,! ,atomic ,f+]pr9t3                    
,neutron ,activation ,analysis          
by                               ,b]n>d 
,keis*                                  
,,cont5ts        ,,introduction         
#d    ,,:at ,,is ,,neutron ,,activation 
,,analysis8                             
#e    ,,! ,,s5sitivity ,,( ,,neutron    
,,activation ,,analysis                 
#aj    ,,h[ ,,& ,,:]e ,,to ,,use ,,x    
#ai        ,9 a ,physics ,laboratory    
#ai        ,9 a ,hospital               
#bh        ,9 a ,pla/ics ,plant         
#cb        ,9 a ,museum                 
#ce        ,9 a ,crim9ology ,laboratory 
#db    ,,summ+ ,,up3 ,,:at ,,lies       
,,ahead                                 
#df    ,,app5dix                        
#di    ,,read+ ,,li/                    
#eb    ,,motion ,,pictures              
#ed              ,u4 ,s4 ,en]gy ,rese>* 
& ,developm5t ,adm9i/ration             
,(fice ( ,public ,affairs               
,wa%+ton1 ,d4,c4 #bjede                 
,libr>y ( ,congress ,catalog ,c>d       

,numb]3 #gi-ahbeef                      
#aigb                   ,illu/ration3   
,photograph1 spiral galaxy    ,! ,u4 ,s4
 ,en]gy ,rese>* & ,developm5t           
,adm9i/ration publi%es a  s]ies (       
booklets = ! g5]al public4    ,please   
write to ! foll[+ address = a title li/ 
or =  in=mation on a specific subject3  
,,us]da--,te*nical ,in=mation ,c5t]     
,p4 ,o4 ,box #fb      ,oak ,ridge1      
,t5nessee #cghcj                        
,illu/ration3 ,photograph3 %elf ) *9a   
,a #ai? c5tury photograph re/or$ by     
neutron activation4 ,?is    picture1 :i*
 is 9 ! collection ( ! ,smi?sonian      
,in/itution1    0 expos$ to neutrons 9 a
 nucle> reactor & !n plac$ 9    contact 
) mod]n photographic film4 ,! orig9al1  
:i* _h be5    tak5 by ,william ,h5ry    
,fox ,talbot :o began 8 c>e] 9 #ahcd1 is
    badly fad$4                         
,,introduction      ,y are a physici/   
inve/igat+ ! prop]ties ( semiconductors1
  :i* are mat]ials us$ to make          
transi/ors4 ,! electrical prop]ties  (  

"o specim5 are n q l ! o!rs t y've      
/udi$4 ,:at  makes ?is specim5 diff]5t8 
,,or    ,y are a physician treat+ a     
pati5t :o1 because ( a sev]e calcium    
defici5cy1 has be5 suff]+ f o/eoporosis 
7a s(t5+ ( !  bones74 ,are y on ! "r    
track ) y\r treatm5t8                   
,,or    ,y are an analytical *emi/ work+
 = a pla/ics manufactur]4 ,y  h be5 ask$
 by ! plant sup]9t5d5t to det]m9e :y "s 
( !  pla/ic com+ f ! plant has be5      
discolor$4                              
,,or    ,y are a curator work+ ) !      
anci5t co9 collection 9 a l>ge  museum4 
,a donor has j giv5 ! museum a gr\p (   
#ej gold co9s  presumably ab\t #aejj    
ye>s old4 ,are !y g5u9e8                
,,or    ,y are a sci5ti/ work+ 9 !      
crim9ology laboratory ( a l>ge          
metropolitan city4 ,a detective br+s y a
 m9ute sample ( pa9t tak5  f ! clo?+ ( a
 hit-&-run victim4 ,he has a suspect ^: 
automobile pa9t seems to mat* t sample4 
,c y det]m9e 8 guilt  or innoc5ce8      
,neutron activation analysis c be us$ to

 solve ea* ( ^! problems  & _m m4 ,!    
solutions to ^! p>ticul> problems are   
expla9$  on pages #ai-df4               
,! ,atomic ,f+]pr9t3                    
,neutron ,activation ,analysis          
by ,b]n>d ,keis*                        
,,:at ,,is ,,neutron ,,activation       
,,analysis8      ,to und]/& neutron     
activation analysis1 y %\ld be acqua9t$ 
)  a few basic concepts4 ,! nuclei (    
atoms are /able only :5 !y  conta9 c]ta9
 numb]s ( neutrons & protons4 ,! numb] (
 protons  9 an atom's nucleus det]m9es  
an elem5t's id5tity2 ! numb] (  neutrons
 usually det]m9es :e!r or n t atom is   
radioactive or  nonradioactive          
7/able74#a    ,?us1 :ile all sodium     
atoms conta9 #aa protons1 only ^? sodium
 atoms  t conta9 #ab neutrons are /able4
 ,a radioactive sodium atom conta9s  a  
diff]5t numb] ( neutrons4 ,= o!r        
elem5ts1 !re may be m  ?an "o numb] (   
neutrons t results 9 /ability2 =        
in/ance1  !re are #aj /able atoms       
7isotopes7 ( t91 ea* conta9+ a diff]5t  

