I.D.L. has been active in the devclopment of multi-channel analyrers, and has produced models with as many as 2000 channels. Currently, trsnsistorized 200and 4Okhannel analyrers w e in pradnction. These instrumpnt,s utilize a mag-
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Figure 43.
Detector.
OUTPUT
A particularly extensive line of nuolenr detectors and electronic gear is available from Radiation Counter Laboratories, Skakie, Illinois. This company manufactures a wide variety of G.M., proporbional, gas flaw, and neutron deteotors, as well as specialized glassware and accessories. I n addition to a full arsenal of conventional vacuum tube instruments, this n~anuiacturerhas introduced a complrtr: line of tmnci~torised instrnnlenk
Block diogrom of the Victoreen Model ST-200D.duol input 200-channel spectrometer.
composed of modular huilding blocks which can be combined in a. variety of ways to form different systems. I n addition, each module contains its circuitry in the form a i plug-in printed circuit boards, which can be quickly and conveniently removed for testing, or replaced iar repair or to redesign the module. This type of instrument design is shown in Figure 46.
Figure 44. A typical low-level rcintillotion counter in which a ring of photomultipliers surrounds *he scintillotor well.
Tho four-module instrument shown consists of, from right to left in t,he Figure, a high voltage supply (No. 20703, Q615), a linear amplifier with discriminator (No. 20112, $535), a. five-decade sealer (No. 20303, 8920), and a timer (No. 30004, $643). A low voltage supply (30.20710, $550) is also required, and is contained in the in~trumentcabinet a t the rear a i the modules. The scaler modulo e m be replaced by ,y ratemeter module ii continuous read-out is desired. The linear amplifier module can be ~uhstitutedhy a single-ch:~nnel pulse-height analyzer if spectral analysis is required; automatic analysis can he obtained by using an electronically swept single-channel analyzer module, and connecting a recorder to the output plug of the ratemeter module.
Figure 45. Numerical read-out display unit utilized in some of the inrtrvmentr of Radiation in~trumentDevelopment Laboratory. The numem1 tho? is seen is selected by electronic choice of one of the lampr, which then projects the imoge of the digit in i b path onto the screen.
R.C.L. has heen one of the pioneers in the rnmmeroial development of gamma ray spect.rometers with magnetic memory cores, and its most rceent instrument of this type is a 2048 Channel Analywr with ( T o r d i k e d on page A47n)
Volume
38, Number 7, July 1961
/
A477
Figure 46. lllvrtrating the design of the Rodiotion Counter Laboroforier line of tranrirtorized nuclear instruments, featuring the use of plug-in circuit boards and moduior canrtruction.
which i t is possible to usc 16 different. inputs of 128 channcls cach, or any r o w binntion of thcse unita. Othrr specialized R.C.L. imtrumentntion includes a slou.-neutron time-offlight analyzer, s. 54ecade glow tube scaler kit (No. 20304K, $249), a noutron generator for nuclear activation work, and walk-in, low-level counting systems for. whole hody monitoring.
Other Manufacturers The preceding descriptione should suffice
t o show the great variets of commercial instrumentation currently available in t h e nuclear field, and the multiplicity of manufacturers. Those companies which have been treated above are, however, only several among many in this field. Space does not permit giving equal treatment to all the instrument makers who are currontly producing nuclear measuring equipment. The companies t h a t were selected for detailed description above were those which produce the prinicpal types of instruments either in their most typical (Contin,ued on page 6480)
Volume 38, Number 7, July 1961
/ A479
form or in a form most amenable t o this type of descriptive explanation, Since the principal types of commercial instruments have now already been treated, in the form of specific examples, we shall now only List the remaining major producers and distributors of these types of instruments. Ad-Yu Electronics Lab., Ino., Passaic, New Jersey--delay lines. Ameray Corp., Kenvil, New Jersey-shielding. American Tradair Corp., Long Island City 6 , Yew Y o r k i n ~ p o r l e rof EKCO Electronics, Lld., England, scalers, scinlillalion, counting systems, &lectors, general electronics. Applied Physics Corp., Cary Instruments Iliv., Monrovia, C a l i f o r n i a i a i z a t i o n chambers and electrometer amplifiers. AtamafitersBuntaine Corp., St. Louis 22, Missouri-distn'bulor oj'sa?,rple preparation and handling epipmml, and electronic pa?. Atomic Accessories, Inc., Vallry Stream, S e n York-disln'butms o,l emplete line of nuclear supplies and instrrmrenlalim~, including training aids and kits. Atomic Center for Instruments and Equipment, S e w York 17, N. Y.