lanl hb of radiation monitoring 3rd ed. la-1835 11-1958

8/12/2019 LANL HB of Radiation Monitoring 3rd Ed. LA-1835 11-1958

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LOSHAN

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LA-I 835 (3d cd,)

ALAMCX 5DBCX2KOFRADIATIONMC) PUTC)RING

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DO NOT CIRCULATEPERMANENT RETENTIONREQUIREDBY CONTRACT


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+os Alamos Handbook

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fsfj ofIhDIATION MOhUTORING

LA-1 835 (3d cd.)

Compiled and Edited byJerome E. Dummer, Jr.

Odginally Compiled and Edited byRobert F. 8arker

Los Alamos Scientific Laboratoryof the University of California

Los Alamos, New Mexico

November 1958

Contract W-7405-ENG. 36 with the U.S. Atomic Energy Commission


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UNITED STATESGOVERNMENT PRINTING OFFICE

>=WASIHiGTON : 1959I

For sale by the Superlnt@dent of Documents, U. S. Government Frlntlng OftkWashington 26, D. O. - Price 65 csntri


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PREFACEThe first edit ion of t he G enera l H andbook for Ra di-

a t ion Monit oring w a s prepa red by Robert F . B a rkerin 1952 as a n a t t em pt t o provide t he members of t heMonit oring G roup a t t he Los Ala mos S cient ific La bo-ra t ory w it h t he ba sic da t a w hich it w a s felt should bea va ila ble t o t hem a t a ll t imes. I t ra pidly beca me a p-pa rent t ha t m a ny ot hers ha d felt t he sa me need for aconcise, pocket -size compila tion of t h is sort , bot h fort ra in ing a nd reference, a nd t he dema nd very prompt lyexceed ed t h e s upply .

As m ight ha ve been expect ed, t he or igina l ed it ioncont a ined some mist a kes a nd in 1954 a second edit ionw a s prepa red, a ga in under t he compet ent edit orship ofRober t F . B a rker . In t he second edit ion a bout t heonly cha nges w ere t o elimina te t he errors t ha t ha d a p-pea red previously a d t o rem ove a few loca l referencest ha t w ere crypt ic t o t he la rger a udience t he bookletn ow com m a n d ed .

This, t he t h ird edit ion, ha s been a lmost ent irelyrew rit t en m -d it s publica t ion w a s dela yed t o permitinclusion of t he most up-t o-da te da ta for perm issibleexposures a nd permissible body burdens. The forma trem a ins uncha nged, how ever , a nd t he ha ndbook is st illdesigned t o serve t he puI poses of t he Los Ala mos S cien-t ific L a b or a t or y .Not a ll of t he qua nt it ies given ha ve officia l sa nct ion ;t here a re som e inst a nces w here oflicia l num bers do notexist , but it is necessa ry t o est nblish some level w hichca n serve a s a guide in loca l w ork. Orga niza tions out -

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1side Los Ala mos ma y not a gree w it h a ll t he rules a nd 1policies set fort h , but a ga in it is empha sized t ha t t hey 1w er e a dopt ed for loca l use. N(fent ion of a ny commercia l ~product does not const it ut e a n endorsement ; for cer t a inpur poses n o in st rum en ts a r e com plet ely sa t isfa ct or y. i

The edit or of t his ha ndbook, J erome E . D ummer, I1 Iha s been a ided by ma ny members of t he H ea lt h D ivi- :

sion. S uggest ions for improvement of a fut ure edit ion ~w ill a lw a y s be a ppr ecia t ed. ,i)

THOMAS L. SHIPMAN, M.D.H eal th D i vi si on L ead er jI

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CONTENTSSectionPREFACE . . . . . . . . . . . . . . . . . . . .

1.2.3.4,5.6.7.8.9,

10,11.l~ o13.14.15.16.17.18,1 3.

Monit or s Check List . . . . . . . . . . . . .Ra dio C ode . . . . . . . . . . . . . . . . .E mergency Monit or ing . . . . . . . . . . . .P rot ect ive J fet hods . . . . . . . . . . . . .L .4S L Ra dia t ion S a fet y P olicies . . . . . . . .P er missibleD ose a n d Xlea s ur em en tU n it s. . . .P ermissibleC ont a m ina tion Levels . . . . . . .D econt a mina t ion . . . . . . . . . . . . . .Ma xim um P ermissibleE xposures . . . . . . .Ta ble of Isot opes . . . . . . . . . . . . . .Monit or ing Inst rument s . . . . . . . . . . .Alpha Xlonit or ing . . . . . . . . . . . . . .B et a -G a mm a Monit oring . . . . . . . . . . .Neut ron Rlonit oring . . . . . . . . . . . . .Trit ium R1onit oring . . . . . . . . . . . . .P ersonnelD osimet ry . . . . . . . . . . . . .U rina lysi s . . . . . . . . . . . . . . . . .Air S a mpling . . . . . . . . . . . . . . . .Respira tory P rot ect ive E quipm ent . . . . . . .

APPENDIXES . . . . . . . . . . . . . . . . . .

mEa31MEEI52EIEKa67Ei iEa73ma77m m83mEia89mm6 EIEaI9 I EEN111ml llEa

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1. MONITORS CHECK LISTThis is a reminder list of some eq uipment a nd opera -

t ions t ha t ma y be req uired t o a ccomplish a monit oringjob. B e sure you ha ve w ha t you need. Addit iona l Tcheck list s a re given a t t he conclusion of t he va r ious Isect ions on specific t ypes of monit oring.A, Equipment

(1) P rot ect ive clot hing (proper t ype of respira tor .protection).( 2) F ilm ba dges (body a nd/or w rist ).(3) P ocket dosimet ers a nd cha rger .(4) S urvey met ers (t ype a nd direct ions for using).(5) Tolera nce t a bles, t olera nce t imes, neut ron survey

da t a sheet s.(6) S igns (ra dia t ion), t ags, rope, source t ongs.(7) Air sa mplers a nd filt ers.(8) Miscella neous: pa per , pencil, ca rdbo~ r d boxes,

ma sking t ape, chnlk, grea se pencil.(9) Vehicle (ga s, t rip t icket ).

B. Operations(1) C heck for cont a mina t ion on surfa ces, equipment ,

anc l personnel .(2)(3)(4)(5)(6)

L im it spr ea d of con ta m in a tion ,D econt a mina t e (a gent s a n d fa cilit ies).D ispose of cont amina ted w a st e.Ta k e n ose sw ipes.C ollect ur ine

plet ely filled ou t).(7) S umma rize in

specimens (cont a iners-t a g com-w rit t en r epor t.

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1o-o1o-110210-310-410510-610-710-8

109lolo10-1910-201o2110-3610-9510-9710-9810-99

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2. RADIO CODEOpera t ions norma l a t t h is loca t ion or opera t ion.R eceiv in g poor ly .R eceiv in g w ell.S t op t r a nsm it t in g.O.K. Roger . lNfessa ge received a n d under-

s tood .Relay,Busy .Out of ser vice.In service (G ive na me of opera tor w it h first 10-8

ca ll, e.g., S t a t ion H ickory 3 t o S t a t ion 7,10-8, Doakes).

Repeat .Out of service subject t o ca ll (G ive t elephone

n um ber or loca t i on ).Ret urn t o your st a tion; come t o t his loca tion.Wha t is y our loca t ion? or, My loca t ion is . . . .C a ll t his st a t ion or loca t ion by t elephone.C or rect t im e.Ra dio check (Answ er w it h 10-1 or 10-2).Arr ived a t scen e.F in ish ed w it h la st a ssignm en t.E mergency w it hin sect ion or a rea .F ir e a t ....

The w ord Broadcast repea t ed t hree t imes mea ns agen er a l or ext rem e em er gen cy.

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EMERGENCY MONITORINGA. Emergency Equipment

Th e emer gency vehicle, ra dio ca ll S ta t ion H ickory 3,is eq uipped w it h respira tors, a ir sa mplers, prot ect iveclot hin g, sign s, bla nket s, first -a id kit , et c. S urveyinst rum ent s ca n be obt a ined in t he lMonit or ing Office.Wit h t he inst rument supplement , t he vehicle shouldpr ovide a self-sufficient opera t ions ba se in a w ideva riet y of ra dia t ion emergencies. Filmbe picked up from t h e P hot odosimet ryneeded.B. Philosophy and Procedures

Fil~ t Obt a in a ll rea dily a va ila ble

ba dges m a yD a rkroom if

informationbefore proceeding on a n y em ergency . B e cert a in it isa n emel g ency, t hen proceed, using m a ture judgment ,common sense, know ledge of t he ha za rds, a n d a lla va ila ble eq uipment t o limit t he number of personnel,a nd t heir exposure, t o a w orking minimum.

E mergencies w ill proba bly be of t he follow ing t ypes:(1) S pill of r a dioa ct ive m a ter ia l.(2) E xplosion (ch em ica l or n uclea r ).(3) F ir e.(4) D ispersa l of ra dioa ct ive ma t er ia ls by fire or

explosion.Of t he a bove, in genera l, (1) a nd (2) w ill proba bly beloca l, but (3) a nd (4) m a y a ffect t he communit y. I nca ses r ea ch in gr es pon s ib le a n d

d is a st er pr opor t ion s,t he LAS L posit ion w ill

ALOO w ill bebe only t ha t of a

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t ech nica l a s sis ta n t . (D efin it ions of a bbrevia t ions w illbe found in Appendix D a nd a glossa ry of t echnica lt erms in Appendix Q.)

The monit or should be a self-sufficient unit , a ble a ndeq uipped t o st ep int o a ny sit ua t ion a nd t a ke over t hen ecessa r y m on it or in g du ties. H e must ha ve a know l-edge of t he ma teria ls being used, t heir usua l loca tion ,a nd a n a ct ive ima gina tion in deducing just w ha t sort ofa ccident s ma y occur in t he use of t hese ma teria ls.C, Remember

(1) Assume a ll t ypes of ha za rd a re present unt ilpr ov en oth er w i se.

(2) G amma ra dia tion should be t he first a nd ea siestt o d et ect .

(3) E xplosives, chemica ls, or ot her t oxic ma ter ia lsma y be a problem.

(4) Ma ke qua lit a tive check on G a st pump a ir sa mplew it h P eeWee a nd/or G M inst rument .

(5) P rot ect , monit or , decont a mina te, a nd list na mesof a ll per son nel in volved .

(6) Not ify a n H-1 supervisor a s soon a s possible.

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4 PROTECTIVE METHODSRa dia t ion ha za rds a re usua lly divided int o t w o

cla sses, ext erna l a nd int erna l, t he t erms referring t o t heloca t ion of t he source of ra dia t ion w it h respect t o t heper son b ein g exposed . Met hods ha ve been devised forprot ect ing t he ra dia t ion w orker a ga inst bot h ~ pes of ~radiat ion.A. Internal Radiation

Int erna l ra dia t ion refers t o ra dia t ion from ra dioa ct ivema t eria l t ha t ent ers a nd irra dia t es t he body from t heinside unt il it is elimina ted or deca ys ra dioa ct ively .P rot ect ive met hods for t his t ype of ra dia t ion obviouslya re prevent ion of ent ry in t o t he body a nd elimina tionof a ny ma t er ia l t ha t ha s ent ered. E xcept in a very fewca ses, elimint it ion by mea ns ot her t ha n biologica l t urn-over or ra dioa ct ive deca y is impossible. F or t hisrea son, ra dionuclides w it h long ha lf-lives t ha t rema inin t he body for long periods of t ime (e.g., P U 239,SrW)arecon sid er ed especia l ly h a z a r dou s. E nt ry of ra dioa ct ivema t eria ls t o t he body ma y be ga ined by inha la t ion,ingest ion, inject ion, or a bsorpt ion t hrough t he skin.

A va riet y of respira t ory prot ect ive devices is a va ila blet o a t t empt t o cont rol inha la t ion of ra dioa ct ive pa rt icles.These devices a re illust ra ted in S ect ion 11 a nd t heiruses a re descr ibed in S ect ion 19. Met hods a re in uset o eva lua te a irborne ha za rds by a ir sa mpling (S ec. 18).N ose s w ipes (S ec. 7) t a ken a t t he end of a w orking periodgive a n indica t ion w het her ma ter ia l ha s been inha led.