numb] ( neutrons 9 _! nuclei4    ,! fact
 t nuclei c absorb additional neutrons1 
:i*1 9 _m  cases1 results 9 ! conv]sion 
( a /able nucleus to a radioactive  "o1 
makes neutron activation analysis       
possible4 ,because radioactive  nuclei  
decay 9 unique ways & yield radiations t
 are (t5 di/9ct  & c be measur$ ev5 9 v 
small am\nts1 measurem5ts ( ^!          
radiations c det]m9e ! k9d & ! numb] (  
radioactive atoms  t are pres5t4    ,9 !
 mo/ common type ( activation analysis1 
! neutron bomb>dm5t  ( a sample is p]=m$
 9 a nucle> reactor :]e ! neutrons t    
/rike ! t>get atoms h be5 sl[$ d[n s t  
!y h v  little en]gy ( motion4 ,9 ?is   
case1 ! usual reaction betwe5 !  t>get  
atoms & a neutron results 9 ! capture ( 
! neutron &  ?is creates a nucleus ) an 
atomic weight ( "o m unit ?an x  />t$ )4
 ,?us = sodium z f\nd 9 nature 7symbol  
,na7         sodium-#bc  a neutron      
radioactive sodium-#bd  gamma rays#b    
,! numb]s d5ote ! atomic weight ( !     
atom1 :i* is ! total  numb] ( protons & 

neutrons 9 its nucleus4    ,9 a nucle>  
reactor1 !re are _m1 _m neutrons t c be 
us$ 9  ?is reaction2 approximately #aj  
to #aj 7#aj is a million million2  #aj  
is a hundr$ times #aj7 pass ?r\gh ea*   
squ>e c5timet] (  t>get area e second4  
,n all ^! w /rike ! nuclei ( sodium     
atoms4 ,( ^? t d1 n all w be captur$4 ,a
 ma!matical  relation%ip t tells h[ _m  
atoms ( sodium-#bd w be creat$ 9 a      
cubic c5timet] ( ! t>get 9 "o second is3
                                  ,n    
,nt    :]e ,n is ! numb] ( sodium-#bd   
atoms creat$ dur+ ea* second 9  a cubic 
c5timet] ( ! t>get2 ,n is ! numb] (     
atoms (  sodium-#bc 9 a cubic c5timet] (
 ! t>get2  is ! numb] (  neutrons cross+
 a squ>e c5timet] p] second 7call$ !    
neutron  flux72 t is ! "t 9 seconds t ! 
t>get is 9 ! reactor2 &   is a numb] t  
repres5ts ! probability t ! conv]sion ( 
sodium-#bc to sodium-#bd w occur4 ,?is  
la/ numb] is call$ a 8cross  section0 & 
x is express$ 9 8b>ns04 ,"o b>n is equal
 to #aj-bd  squ>e c5timet]1 :i* is      

approximately ! cross-sectional area ( a
  typical atomic nucleus4    ,9 an      
activation analysis exp]im5t1 ! analy/  
wants to det]m9e !  numb] ( t>get atoms 
7,n 9 ! above example74 ,he c measure h[
  long ! t>get 0 9 ! nucle> reactor2 !re
 are ways ( measur+  ! neutron flux1 2 &
 ! cross section is fix$ & g5]ally kn[n 
= ea* t>get nucleus4 ,s1 by measur+ !   
numb] ( radioactive  atoms creat$ 7,n71 
he c calculate ! numb] ( t>get atoms4   
,see  ! figure on ! next two pages4     
,actually1 to get ! mo/ accurate        
results1 !re are c]ta9 practical  tricks
 he c use t increase ! accuracy4 ,"s (  
^! w become  app>5t 9 lat] sections (   
?is booklet4    ,! mo/ important ( ^!   
8tricks0 is ! use ( a 8/&>d0 or         
8comp>ator04 ,?is comp>ator is simil> 9 
=m & composition to !  sample to be     
measur$ b conta9s a kn[n quantity ( !   
elem5t to  be det]m9$4 ,! /eps us$ = !  
analysis are simple4    #a4 ,put !      
sample & comp>ator toge!r into a reactor
 & bomb>d  !m ) neutrons4    #b4 ,remove

