Teaching radiochemistry at Massachusetts Institute of Technology

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TEACHING RADIOCHEMISTRY AT MASSACHUSETTS INSTITUTE OF TECHNOLOGY CHARLES D. CORYELL and JORN W. IRVINE, m. Massachusetts Institute of Technology, Cambridge, Massachusetts

THE DEVELOPMENT OF RADIOCHEMIgTRY nature (of great interest in geochemistry and in chemical It is just fifty years from the discovrry of radio- cosmogony) are principnl parts of the subdivision of ~ Accordinp; to the latest tabulation activity by 11. k q r l e r e l (189.5) to the detonation of 1 8 0 1 0 ~chemistry. ( 1 ) . 272 stable nuclenr slxcics are found in nature, tothe first atomic bomb (July 16, 1945). n u t only thfifths of this period wns rcquird for the clevelopment of mther wit.h 10 \.e.er2- long-lived species that can be atomic pllysics from the discovery of the rleetron hmdled ns if stable. The number of rndionnclides (IT. C m k r s and J. J. l'lIomson, 180.5) nn(l the x-ray k n o w is over TOO a t the pre.scnt date. Cl~emicnl (IV. C. Riintw, 1895), through the work of 11. Planck, work with rndioart ire nrntcrials compriws the s u b A. Einstpin, N. Bollr, nnd :I. Sommrrfeld to the division of radioeliemislry. This is the chemistry of hiinewn-like l,irtll of tllr qllantommeellonics (I.:. the production, isolation, and identifirntion of radioSchrordinper, 1'. ;\. ht. Ilirac, I\'. IIeiwntrrg, 1925). nurlides, inCllldiIIp;tr:Lcer annlysis, trneing, and chemical Jleea~~.se raflioaetirity wns disco\.rred by physicists and studies of phenomena associated witlr nucleogrnesis the chemical i ~ s w t s\vere exploit^ rflwtivrIy by (hot atom chemistry). llnrie Sloclowskn C ~ ~ rf ioeu n d d them, and h e c n ~ l the . ~ ~ w r kwas rplatal t o rind over- rndiochemistr?. in her searrh for radium, and a t the shado~ved by atomic physirs, nrlclrar chrmistry h m =me time f o l d e d its enginering annlopue radiochemienginrering, on whir.11 the rnrli~~n~-menothori~~mnot until this decade meived a frnction of tllr attention polonium industry rests. Chemicnl problrmu wnit deserves from the chrmirnl fratrrnity.' M o r e ~vrKO much further in n disrussion of nuclear tinted with the interactions of high-speed p:$rtirles and chemistry and rndiochrmistry, a few definitions are in 11igh-enerm eleetromwetic radiations with matter ordrr. Nuclear rhrnrist.ry deals wit11 the chemical m:rke up the field of rwladian cl~onisfrr~. a-pwts of IUlclear tr:msformntion, of the separation and Isotope chemistry is limited to the 61 elements ,\.ith study of nurlear sprcirs (stnhle or radioactive), of t,,.~ or more or near-stable isotopes forlnd in radioactive rlrrny, i~ndthe I I W of nuelidm' as tools in nature. yntllrlll ,.ndioartirity of urnnirlm and thochrmicnl resenrcl~. rium provides 11s with six morr transitory elements ('hemicnl w r k with nonnntural mixtures of isotopes, (polonium, ,.dillm, nctinillm, radon, protartinillm, or interpret:~ti~~ns of drrintions from the nonn in frnnrium), which were found nnd chnmctrrizrul with the t ~ ~ h ~ ~priw b l have frequently boned nu- terhniques of rndioel~entistry. The.se were first dereldear phyairista with Nohel P r i r . in Chemistry: E. Rutherford oped I>?.lime. Curie in 1896 and Inter extrnrlcd by A. ( ~ m )M. , S. Curir (1911). F. W. Anton (1922). and F. and I. Del~ierne, C;. C. Schmidt, Soddy, Rutlirrford. F. JoliobCorie (1035). Surlear chcmiste have nlso hm rewadd pllllrt)l, A ~ S, l[eyer, ~ ~K. 1:&janS, , ~ l ~ =ise l ~ ~ , by thocommitlw: F.Salrly(192L).II. C. Urey (l034),G. Iievcsy ll"itner~ F' ' Darn* others in the next years, (1043), find 0.IInhn (1944). For the mmplete picture in nuclear science to dnte, \vr mny wld thcnamesof the prizewinners inc.hlciing in the United Stntm, J I . N. MrCoy, R. B. in Suclrar Physics: A. A. kquerrl, P. Curie, and 11. S. Curie I~nltn.~rnl, H. Schlundt, and S. C. Lind. l'ransitory (lm?),A. It. Compton and C. T. II. Wilson (1927). J. Chsrlrick specirs in the naturnl rnrlionetirity fllmilies furnish (19351, V. 1.'. llarsand C . D. Andemon (lQ36). 1.;. Femi ( 1 Q W . trnrrrs for thnllillm,lnl(l, bismuth, rind tllorillm, E.0.Laannrc (1039). P. 51. S. Rlacketl (1947). Il. Yuknwa (1048), C. F. Powell (1940), and thnt of one rncliobiolallist prim With the di~covrry of nuclear transmutation hy winner in hldirinr, If. J. hlfillr.r (1941;). I n t h r judgmcnt ~ , ~ ~ h ~in, 1918, + ~ rfollo,,.ed d by tile development of the of them &mmit.tms, nuclear chemistry hns not been set spnrt rlrrtronuclear accelerators of J. D. Cockcroft, R. J. from nudear phyrim. ' T h o word rantops, as defined by F. Soddy ( d ) , is applied to Vnn de Ornnff, and esp+cially of the cyclotron of E. 0. one of ~everal nuclear specin, of the same nuclear chnrge 1,nwwnce (1932) and the discovery of artifirinl rndio(proton number) but dimerent maas number, ~ W P Y activity ~ ~ K by the two JolioeCuries (1934), science was the Pame place (ww r m ) i n the periodic .Wtem. Nllcle~r presented a flood rndionllclides, ,\.ith isomers, of the samc proton nurnher Z and neutron numhr .\', useful radioisotopes of all of the 81 stable elements, and A, are known; the= dincr only and thus the msp.l in quantum numbers and enerm mntenta. T. 1,. Kohman (3) nll other elements up to nnd inclucling plutonium. has introduced the word nwlidc for "a specin, of atam rhnr- The slo\messof to partiripate even in the acterircd by the conatitntion land e n c r ~ofitn l nucleus" Note 8tll,jyof many nccessible syntlletio elements is that the chemist works with nuelidea, not with bare atomic in ,lie illustrated by the w r y few papers by chemists challengnuclei,and tl,Rt tho word isotope is oftcn misnpplid in^ the fantastic stnlcture of claims in l93t-I939 for newepapcrdominstd world.