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P revent ion of ent ry by ingest ion is ma inly a ma tt er ofgood h ousekeepin g a n d obser va n ce of t he r ules pr oh ibit -ing ea t ing, dr inking, or smoking in cont amina ted a rea s.Wa shing a nd monit oring t he ha nds rout inely beforeea t ing or lea ving t he cont amina ted a rea is ma nda tory.E nt ry t hrough open cut s or a bra sions or a ccident a l in-ject ion s a llow s deposit ion dir ect ly in to t he blood st rea ma nd is t herefore ext remely ha za rdous. When open cut sor sor es exist , h an dlin g of cont a min at ed ma t eria l sh ouldbe a voided. Absorpt ion t hrough t he skin is a n ent rymet hod of some r adioa ct ive ga a es or va por s, e.g., t rit ium(Sec. 15). E xposures of t his t ype ca n be prevent edonly by ut ilizing closed syst ems, hoods, or , in emer-gen cies, w h ole-bod y pla s tic a ir -lin e su it s.

S econd only t o prevent ion of int erna l ra dia tion bya ssuring clea nliness t hrough const a nt monit or ing a ndt h e u se-of en t ry -pr even t in g d evices is t h e d et er min a t ionof t he a mount of ra dioa ct ive ma t er ia l ent er ing a ndrema ining in t he body a nd t he subseq uent eva lua tionof t his informa t ion in t erms of ra dia t ion dose. This isa ccomplished prima rily by ra diologica l exa mina t ion oft he body excret a , usua lly t he urine (Sec. 17). Othermet hods, such a s w hole-body count ing, specific orga ncount ing, a n d br ea t h sa mpling, h avi t heir specific a ppli-cations. As a genera l rule, t he a bove procedures a remost a ccura te if ma de a s soon a s possible a ft er t he int akeoccurs. S pecific procedures for t rit ium urine a ssa y a regiven in S ect ion 15D.B. External Radiation

E xt erna l ra dia tion is ra dia tion t ha t comes direct lyfrom a ra dia t ion source or from cont amina t ion of eq uip-ment , clot hing, or t he person himself. E xt erna l expo-6

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sure ca n be received from /3, X or ~ , a nd neut ron1 ra dia t ion. Na tura l a pa rt icles do not const it ut e a next erna l ha za rd a s t hey ca nnot penet ra t e t he out erla yer of skin. C ont a mina t ion is cont rolled by pre-vent ing it s occurrence or by prompt ly removing it(S ec. 8). Remova l is much ea sier if surfa ces ha ve beenfirst furnished w it h prot ect ive coverings or coa t ings.Kra ft pa per or st r ippa ble pa int ca n be used on floors1 or ben ch es; pr ot ect ive cover a lls, gloves, a n d ca ps sh ou ldbe used by personnel in pot ent ia lly cont amina t ed a rea s.

I Where complet e remova l of cont a mina t ion or t hesou rce of r a dia t ion is n ot possible, t hr ee gen er a l m et hodsof prot ect ion t ime, dist a nce, a nd shieldin ga re used.The met hods w ill be discussed sepa ra t ely , but in, pra ct ice judicious use of a ll t hree is a dvisa ble.

Time Ra dia t ion exposure ca n be kept below t hema ximum permissible limit s by rest rict ing t he t imespent in t he ra dia t ion a rea . The sa fe or permissible exposure t ime (S ec. 9C ) in t erms of hours or minut es

I per w eek is a convenient met hod of expressing t heext ent of a ra dia t ion ha za rd. .$s a ny unnecessa ry ra dia -t ion exposure is considered t oo much, every effor t

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a rea even below t ha t deemed permissible bym on it or in g m ea s u rem en t s .

2. D ist a n ce. The int ensit y of ra dia t ion from asource of ra dia t ion decrea ses w it h t he dist a nce fromt he source. For a point source, t h is &ecrea se isinversely proport iona l t o t he sq ua re of t he dist a nce,hence t he t erm inverse sq ua re la w. For monit or ingpurposes, point source condit ions a re met w hen t hedose mea surement is ma de a t 2 ft or more from a source

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w hose la rgest dimension is no m ore t ha n 4 in. E x-pr essed m -a for muln .,

where D k t he dose ra t e a t a dist a nce R from a pointsource, a nd d is t he dose ra t e a t a different dist a nce r .D ose ra tes a nd dist a nces must be expressed in t he sa meunits. Tw o exnmples a re given a s demonst ra t ion oft he inverse sq ua re la w:

E xam pl e 1: 45 mr/hr is mea sured a t 100 cm. Wha tis t he dose ra t e a t 10 cm from t he sa m e source?

a?=45x~2=45 10f~j=4500 mr/hrExam pl e 2: 800 mr/hr is m ea sured a t 20 cm. At

w ha t dist a nce is t he dose ra te 200 mr/hr?2=Dx:;=+x:=4800%=JmI n simple la ngua ge, doubI e t he dist a nce, get one-fourt ht he dose ra t e; ha lve t he dist a nce, get four t imes t hedose r at e.

Not e: The inverse sq ua re la w is a ccura te only w hent he dist a nce is la rge compa red t o t he source a nd det ec-t or size, a nd a lso w hen negligible sca tt er ing or a bsorp-t ion occurs in t he medium in w hich t he dist a nces a mmea sured. When t hese condit ions do not exist , t heinverse sq ua re la w is, a t best , a rough a pproxima tion .

3. S h ield in g. S hielding is t he int erposit ion of suit -a ble ma t er ia l bet w een t he source of ra dia t ion a n d t heposit ion w here dosa ge must be reduced. The shielding8


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met hods of ~ , ~ , a nd neut rons a re very different a ndw ill be discu ssed sepa ra t ely .

a. / sh iel d in g. B pa rt icles rea ct w it h ma t t er ma inlyby sca t t er ing of nuclei, ra dia t ive inela st ic collisions,a nd ioniza t ion. D espit e t he complexit y of ~ a bsorp-t ion, it is a pproxima t ely exponent ia l; i.e., for ea chincrement of a dded shielding, t he sa me reduct ion fa ct oris ob t a in ed . This permit s @ shielding t o be expressedin t erms of ha lf-t hicknesses, or t he t hickness of ma t er ia lw hich must be int erposed t o reduce t he number ofpa r t icles pa ssing t he shield t o one-ha lf t he origina lnumber st riking t he shield. Alt hough t he ha lf-t hick-ness concept is usa ble, t he t hicknesses req uired t oreduce t he int ensit y of even energet ic @ pa rt icles byone-ha lf a re so sma ll t ha t it is more convenient t oexpress ~ shielding by t he a mount of ma ter ia l req uiredt o st op al l t he P pa rt icles of a cer t a in energy (AppendixI). Not e t ha t since t he ma ximum energy is plot t eda nd t he a vera ge energy of a p spect rum is a bout one-t hird t he ma ximum, t he t hicknesses given in Appendix Ia re conserva t ive or sa fe.

One &a bsorpt ion process, ra dia t ive collision, pro-duces elect roma gnet ic ra dia t ion ca lled bremsst ra h- lung. These a re simila r t o ordina ry X ra ys, exhibit inga n energy spect rum from zero t o t he ma ximum Benergy , w it h a vera ge energy roughly one-t hird t hemaximum. The product ion of bremsst ra hlung is pro-port iona l t o t he sq ua re of t he @energy a nd t o t he a tomicnumber of t he a bsorber, ma king t he use of light ma -t eria ls for f? shields ndvisa ble. This pra ct ice is usua llypra ct ica l since a few millimet ers of lucit e or a luminumis sufficient t o st op @ pa rt icles of a round 2 Mev. Thecrea t ion of bremsst ra hlung in light ma t er ia ls such a s

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t hese is ra t her inefficient , on t he order of 10% [Ap-pen dix C ).

b. X a nd ~ Ra ys. X a nd Y ra ys a re a bsorbed byt h ree m a in pr ocess es :

(1) The phot oelect r ic effect , w hich is a n int era ct ionbet w een a ~ phot on a n d a bound elect ron in w hich t he~ ra y disa ppea rs a nd a n elect ron is eject ed. Thisprocess becomes more effect ive for higher a tomic num-ber a bsorbers a nd low phot on energy.

(2) The C ompt on effect , in w hich a phot on int er-a ct ion w it h a free elect ron produces a low er energysca t t ered phot on a nd recoil elect ron.

(3) P a ir product ion, in w hich t he phot on energy isent irely used up in t he crea t ion of a posit ron a nd a nelect ron in t he presence of nuclei. The energy re-

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q uired by a phot on t o crea te a n elect ron-posit ron pa ir Iis 1.02 Mev or more, a n d t he process is most effect ivefor high a tomic number nuclei. .,.

The complexit y of t hese processes ma ke it con-venient t o cla ssify shielding met hods a s na rrow bea m to (good geomet ry) a nd broa d bea m (poor geomet ry).I n t he na rrow bea m ca se, none of t he C ompt on- isca tt ered phot ons rea ch t he det ect or a nd a tt enua tion Iis t ruly exponent ia l. The use of H VLS a nd TVLS I(Appendix G ) is permit t ed w it h good geomct rv. In ,broa d bea m geomet ry, t he ca se in most pra ct ica l a ppli-ca t ions, some C ompt on-sca t t ered phot ons a re det ect ed Ia nd a dd t o t he t ot a l in t ensit y. This increa se in in-t ensit y ca used by sca t t er ing is ca lled buildup, a n d Qt he a mount of buildup increa ses w it h t hickness, B roa dbea m ~ a t t enua t ion for severa l y emit t ers in severa lma ter ia ls is given in Appen dix H . .10


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When la rge ~ sources a re ha ndled behind open t opshields, ~ ra ys sca t t ered fmm t he a ir or ot her ma t eria la bove t he source w ill cont ribut e considera bly t o t hedose. There is no object in reducing t he int ensit yt ra nsmit t ed t hrough t he shield t o a level much low ert ha n w ill be produced by sca tt er . The. effect of sca tt erma y be reduced by t he a ddit ion of a t op shield, t het hickness necessa ry being considernbl-y less t ha n t heside shield. Open t op shields a re not pra ct ica l forgrea ter t ha n a bout 25 curies of a ~ emit t er .

c. N eu tr on Shielding. The a tt enua tion of neut ronsis a ccomplished by ela st ic a nd inela st ic sca tt er ing a ndr a dia t ive ca pt ur e. The genera l procedure for neut ron1 a t t enua t ion is t o slow dow n t he energet ic neut rons bysuccessive collisions w it h nuclei t o energies w here t heproba bilit y of ra dia tive ca pt ure is higher . All ca pt ureprocesses proceed more ea sily a t low er n eut ron en ergiesa nd a lmost a ll result in t he emission of hig?~ energy ~ra dia t ion . The a t t enua t ion of t hese ra ys must becon sidered in t he sh ield design.

In shielding la rge neut ron fluxes such a s a re foundnea r rea ct ors, t he genera l procedure is a s out lineda bove; i.e., slow t he fa st neut rons w it h hydrogenousma ter ia l such a s w at er or concret e (ela st ic sca tt er ing)or hea vier nuclei (inela st ic sca t t er ing); ca pt ure t heslow ed neut rons using H L(n,~ ) H * or simila r rea ct ion ;ca pt ure t herma lized neut rons w it h ca dpiurn (n,~ ) ori simila r rea ct ion ; shield a ga inst ~ ra ys w it h ext erna lshielding or a dd loa ding (iron shot ) t o t he hydrogenous\ ma ter ia l. I t must be empha sized t ha t neut ron ca pt ure~ ra ys me oft en very energet ic, t he 2.2-Mev ~ ra ysfrom t he prot on rea ct ion being one of t he low er. Ava r iet y of rea ct or shielding ma t eria ls ha ve been de-

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veloped including a n a lloy of a luminum a nd boron(B ora l) a nd specia l loa ded concret es. As in t he ca seof ~ shielding, open t op shields must be exa minedca refully for a ir sca t ter , oft en ca lled sky-shine.

F or shipping or la bora t ory purposes, pa ra ffin is asuit a ble neut ron a t t enua t ing ma t er ia l. I t is con-venient t o use t he concept of H VL J S for rough designof pa ra ffin shields for sma ll neut ron sources. Para f f inI I VLS for 4 t o 5 Mev (e.g., P o-B e, Ra -B e, or P u-B e)a nd for 1-~ Mev neut rons (fission or mock fission) a re6.93 a nd 3.2 cm, respect ively . B y use of t he semilogplot of Appendix J , t he a mount of pa ra ffin needed fora cert a in reduct ion in flux or t he effect iveness of acert a in a mount of pa ra ffin ca n be det ermined.