 !m & measure ! radioactivity produc$ f 
! sample4    #c4 ,comp>e ! radioactivity
 ( ! sample & ! comp>ator &  calculate !
 am\nt ( ! elem5t 9 ! sample z a        
proportion3            7,radioactivity 9
 sample7_/7,radioactivity 9 comp>ator7  
7,quantity ( elem5t 9                   
sample7_/7,quantity ( elem5t 9          
comp>ator7      ,neutron ,activation    
,analysis3 ,detect+ ,sodium 9 a ,sample 
( ,pla/ic    ,/ep #a4 ,weigh a sample & 
a /&>d 9 qu>tz tubes4                   
,illu/ration3 ,piece ( pla/ic2 ,/&>d    
sodium c>bonate    ,/ep #b4 ,seal tubes 
9 package = reactor irradiation4        
,illu/ration3 ,seal$ alum9ium c2 ,seal$ 
qu>tz tubes2 ,sample2                   
,/&>d    ,/ep #c4 ,bomb>d ) neutrons =  
ab\t #c h\rs 9 a reactor4               
,illu/ration3 ,neutrons    ,/ep #d4     
,remove sample & /&>d f tubes & place 9 
sep>ate  pla/ic conta9]s to measure     
gamma rays4    ,illu/ration3 ,pulse     
height analys]2 ,sample2 ,/&>d2 ,gamma  
rays f   ,na-#bd2 same conta9]1 di/ance1

 detector2 ,sodium iodide sc9tillator   
,/ep #e4 ,obta9 gamma-ray spectrum =    
sodium-#bd 9 bo? sample &  /&>d4        
,illu/ration3 7*>t7 ,en]gy vs4 ,sample  
spectrum2 ,en]gy --,/&>d                
spectrum    ,/ep #f4 ,use /&>d to       
calculate #a4cg ,me,v gamma rays c\nt$  
p] m9ute  p] gram ( sodium 7c_/m_/g,na74
          c_/m_/g,na  7c\nts_/m9ute     
measur$ 9 #a4cg peak 7%ad$ area         
above77_/7grams ( sodium kn[n to be 9   
/&>d 7/ep #a477    ,/ep #g4 ,use        
c_/m_/g,na & #a4cg ,me,v gamma rays     
c\nt$ p] m9ute 9 sample  to calculate   
grams ( sodium 9 sample4                
grams ,na 9 sample                      
7c\nts_/m9ute measur$ 9                 
sample7_/7c_/m_/g,na 7/ep #f477    ,/ep 
#h4 ,calculate p]c5t sodium 9 sample4   
sodium    7grams sodium 9 sample 7/ep   
#g477_/7weight ( sample 7/ep #a477  #ajj
                     ,,! ,,s5sitivity#c 
,,( ,,neutron ,,activation ,,analysis   
,!re are sev]al factors t det]m9e !     
s5sitivity ( ! me?od4  ,"s are v>iable  

)9 limits & "s1 l ! cross section1 are  
fix$4 ,"t is v>iable to a degree1       
p>tially det]m9$ by !  half-life ( !    
nuclide creat$ & ) an upp] practical    
limit  det]m9$ by h[ long we want to    
wait = an analysis4    ,! crucial /ep 9 
! analytical proc$ure is ! measurem5t ( 
!  numb] ( radioactive atoms t 7 creat$4
      #a4 ,h[ d we measure h[ _m        
radioactive atoms are pres5t8      #b4  
,s9ce !re w usually be a mixture (      
elem5ts 9 a t>get1 &    _m ( ^! w be    
made radioactive1 h[ c we tell "o f     
ano!r8      #c4 ,s9ce radioactive atoms 
are con/antly 8disappe>+0 by            
radioactive decay1 h[ d we obta9 ! numb]
 ( atoms creat$ f a    measurem5t made  
"s "t aft] ! bomb>dm5t has tak5 place8  
,&    :at ( ^? atoms dis9tegrat+ :ile   
o!rs are /ill be+    creat$ 9 ! reactor8
    ,radioactive atoms almo/ always     
decay by emitt+ negatively *>g$  beta   
p>ticles usually accompani$ by gamma    
rays4 ,in/rum5ts c detect  ^! k9ds (    
radiation1 & x is by measur+ ! radiation

 t we  det]m9e h[ _m radioactive atoms  
are pres5t4 ,to d ?is we h to  "k !     
types ( radiation emitt$ by !           
radioactive atoms we are  try+ to       
measure4 ,=tunately ea* k9d (           
radioactive atom decays )  a unique     
8patt]n0 sci5ti/s call a 8decay s*eme04 
,! figure on !  next page %[s a         
simplifi$ decay s*eme = manganese-#ef1  
:i* is  produc$ by activation (         
manganese1 & a diagram %[+ :at !  decay 
s*eme means4    ,until a few ye>s ago1 x
 0 difficult to measure ! numb] ( gamma 
rays ( a p>ticul> en]gy t 7 be+ emitt$  
by a mixture (  radioactive isotopes    
unless !re 7 only a few su* gamma rays )
  v diff]5t en]gies4 ,today in/rum5ts   
are available t c really  pick !m out ( 
a complex mixture4 ,?us x is usually    
possible to  8sep>ate0 ) electronic     
in/rum5ts ! radioactive elem5t we are   
int]e/$ 9 measur+4 ,"s ( ! examples bel[
 w %[ h[ ?is  might be accompli%$4      
,ea* radioactive nuclide#d also has a   
*>act]i/ic half-life1#e  :i* is a       