JANUARY, lsSl

t ransumnic elements. The world-shnking discovery of the fission reaction !\.as made, however, by the most difficult path-the chemicnl o n e b y 0. Hnhn nnd F. Str~wmnnn(4) in 3938 in Berlin, after nn honornhle fnilurc by Mme. JoliotCurie and P. Snvitrh (C). The profusion of cyclotrons, especinlly in the United Stntcs, hnd, however, given imprtus to the sprend of rndiorlwmistry nmong physirists, to the trnining of cyrlotron rndinchrmists, nnd to the orienting of medicnl w ~ r k r n to the utility of rrulionctivity in re.senrch nnd thcrnpy. l'hr chief crnters in this r o m t y were a t the University of Cnlifornin nt Iierkeley (where seven s-ynthctic elements were destined to be synthesized), C'hicngo, h v due, Michigan, Rochester, I'rinrrton, Columhin, Ynle, Hnwnrd, nnd 32. I. T. On Dec. 6, 19-11, work on all aspects of nuclenr e n e r q began in great earnestness (6.7 . 8) nncl the tasks nnd proqwcts of rndiochemistry nnd isotope rhemistry, in nll thrir rnmificntions, commnncld the nttrntinn under strict cover of thousnnds of chemists nnd chemicnl engineers. Except for n relatively few prefiwion rndic* rhrmists,'most of the ~vorkersinthe field in thiscountry rercived apprenticeship a t one of the wnr lnhorntories or a t their successors uncler the Atomir Enrrgy Commission. Uecnuse of the existence of n vigorous nntionnl prcgram in research in nuclenr science, awocinted with govrmment-sponsord militnry nnd industrinl drrrlopmcnt, cmploymmt prospectn in nuclenr chemistry hare heen, nncl prnn~isrfor a long time to I*, excellent. If one mnsidrrs the rRort sprnt, h o v r v r in re.senrch in nurlenr physics, and in npplicntions of radiotracer chemistry in the nntnrnl sciences nnd in npplid fields likr m e t n l l u ~ resenreh , mrdirine, nnd medirnl dingnosis nnd thernpy, it will he seen thnt chemists in this country nre still bark~vnnlin nuclenr chemicnl research, nn they were in the prc-cyclotron nncl pre-fisrrion dnys. NUCLEAR CHEMISTRY AT M. I. T.