Example: I f it is desired t o reduce t he fa st neut ronflux from a P o-B e source t o 10~ 0 of it s unshielded va lue(e.g., from 100 t o 10 n/cm2-see) using pa ra ffin ,rea d from t he semilog plot of AppendL ~ J t he number ofH VLS necessa ry t o reduce t he int ensit y t o 10% a s 3.3H VLS . 3.3 X6.93= 22.9 \ cm, or a bout 9 in. of pa ra ffin .I f t he effect iveness of 6 in. of pa ra ffin for a P o-B e shieldis desired, 6 in .= 15.2 cm; 15.2 cm/(6.93 cm/H VL) =2.2 H VLS w hich, on t he curve, indica tes a reduct iont o 22%

This met hod w ill give unsa fe a nsw ers for shields lesst ha n 2 H VLS t hick. The flux a t t enua t ed is t he fa stflux a nd t here w ill rema in considera ble t herma l neu-t rons. These ca n be a bsorbed in ca dmium if necessa ry.

4. Wa st e D isposa l a nd Lea k Test ing. Tw o ot herprot ect ive mea sures t a ken t o prot ect personnel a re t hedisposa l of ra dioa ct ive w -a st es a nt i t he t est ing of ra di-a t ion sources for lea ks. Wa st es of shor t -lived isot opesca n be st ored t o a w a it deca y. Ot her w a st es must be12


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pa cka ged, la beled w it hburied in a segrega teda pproxima t e loca t ion in

I

isot ope, origin, a nd da t e, a nclpit . Records a re kept a s t ot h e even t r eco~ -er y is n ecessa r y

orreuseof t hesit eispkmned. Inca ses ofla rge a mount sof slight ly cont a mina ted combust ible w ast e, burningw it h pr oper ch ecks on a irbor ne a ct ivit y is a dva n ta geou s.

Ra dioa ct ive sources should be lea k-t est ed w heneverda ma ge or det eriora tion of t he ca psule is suspect ed, ora t lea st once ea ch 6 mont hs. This rout ine check a lsoserves a s a n invent ory a nd a ssures t ha t t he propera ut horit ies a re a wa re of t he loca tion of sources. Thet est ing of ra dium (or Ra -B e) sources is a ccomplished byt est ing for ra don (a ct ua lly Rn da ught ers). The sourceis pla ced in a sma ll sea led ja r w it h a 2 or 3 in. dia met erfilt er pa per (not in cont a ct w it h t he source) for 12 t o24 hr. A count in excess of 50 c/m fl+ ~ w it h a less t ha n10~ o efficient , w ell-shielded, gla ss-w a ll G -M count er isconsidered t o be a dirt y or lea king source. A highcount on a recheck a ft er t he source ha s been scrubbedw it h t richloroet hylene indica t es t ha t t he source is lea k-ing a nd must be resea led. P lut onium a nd S rW sourcesa nd neut ron sources cont a ining a emit ters (P o-B e, mockfission) sh ould be ch ecked freq uent ly for lea ks using t hesw ipe t echniq ue (S ec. 7). Any source t ha t sw ipesposit ive is clea ned a nd rechecked.

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5 LOS ALAMOS SCIENTIFIC LABORATORYRADIATION SAFETY POLICIESA. Individual

I ndividua ls a t t he Los Ala mos S cient ific La bora t oryw ho ha ve a ny cont a ct w it h ra dioa ct ive ma t eria ls orr adia t ion a r e respon sible for :

(1) K eeping t heir ow n exposures t o ra dia t ion a nd a lso t hose of ot hers a s low a s possible a nd, specifica lly ,below t he ma ximum permissible levels recommendedin S ect ion 9. E xcept ions a re exposures received inmedica l exa mina tions a nd t rea tment s a nd, w it h priora pprova l by t he H ea lt h D ivision, in ca ses w hereurgent sit ua t ions req uire exposures in excess of t her ecom m en d ed lev els .

(2) Wea ring t he prescr ibed monit or ing eq uipment(pocket dosimet ers, filrrReq uest ing t ha t neut ront o 0.1 r em is suspect ed.

(3) S urveying ha nds,a ct ivit y a nd removing

ba dges) in ra dia t ion a rea s.films be rea d w hen exposureshoes, a nd body for ra dio-loose cont a mir ia t ion t o t he

t olera nce levels before lea ving t he a rea , in a ccorda nce ~w it h t he recom men ded decon ta min a tion procedur es. 1

(4) Wea ring a ppropria t e prot ect ive clot hing w hen- iever clot hing cont a mina t ion is possible, a nd not w ea ring ,such clot hing out side t he La bora t ory a rea s. Usinggloves, hoods, a nd respira t ory prot ect ion (respira t ors or ,supplied a ir ma sks, a s recommended by t he H ea lt hD ivision) w hen necessa ry. U sing proper t echniq uesa nd fa cilit ies in opera t ions involving ra dioa ct ive ma -terials.14


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(5) Observin g t he recom mended procedures in rega rdt o ea ting a nd smoking in cont a mina ted a rea s.(6) Report ing injur ies a nd ingest ion or inha la tion

a ccident s prompt ly t o t he H ea lt h D ivision und ca rryingout t he recommended correct ive mea sures. coop- cra ting in a ny a nd a ll a tt empt s t o eva lua te exposures,pa r t icula rly by prompt ly ret urning req uest ed urinespecimens.

(7) C a rrying out recommenda t ions of t he H ea lt hD ivision in roping off ha za rdous a rea s, post ing w a rningsigns, a nd ot herw ise cont rolling specia l ha za rds for mw hich t hey a re responsible. C ont a ct ing t he H ea lt h ID ivision (G roup H 1) for recommended procedures inhigh level ra dia t ion a rea s or w hen condit ions a re a lt ered Isignificantly.

(8) C lea ning up cont a mina t ion for w hich t hey a re ~responsible. Arra nging for a survey by G roup H 1 a ndca rrying out t he decont amina t ion recommended for t hea rea w hen cha nging loca t ions or ending a n opera t ion .

(9) P roper st ora ge a nd la beling of ra dioa ct ive ma - ~t eria ls for w hich t hey a re responsible.

(10) P r oper pa cka ging (sea led cont a iners w heneverpossible) a n d la belin g (or igin a n d da t e) of con ta m in a tedw a s te m a t er ia ls.B. Supervisory

responsible for ensuring t ha t t heresponsibilit ies a re discha rged bycont rol, a n d a re fur t her responsible

t S upervisors a rea bove individua lt hose under t heirfor:

(1) Inst ruct ing t hose employees for w hom t hey a reresponsible in t he use of sa fe t echniq ues a nd in t hea pplica t ion of a pproved ra dia t ion sa fet y pra ct ices.

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I(2) P roviding such st a ff w is req uired for pa cka ging . icont a mina ted w a st e a nd for decont a mina ting a nyt hingfor w hich t hey a re responsible.

(3) Furnishing informa t ion t o t he H ea lt h D ivision ;concerning individua ls a nd a ct ivit ies in t heir a rea s, pa rt icula rly a ddit ions t o or delet ions from t heir Iper son nel r ost er s. 1I

(4) C ont a ct ing t he H ea lt h D ivision w henever ma jorcha nges in opera tiona l procedures, new t echniq ues,a lt era t ions inmight lea d t oC, Monitoring

Th is g rou p

physica l pla nt , or new opera tions w hichIiI

per son nel exposu res a r e a n t icipa t ed .Group, H-Iis r es pon sible for :

(1) F urnish ing consult ing services on a ll a spect s of :r a d ia t i on pr ot ect ion . i

(2) G enera l surveilla nce of a ll ra dia tion a ct ivit ies,including a ssist a nce t o individua ls a nd supervisors ind is ch a r g in g t h eir r es pon sibilit ies .(3) D ist ribut ion a n d pr ocessin g of personn el m onit or-ing eq uipm ent , including keepin g of per sonnel exposur erecords, not ifying individua ls a nd t heir supervisors ofexposures grea ter t ha n t he permissible levels for t heirsit ua t ion, a nd recommending a ppropr ia t e rest rict ions.

(4) S upervision a nd coordina t ion of t he w a st e dis-posa l progra m, including keeping of w a st e st ora gerecords.

(5) A cont inuous progra m of environment a l ha za rdeva lua t ion a n d ha za r d elimina t ion.

(6) S tora ge, lea k t est ing, issue, a nd disposa l of ra dio-a ct ive sources; supervising t he shipping of ra dioa ct ivema t eria l. F ur t her , t he inspect ion of req uest s for


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sources t o a ssure st a nda rdiza t ion of ca psules for genera lutility.

(7) S cheduling urina lysis mea surement s w hen re-quired.

(8) D econt amina t ing la rge pieces of eq uipment (e.g.,mot or vehicles) a nd a ssist ing personnel decont amina t-ion in ca ses of cont a mina t ed w ounds or persist entper s ona l cont am ina t ion .

III

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6 PERMISSIBLE DOSE AND MEASUREMENTUNITSRa dia t ion brings a bout a cha nge in ma t t er only by

vir t ue of t he energy t ha t is a ct ua lly a bsorbed by t hism at t er . A biologica l effect ma y a lso depend on t het ype a nd energy of t he ra dia t ion, ma king possibledifferent biologica l effect s from eq ua l energy a bsorp-t io~ lo I t is t herefore convenient t o mea sure exposurein purely physica l t erms a nd use a n a ddit iona l fa ct ort o a llow for t he rekzt ive biological electi veness (RBE)of different t ypes a nd energies of ra dia t ion. (Defini-t ions of a ll it a licized t erms a re included in t he G lossa ry,Appen dix Q.)

I t ha s a lso become desira ble t o ma ke a dist inct ionbet w een t he X or ~ ra dia t ion t o w hich a person mightbe exposed a nd t he energy a bsorbed from t he ra dia t ionloca lly by t he person. The former , a field mea sure-ment , is designa t ed exposur e dose a nd is mea sured inroentgens. The la t t er , w hich depends on t he fielda nd t he ma t er ia l under irra dia t ion , is ca lled t he absorbeddose a nd is expressed in Tads. Absorbed dose ca m beca lcula ted from exposure dose mea surement s or fromot her mea surement s of ioniza t ion, chemica l effect s, ord ir ect ly by ca lor im et ry .

S ince, in ma ny inst a nces, t he a lxorbed dose ca n beinferred direct ly from exposure dose mea surement s, t heroent gen is likely t o rema in t he unit of choice forpra ct ica l X- or ~ -ra y dosimet ry up t o a bout 3 Mev. Anumber of ot her unit s current ly recognized or in w ideu sa g e a r e d iscu ssed below .18


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The r ad has been a ccept ed a s t he unit of a bsorbeddose (i.e., t he a mount of ra dia tion impa rt ed t o ma tt erby a ny ionizing pa rt icle per unit ma ss of irra dia t edma t eria l) a nd is 100 ergs/g of a ny ma t eria l. Thegrarn- rad is t he unit of integral absorbed dose (i.e.,thesummation of the energy absorbed throughout a givenregion of interest), 1 gram-rad being 100 ergs. ln-t en xit y a n d q ua lit y of r a dia t ion a r e expr essed in er gs/cm 2-sec (or w a tt s/cm2) a nd ergs/cm2 (or w a t t s-sec/cm2),respectively. The r em is the unit of RB E dose a nd it suse should be rest r ict ed t o ra dia tion prot ect ion prob-lems, e.g., w hen it is necessa ry t o a dd dosa ges from ava riet y of ra dia t ions, especia lly for record keeping.The RB E dose in rem eq ua ls a bsorbed dose in ra dst imes RB E. Va lues of RB E for a ll ionizing ra dia t ionsha ve been recommended (NB S H a ndbooks 59 a nd 63).

S evera l unit s formerly used a re now obsolet e. Oneunit enjoying w ide usa ge unt il recent ly w a s t he rep(roent gen eq uiva lent physica l). Origina lly defined a st ha t dose of ionizing ra dia t ion w hich produces a nenergy a bsorpt ion of 84 ergs/cm3 in t issue, it w a s la tercha nged t o 93 ergs/cm3 of t issue t o more a ccura t elyrepresent t he energy a bsorbed per cm3 of a q ueoust issue irra dia t ed w it h a dose of 1 r of X or Y ra ys. Therep w a s oft en used in expressing doses due t o P ra dia -t ion . The difference in ma gnit ude bet w een t he repa nd ra d in t issue is insignifica nt in t he est ima t ion ofpermissible doses .

P ermissible dose is current ly defined a s t ha t a mountof ionizing ra dia t ion w hich, in t he light of presentknow ledge, is not expect ed t o ca use a pprecia ble bodilyinjury t o a person a t a ny t ime during his lifet ime.The ba sic va lue of t he m axi mum per mi ssi bl e dose

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(MP D) ra te ha s undergone severa l cha nges since firstbeing set in 1931 a s 0.2 r/da y. The current ly a ccept ableva lues for occupa tiona l exposures a re summa rized inS ect ion 9.

NOTE . S uch va lues a re st r ict ly for occupa tiona lexposures under controlled conditions and should bedivided by 10 for nonoccupational exposures.