measure ( h[ fa/ ! radioactive atoms    
*ange 7transmute7  to atoms ( ano!r     
elem5t4 ,9 a reactor1 ev5 :ile !y are   
be+  produc$ 9 ! t>get1 atoms ( !       
radioactive nuclide are decay+  ) !     
p>ticul> half-life ( ! nuclide4 ,!      
ma!matical laws t  gov]n ?is process    
tell u t ! numb] ( atoms det]m9es !     
am\nt ( decay2 i4e41 ! m atoms !re are1 
! great] ! am\nt  ( decay 9 a giv5 p]iod
 ( "t4 7,! fraction t decays 9 t  "t is 
con/ant47 ,z a result1 ! t>get ev5tually
 becomes  8saturat$01 t is1 ! rate (    
production equals ! rate ( decay4  ,:5 !
 irradiation is fir/ begun1 ! numb] (   
radioactive atoms  increases /eadily4 ,b
 ev5tually1 ?is rate ( increase sl[s d[n
  until1 at saturation1 fur!r           
irradiation no long] increases ! numb]  
( radioactive atoms pres5t 9 ! t>get4   
,illu/ration3 ,! en]gy ( a gamma ray is 
equal to ! en]gy   diff]5ce betwe5 ! two
 levels involv$ 9 ! gamma-ray emission4 
,an en]gy level diagram4 ,! slant$ arr[s
 indicate radioactive    decay by       

beta-p>ticle emission4 ,9 ea* case1     
manganese-#ef decays to    a c]ta9 en]gy
 level ( iron-#ef4 ,on ! "r ! en]gy (   
ea*    level is indicat$4 ,foll[+ a beta
 emission to a high-en]gy    7excit$7   
/ate 9 iron-#ef1 "o or m gamma rays are 
emitt$ until    ! nucleus is de-excit$  
to ! level m>k$ z]o4 ,! v]tical    arr[s
 indicate gamma rays emitt$ dur+ !      
de-excitation process4    ,! en]gy ( ea*
 gamma ray is ! diff]5ce betwe5 ! levels
    involv$ 9 ! *ange4 ,! numb]s above !
 v]tical arr[s indicate    ! relative   
proportions ( gamma rays ( diff]5t      
en]gies emitt$    f t level4      ,!    
ma!matical relation%ip t describes !    
irradiation process  exactly is3        
,a  ,n 7#a - e-t7    :]e ,a is !        
radioactivity produc$ 7dis9tegrations p]
 cubic  c5timet] p] second72 ,n is !    
numb] ( t>get atoms p] cubic  c5timet] 9
 ! sample2  is ! neutron flux 7neutrons 
p] squ>e  c5timet] p] second72  is !    
cross section = ! reaction 7squ>e       
c5timet]s72  is ! dis9tegration         

con/ant#f = ! radioactive  atoms produc$
 7numb] p] second72 ! numb] 8e0 is !    
base (  natural log>i?ms2 & t is !      
irradiation "t 9 seconds4 ,note t  =    
%ort irradiation times 7t v small71     
#a-;e-t approximates t1  :ile = long    
irradiations 7t v l>ge71 #a-;e-t        
approximates #a4                        
,illu/ration3 ,graph3 ,decay s*eme =    
manganese-#ef      ,maximum ,en]gy      
,betas    #b4hd ,me,v                   
#ec    #a4jc ,me,v                      
#cj    #j4gbj ,me,v                     
#af    #j4cj ,me,v                      
#a                             ,gammas  
#j4hdg ,me,v                     #fh    
#a4haa ,me,v                     #bj    
#b4aaj ,me,v                     #aj    
,o!r ,en]gies                 #b        
#b4edc ,me,v    #b4feh ,me,v    #b4ieg  
,me,v    #c4ci ,me,v                    
7avge #a4d gammas p] beta7      ,?is    
summ>izes :at ! decay s*eme or en]gy    
level diagram %[s 9    t]ms ( ! relative
 am\nts ( betas & gammas emitt$ 9 !     

decay    ( manganese-#ef4 ,?us1 y c\ld  
obs]ve m ?an ?ree times z _m    gamma   
rays hav+ an en]gy ( #j4hdg ,me,v ?an ( 
#a4haa ,me,v1 etc4 ,note    t :ile "o1 &
 only "o1 beta is emitt$ 9 ! decay ( "o 
atom    ( manganese-#ef1 two gammas c   
sometimes be emitt$ 9 "o decay4    ,(   
c\rse1 :5 ! t>get is remov$ f ! reactor1
 ! numb] (  radioactive atoms beg9s to  
decrease accord+ to ! *>act]i/ic        
half-life ( ! nuclide4 ,! ma!matical    
expression t describes !  process (     
radioactive decay ( a s+le nuclide is3  
,at  ,ae-t    :]e ,at is ! radioactivity
 ( an isotope at "s "t1 t1 aft]  ! end (
 ! irradiation1 & ,a is ! radioactivity 
at ! end (  ! irradiation4              
,illu/ration3 ,fraction ( saturation    
sodium-#bd activity vs ,"t (            
irradiation 7h\rs7      ,! activation ( 
sodium-#bc to sodium-#bd1 :i* has a     
half-life ( #ae    h\rs4 ,! horizontal  
l9e m>k$ #a4j repres5ts ! 8saturation0  
activity level = a sample ( sodium ( a  
c]ta9 size 9 a con/ant    neutron flux4 