The end of World Wnr I1 found hfassachusetts Institute of Technology, with the authors ns senior stafl membern, representing the interests of nurlenr chemistry nnd its relntinns to inorganir and genrrnl rhemistry, and with the Institute prcpnml to lnunch a strong progrnm on nll fronts of nurlrnr science nnd enginrering not involving rlnnnified work. There hnd h n a brond p r q r n m in nuclenr physics hefore the war, with a legncy of an operating 42-in. cyclotron, eevernl Vnn de GrnnR machines, nnd mnny physicists npprecintive of the problems of nurlrnr rlremiutry. The npplied rndionctivity work cnmed out under the general direction of Prof. R. D. Evnns in the Rndionctivity Center had led to the infection of msny depnrtments with nn interest in tmeer techniques, nnd hnd been the 'The Berkeley g r o u p have had mch an important role thnt it may be useful to name the radiorhemista prominent there by 1941: W. F. Libby, 11. D. Kamen, S. Ruben, C . T. .%ahor& 13. !kg&, J. W. Kennedy. A. C. Wahl, G. Fridlnndcr, I. I,. Chnikolf, 1. Perlman. D. C. DeVbult, R. W. Stouphton, S. C . Etrelish, M. I.. Perlman, W. I?. Cohn, and A. S. I3rown.

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basis for much intensive coolrrative work with gmups in vnrious I h t o n hospitals. The evidence indicnted thnt the nuclenr chemistry work ought to be integrated well with the chemistry depnrtment's progrnm, especially thnt in inorgnnic chrmistry, thnt it should br taught with the minimum of physics necessnry to make it unclerstandnble, and that the course work ~hoolclhe oricv~trclfirst townrcl the chemicnl nnd t.lw npplied ~iclr111 Iw of benefit to genernl chemicnl resrnrrh nncl to rrsenrrh workrrs in enginrering nnd n~erlicine. Nuclmr rhemistry is tnught t d n y in severnl chnnnels. Two leeturn are givrn t o the first year chemistry course (Course 5.01 takrn hy all 31. I. T. students), one nit11 dcmonstrntions of the eRccts of a, 8, and 7 radiations, neutron nctivntion, nnd half-life (309 Rhlo%parnted by water extrnctim from RuI0' as mthenium tetrnxide in cnrhon tetmchloride). A seniorgrnrloate ronrae in instmmentnl nnnlysis (Course 5.15, tnught hy Profs. D. N. IIume and L. R. Rogers) contains a mnjor experiment in radiochemicnl n w y nnd Ceiger-counter behnvior. .4n introduction to nuclenr structure, rndimrtirity, nncl to the chemistry of the synthetic elements is given in the required senior coursc in inorgnnic chemistry (Course 5.061 of Prof. W. C . Schumh). The grndunte students in nuclear chemistry and those in physicnl, nnnlyticnl, and orgnnic chemistry who are using mdiwhemicnl techniques all report thrir renenrchrs in the appropriate grnrlunte m a r c h seminars in inorgnnic, physirnl, nnnlyticnl. and orgnnic chemistry. Indmt, thew nre three nutonornous groups of stnR nnd grncluntr students with mnjor c~mphasin on rndi~rhemistry, namely the inoxnnicnurlrnr chemistry group (Copell-Inine), the nnnlyticnl gmup with emphnsis on the nnnlyticnl chemistry of the f i d m product elements (under Profs. D. N. Hume and L. n. Rogers), nnd the orgnnic rndiochemistry p u p specializing in tracer studies of orgnnic structures and rrnction mechnnisms (under Pmf. J. I). Iloherkv). These groups contnin in nggregnte nbout 10 senior students doing experimental B.S. thesis work, nbout 25 utudcntn doing Ph.D. thesis wwk, nhont seven p o s t doctornl fello~vs,and nhout five technical mistants. In nddition, rndionuclidrs nre uaed ns nn importnnt resenrch t o d by three or four othcr m a r c h groups in physicnl nnd o r p n i r chemist.ry in the depnrtment. nnd by numemus gmups in metnllurq, f m l terhnoloq, mechnnicnl enginwring. and hir~loxy. The 1nst.itutr founded in 19-15 an interdepartmental facility known n.7 the Lnhorntop for Nuclenr Science and Engineering under the elircrtorship of Prof. J. R. Znchnrins of the physics depnrtment. The aasoeinte director is Prof. E.R. Gillilnnd of chemirnl cnginerring, and the dministmtive hend is Mr. M. 3f. 1lnl)hntrl. This body acts as a central aplrncy for supp~~rting activities in nuclenr science, for providing for tIw eonstmction and maintenance of heavy equipment, nnd for fostering active collnborntion nmong the rr.senrch staffs of mnny departments. A t the present date,