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7. PERMISSIBLE CONTAMINATION LEVELS

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The va lues list ed below a pply in t he genera l ca se.S ound judgment w it h considera tion for t he hea lt h a ndsa fet y of personnel a s w ell a s t he economic a nd lega la spect s of t he sit ua t ion ma y necessit a t e revisions incert a in ca ses. I t should be remembered t ha t ma ny oft hese t olera nce va lues a re designed for use under con-t rolled la bora tory condit ions, w here levels t ha t ca n bet olera ted by sensit ive eq uipment a re oft en low er t ha nthose w hich const it ut e a n a ct ua l ha za rd t o personnel.S ince va lues a re oft en est ablished by t he low er limit s of msensit ivit y of t he monit or ing inst rument s in use, t heselevels ma y not a pply t o incident s occurr ing out side oft h e la b or a t or y. C onformit y w it h t he prescr ibed t oler-a nces is det ermined by cont a ct mea surement s w it h Ieit her a n open-w indow G M inst rument or a P eeWee.In t he genera l ca se, a cert a in a mount of ~ cont amina t ionca n be a llow ed if t he cont a mina t ion ca n be demon-st ra t ed t o be fixed, t ha t is, if it ca nnot rea dily . bet ra cked, become a irborne, or ot herw ise be inha led oringested.A. Swipes

A (sw ipe is a procedure used t o det ermine t hepresence of cont a mina tion a nd w het her or not t he con-t a mina nt is likely t o rub off, t hereby present ing a po-t ent ia l inha la t ion or ingest ion a nd cont a mina t ion con-t r ol pr ob lem . A sw ipe is ma de by rubbing a piece ofa bsorbent t issue, filt er pa per , or cheese clot h over t hea rea in q uest ion a nd count ing it w it h a n a ppropria t e

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.. . .- . ----- .- .--

meter. The sw ipe ma y be moist ened for 13~ , but notfor a since moist ure ma y prevent a s from being moni-t ored. B oot ies, a ppropria t ely checked a ft er beingw orn t hrough a cont a mina t ed a rea , ca n give a goodin dica t ion of t he likelih ood of sprea din g t he con ta min a -tion.

Nose sw ipes, a met hod of det ermining t he effect ive-ness of respira tory prot ect ion, a re ma de w it h a 3 x ~ in.st r ip of pa per w ra pped t ight ly w it h t weezers a round t heend of a sw ab st ick. Applica t or s a r e d ipped in dist illedw a t er a nd used by t he subject t o sw a b ea ch nost r il.B ot h sw ipes a re pla ced in a n envelope w it h na me, da te,a nd sit e. Aft er drying, t he out er 1 in. of pa per iscoun ted in a ga s-flow pr opor tion a l coun ter .B. Contamination Levels

&y mea surement s a re ma de a t cont a ct w it h a n open-w indow G -M coun$er , a mea surement s a t cont a ct w it h 60-cm2 P eeWee probe. B ot h mea surement s a rer ea d in gs a bove ba ckgr ou nd.

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. .

wom&----------------------NosswIws ------------------Skin -------------------------Bench tops and flood---------Vehicles (for continuing Proj-ect use).Vehicles (for public sale) ... . . .Clothing (personal) -----------Shoes (persona) and safety) ---RMpbhm -------------------Uranium transport containers(intraplant).Equipment (for use In con-taminated areas).Equipment (for use outsidethe project in contaminatedareas).Equipment [for use in cleanareas, e.g., outside the Proj-ect (gas cylinders, salvagematerials); in Counting orphotographic labs; tn ma-chine shops or stock rooms]$Tritium contamination ------

b? (mradspr). ..

Ia (c/m)Sr~ Others

Refer all potentially Contaminawd wounds to theMedical Group and H-1 Supervisor.------------- -------------- SO(each swipe in 50%efficiency counter).rl.05---------.o----------wD.05---------.0----------D.05---------.0----------00No detectabl e activity of any kind.o.05---------1.o----------000.05xterior. 6.0exterior.. 500exterior.0.05 lnterior- 1.0interior. - S00interior.0.05N. S.t--- 1.0N. S.t---- w N.S.t-..-.--..---- ------------- - 250 ( swipe) .0.05------- - 6.0--------- . Varies with situationusually about 500elm.No health hazard; recipient must receive writtenstatement = to extent and kind of Coritaznfnatloriand must be able to handle it. Transfer requ&H-1 Group Otlice approval.No detectable activity of any kind.

Refer all trltium contamination to H-1 GOLIPOfliceexcept as noted in Sec. 15.f, after two attempts qt skin decontamination, more than 3 mradslhr remain,notify H-1 Group Oftice and send subject to Decontamination Room (12S)at MedicalCenter. If less than 3mrads/hr but greater than permissible levels, release but recheckfollowing day. Measurements should be made after skin has been washed.tN.S. signifies no detectable activity using swipe technique.$Certatn salvage materials, especially bulk quantities for reprocessing, carry highercontamhmt ion tolerances. Refer to H-1 Group Otllce.


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8. DECONTAMINATIONRemova l of ra dioa ct ive cont a mina nt s fa lls int o t w o

g en er a l ca t eg or ies, decont a mina tion of people a nddecont amina t ion of things. I n genera l, first a t -t empt s a t decont a mina t ion ca n be ma de under t hem on it or s s uper vis ion . E very effort should be ma de t ocont rol a ny sprea d of t he cont a mina t ion during decon-taminat ion. This ca n be a ccomplished by:

(1) Alw a ys w orking in t ow a rds t he cent er of con-taminat ion.

(2) Ta king ca re not t o t ra ck t he cont a mina t ion ,w hich implies complet e know ledge of w here t he con-t amina t ion lies, a nd proper use of prot ect ive clot h ing,es pecia l ly s hoe cov er (boot ies).

(3) C overing clea n a rea s in t he vicinit v w it h kra ft.paper.(4) B eing a w a re t ha t t he run-off solut ions a nd a llmops, ra gs, a nd brushes used in t he decont a mina ting

a r e pot en t ia lly con t a min a t ed .G ross, w idesprea d, or pe~ ist ent problems should beha ndled by specia list s, H 1 D econt amina t ion S ect ionfor object s a nd H 2 I ndust ria l Medicine for personnel.A. Personnel Decontamination

P eople a re decont a mina ted for t w o rea sons: (1) Toprevent possible t ra nsfer , especia lly of ~ emit t ers, t oin t erna l orga ns by ingest ion or t hrough cut s or ~ bra -sions, a nd (2) t o prevent ext erna l exposure or possiblera dia t ion burns. I t is obvious t ha t in bot h ca ses24


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prompt remova l w ill reduce t he pot ent ia l ha za rd. I tis a lso a ppa rent t ha t met hods used t o effect decont ami-na tion must not sprea d init ia lly loca lized ma ter ia l ora ssist t he cont amina nt in ent er ing t he body (excessivescrubbing w hich a bra ids t he skin).

Skin. Over t he yea rs ma ny procedures, some q uit elengt hy a nd involved, ha ve been devised for t he re-mova l of cont a mina tion from ra dia tion w orkers. Thefollow in g rela t ively sim ple pr ocedu res h a ve been w idelyused a t LAS L for t he remova l of a va riet y of cont a mi-na nt s, most ly a emit t ers, from w orkers. Ot her moredra st ic mea sures a re a va ila ble under medica l super-. . Ivlslon. I

(1) D et ergent a nd w a ter w a sh.m2) Turco H a nd C lea ner (Turco P roduct s, Inc., Los sAngeles). A commercia l liq uid ha nd clea ner developed Ispecifica lly for removing ra dioa ct ive ma teria ls from

skin. G ood result s w it h plut onium, ura nium, a nd ~ -y Iemit ters. C ont a ins la nolin t o reduce skin irrit a t ion. .(3) Ta rt a ric-C it r ic Acid .Mixt ure. H a lf-a nd-ha lf

mixt ure of t he a cids; used rout inely a nd successfullyfor plut onium but somew ha t irrit a t ing w it h prolongedusage.

(4) C it r ic Acid P ast e. G ood for a emit t ers.B. General Decontamination

IE xperience ha s show n t ha t t echniq ue is oft en more

import a nt t ha n t he specific decont a mina t ing a gentused. F or t his a nd ot her rea sons, it is difficult t o a s-sign a best met hod for a cer t a in decont a mina t ion prob-lem. S ever a l specific m et hods used a t LAS L---su ccess-ful but not necessa rily t he best --me list ed below . I t

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is a lw a ys w ise first t o t ry t he follow it ~ g five simplemethods:

(1) D a mp ra g.(2) Wa t er a nd det ergent .(3) D ilut e complet ing a gent such a s Versene (sonk-

ing in Versene is considera bly bet ter t ha n simple w a sh-in g) . Act ion is a ccelera ted if t he Versene is hea ted.

(4) Mild a cids ~ cit r ic, low norma lit y H C1 or H NO,).(5) C ombina t ions of t he a bove.C )t her met hods used by t he D econt a mina t ion S ect ion

include va cuuming, va cu- a n d sa nd-bla st ing, ult ra soniccleaning, and high pressure steam.C. Specific Methods

Met a ls. Oily surfa ces must first be removed; t henhigh norma lit y a cids a nd even concent ra t ed a cids ora qua regia ma y be used if sur fa ces ca n st a nd t his roughtreatment.

Concr ete or B r ick . S olut ions of H C 1 a nd I gepa lused w it h com mer cia l scr ubber s.

Glassware. Ordina ry chromic a cid clea ning solut ion.Linoleum. I f w ell w a xed before cont a mina tion, re-

mova l of w a x w it h solvent s or scouring pow der a ndst eel w ool w ill decon ta m in a te.

Wood. N o hope short of sanding or planing.Pain ted Sur faces. P a i nt r em over s.

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9 MAXIMUM PERMISSIBLE EXPOSURESA Whole-Body Exposure

The maximum permissible accumulated whole-bodyoccupational dose, in rem, at any age greater than 18,is comput ed hlP D = 5(lV-18), w here iV is t he a ge inyea rs, provided no a nnua l increment exceeds 12 rem.Not more t ha n one-fourt h of t he 12-rem ma ximumpermissible yea r ly dose (3 rem) sha ll be t a ken in one-fourt h of a yea r . These va lues ma y be doubled w henonly t he skin of t he w hole body is exposed. Not e t ha ta lt hough permissible w eekly doses a re no longer speci-fied, t hey a re used t hroughout t he ha ndbook for con-ven ien ce, es pecia lly t h e O.3 rem/w k ba sed on t he former ,MP D of 15 rem/yr. m

The a ccept a ble yea r ly exposure a t L AS L is 5 rema nd t he 12-rem ma ximum is used (1) only w hen t he Ia ccum ula t ed exposure a ft er t he a ge of 18 is docum en ted,(2) t hen only in ca ses w here judicious use of exposureha s been ma de, a nd (3) w hen, in uniq ue a nd unusua linst a nces, a ft er due considera t ion ha s been given,rest r ict ions w ould result in ser ious impa irment t o t hefunct ions of t he La bora tory. Yea rly exposures grea tert ha n 5 rem ca n be a llow ed only w hen it is document edt ha t t h is exposure w ill not viola t e t he 5(lV-18) rule.Administ ra t ion of t he a bove MP D policy a nd t heur t her L AS L rest rict ions ca n become complica ted for)he except iona l ca se. The necessa ry informa t ion is]ft en difficult t o obt ain , for inst ance w hen a n employee

previously w orked a t a not her inst a lla t ion a nd doesha ve a n a ccura t e record of his pa st exposures, or

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1

.- . ---- .. . .. _

w hen he h a s w orked a t ~ AS L for a number of yea rsa n d it is necessa ry t o do t he ~ ime-consuming job ofcompiling his cumula t ive exposures. The genera lt endency is t o limit exposure w henever possible.

Th e 5 rem/yr w ill be ha ndled on a 0.1 rem/w k ba sisbut t hk does not imply t ha t 0,1 rem/w k sha ll be t heupper lirnit of w eekly exposure. Whenever 0.1 rem/w kis exceeded specia l mea sures a re t a ken, These speckdmea sures include not ifica tion of supervisors t ha t oneof t heir people received a dose w hich, if cont inued fora yea r, w ould result in more t ha n 5 rem. Overexposurereport s me issued only w hen 3 rem is exceeded in aca len da r q ua r t er .B, Extremity Exposure

Th e ma ximum permissible a ccumula ted dose in t heha nds a nd forea rms, a nd feet a nd a nkles is 75 rcm/yr.S ince t here is no a ccumula t ed a ge rest rict ion onext rem it y dose, a w eekly dose of ~ .5 rem is used.S uit a ble w rist -t o-finger ra t ios h ave been developed ex-periment a lly t o a void t he use of finger ba dges.C . Summary

Whole-body a nd ext remit y permissible exposures a res um ma r iz ed a s follow s :

28

1


35/186

WHOLE 130DYrem3faximum permissible yearly dose. ---- _ __ _- 12

Maximum permissible accumulated dose. _--- 5( ZV-18)Administrative permissible yearly dose _ _ --.- 5Maximum permissible quarter-year dose- ---- 3Weekly dose togive5rem/yr -------------- O. 1

NOTE: For B or X rays below 40 kev average, the above valuesmay be doubled. Also, if the ~ does not exceed the abovevalues, the (3+Y sum may be doubled.