,note t aft] ab\t #abj h\rs1 ! activity 
( !    sample is )9 #a ( ! value at     
saturation1 :i* is ! mo/    active t    
sample w ev] become at a giv5 4 ,note   
also t aft]    ! fir/ #ae h\rs 7#a      
half-life7 ! sample is exactly half way 
to its    value at saturation4 ,?us long
 irradiations are useful to increase !  
s5sitivity ( ! analysis1 b only up to a 
c]ta9 po9t4    ,! result ( all ?is is t 
! s5sitivity ( an analysis dep5ds 9     
practice on a numb] ( practical z well z
 !oretical factors3      #a4 ,! cross   
section ( ! t>get elem5t4    #b4 ,!     
half-life ( ! radioactive isotope       
produc$4    #c4 ,! "t available =       
irradiation4    #d4 ,! flux ( neutrons  
available = irradiation4    #e4 ,!      
promptness ) :i* we c beg9 measur+      
radioactivity &            ! effici5cy (
 ?is measurem5t4    #f4 ,possible       
int]f]5ces due to ! pres5ce ( elem5ts   
yield+ !            same radioactive    
elem5ts or ^? yield+ v simil>           
radiations4    ,9 ! next section ( ?is  

booklet1 !re are sev]al examples t  w %[
 y h[ all ?is works 9 practice4 ,b to   
summ>ize :at  ^! factors mean 9 t]ms (  
s5sitivity let u look at ! *>t 9  !     
figure on page #ah4 ,"h all ! elem5ts   
are arrang$ 9 a p]iodic  table4 ,!      
s5sitivities are %ad$ 9 cod$ ranges     
repres5t+  measurable quantities4 ,!y   
are calculat$ on ! basis t !re are  no  
int]f]5ces1 t ! neutron flux is #aj     
neutrons p] squ>e  c5timet] p] second1 &
 t we c measure #ajj gamma rays p] m9ute
  )\t mu* difficulty assum+ a gamma-ray 
detector effici5cy#g (  #aj4 ,! elem5ts 
label$  yield radioisotopes t emit few  
or no  gamma rays & c only be analyz$ by
 neutron activation us+  appropriate    
*emical sep>ation proc$ures foll[$ by   
beta  radioactivity measurem5ts4 ,su*   
*emical sep>ation proc$ures 7to  remove 
unwant$ radioactive isotopes ( o!r      
elem5ts7 are also  sometimes useful to  
improve ! s5sitivity ( ! analysis (     
gamma-ray  emitt]s if necess>y4         
,illu/ration3 ,graph3 8,fraction (      

,sodium-#bd rema9+0 vs4 8,"t (          
decay 7h\rs70      ,! radioactive decay 
curve ( sodium-#bd4 ,! v]tical scale is 
n    l9e> b log>i?mic4 ,?us1 ea* factor 
( two 9 radioactivity    occupies ! same
 di/ance along ! v]tical axis4 ,:5 two  
samples    are be+ analyz$ = sodium by  
activation analysis1 !y mu/ be    comp>$
 at ! same "t aft] !y h be5 remov$ f !  
neutron flux4 ,if ?is p]iod ( "t is     
diff]5t1 !n a correction    mu/ be      
appli$ to "o ( !m1 bas$ on ! decay curve
 %[n "h1    to all[ = ! diff]5ce 9 decay
 "t = ! two4 ,wait+ too    long aft] !  
irradiation is complet$ results 9 mu*   
poor]    s5sitivity = ! analysis dep5d+ 
on ! half-life ( !    activation        
product4 ,9 ?is case1 aft] #b days x    
takes approximately    t5 times z mu*   
sodium to yield ! same radioactivity z x
 w\ld    if ! sample 7 measur$ :5 x 0   
fre% out ( ! reactor4    ,x is n        
practical to det]m9e a few elem5ts1 %[n 
9 black squ>es1  by activation analysis4
 ,"s o!rs1 l oxyg5 & nitrog5 7label$    

,,he71 c be measur$ by us+ o!r          
projectiles l fa/ 7m  en]getic7         
neutrons1 or protons or deut]ons#h      
produc$ 9 a device  call$ an accel]ator4
 ,o!r elem5ts1 ^? %[n 9 :ite squ>es1 c  
be detect$ ) su* great s5sitivity1 t "o 
c f9d "s 9  almo/ ev]y?+4 ,= example1 if
 y _h a cube ( 8pure0 alum9um  only #a  
millimet] on a side1 y c\ld detect gold 
9 x if !re 7  only "o atom ( gold = e   
fifty billion atoms ( alum9um4    ,:ile 
x isn't (t5 t y w\ld want to f9d a gold 
ne$le 9 an  alum9um hay/ack1 ! next     
section pres5ts "s practical            
applications4 ,imag9e y\rself z ! p]son 
) ! problem 9 ^!  situations4           
,illu/ration3 ,p]iodic table ( elem5ts1 
) s5sitivity code    99 ,? & ,u are     
radioactive b ) su* long half-lives t   
neutron activation analysis c be us$ =  
_! det]m9ation4     g  ,microgram       
7"o-million? ( a gram7                  
,,h[ ,,& ,,:]e ,,to ,,use ,,x      ,9 a 
,physics ,laboratory    ,! ,problem     
,y are a physici/ inve/igat+ ! prop]ties