18

support is considerable in the departments of physics, chemistry, electrical engineering, and chemical engineering, when? interests interlock in a program for nuclrnr engineering as well as for nuclear science. Nnny chemistry students, unclergradoate nntl gradaate, tnke ns rlrctives the junior physics r o u m s in atomic physics (Course 8.05, I'rof. 11. 3Iurllcr) and introductory nuclear physic^ (Collm 8.06, l'rof. 31. Deutsch), nnd all tnke chemistry courses in atomic and molcculnr stmcture (Course 5.67, I'rof. R. C. Lord, or Course 5.i5, Prof. L. Ilnrris) which prove to be raluahle hnrkgrountl for nuclrnr theory. The majors in nuclenr cl~emistry takr, after the rndiochemistry corme d e s c r i l d helow (Courses 5.09, Rndiochemistry, and Course 5.091, Rndiochemistry Laboratory), severnl more of the eight prnduntc courses in nurlenr physics, especially one on neutron physics and nuclear engineering (Course8.57, Prof. C. Goodman). This last rourrre is the hnsis for the clevrlopment 111the well-known review of nuclrnr science nnd engineering edited hy C. C:oodman (I)). When the number of students with central interest in rndinchcmistry is larger, it is hoped to introduce a d v n n c ~ colloquia l in nuclear theory for chemists and in mdioactivit.y in chemistry.' The research interest of the grndunte students .seems to fnll about equally in the t.wo clnsses of interest. Severnl of the engineering departments of hl. I. T. are encouraging tbrir students t o tnke electives in nuclear science na a prepamtion for adnptation to the applied fields of atomic energ?l. The I n ~ t i t u t ehas for two years l w n operating n prncbice schrml jointly among the three operating plants in Oak Ridge (the diffusion nnd the r l e c t r o m ~ e t i cisotope sepnrat,ion plants, and the pile-radioehcmicnl engineering plant at. the Oak Ridge. Nationnl 1.nborntorirs) whrrr? qunlifinl N u a t e engineering students with AFX: security clearance receivc 22 w e k s rxperience in industrial nuclear operntions. This Oak Ridge Practice School, under the direction of I ' d . J. E. Vivian, is having a profound effect on the development of nuclear trends in engineering circles. Likc most of the universities of the country, hl. I. T. is m o c i n t d with the research-training program of the Atomic Energy Commission's National Laboratories, Iring officially affilintd with the Brookhavrn National Lahorntory na an nctive member of the Associated I J n i v e d i r s , Inc. This bond has been very important a t the faculty level, nnd with the starbup of the large 13rookhnven pile Aug. 22, 1950, and the completion of t h r IIot Laboratories, it is anticipated that fruitful exchange will occur a t the grnclunte student level. I'rcsent hopes to have an unclnssified face at the pile and to retain an unclassified area in the Hot Laboratory mnke the prospects much more attractive for us and for all other research institutions in the Northeast. 4 Pmhahly h a a d on A. C. W A AND ~ N. A. Ronmn. Editora, "Radionctivity Applied to Clmnintry," John Wilry and Sons, New Y d ,aeheduld far apprerxnm in 1951.