EXTREMITYremMaximum permissible yearly dose- -- __ - _ - _ _- _ 75

hlaximum permissible weekly dose-- ---- _-- _ - _ 1.5NEUTRON WHOLE BODY

Xeutron energy._ . Thermal (3X 10-2 ev)-..-l100ev_ ---------- _---:5Xl@ev -------------2X104 ev --------------0.1 hlev ______________0.5 Mev---------------1.0 Mev---------------2.5 hlev --------------5.0 Mev-------------7.5 N1ev--------------10 3fev----------___-10t030hlev ---------

I

RBE-

32

2.5581010.58776.5----- ----

Flux to give 0.3rem in 40 hr(n/cm%ec)-.20001550170085025090556055505030

0.3 rem MPD(n/cm~wk)-

288X 106223X 108245 106120X 10636. OX 10613.ox 1067. 92X 1088. 64X1087. 92X 1087. 20X 106702OX1O64. 32X 108

The last two columns may be divided by 3 to obtain values based on 0.1rcm/wk.NEUTRON EXTREMITY

Neutron extremity dose may be five times the whole-bodyMPD. 29


36/186

. .

D. Permissible Exposure TimesI t is oft en useful t o express permissible dose in

t erms of t he t ime it t a kes t o receive such a dose.This ca n be ca lcula ted by dividing t he permissible dosera t e by t he mea sured exposure ra t e. The choice ofpermissible dose ra t e must depend on t he t ype, dura -t ion, et c., of t he oper a tion.

Example T mea surement s show a n exposure dosera t e of 7.5 mr/hr (0.0075 r/hr) a t n cert a in posit ion.U sin g a s per missible r a te 0.3 r /w k, (0.3 r /w k)/(().()075r/hr) = 40 hr/w k a t t his posit ion. This is a n exa mpleof a shor t t erm opera t ion . I f con tin ued in defin it ely ,t he 0.1 r/w k permissible exposure ra te should be used.

Exam pl e 2: S uppose a I -Xlev neut ron flux of 55n/cm2-sec is mea sured. S ince t he n/cm2-w k t o give0.3 rem/w k is 7.92X 108 n/cmi-w k, (7.92X 106 n/cm2-w k)/(55 n/cm 2-sec X 3600 sec/hr) = 40 h r/w k a llow a blea t t his posit ion t o give 0.3 rem/w k.

Exam pl e 3: E xposures in mixed fields (sa y ~ ra ysa nd neut rons) must be limit ed t o t ha t a mount of ea chso t ha t t he t ot a l exposure is permissible or less. S up-pose 25 m r/h r ~ a n d 100 n /cm 2-sec (1 h fev) m -e m cm .ur edsimult a ,neously . 25 mr/hr is 3.33 t imes permissiblew eekly ~ exposure 25/7.5=3.33 , a nd simila rly 100n/cm2-sec is 1.82 t im es per missible (100/55= 1.82). Th ecombined effect (1.82+ 3.33= 5.15) is 5.15 t imes per-missible, or t he a llow a ble t ime must be divided by5.15 (40 hr/5.15= 7.77 hr/w k), giving a permissible7.77-hr exposure in a 40-hr w eek t o give 0.3 rem.

30


37/186

--- .

10. TABLE OF ISOTOPESTh e follow ing t a ble present s pert inent da ta for ma ny

ra dioa ct ive isot opes or isot ope cha ins. E lement na mea nd a t omic number (2) a re list ed a lpha bet ica lly incolum n (1). C olumn (2) ident ifies t he isot ope, givingelement a bbrevia t ion ,w it h t he ma ss number (a t omicweight , A) as superscr ipt . An m follow ing t he ma ssnumber signifies a met a st a ble st a te (see Appen dix Q).When only one da ught er is significa nt in det erminingNIP C, it is ident ified in t he sa me ma nner a s t he pa rent .When t w o or more da ught ers a re import a nt t hey a rea bbrevia t ed + drs.

In column (3) ra dia tions t o be expect ed (w hen moni-t or ing) from t he isot ope or isot ope cha in a re given.a signifies a lpha pa r t icle emission; p signfies eit her melect ron or posit ron emission; Y indica t es ga mma ra yemission; X, used only w hen no ga mma s a re emit t ed,signifies elect ron ca pt ure X ra ys; ~ %f. signifies t ha tspont a neous fission neut rons a re emit t ed. ,

columns (4) a nd (5) give t he ma ximum permissibleconcent ra t ions in a ir (MP C a ) a nd w a t er (MP C W) indisint egra tions per minut e per cubic met er (d/m-M3)a nd disint egra t ions per minut e per lit er (d/m-L),respect ively . MP C va lues w ere t a ken from a prepub-lica t ion copy of t he Report of C ommit t ees (I C RPand NC RP ) on P ermissible D ose for Int erna l Ra dia -t ion 1958 R evision a nd a re subject t o revision.Va lues a re given for occupa t iona l -exposures of 40 6hr/w k, 50 w k/yr for a cont inuous 50-yr w ork period. I.-----.-.[134--------------P$J+drs .. . ------[rl~.-.--..---..-w$~.---..-.-----[rlu--.-...------Fe$$---.-----.--.FeSO------------Kr$~m+dm.----.Krt~-...-------..Kr$~...----..---.Lal~O. . . --------PbZoJ-.-..---.---Pbllo+drs----...Pbllz+drs.-----.Lu177-----.-----.hfn$a------------hfn~h-----------Mn~.----.---.-.Hglslm+drs.-.-.l~gl47-------- ----Hg2w_----------hfo~+drs -------

See footnotes at end of table.40

(3)R:xl .&ns.Y----------l%Y-------J9,y-------B----------/%Y-------6, r-------/%7-------l%7-------0) 7-------P, 7-------B, r-------Y.. -. -.. . . .6, Y-------6, Y-------x---------d, 7-------1%7-------P, -r-------i% 7-------

6 , 7 ------

Y---------=, P I -r ----a j A v----P , - r --- ---)% 7------Y ---------P , Y--- -- -

7---------Y---------B, Y------P , 7 ------

(4)MPCa(d/m-M$)

4.2xl@2. 3xlo~1.6x1W5.7xlo~d z.7xlo4d 5.5xlo.ld 2.9xlo4d 8.OXIO~d l.lxloSd 1.7x14)4d 3.6xloJ

3.7X1042.9X1056.7xI041.9X1043.4xlo~

e 1.OX1O7e 1.8X1OI0 1.5X1044.6X1049.OX1OS2.9xlo~4.OX1O42.9xlo~9. 7X1058. 7X10~I. 2x1071.7X1042.7X1041.6x10~1.6x104

(5)\fPcw(d/m-L)

4.8X10112.7xlo~1.9X1OI16.6x10~d I.sxl(j$d 3.6x10~dz.0)(10Sd5.7xloIld 7.2x10~d 1.2x107d 2.5x104

9.9XI077.8XI041.9X1O$5.4X1079.3X1OO()(0)(0)

1.Oxloll3. 1X1O9.Oxlo1.3xlo~6.6X101(2.6x102.4X1O3.3X1O1.3XI02.OX1O1.2X1O1.2XI0


47/186

. . ..-

33 bK6.o K33 bK30K

dloo Td2.5 TdO.73 TdO.26 TdO.31 TdO.20 TdO.32 T36 bK5.9 K6,8 bK

l.l XIW Sp19 Sp(e) TB(s) TB(Q) TB8.7 b L26 bK0 44 K0.022 K21 bB5.3 b p18 L].8 bp4.1 K15 K3.6 K8.4 K

(7)Half-lives

T,1.75h49d4.5h

6)(1014y

13.3d. 72x1OTY8.05d2.33h20.8h52.5m6.70h

12d74,5d19.Oh2.94y45.ld4.4h10.6y78m

40.2h52h19.4y10.64h

6.7d5.55d3Wd2.58h

24h65h45,ad67.Oh

TbWd6odOod6od

138d138d13M138d138d138d138dm5od5od

(0)(0)(0)

531d531d631dlmod5.7dZd5.7d

14.5d14.5d14.5d3d

(8)gJc

1.3OX1O+. 27X1O+.65XIO+1.92X1OII. 28XIO+6. 18X1(P1.06X1P).79X1O-IL81x10_?).73X1O-3).W2X1O-7I.74X1O-$1.O9X1O-41.17XIO+L 50XI0-42.O3X1O-41.19xlm2.58x10_~3.6OX1O-I1.79X1M3.36xl&I1. 13xlo-7. 18x10_9. 07xlo-2.21xlo-1.24Xl&4.5oxlo-l.51xlo-4.08xlo-7. llxlo-2. llxlo-

(9)Clg

1.59X1072.34X1046.06x106,2IX1O-I27. [email protected])([email protected]@5.75X1049. [email protected]@3.ssxlo~2.78X10~5.59X1O2.98X10~88.:1.39X1O1.10X1O4.52xlO8.O6X1O2.17X1O6.62xI02.45X1O1.4IX1O4.74xla

(lo)%tegory andshippingexempt mg

H 8.5XlfiII 5.8X10_JIr 2.2x1 o-7H 2.6X101III 1.7X10_4II 8.3XIO$H 1.1X1O+11 1.3X1O-7II 1.2Xl&7:11 5.OX1O-:II 3.9X1O+[H 2.3Xl&$[11 2.6X1O+[11 1.6x1O+[11 6.1X104[11 2.7X10-~

(0)(o)(e)III 2.4X1O+111 4.5xlo-aI 1.1X1O+I 7.2Xl&tIII 1.2Xl&~111 3.OX1O-$III 1.7X10_t111 6.2Xl&s111 2.OXIWIII 5.5x10_~II 9.6x10_~111 2.8X1O+

41


48/186

. .

(1 )

Element (Z)

Neodymium (60)..-.

Neptunium (93).. . .

Nickel (28)----------

Niobium (41)--------(Columbium).

Osmium (76)--------

Palladium (46)------

Phosphorus (15)----Platinum (78)-------

Plutonium (94)-.--.

Polonium (84) --.. -,Pottuwium (19)_---,

(2) (3)

Isotope Radiationsemitted

xdli4 ------------ a . . . . ------Xd Jl+dm . . ----- 6, y-------~dliO+I~nlllo-.-- p, y---...,Xpnl+Pni~-. . . . a,~, -f....Xpn9+drs ------- a, f9,7.. -.si3s-.--.----.--- X---------sl6s.------..--.- ls-..------,N1e3--------.--.- ~,~...---,xb$.lrn----------- y - . . . . . . . . .XbQ~-.-.-..---.. /3,-1------Nb$l-.-.-.--..-- I?,y...--.o.sl s. .- . . ..-... - y..-. -----Osmra+drs ------ /2,y------Osl l +I rI Um- - - -, y- -----os l ~------------ f 7 ------p d l ~+l l h l ~m . -. y... ------pdB+Ag~m..- . &y ------P~~.-----..--.-- - B.-. -.. -..1t19~-..-. ----- . y-..---.--~>t19Sm+pt193- . .y- - . . - - . - -pt193- - - - - - - - - -x- - - - - - - -pt197m+pt197. -~- p,y-..---I-tw---------- . /% Y------

ru~~------.--.. . a, -r------Pu139-------.--- - a, y------pu240 -.--.------ - a , y. .-- ..pu2fl+dm-----. . a, fY,T---Putii--..-.--.-. . a---------P0210----------- . a, y------Ic42---- - - - - - - - - - . / 3,7---- - -

(4)?irPc.(d/m-MJ)

1,9x1027.7)(10$3. )(1079.31.0)(107

[email protected]~2.2X1074.3xlo~

1.OXIV2. 1X1O:3.3X1O$2.4xI011.3X1071.OX1O73. IX1048.7xl@

7.7XI033.oxlo~2.5X1072.3x10~6.7x10?I.) X107

4.43.93.92. ixlo~4.1l.l XIW

70Oxlw

(5)N[PC.(d/m-L)

4.2X1O$1.7xlo~o7.Oxloll2. 1X1O$2. [email protected]*2.4XIOIQ4.8X101Z8, 7X1076.6x1O*3.6x1092.8X10~4.8X1071.4X103

5.7X1047.8X1076.6x10~6.3xlo~1.9XIU3.oxlo~3.3XIO3.Oxlo3.Oxlo1.5X1O3.Oxlo:4.6x1O

4.8X1OSee footnotes at end of tnble.