 ( semiconductors1  :i* are mat]ials us$
 to make transi/ors4 ,:5 y apply a      
voltage  to "o specim5 ( silicon 7a     
semiconductor71 x doesn't behave q  l ! 
o!rs t y've /udi$4 ,! electrical        
prop]ties ( ?is  odd specim5 are unusual
 & int]e/+ & c\ld lead to a new type (  
transi/or4 ,:at makes ?is specim5       
diff]5t f ! o!rs8 ,v  small am\nts (    
impurities c cause l>ge *anges 9 !      
electrical  prop]ties ( semiconductors4 
,y w\ld l to obta9 a *emical  analysis (
 ! mat]ial1 b y\r colleagues 9 *emi/ry  
tell y !y  w\ld h to dissolve a good    
size "p ( y\r sample to analyze x &  y  
are reluctant to give x up4 ,h[ d y d x8
    ,! ,solution    ,y decide to try    
neutron activation analysis4 ,y realize 
y won't be  able to detect all !        
elem5ts1 b _m ( ^? t might affect       
semiconductor p]=mance c\ld be detect$ q
 easily4    ,:at w y ne$8 ,a s\rce (    
neutrons to activate ! mat]ial & a      
gamma-ray spectromet] to measure !      
radiation f ! mat]ial  aft]w>ds4 ,?is   

spectromet] detects & measures gamma    
rays & sorts  !m accord+ to _! en]gy4 ,y
 f9d t y\r fri5d d[n ! hall1  :o is a   
nucle> physici/1 has a gamma-ray        
spectromet] t  incorporates a           
li?ium-drift$ g]manium cry/al z a       
detector & a  pulse height analyz]4 ,!  
g]manium detector is a device t s5ses  !
 gamma rays t ent] x & gives electrical 
signals relat$ to !  en]gy ( ! gamma    
rays4 ,x 0 inv5t$ only a few ye>s ago & 
has a  v f9e resolution4 ,t is1 x c     
easily 8pick out0 gamma rays t  are only
 slightly diff]5t 9 en]gy4 ,= example1 =
 gamma rays )  en]gies ( approximately  
#a ,me,v 7million electron volts71 x is 
n  unusual to di/+ui% betwe5 gamma rays 
t diff] by only #b or #c  t5?s ( a      
p]c5t4 ,! pulse height analyz] is an    
electronic device  t sorts ! electrical 
pulses f ! detector accord+ to _!       
en]gy4                                  
,illu/ration3 ,gamma-ray detector       
,a li?ium-drift$ g]manium-cry/al        
gamma-ray detector4 ,! l>ge    conta9]  

is a res]voir ( liquid nitrog5 t keeps !
 detector    cool$ to a temp]ature (    
-#aif ,c5tigrade 7#cba bel[ z]o1        
,fahr5heit74 ,! lead brick %ield keeps  
out mo/ ( ! gamma rays    t come f      
naturally radioactive mat]ials 9 ! room4
 ,!    pla/ic slots hold c>ds ^u :i* !  
samples are m\nt$ =    c\nt+4 ,sometimes
 ! detector is arrang$ v]tically &      
samples    are plac$ on %elves above x4 
,illu/ration3 ,gamma-ray detector       
,:at ab\t ! neutrons = ! irradiation8   
,al?\gh !re isn't a  suitable nucle>    
reactor#i 9 y\r city1 !re is "o at a    
univ]sity  only an h\r away by jet4     
,s9ce x may take a few h\rs to get !    
sample to ! c\nt] aft] irradiation1 y   
won't be able to look =  %ort-liv$      
activation products1 i4e41 ^? )         
half-lives ( up to an  h\r4 ,h[ev]1 ?is 
w exclude only a few elem5ts f          
detection4                              
,illu/ration3 ,pulse-height analyz]     
,a pulse-height analyz] us$ = gamma-ray 
spectrometry4 ,a gamma-ray    spectrum  