JOURNAL OF CHEMICAL EDUCATION LECTURE MATERIAL IN FADIOCHEMISTRY

The department of chrmirtry hns two courses in rndiochemistry intimately interrrlntnl. These are Coume 5.09, Radiochemistry, vith three hours of class and three hours of prrpnrntion n week for one semester (6 units), and Course 5.091, d i s c u x d in the next section, with three hours oi lnhorntory n week (3 units). The lerture course may he taken without the laboratory course 11ut the lnhorntory i~nckgroundis retained by detailed discussions of the lnhorntory experiments in one leeturc rnch week. The pnir of courses is o N r d in the fnll Remester, and it is open to outstnnding seniors in chemistry nnd physics, and t o gmdunte studrnts who have hnd physical chemistry laboratory and who have 11nd or are taking ndvancetl inorgnnic chemistry. Two outstanding new text 1)ook~are u w l for the course, that hy Fri~dlnnderand Kennedy (10) nncl thnt by Williams ( 1 1 ) . I%ecauseof the requirrmrnt thnt laboratory work stnrt in the mcond wrek 01 t l ~ c course thr lertures st,art with C h n p t ~ rVIII of the first. text and thr students receive rrprinta of 11 genernl introduction to rndiochemirnl memumment (1" nnrl rending assignments in R. D. Emns' chnptcr 1 of the Gorulman volume 1 (9). The order of presentation of lecture material is given in Table 1, togrther with references to topical pnpers that arc streswd in the course. Xumericnl problems are assigned nrnrly every week and t l i s c u d at the lecture on laborntory work. The problems are c h m n to emphnsize rhemical a s p e t s of nuclenr chemistry or applications to chemi&y or to the lnhomtory of the Iect,ure work (reactions and equilibria involving tnmsitory or svnthetic rlements, decay properties of unknown nriclides, counter effiriency, separations of species in ryrlotron tar&$. The stuclents are enc o u to~ explore the broad posibilities in research of the problems and to experiment with the techniques of intelligent estimation and the best methods of computntion. Four examinations of one hour each are given in 6he course. In Rome terms a p a p r is required of the student covering the nnclear nnd chemical ~ u i r e ments for the solution of a laborntory problem in applied rndiochemistry in n field of his interest. An effort is made to draw to the student's attention many of the important papers of recent date that represent new landmarks in a fnat-changing field. Some of these are nnclnsqified reports or derlndficd documents (MDDC or .\E('I))5 fmm the hlanhnttnn Project or the various Sntional Isboratories of the Atomic E n e w Commission. Others(20,$5, e6) represent major collections of mwnreh papers or survey papers of the Nntionnl Nuclear E n e m Series, a useful collection of information from the wartime work of the Ilnnhnttan Project, about half of which is now in print.'

' Ohininahla from the Technical Information Branch of the U. S. Atomic E n r w Commission, P. 0. f i r E, Oak Rid-. Tennee. 0 The Nationd Nudear E n e w 8eriea. in eight divisions, w publislwl for the Atomic Enera Commission by the hlcCrnwHill h k Company, X r w York.