42

I


49/186

(6)q (PC)8ndcritical organ

0.14 B9.5 L2.9 b L

1.3x1OS B160 B4.1 b B300Bs38 TB12 bB

18 K6.8 b Ks28 TB] ( I b~100 b~72 K5 b~11 bK

0.044 B0.044B0.0 4B0.93 B0.046 B0.034Sp

.

(7)IIalf-lives

T r

2XIO15Y11.3d

2h2.2oxlo~Y

2.33d8x10~y

8ny2.56hIoy35d74m95d14hlod31.5h17d13.6h

14.3d3.Od3.sd500Y84hn18h

89.6Y2.44X104Y6.6x1OJY13.2y3. 8x10~y138.4od12.47h

Tb1S KM131d131d

7.3xloki7.3xloki

&mdloood760dImod

Sd5dSdSd3od30d

257dOod60dOod&Id6od

7.3x104d7.3x10~d7.3xlo4417.3x104d7.3x101dw58d

(8)g[c

8.O2X1OII1.27xlo-~9.49xlo-~1.45X1024.26X10-J

13.21.toXlo+5.3OX1O-2.59XI0-32.54XIO+3.81X1O+1.34X14)-48.52x1O+2.34xlo-~1.94XI0-1.34X1O+4.72x10-T3.50X IO+4.38X1O-85.16x1042.69x1 O-I8.37X10-S1.13xlo-~5.94XI0-316.2

4.418.86X1(H2.56x1022.22X1O-41.67X10-1

(9)c/g

1.25X10_l~7.87X1O41.05X1W6.9OX1O-12.35X1O$7.60XI0-271.41.89x10~3.MX1023.94XI042.62x1077. 46X1(P1. 17xllY4.27XI045. 15xlo~7.46x1042. 12xlo~2. 8GX1OJ2.2$xlo~1.94X1053.721. I9X1078. 85X10~

16.86. 17x10-22.27X10_l1. 13xlo~3.91X1O-J4.5OX1O35.99X104

-.

(lo)Catwory andshippingexempt mg

111I.lXIO1lIII1.7x10-~1111.3I0-71112.OX1OJ1115.8X10-1III 18.1111.910-~1117.2X1O+III 3.5x1O+1113.4x1H1115.11O-81111.8Xl&41111.2x1O+1113.2X1O+1112.6XIO+III1.810-~1116.3x10-71114.7x10-S1115.9X1O+1117.OX1O+III3.6X1O+HI 1.lx10_71111.5X1O+I 5.9x1O+I 1.6I 4.4XIO+I 8.910-~III 3.5X10~I 2.2x10_$

1112.310-T

43

,iII


50/186

. ... .

(1)Element (Z)

Praseodymium (59).. -

Promethium (61). . . . .

Protactinium (91)----

Radium (88)---------

Radon (86). ..--- . . . . .(Emanation)

Rhenium (75)--------

Rhodium (45)--------

Rubidium (37)_--...

Ruthenium (44). . . . . .

(2)Isotope

Prl~~------.--.-Prl~3.--.-------Pml{?+Sml~~--.Pml{~..--..----PanO+drs ------Pa~+drs.-----Pa~~.-----.----Ram+drs ------Ra2tl+dm---.--Ra=+drs -----Ram+drs ------Rn220(Emm)

+drsEquilibriumMixtureRnZ22(Em222)

+drsEquilibriumMixture

Rel~..-----..--RelEO+Osl$Sm---Rel~~-----..----RelS1+Os118m--Rhlo2m.--------RhlO ...-----..-RbM-----------Rb17- - - - - - - - - -Ruw+drs ------Rul~+Rhlo2m--RulO$+drs ------Rul~+RhlM__

See footnotes at end of table.

44

(3)~~:ig;;dn

P,Y-----P---------d, Y------/3,y-.---.%1%Y---%A 7---u, &7---%P) Y---%PJY---a, Pt 7---a, &Y---aDA 7---

a,l% ~---

7--------/?,y-----P--------6,7-----7--------19,y.----@,-r-----9--------Y--------fll,-f-----f?,y-----1%Y-----

(4)MPCa(d/m-M-)

[email protected]$6.7X1043.9XIW9.2X1O-1I.3X102

3.3X1021.lxlw2.IXIIY17.i2.Oxlw

{2.Oxw

s6.7XWd3.6XI04j2.OX1O7d4.9X1O23.7xlo~2.X1O7

[email protected]@7.3X1(F3.4xl@

(5)MPc.(d/m-L)

1.9X10112.6X101O3.3X1091,6X1OI18. 7X1072. 1XI073. lXIOIO

4.2X104 1.3X1O$2.7X1OJ2. 1X102

()

()

4.4X107d 3.3x101i 1.8x1OId 4.5X1076.OX1OJO3.3xl@ [email protected].?Xlo?


51/186

. ..-. . . . .

(6)q (JAC)ndcriticalorgan

7.o bB17 bB&3B16 bB

0.074 B6.8x1O+ B42 Ks O.071 TBs O.071 TB0.10 B0.057 B

(i) LU

(i) Lll

s80 TBdlg bT

J 310 sd6.8 bT210 bK41 b~s28 TB160 P~ bKI(3 bK

1,(3 bK2.8 bK

(7)Half-1ivesT ,

19.3h13.7d2.52y52h17.7d3.43X1OV27.4d

11.68d3.64d1622y6.7y52s

3.825d

o.2y91hSxloq17h5.4m36.sh18.6d5xloloy2.8d41.Od4.5hl,oy

Tb

IsCod1500dlsoodlsood

7.3xlo~d7.3x10~d5.lxlO~d8.1XIWd8.1X1O%I1.6XlCVd1.6XlfYd

(i)

(i)

3d3d25d3d28d2&i45dOod

2.Sd2.Sd2.Sd2.5C?

(8)glc

B.i3X10_71.soxlo-~1.O3X1O-32.47X1O-33.llxlo-~22.14.aaxlo-~1.99xlo-~6.23X10-61.024.26X10-J1.OIXIO-9

6.39X10-C

1.02xlo-t5.39X1O-32.60XI071.02x10-S2.95X1O+1.22X1(F61.22xlo-~1.21x Io72.08xlo+3.23Xlo+l.soxlo-~2.95X1O-4

(9)c/g

1.15X1LF6.67X10~9.71XI034.O5X1O33.22X1044.S3xlo+2.05XI045.02xltY1.ooxlo~9.8OX1O-12.35X1039.90X1(Y

1.54XI05

9.aoxlo~1.86xlo~3.85X1N9.aoxlo~3.39X1OJ8.20XIO:8.2OX1O8.26X10_[4.81X1O3.08xlo6.67XICF3.39X1O

(10)Categoryandshippingexempt mg

[11 1.2x1O+[H 2.OXILV[1[ 1.4xlo-~[11 3.3X10_0[. 3.IXIN[Ix 30.[11 6.6X1O-51 2.OX1O+I 6.2X1O+I 1.OX1O-1I 4.3X1O-4

(i)

(i)

111 1.4X1O-4111 7.3X10AIII 3.5X107111 1.4X10-SIII 4.OX1O+111 1.6X10+111 1.6X10-$111 1.6X107111 2.8X1O+III 4.4X1O+III 2.ox1o-7II 4.OXIO+

4 5

I


52/186

.-

(1)Element (Z)

Samarium (62). . ..-

Scandium (21)-----

Selenium (34)... . . . .Silicon (14)---------Silver (47)-.. . . . . . .

sodium (11)-------Strontium (33)----

(Sr~-Yrn). . . . . . . . . . .

Sulphur (16)--------Tantalum (73).... . .Technetium (43)..-.

Tellurium (52)-..--

(2) (3)Isotope R:w&t&y

sml~T-..--...---. a.------.--sml~l.-.---..-... j%-r-------Sml~.-----.----- 1%Y-------sc4~...-.--..---- IY,Y-------sc~l.-.-.--.----- B,7-------s@4------------- 0, Y-------Se~~.---------- - y----------si~l------------- - 6, Y.-... -.AglO~.--.----.-. - y----------AgllOm+AgllO..- - p, y-------Aglll+cdlllm--- - ~, -r- . . . . . .

~an ------------ - 1%7------Xa%~----------- - A Y-------Sra------------- - @---------Sr~+Y~..- ---- - B---------Sr~I+drs. . . . .. . . l?,Y------Sr$z+yfl.--.--- - /?,y------Equilibrium lY---------Mixtures$------------ -- B---------Talsl@J+\~lk- -- f3,~------TcWrn+TcQJ---- [email protected] -- y---------TcQlm+Tc$l...-- y---------Tc97----------- -. x--------T~99m+Tc99--- -- ~,y----..TcOS..-.-----.. -. (3---------Te123rn.-....-. -- 7---------I Iel~?m+Tels?---- ~, 7------Tel17----------- A-r------

See footnotes at end of table.4 6

(4)MPC.(d/m-MJ)

1.6x1031.5X1037.OX1OJ5.3X1031.3X1074.4X1042.9xl&4.4X1076.2Xl@ 2.OXICP7.OXICF3.7xl@ [email protected]~3.6X1(P1.0XI075.8x102

k [email protected]@2.9X107*5.Sxlos6.2X1OJ8.OX1O.. I 3.Oxlo:.. 2.4xlo~

(5)MPC.(d/m-L)

[email protected]$1.6X1OII1.2X1OIJ2.9X1011.Ixloll2.OX1O73.3X1O$

1.4X109 4.8X1W1.6x10~ 2.5X1(Y*2.6x1078.1XIW3.6x1034.5xlo~1.3X1037.2xl@

k 4,oxl~2.Oxlo7.2XI06.6X1O7.2XI02.7X1O

4,8XI05.7X1O1.lXIO

I4.2X1O3.3X1O

II


53/186

-.. ..-..-..=

(6)Atkl :;:rl

0.12 B110 B16 bL13 L4S bL&7 bL88K

14 b LU3 1 b1B12 bTB~ bK 13 TBs7.3 bTB4.1 B2.1 B2.5 bB1.9 bB

,------- ------

k 9] Tg7.3 L60 bK12 bK18 bK63 bK

* 240 bTB13 bK15 K6.6 Klb bK

(7)Half-livesT ,

.3X1011Y100Y47.oh85d3.43d1.83d

127d265h

4od270d7.Sd2.6Y15.Oh51dmy9.6ih2. 6h

---------

87. IdllmWI-n4.3d92dlwy6.04h2 12xlo3y58dlo5d9.35h

T b

1500d1500d187d36d36d36dlldOodSdMlodlldlld

[email protected] d1.8XlWd1.8X1OW--------- .

623c400(2&2(R20(m1(m3&3&30

(8)glc

5.32X107.21XILW.29X1O+.wxlo-~.23)(10+L72xl&T.23X1O-$.62X1O+L21xl&$1.27X1O+).36X1O-C1.59X1O-4I.15X1O-?3.47X1O-37.02xlo--:2.8oxlo-~7.62X1O+.-------- .2.23xlo-1.56xlo-2.65xlo-3.ltixlo-6.82X10_2.7(l.90xlo-58.5.54xlo-l.02xlo-3.78X10_

(9)Ctg

. 88X1O-823.84.37)([email protected]([email protected]~6.29X1(P8.7OX1O42.88xlo~1,42XIU3.57xla1.31xlo~------- . ..

4.29X1O6.41X1O3.77X1O3.16X1O1.47X1O3.7oxlo-5.26X1Cl.7lxlo-1.81xIC9.80X1(2.65X1(

(lo)ategor andrhlpp ngexemptrng

[1 7.2X1O?[1 5.7xlo-~[1 3.IX1O-4[1 4.OX1O-311 1.7X1O+11 9.lxINII 9.8x10-~II 3.5x1WII 4.3x1CN11 3.lXIN11 8.6xlC@II 2.lxIWII 1.6XW7I 4.7x1O+:1 9.5X1O-4[11 3.8X1O+[11 1.4JX10_7..---------.--

[11 3.4xlo-~[11 2.1X1O-4111 3.6X1N111 4.3X1O-4111 9.2xl&~111 3.6111 2.6Xl&t111 79.111 7.5XNFIII lo4X10_4111 5.lxlO+

4 7

I


54/186

..- --

(1)Element (Z)

Tellurium (52)-------Continued

Terbium (65)... ------Thallium (81)---------

Thorium (90). --------

Thorium, Natural ... .