is display$ on ! television scre54 ,data
 is pr9t$ out    automatically on !     
electric typewrit] & also may be plott$ 
z a    graph on ! pap] to ! left4 ,9 o!r
 sy/ems1 data may be cod$    onto pun*$ 
pap] tape z well4 ,su* tape may be      
8read0 by a comput]    t c be programm$ 
to use ! data to calculate :at          
radioactive    isotopes are pres5t & _! 
quantities4    ,n[ y are ready to beg9 !
 analysis4 ,?is w be a qualitative      
analysis s9ce y are m]ely look+ = a     
significantly diff]5t  elem5t 9 t       
silicon cry/al4 ,h[ mu* ( x is pres5t is
 only (  second>y int]e/4 ,!re=e1 if y  
f9d any?+ diff]5t1 y w  rely on an      
approximate calculation to tell y 8h[   
mu*04                                   
,illu/ration3 ,nucle> reactor      ,?is 
is call$ a 8swimm+ pool0 reactor because
 ! nucle> fuel1    built into metal     
rods1 is held 9 a framework at ! bottom 
( a deep    pool ( wat]4 ,! wat] s]ves z
 a %ield to protect work]s f    !       
radiation & also helps ! reactor 8g0 by 

sl[+ d[n neutrons    to make !m m likely
 to int]act ) ! t>get atoms4 8,swimm+   
pool0 reactors are frequ5tly us$ =      
neutron activation analysis &           
typically provide neutron fluxes ( ov]  
#aj 7#aj million million7    neutrons p]
 squ>e c5timet] p] second4              
,illu/ration3 ,qu>tz capsules      ,^!  
seal$ qu>tz capsules conta9 samples to  
be irradiat$ 9 a    nucle> reactor4 ,!y 
are ab\t to be plac$ 9 ! alum9um c1     
:i* w be seal$ & position$ at ! end ( an
 alum9um pole1    close to ! core ( a   
8swimm+ pool0 reactor4 ,(t5 samples are 
plac$ 9 pla/ic tubes & are c>ri$ 9 & out
 ( a reactor by air    pressure 9 a     
pneumatic tube sy/em4    ,y c>efully    
scrape (f a small am\nt ( mat]ial1 weigh
 x on a  s5sitive balance1 & put x into 
a %ort piece ( pure qu>tz tub+4  ,y d ! 
same ) an ord9>y piece ( silicon =      
comp>ison &  !n seal bo? tubes ) an     
oxyg5-gas tor*4 ,al?\gh ! tubes are  bo?
  in* 9 diamet] & ab\t #a in* long1 !   
fir/ tube is j  slightly long] s y w be 

able to det]m9e :i* is :i* aft]  !      
irradiation4    ,(f x goes to ! reactor 
9 a c>efully wrapp$ package along )     
in/ructions to irradiate ! tubes = #ab  
h\rs 9 a neutron flux (  ab\t #aj       
neutrons p] squ>e c5timet] p] second &  
to return !m  z quickly z possible aft] 
!y are remov$ f ! reactor4    ,! foll[+ 
week1 ! samples are deliv]$ ab\t #d h\rs
 aft] !y  7 remov$ f ! reactor4 ,work+  
quickly b c>efully1 y note  t !y are    
radioactive b easily h&l$ by ord9>y     
laboratory  te*niques4 ,y break ! qu>tz 
tubes "o at a "t & atta* ea* (  ! two   
pieces ( silicon to a c>d ) self-/ick+  
tape4 ,!n y  place ea* c>d1 9 turn1 on a
 hold] close to ! gamma-ray detector  = 
a p]iod ( #aj m9utes4 ,a spectrum1 :i*  
is a graph ( ! quantity  ( radiation    
record$ 9 ea* increm5t ( en]gy ov] !    
range  obs]v$ = ea* ( ! samples1 is     
plott$ automatically at ! end (  ! c\nt+
 p]iod & y may n[ comp>e ! compositions 
( ! two  samples4 7,see ! figure on !   
next two pages47    ,! two spectra are  

virtually id5tical except t ! suspect   
sample  has "o obvi\sly diff]5t peak 9  
*annel #aeg & a some:at small]  peak 9  
*annel #ahc4 ,ref]r+ to an en]gy        
calibration curve = !  pulse height     
analyz]1 y f9d t ^! *annels correspond  
to #j4eei  & #j4feg ,me,v respectively4 
,a se>* ( a table ( nuclides1 arrang$ by
  gamma-ray en]gy1 reveals t ?is        
comb9ation is emitt$ by  ars5ic-#gf1 :i*
 w\ld be ! activation product = ars5ic4 
,o!r  data also indicate t = ars5ic !re 
%\ld be a numb] ( small]  peaks1 includ+
 "s correspond+ to en]gies ( #a4baf1    
#a4bbh1 #j4fbd1  & #a4dda ,me,v4 ,a     
clos] look at ! spectrum ( ! suspect    
sample  reveals t ^! are also pres5t4   
,f9ally1 not+ t ! half-life ( ars5ic-#gf
 is approximately #bg  h\rs1 y wait a   
day & c\nt ! sample aga9 9 ! same       
position z  ! previ\s c\nt4 ,a decrease 
9 ! heights ( ! #j4eei & #j4feg ,me,v   
peaks1 by a little less ?an half 9 #bd  
h\rs1 confirms t ars5ic is  ! unusual   
elem5t 9 ?is sample4 ,x may n be ! only 