JANUARY. 1991

measurements, nnd clualitntive nnalysin of @ spectm, into the chemical problems of fission, artivntion, nuclide wpnrntion, and the behavior of ions a t low eoneentrntionu. One experiment is devoted to the measurement of r-my energies. An out,line of the experinicnts performed is given in Tnble 2. The first experiment requirrs quite nn army of mdioactive mnterinls, dl hut Srqobeing borrowed, together with all nvnil:hle survey instn1mcnt.9 for fnmilinrizntion and cnlihmtion. In 1q;xprrimrnt 2, the stu~lents plppare a personal reference ,98-xt.nntlnrcl from lend foil TABLE I containing Ph"O, and study the wpnrntion and cor~nting of Rin0 from nnother snmple. - The Isst three experimcnts (10, 11, and 12) are o p The Fundamental Particlea tionnl a t the prewnt time. They allow the student Tho Suelcus with advanced interestq nn opport,unit.y for additional Spntnneoua Nuclear T m n s formstion (Rnclioactive work. New experiments will be ncldcd to this group, Ikeny) and as experience dictates they will be moved up into Intvrnctitm of Radiation Coryell ( I t ) , Glendenin (IS) the required group us ndditionn or auhstitutions. Electronic ecpipment for tho courrrc! consists of six i g e r - ~ e c r( G - ) countern and scnling units. Joliot-Curie (14) Spceinl S o b LRraoi(;mwth and Lhcay Four of these are rewnrch rqoipmcnt but nrc resewed Slweinl Sotcr. Brightan (16) mostly for course n w t\vo nftrrnoons each week for most of the term. The counters are commercinl unita Irvino (ISo.16bl ~arrctt'(17) . from various manufacturers housed in s h d n n l shields Corycll (1.9). I ~ n (I#) e as described elsewhere (19). The sealers a m simple Cory14 nnrl Supnrman ( W ) ( k x , h n n (9) binary scnlrof-128 constructad in the rlectronic shop G l m , Ihrkcr, nnd Tompkina (81) of the Lahorntory for Xuclcnr Science and Engineering. T i n (2P). A SjmpoThree Iauritsm clertraqcoprs are uecl in the standsiuw (2,i) S.ynthetic Elements, Heavy arc1 manner (I?). They all have bhin aluminum Elcmcnt Chemistry, nnd windows for @-my mensuremmt. A G-M flow-type FFnhora (t4, f6.26) the I'eriodic Syrtcm counter with snmple holder inserted is availablc and is Rndioehemienl Fq,nrstion; Speeial S o h h r s of ( h r y i t q used for the mea*urcment of w r y soft 8-mdintion. A Ch~.n~irnl ENwh 111 Nuclear 8cintillation counter a w m h l y is under constn~ction. Libby (n), Edwards nnd D w i m This i8 u flexible unit designed for a, 8, and y-my (28) counting. Integml nnd rliffcrential pulse height disLewis (B) criminntion will lx? po~qiblrwit,ll the equipment. DcVault (SO) Survey meters ancl personnel monitors are provided by the Health Physics Division of the Medical D e p n r t ment of >I.I. T. The ~turlentawear mdintion meters only when ork king with the neutron source or a t t.he Authorilrtlivc pnpora on fundnmentnl rticlm have m u d , cyclotron. The development of the responsibility of for instnnw, in Scienlific A m m i a n (G.%. tirnv) June, 1018; each mdiochemist to himself, his colleagues, and to his Phyairs 7 ' h y (R. 1'. Veynmnn) Junc, 1988; nnd Lifr. Oct. 10. inst,ruments and experimrnts is made 11 cornentone of 1'JIO. the teacl~ing. Since, the Geiger-Mueller countcrs are more sensitive by a factor of fnr more than n t,housnnd to activity than is u living orgnnim,' pemnnel are The labomtory work in radiochemistry is offered as a automntirnlly protected hy the precautions that lend eepamta coune in order thnt students from other to relinhle measurement. In the five years of ollr departments can take the lectures for credit without experienre no rase of significant personnel rontaminnthe lnbomtory. This division is arbitmry and does not tion or no ewe of serious contaminntion of countcrs reduce the claee interrelntion between the two counes. or absorbers has occumd. Thc counting room ir ep Three hours a week are nssigned to labomtory work nmte from the lnbomtory, ancl no uncovered sample mny although it irr admitted that t h r students find it neces- be brought into it. Radionctive mnterial nee& for the laborntory c o n m snry to devote some more time for prepnrntion and are not large. E ~ t i m n t eof ~ these needs are given in report writing. Experiments are designed to lead the student gradu' A rrsdi>~tion field giving 6 millimenQonn per hour (n rnnally through the elementary physical principles of servative current vdue for the maximum permiwiblo d m for nn detection nnd measurement of rndioactivity, radio- ghr. day) will give over ROO count* Irr rxvmcl in nn onlinnry active deeny and chain relation~hips, @-my energy Geiger-.\luller countPr. The remainder of the litemture references of Table 1 represent pnpers that go into Rome drtnil almut mbjecta pertinent to the intcrests of the instructors of the roursc. Pnrt of the philosophy of this courrrc! is thnt nuclear chemists should follow their own interests, ~ i n c ethe field is the crossronds between well-organized nuclear physics ancl the large variety of fields in c n ~ i nrcring, biology, and meclirine \vhcrc rndiorhemisty in an annlytirnl tool.