Thulium (69)-------Tin (50)-------------Tungsten (74)-------(Wolfram).

Uranium (92)--------

2)

Isotope

?eli$m+drs....--?elfl+Il~$.--.--.:el~l~+drs.-----?e1s2+113~-------~bMO+Dy140m--rim------------rw----...----.Plies-----------plM-.-.--..---.rhm+drs...---,rh~l+drs ------rh~o.----------rhm+Panl----lh2~2+drs-.----~hW+paZ$f.---EquilibriumMixture.~ml?o+ybllornTmlll...-.-----Snll$+InllJ=.-..Snl~~+drs..----wl:l---.------_W18S----------W1lT+drs------Ul~O+drs.------JU~~~+drs...---u2J~------------ua3~---.----._-.U~J~+Thi$l.---u~~-..---.-----U23:--------.--.

See footnotes at end of table.4 8

3) 4)

R:&&ns MPCa(d/m-M~).

p,y ------- 1.8X10~l%Y------- 6.4X107l%Y------- 2.3Xl@9, y------- 7.7x 10$9,y------- 2.3XIOJY----------?----------Y----------f% Y-------%A -Y----%A Y----a~1%----U,l%y---a, 1%----/% Y-------

%/% Y----1%7-------@---------7----------A Y------ -Y--------- -

0,7------ -l%Y ------ -a, /%7--- -a$A r----a17----- --aj 7----- --a, A 7-- --al -Y---- --a$7----- --

1.9X1071.1X1OT2.3X1041.4xlo~4.7X1W13.5.14.1X1079.3X1O-11.3X1O

5.2

8.OX1O2.5X1O8.OXlO7.3X1O5.oxlo2.2X1O

4.2XI04.6X1O3.5X1O4.Oxlo4.Oxlo4.4)(104.2X1O81

(5)MPCw(d/m-L)

2.4X1068.7X1O$3.0XI07L 1X1075.1X1091.9X1049.9X1072.2X1271.3X1071.1X1072.8X10~1.1X1OS9.3X1OII2.Ixlol3.Oxlol7.5X104

1.8X10i5.7xlo~4.2X1O;3.6X10;1.4X1O6.OXlO~L 1X1O1.Ixlo8.2X1O9.oxlo9.oxlo9.7XI09.7X1O1.9X1O


55/186

. . . ..

(6)g (w) andcritical organ

2.9 K5.3 b~4.3 bK3.4 bK16 B

37 b~41 bK17 bK14 K9.3xlcra B9.4x10-~ B0.050 B47 bB9.oxlo-~ B3.5 B. . . . - --- ------

9.3 B93 DB26B6,5 bB

9.1X1O-3 K0.047 B0.052 B0.052 B0.056 130.055 B4.7X1O-3 ml

i )1{a\f-lives_

T ,

w;4m30h3.2dW

[email protected]

-------- .]2id1.9yl12d9.Sd140d74d24.oh

20.8d74y1.62X1O$Y2.48X1O$Y7.13xlo~y2.39x lo~y4.51X109

...Tb-

3odWd3od3odloood

7d7d7d7d7.3X10~d7.3X10~d7.3x10~d7.3xlotd7.3X10~d7.3X10td------ -..

loood1Oood10M1Oot

4d9dId

3043004300(300(3oa300(304

(8)g/c.

.25xlo-~. O?xlo-s. [email protected]. 72X1NI. 61X104.85XI0-3. 70XI0-3).19xlo-~I.21X1O-351.3[[email protected],---------1.65X10-~9.O5X1O-49.68xlo-~9.08XI0-61.94XI0-4I.O5X1O-4L43X1O-43.Nix 1O-J4.78X1O-:1.O5X1O1.62X1O4.67X1O1.57X1043.Ooxiod

(9)Cig

3.WXI041.WX107B.OOXIOS3.loxlo~1.o$xlo~5.81X1052.17xlo~5.41X1045.88xlo~3.13X1048.26XI02.95X10-Z5.32X10~1.11X1O-72.32X104-. . . .- ---

6.06X10:1.Ioxlo:1.O3X1O1.Ioxlo5.15XI09.52X1O6.99X1O2.73X1O

20.9.48xlo-6.17X10-2.14x Io-G.35xlo-3.33xlo-

(10)ate~oryandshippingmempt mR

: 4.4X1O-4I 6.8 X1O-$:1 1.7X1O-44.4XI0-71 l,3x10-~[1 2.3XIO+[1 6.2X1O+[1 2.5Xl&$[1 2.3Xl&J

3.2X1O+1.2x1o-4[1 69.II 2.5X1O+II 1.2XI07I 5.8X1CH---------- . . . .

II 2.2x1o-411 1.2X1O-311 1.3X1O-4,11 1.2xlo-~,11 2.6X10_4:11 1.4X10_4III 1.9X10_6I 3.7X1O-4I 4.8X1O+11[ 2.GX104111 2.2X1OY111 6.3XI05111 2.1X104111 4.0xI04

4 9

I

i

III


56/186

1

II1

1)Element (Z) I

.. Umnium (92). .-... -..Continued

\anadium (23).. . . . . . . .Xenol] (W)------------

Ytterbium (70)... . .. . .Yttrium (39).. . . . . . . .

Zinc (30). .. . . . . . . . . . . .

Zirconium (40) . . . . .

(2) (3)Isotope Radiationsemitted

.

.:33 f~~d a, fl, -f..-(40pi]mvz3Y)(atur~l l-r:mi- a, B,7---um, Tuhalloy)ralloy (93mc).- . a,/3, y..-)ralloy (-tO~C).. a,/3, y.-.D-3S. .-- . . . . . . a, f3, y...k-~~. . .. . . . . . . .-. B, Y------Kc131m.. .. . . . . ..SN33 . . . . . . . . . ..-.SC133+C513SIU.- --

YNT . . . . . . . . . . . .

Y~G... . . . . . . . ..-Y~:m+Yol.-....-Y l . . . . . . . . . . . . . .Y93 . . . . . . --------Ys+drs . . . . . . . . .Z1163 . . . . . . . ..--..ZIi69m+Zn~9. ---.Znoq . . . . . . . . . . . .~f-tl+ ~h93m- ---,Z]$$+drs... - . .WJ+rirs. . . . . . . .

9, y..-..-9,7. . . . . .p, y.....-P,Y------6---------f%Y-------P9Y-------B, y..-. .. ./3, ?.....-.

B Y-------@, Y-------/Y . . . . . . . . . .

f%+-------e,y.-.....B,-y.... . .

4)31PC.(cl/m-Yfl)

4.OX1O1~J

4.3X1014.6Xl&825.9X1O$

e3.7xlo~C3.3X1Oc9.4X1O{6.OX1O1.1X1O1.3XI08.OXlO1.3X1O4.9X1O

, p.~xlo4.Ixlol. fixlc2.7X1(*2.9X1(6.3)(1(

(5) IMPc.(d/m-L)

8.9X1051.9X1069.6x10~9.9X1O31.9xlo~7.Oxloi()()()1.3X1OI2.6X10112.9X1OI1.8X1O2.9XIOI1.Ixlol=6.4XI0I.lxlo4.5XI06.3X1O?&4xlc1.5X1OI

Major portion of body critid; h.asedon 0.1 rwn~ vk.b The gastrointwtir-d trnct as cri[ical organ should be ev,lnlint,fI ifcllronlc or largeexposures are involved.c Calculated to give 0.1 rcnl/\vk if body k surroumlcd hy an infinite volume of tIl~gas. XlPC~, q, and 7*art, mwmingicss. Shiplling exempt quantities not calculated.d 13sscdon O.fjrunl/wk; fwtor Ofz allolvcd bCCUUSChyroid is the crlticnl orgnn.GBnsml on lW ICRP rl,commendations. Calclllations silow that thcs$ numhc=are MC for fission prodllcts 11.sshan Qyf-vu-soid.

f Half-life vurles with time. 1hcllulf-llfc at any time t after formation is apprrXi-mntely t.I B~cd on clthcr T20 or ]ITO, not T2; assllmcs SO~o[ntakc by skin absorption50

s


57/186

----- .-

6)g @c)andcriticalorgan

0.051 B

1.9XI0-3 =K0.056 B0.058 B4.8X1H K7.9 bK(o) TB(o) TB(o) TB26 bB3.3 bB4.8 bB5.0 B21 bB

2,2 bB

61 TB0.31 Pr0.76 Pr13o B~18 TB4.9 bB

(7) (8)Half-lives

~ NCT ,. . . . . . . . . .----------. . . . . . . . . .. . . . . . . . . .----------

16.ld12d5.27d

9.2oh4.Id

64.2h50.3m56d3.6hloh245d13.8hSm

1.lxlcPy63.3d17.Oh

Tb I---------- 97.1---------- 1.46X1(Y-------- .- 1.43XI04---------- 4.81X1O{---------- 229XM%

74d 5.91xlti() 1.12X1O-5() 5.36X1W(6) 3.96xl&t

1000d 5.49XI0-41.8X10~d 1.84X1(H1.8X10(d 2.43X1O-I1.8X10~d 4.04xlo-~1.8X10td 1.05xlo-11.8X10td 2.96X10_l

933d 1.22xl@144i~ 3.O3X1O-;14d 1.9oxlo-loood 2.85X1O450d 4.6oxlo-loood 5.25xl&

(9)c/g

.03X1Hi.65x10-?

[email protected]~s 43XW4.11XI072 48X1049.52X1([email protected] 26XI03.slxlo-~2.17X1O1.9oxla

(lo)2at.egoryandshippingexempt mg

II 1.3X1(Y:11 2.OX1O4[11 1.9XI04[11 6.5X104[11 3.1XI04 [H 8.OXIN

(9(9(9[11 7.4X1O-4

III 2.5X1O+111 3.3x10_$111 5.5X1(WIII 1.4X10_7111 4.oXIO+II 1.6X1F11 4.1XIO-$111 2.6XIO+111 3.8X1(PIII 6.2X1O+111 7.IxIO+

h Exempt amounts Of trltlum are 5.2x1c4-4cc STP of the gas, 5.0x10_7CCofpure TIO.~Adopted value,b~d on long experience of man. M PC., 9,and Tb arc rnean ng-l ess. Shipping exempt quantltie.s not calculated.Jl]- Ono.G~m/~k; f~tor of 2allowedbecau~ skin ~ the criti~l o~~.k Basedon 0.1rem/~k; gonads are the critical organ.1LASL calculated value; not Inc]udcdin ICRP prepubliration,UICalculated on basisof toxicity, not radiation damage.II.Natural uranium deplet~ in U~Jscontent. The specific activity depends onisotopic analysis; values given in the tabie arc for D-38 with about 0.3V0Ws.

51

I


58/186

-.

11. MONITORING INSTRUMENTSA. Radiation Survey Instruments

In t he follow ing list ing, t he inst rument s show n inFigures 4, 7, 10, 11, a nd 12 a re used only occa siona lly a tLAS L; t hey a re included here for ident ifica t ion pur-poses.FIGURE 1.SURVEY NIETER,

TRi (I) Model 101 DC (TritiumSniffer)-ion chamber, sensitiveto any ions (produced by /3s, TS,an open flame, etc.) in air drawnthrough the 660-cc chamber; 4scales have been calibrated totritium water vapor, giving full-scale readings from about 1(P to10S ~c/Ms; three models, oneoperating on AC, one on DC, andone on DC with an AC-operatedblower; 23 lb.

SURVEY METER, TRI (I) Nfodel 120 (BalancedSniffer)dual ion chamber with deionizer; relatively insensitiveto s and ions formed outside the chamber; similar in appear-ance and size to Rlodel 101; 5 ranges give full-scale indica-tions for 2X 102 to lV pc/Wo

52(

I I


59/186

r FIGURE 2a. S~RVEY METER,ALP (P) Nlodel 2111 or 48--A(PeelVee)proportional counter;a-sensitite probe has steel gridover 0.25-mil mylar; effective areaabout 60 cm2; probe is delicate,microphonics,and affected by mois-ture, organic vapors, barometricpressure, high frequency electricalinterference; requires frequent cali-bration checks with uraniumsource mounted on case; 2 rangescover 0-20,000 c/m; 0--200,000 and0-2,000,000 c/m models available;activity indicated on meter andearphones; 19 lb.

FIGURE 2b.SU RVEY METER, ALP (P) Model PAC-1(Eberline Pee\Vee)transistorized version of hlodel 2111 or48-A with similar probe; 3 ranges cover 0-100,000 c/m; 6}; lb.(Shown in above illustration at left.)