-distributor of survey meters, scalem, other qrripm~nl. Atomic Products Corp., Center !Koriches, Long Island, New York-aucessories and handling equipment. Atomium Corp., Wdtham 54, Xnssachusetts-specialized detectors and countingsystems. Automation Inc.. Los Aneeles 44. California--precisi& scaler. Baird-Atqmie, Inc., Cambridge :38, Massachusctts-cmnplete line qf electronic geat and eotmting systems. Bcckman Instruments, Berkeley Division, Richmond California-electronic timing, counting, and digilal printing equipwzent. Uetectolrth, Inc., Chicago 26, I l l i n o i p probes and p ~ e e i s i aelectronic gear, including spect~ometers. Eldorada Elcctronies, Berkeley 10, California-precision electronic gear, from sealers lo spectrometers. Farro Scientific Co., Evamton, Illinoisradioehron~atogramscanner. General Electric,Schenectady, New Yorkdetectors, andsome eleetraie unils. Gym Electronics Corp., La Grange, 11linois-pawe? supplies, eledrovbele7 awplifiers, mlemele~. Hamner Electronics Co., Inc., Princeton, Xeu- Jersey-precision electronic gear from powcv supplies lo automalic gamma speclrornetem; also some detectors, esp. n e t d m counlers. Heulet,t-Pnckard Co., Palo Alto, California-eleelronic countem, limers and digital printer.?. Hughes Aircraft Co., Nuclear Electronics Lab., Los Angeles 45, Californiasolid slate radialion deteelors. Hupp Instrumentation, Los Angeles 25, California-electronic limms and counters. International Nuclear Corn... Xashville 11, Tennessee--scalers, pulse height analyzer. Interstate Electronics Corp., Anaheim, California-coincidence analyzer. Isotopes, Inc., Westwood, New Jerseyphosphors, betaflow counter. -'
.
(Conlinzied a page A@$)
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John Fluke hlanufaeturing Co., Seattle 99, Washington--powev supply. Kahl Scientific Instrument Corp., El Cajon, Califarniaimporter of nuclear electronic gear made bv Frieseke and Horpfner, Germany. Land-Air, Inc., San Leandro, Californiasurvey metem, monitors. Landis and Gyr, Inc., New York 36, New Y o r k i m p w t e r s of G.M. tubes, survey metem, sealers nmde by Landis and Gyr, Suiberland. Nuclear Corporation of America, Denville, New Jersey-mmple preparation deuice. Nuclear Enterprises, Ltd., Winnipeg 21, Manitoba, Canada-phosphors, scintib lotors, somedetection epuipwwnt. Nnrlear Instmments and Accessories, Inc., New York 10, New Y o r k 4 i s tributo~ of complete line of detectors, handling epipmcnt, and shielh; some electronic gear. Nuclear Measurements Corp., Indianapolia 18, Indiana-complete line of detector mounts and counting systems; specialization in moniloring instrumahlion Joy awas, atmospheres; gamma spectrometers. Nuelear-Ohio, Inc., Bay Village, Ohiodelectors, yemole pipeller. Nucleonic Corporation of America, Brookl~-o31, New York-eon~plete line of detectors, nuclear accessories, electronic gear. Picker X-ray Corp., Nuclear Division, White Plains. New York-corndele line of detectors and electronic gear, much of i t designed f m training and medical applic~tions. Pilot Chemiesh, h e . , Watertown 72, Massachusetts-phosphm and scintillation detectors. Planehcts, Chelsea, !dirhignn-sample preparation supplies. Radiation Equipment And Accessories Corp., Lynbrook, New Yorklleteclor eryslals, sample preparation and handling equipmad, sealers. Sharp Laboratories, Ine., La Jolla, California-low level beladelectionsystem. Technical Associatetes, Burbsnk, California-nutomalie sample ehangw. Technical Mensurement Corp., North Haven, Connecticut-pulse height analyzers and data handling eg.uipmen1. U. S. Nuclear Corp., Burhank, California-sowces, delectors, monitors, scalers. Universal Trltnsiator Products Corp., Westhury, Long Island, New Yorksurvey meters. Wdkirt Co., Inelewood, Califarniacamting cirnritrg,.
BIBLIOGRAPHY Teachers interest& in oblainthg fedwal aid in setting up course work in nuclear fields should consult: U.S.A.E.C., Division of Biology and Medicine, "Grants for Purchase of Equipment in the Fields of Nuclear Technology as Applied to to the Life Sciences, Feb., 1959 (Rev). U.S.A.E.C., Office of Isotopes Development, "Grants for Equipment t o be used in Radioisotope Technology Edocntion," Oct. 1, 1959 (Rev).
,
Nezt: Chromatoyraphic Equipment.
A482 / Journal of Chemical Education