JOURNAL OF CHEMICAL EDUCATION

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Table 2. As can be seen, natural radioactive sources and radionuclides obtained from the Isotopes Division of the AEC constitute the bulk of materinl used. A g d neutron source of some type is neeewry for some

Outline of E.p.rirnent.

-

TABLE 2 f o r t h e Radiochemtstry Inbontorg -

-

3

Radimdirc d c t i a l for I2 aludcn(d

llcalth Physics Inrtrumcntation

Introduction t o Trrhniques of B-ray Counting

i

' Fnur radium ntandsnin. 1 to L k of personnel monitora C1nlihrntion of purvey mrtern 25 ma. Cn"on u r e e 4 . 5 me. iirificnlicm of i n r ~ r a cnqunn? law

Pocket ionization ehambcm, film hadgca (nri-t t y p ) , survcy inslrumcntd (clectmrcope, rlrctmmeter, nnd G-\I munter t p x i

j

of 8-r:iy srnttcrina ~Iwwzn~tncnt .ompnriwm of iclntivc n- nnd ilrxr ionirntion

2

-

-

Objwlirrr

No. 1

of the experiments. The rlt~mistrydepartment owns a Ra-Re neutron source rontxinin~ approximately 100 rng. of mdium. Advnnlugr d s o hha h e n tnken of a 1%. Ra-Be source rented hv one of the physirs re-

Une of the Gigcr-Jfueller counter nnd m d a r for nunntilntiw mmurrmrnts htrrminntion of Al nlmrption ctrrvr for ni"@ Pwp:,rntinn of e n u r n for counting Effvrts qli mnlvrinl of naurec mount

I Two

I

8 r ' ~ Y g 0&my n u r m -10 #c. Ph"O w a r m 0.5 M. in equilihrium with Ili'lo and PO'^

G-M

counter, standard shelf nrranwment, amlifier-aenlnr ( X f i or v ~ e r )Icwl , *hidtl

r

G \ I countor equipment

Activities in Equilibrium with Uranium nnd Thrir UR for ('nlilmtina @-myCollnlin9 .\%wmblies DPt~rminnlion f I n hnlf-life (1'1~'") 1,. ~lrc-av,nnd short hnlflik (Pn"') I)? p ~ t and h by

! I a \Iu r imuntcr t r n electmmopen, G equipment

4

b e of the Lnuritwn EIcc. t r o m p and (hmpnrieon with t h ~ 1;-\1 counter

Determinatinn of the lincnritvand 5 re. C!l**in rquilil,rium with rn~itivi1.vof thr elcetm~mpc W'' Cnmpariwn of wnsitirity with tint of then-h1 muntw

5

Study of the G"'-Pr"' C'hnin

%pnrntion nf t h r n two nu el id^ by pwcipitntion of C!!(IO,), \lt.nnrcnwnt of thr hxlf-life of I'r"' I>yvmwth and d w r q curve! An:klwir oi a mmplcx .\I-nh.wrp lion r u r w for A-rat. cnrrcy dctwrninntinnr

3amr SR for Expcrimcnt 4

6

Iodine and Barium Firaim Pmrlorts

Iwlntion of rndinindinc from tin-

10 g. of U aa POt(SO,i, irmd- '3-11 counter equipnlent intcd in neutron flux -10' I for 1-2 hr. or 500 g. of U ns UO:(SOth. M1,O irmdintcd wath I g. Rq-nF11~11trn11 W U I P I ' for 4 hr.