.

ml

53


60/186

FIGURE 3.SURVEY NIETER,NEU (P) hfodel 48-N (ConvertedPee Wee) proportional counter;instrument is a Model W-APeeWee modified for use with aboron-lined probe: 1 in.thick Poly-ethylene moderato r and 20-milcadmium absorber; 4 ranges meas-ure 0-10,000 Ra-Be n/cm~-see;high range mode 1 (red meter)20-200,000 Ra-Be n/cm%ec; cal-ibration chart required; correctionfactors needed for energies otherthan Ra-Be; 20}$ lb.

FIGTJRE 4.SURVEY METER,NEU (P) Model =1 (Rudolph)2-unit fast neutron proportionalcounter; tissue. equivalent chambermeasures 0.210 Mev neutrons; 3ranges measure &500 mrep/hr(approximately equivalent tomrad/hr); 0-0.5 mrep integratingrange; meter readings must bemultiplied by proper RBE tOobtain rem; 10~ lb.

FIGURIC 5.SURVEY METER,BGhl (I) Model 100-A-ion cham-ber; mylar-covered chamber withremovable )$-in. lucite s shield;high range model 0,1-.100 r/hr;low range model 0.02-20 r/hr;requires calibration chart; ~ r~spcmse assumed rad; 8% lb,54

.&d-.. .


61/186

FIGURE 6.SURVEY NIETER,BGlf (I) Nlodel SIC7A and D -1(Cutie Pie) ion chamber; 3 rangescover 25-10,000 mr/hr; somewhatdirectional; /3 response throughend window (1 mg/cm2 mylar)only qualitative without correc-tion factors; calibration chartnecessary; all fifodel D-1 (metalcase) converted to S1 C7A cir-cuitry; D1 has cap, SIC7A hasslide to cover @ window; 3 lb.

FIGURE 7.SURVEY METER,BGhf (I) Model A6B-500-SR(Jordan Radector)ion chamber;2 logarithmic scales cover 0.5mr/hr to 500 r/hr; P window andbuilt-in Sr$Q calibration source;small energy dependence above75 kev; 3)i lb.

FIGURE 8a.SURVEY METER,BGN1 (G) Model S N1-3 (El-tronics)GNI instrument; probewith 30 mg/cm2 metal tube hassliding ~ shield; 3 ranges cover0-20 mr/hr; 9% lb.

FICTJRE 8b.SURVEY METER,BGM (G) Model 261 O-A (Nu-

,

clear)G-M instrument; probe with 30 mg/cm~ glass G-Mtube has rotating P shield; response time somewhat slowerthan SM-3 or Eberline E-112-B; covers same ranges as SNI-3;10 lb.5 5


62/186

. .

FIOURE 9.SURVEY METER,BGM (G) Model WI 12B (Eber-line)G-hi instrument; can uti-lize various probes; with GMtube, characteristics similar toSM-3 and 261O-A; measures a(indicates pc/Mz directly) withZnS scintillator probe; neutron-sensitive probe being investigated;has adjustable time constant (la-beled meter response); 4 lb.

FIGURE 1O,SURVEY METER,GAM (1) Model 300 (Protexi-meter) ~-integrating ion cham-ber; 0-200 mr; operating instruc-tions on bottom; sensitive downto about 30 kev with metal capremoved; energy dependence atlow energies unknown; 5 lb.

FIGURE 11.SURVEY METER,GAM (I) Model SU-10 or T-l B~ ion chamber; 5 ranges cover0-50,000 mr/hr; long warm. uptime; requires frequent zeroinguntil warmed up. 11 lb.

5 6


63/186

FIG~RE 12.SURVEY METER,ABG (I) JIodel SRJ-1 (Juno)-ion chamber; sliding a and ~shield; S1OWw-arm-up time; singlecalibration not reliable for threetypes of radiation; 5 lb.

FIQURE 13. ALPH.4 FLOOR J1ON-ITORproportional counter; 2 scalescover 020,000 cjm; battery operated;large 3 X 18 in. Pee\\-ee-t~pe probe;counts indic~ted on meter and loud-speaker; mounted on rolling platform;wheels must be kept ~~ell lubricatedto prevent static interference in theprobe.

FIGURE l-1, -BET.\-GAJ1llA FLOOR}IOXITORGll instrument; uti-lizes 4 glass-~vall (30 mg/cnlZ) G-Mtubes and suitable GM instrumenton rolling platform; more sensitive todispersed activity than a single tubeinstrument; may become light sensi-tive.

57


64/186

\

,

1I,

i

B. Air Sampling InstrumentsD iscussion of t he inst rument s show n in F igures 15 t o

20 will be found in S ect ion 18, Air S a mpling.FLGURE 15. FILTER QUEEN AIR ES.431PLERSamples at 4 cfmthrough 4 X 9 in. (21 in.~ effective)HV-70 filter paper; sampling rateautomatically regulated by variablethroat orifice; flow rate should bechecked weekly.

FIGURE 16.H1-VOLUM E AIRSAMPLER (STAPLEX)Sam-ples at 20 to 50 cfm depending onfilter media, 20 cfm with glassfiber, 50 cfm with Bhf-2133 respi-rator filters; 4 in. diameter, () X 6in., or 8 x 10 in. filters; can betripod-mounted for sampling atbreathing level.

FIGURE 17.GAST PUMP-AC-operated pump equipped with rota-meter adjustable from 5 to 30liters/rein; uses l% in. diametersampling head and filters; \Vhat-man No. 41, }khatman No. 4,membrane (molecular), and fineglass fiber may be used.

F

F

F


65/186

. . ----- ..- ----

I(3URE 1%.GIRAFFE SAMPLER . .? .

r

.Variation of the Gast Pump; sampling ~head, usually 2}~ in. with H V70 >:paper, mounted on expendable tube , -. ..j-,:;for sampling breathing zone; uses ~..~>,~~;~a.: ; .1

HV-70. - -orifice meter rather than rotameter;usual sampling rate is 2 cfm with

FIG URE 18b.2jf-INC H SAM-PLING HEADNote position oflarge rings to prevent damage tofilter when assembling.

FICURE 10.. NIODIFIED CAS-CADE I hi PACTORCommer-cially available Casella impactorwith additional filter stage; de-signed to sample at 17.5 liters/rein;used for particle size analysis.

59


66/186

I

FIciURE 20.AUTOXIATIC SAll-PLER RECORDER--Con~ binationsampling, counting, and alarm unit;air is drawn through 1 in. diameterportion of filter pnper for 10 minand is counted Ilnder a-sel]sitive scin-tillation probe ~~hile next sample isdrawn; samples at 50 liters/rein withWhat man No. 4 pnpcr; count-rateresults are indic;ited on a meter andrecorded on :~n Esterline-Angiw;alarm sounds at preset level.

C, Respiratory Protective DevicesD et ailed discussion of respira tory prot ect ive equip-

ment , it s uses a nd limit a t ions, ma y be found in S ec-t ion 19.

In t he list ing below , F igures 21 to 24 show h a lf m a s ks ;a ll of t hem ha ve int ercha nge~ ble ca nist ers or cnrtrid~es;the user must be certain the proper canister or cartridgeis in place. .~ filter sl~ ould be used for pnrt icukt es, a na dsorbent for gq ses a nd va pors.FIGURE 21.IYILLSON No. 800

HALF fif ASK.

60 II

I .-. . --- - _ma%


67/186

FICURE 22.lWSA CONIFO H.4LFIklASK.

I

I

FIGrRE 23.AMER1CAN OPTI-CAL R-5000 HALF MASK.

I

24.MSA DIXTFOEHALF N ASK.

61


68/186

FIGURE 25.WILLSON FULL FACEMASK-Chin style DFM filter; effec-tive only for solid particles and fumes.

FIGURE 26.MSA FULL FACEMASK-Chin-type canister holder;may be used with 61ter, gas adsorbentcartridge, or both.

l?I~URE 27.U.S. ARMY M-9 AS-SAULT MASK-Can be fitted withAEC high efficiency filter or Armyall-purpose canister.

62

. -----


69/186

FIGURE 28. ACME FULL FACE _- . IhfASKChin style canister holder; Ican be used with several canisters in-cluding the AEC high efficiency filterand the Army all-purpose canister;mask can be fitted to support pre-scription eyeglass lenses. L

FIGURE 29.SCOTT-O-RAMICFULL FACE MASKC hin-styleDFM filter; effective only for solidparticles and fumes.

regulara nd the Scot t-o-ramic.

FIGURE 30.SCOTT AIR PAKSelf-contained breathing unit; de-mand-t ype regulator; air tank jsupported valve down on the back, -aregulator suspmded on left side oft he ches t ; t wo m as k sava i lab le, t he [

63


70/186

FIGURE 31. hlSA SUPPLIED OX-YGEN BREATHIXG APPARA-TUSSc]f-contained demandtype; OXygeV t an k supported valvedown on the back, demand valvesuspended on left side of chest.

FIGURE 32.filSA CHEMOX OXY-GEN GENERATING APPARA-TUSSelf-contained unit capableof generating breathing oxygen;generator and lungs are suspendedon the chest; equipped with warn-ing timer; directions for use oncarrying case and canisters.

FIGURE 33.SUPPLIED AIR H.4LFMASK-Con~fo half mask suppliedwith respirable air from a 220 ftt H-type cylinder (or, an air compressor);used with constant flow or demandregulator valve; air line limits nlo-bilit y.

64


71/186

I?XGURE 34.SVPPLIED .kIR. FULLFACE J1--\SK.\ hIS.~ ftlll facemask suppliecl ~vit~ respirahle airfrom a 220 fts Ii-type cylinder {or nnair compressor); ~l~ed Mitl~ Const:lntflow or demand regulator vwlve; airline limits mobility.

FI~URE 35. SUPPL1ED AIRHOODPlastic hood \vith transpar-ent window; air supplied from H-typecylinder or compressor.

FIGURE 36.PL.\STIC SUPPLIEDAIR SUITCon~pletely enclosed suitclosed ~~ith ciouble zipper; used inatmosphere where ~vhole body pro-tection is desired (T, HCN).

6 5


72/186

D. Personal Monitoring Devices (See Sec. 16)FIGURE 37.SELF READING DO-SIMETERS AND CHARGINGUNIT--y-ray correction factor ondosimeter; available in severalranges.

FICJURE 38. FILM BADGESS how n open, rea dy for use, w it hcont am ina t ion-pr event ing pet t i -coa t , a n d a s a w rist ba dge.

. .

6 6

J

i(,1III

(

11 II

\8


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12. ALPHA MONITORINGA. Characteristics

a monit or ing ent a ils t he det ect ion of a hea vy, doublycha rged, highly ionizing pa r t icle w it h a short ra nge.The most energet ic na tura l a pa rt icle, 10.5 Mev ha sa ra nge of only a bout 4 in. in a ir or a few roils in lightma t eria l. An a pa r t icle of grea t er t ha n 7.5 Mev isnecessa ry t o penet ra t e t he out er dea d la yer of skin.S ince only a few short -lived isot opes emit c/s of t hisenergy, t he biologica l ha za rd from a pa r t icles is st rict lya n int erna l ha za rd. a monit oring is t herefore a imedt ow a rd t he det ect ion of cont a mina t ion w hich mighthinder delica te ra dia tion mea surement s or ult ima telyfind it s w a y int o t he body a nd t here, beca use of t heint ense ionizing pow er of t he a s , do con sider a bledamage.B. Detection

The cha ra ct erist ic of t he a pa rt icle t ha t elimina test he ext erna l ha za rd a nd t he necessit y for shieldingcomplica t es it s det ect ion. S urvey inst rument s mustbe const ruct ed w it h very t hin w indow s (a few mg/cm2),a nd t he det ect or must be held very close t o t he sit e ofcont a mina t ion t o a llow t he short -ra nge pa rt icle t oent er t he cha mber. Thin films of w a t er or oil ca npa rt ia lly or complet ely prevent a s from being moni-t ored. P orous surfa ces (w ood, concret e) ma y ha rborma ny t imesinstruments

t he a ct ivit y mea sura ble w it h monit or ing

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---~C. PeeWee Survey Meter

The a -monit oring inst rument . current ly in use a tLAS L is t he P eeWee proport iona l count er (Fig, 2a).I t consist s of a t h in w indow probe a t t a ched by a 3-ftca ble t o t he ha nd-ca rr ied inst rument . The 9 x 2 in.probe ha s a n effective area of 60 em2 tmcl the windowis covered with 0.25-mil (1 mg/cm2) mylar, allowingas with energies greater than about 1.6 I t fev t o pene-t ra t e t o t he sensit ive volume. The inst rument ha sa pulse h eigh t select or (PHS) which allows only pulsesabove a certain