Spnrntion nnd clrrontnmination 01 Iln"D from fission product mixture Drwrminntion of h i o n rntc from 1"' nnd Rnl" netivitics 7

1

G-11 eounfrr equipmcnt

I

G I muntcr equipment

Rn-Re neutron nurrc, 1 a. Rn-nF nneutrnn u w m .

0.1

Neutron Actirntinns

g,

or thecvrlotmu tmn-mptsrr CIOS* ~ c t i o n 01 ..\c'"' :,,,,I ;\'p' Cnnn~ntr:xlionof R rndinnuclide by t k l Srilanl-Chnlm~nrc~ction ol \Iwinmmwnt nf the p f f i r i r n e ~ lhi5 pr0cC.P i w \Inh1 I,", Ii\lnO,

8

-

Jleaaurcment of tlre amount ol nntao mrried on LnF, precipi. Inter nr n function of n n + + p r o rrnl, trmpcrntm? of pmcipitn Iton. and nm nf nrwinitntr

1pc. Ra"*in eq~lilibriumwith

C A I counter equipment

JANUARY. 1951

19

'

mtb

, Dctrrmination of the effects of I wwnrtry on 7-my counting and ~llWrl>fl0"

Chrmicnl Z)cpnmtions l Inn I:rrlmnp.

10 8

y 8

I

I

Use of cation exchange rrain for the wpnrntion of enrrirr-fm

GO

p.2..

Ba"'-Ln"a

(cnmer fm)

Ln"O fmm 13n"e

miutum

, '

G->I munter equipmml, I survey rnuntrr, mlulion eounur

1

-

.lIwsuwmrnt of the effect of pH n n d co~nplcrinpawnts on the nflinity 01 ions for tlw m i n

11

' Some Pmhlcm* in >Ira*-

i Ihterminntion of the effect of e l f -

12

1 Cvelotmn Tnmt

! I~leet~uehrmicnl aepnmtion of car- /

I

!

urinc I n w Enrnv ICuli-

'rntinw

Spa-

nbsomtion in the countina

1

riw-frw C u fmm lnmbnrdwl Xi Slvcnt-I

counter equipment

is the availability of countcrs and l~enlth-physics quipment from resenrch chnnnrls for the smnll frnction of the working time thnt they nrr rwd for edurntion. , I he necrtmr~lntinnof long-lived rndionctive sources over the yrnrs cuts oprrntingcosts for rnrlionrtirity to n low levcl. I t is possible that the Isotoj~fDivision of the Atomic Energy CSommi?rqioncan he persun(lcil to prepnrc nn cih~cnton'pnckrt of several rndionr~rlidesnnd a f4d Sb'?'-l)en.llit~m-~nrtnl nrubron sotlrcr if many srhnnls indicntc t,l~cirinterest. The authors hnve lenrnrd a great deal in the working u p of the mnterinl for this course and still nohice cnnsidernble growth each yenr in the lecture ~ o r knnrl in the hnndling of the lnhorntory. The students find thnt rndiochemist~is not simple and thnt its results are not very precise unless they give v a t nbtrntion to trchniquc. l'he experiments are not outlined in great detail for them, or the manner of expected wild.-up specifid minutely, hecnuw it is clcemcd important t o develop n .sense of initintive. Although the experimental work is limiterl to 9, and 7 nmnting, they hnve been exposed to all principles of rndiochemistry except micro-mnnipulntions for the highly specialized field of a emitters, nlmost all of which are hedged hy wcreey re~trictions. I t is felt that this cottnr ha4 found n permnnrnt place in the progrnm of tenching nntl resenrch nt 11. 1. 'r., nnd t11:tt if has found n fnirly stnhle form.

.

The materials listed in Tnble 2 thnt nre purrhard from the LITERATURE CITED Isotopw Division of the AEC am: 5700~C", 5 . 3 ~Corn,25%Srm, (1) \V.