impurity  caus+ ! peculi> behavior ( ?is
 semiconductor1 b x does seem a  likely 
c&idate4     ,illu/ration3 ,graph3      
8,c\nts 9 #bj m9utes p] #c4h ,ke,v      
*annel0 vs                              
8,*annel ,numb]0      ,elem5t           
,c\nts   ,*annel ,numb]    ,gold        
#acjj              #abe    ,sodium      
#ijj              #adj    ,antimony     
#fej              #aej    ,antimony     
#eej              #afj    ,sc&ium       
#bbj              #bdj    ,iron         
#aej              #cjj    ,sc&ium       
#fj              #caj    ,cobalt        
#aaj              #cbj    ,iron         
#de              #cej    ,cobalt        
#ej              #cfj    ,sodium        
#ijj              #cgj    ,sodium       
#adj              #dbe                  
7values e/imat$ f ! graph7      ,!      
gamma-ray spectrum obta9$ aft]          
activation ( a sample ( 8pure0          
silicon hav+ 8ord9>y0 prop]ties ( ?is   
type ( semiconductor4    ,only v small  
quantities ( v>i\s trace impurities are 

indicat$4     ,illu/ration3 ,graph3     
8,c\nts 9 #bj m9utes p] #c4h ,ke,v      
*annel0 vs                              
8,*annel numb]0      ,elem5t            
,c\nts   ,*annel ,numb]    ,gold        
,sodium    #j4eei ,ars5ic-#ge           
#aejj              #aej    ,antimony    
#j4fbd ,ars5ic-#ge              #aij    
#afe    #j4feg ,ars5ic-#ge              
#ace              #age    ,sc&ium       
,iron    ,sc&ium    ,cobalt    #a4baf   
,ars5ic-#ge              #ajj           
#ccj    #a4bbh ,ars5ic-#ge              
#fj              #cce    ,iron          
,cobalt    ,sodium    #a4dd ,ars5ic-#ge 
#be              #chj    ,sodium        
7di/9ct values e/imat$ f graph7      ,! 
gamma-ray spectrum obta9$ aft]          
activation ( a sample (    silicon hav+ 
8unusual0 electrical prop]ties4 ,:ile   
mo/ ( !    spectrum is id5tical ) t     
obta9$ f ! ord9>y mat]ial1    !re is an 
int]e/+ diff]5ce4    ,us+ ! equation    
giv5 on page #ab1 ! approximate kn[n    
values =  half-life1 sample weight1     

neutron flux1 & p]iods ( irradiation &  
decay aft] irradiation1 & an e/imat$    
value = ! numb] (  ars5ic-#gf atoms     
measur$ by ! gamma-ray spectromet]1 y   
calculate  t ! ars5ic cont5t ( ! sample 
is approximately #dd p>ts p]  million   
7ppm74 7,see app5dix47    ,) ?is        
in=mation z a />t+ po9t1 y are n[ ready 
to proce$  ) fur!r rese>* on ! prop]ties
 ( y\r semiconductor1 e4g41 if  y d\ble 
! conc5tration ( ars5ic1 h[ w t affect  
its  prop]ties8      ,9 a ,hospital     
,! ,problem    ,y are a physician treat+
 a pati5t :o1 because ( a sev]e calcium 
defici5cy1 has be5 suff]+ f o/eoporosis 
7a s(t5+ ( !  bones74 ,y ?9k y are on ! 
"r track ) y\r treatm5t1 b  y w\ld l to 
be sure 9 ord] to "k :e!r y %\ld cont9ue
  ! treatm5t or try some?+ else4 ,y w\ld
 h y\r answ] if y  knew t ! calcium     
cont5t ( 8 skeleton _h /opp$ decreas+4  
,h[ c y det]m9e ! am\nt ( calcium 9 a   
liv+ human be+8    ,! ,solution    ,y "k
 t ! usual te*niques = det]m9+ calcium 9
 ! bones  are n v useful4 ,!y are ei!r  

too inaccurate to %[ t y\r  pati5t's    
calcium loss has be5 /opp$ or c only be 
us$ to measure  ! calcium cont5t ( !    
bones 9 8 extremities4 ,! latt] is n    
satisfactory because ^! few bones may n 
be repres5tative ( !  re/ ( 8 skeleton4 
,rec5tly1 h[ev]1 !re h be5 reports (    
neutron activation  analysis ( :ole     
p]sons1 9 :i* ! calcium cont5t ( _!     
bones  has be5 measur$ ) unusually good 
reliability4 ,?is has be5  accompli%$ by
 sci5ti/s & doctors work+ at !          
,univ]sity (  ,wa%+ton ,s*ool ( ,m$ic9e 
9 ,seattle4    ,y manage to obta9 an    
appo9tm5t = y\r pati5t & y accompany    
him to ! hospital = ! analysis4 ,!re he 
is plac$ on a rotat+  plat=m ) 8 head   
encircl$ by a pla/ic helmet & 8 arms &  
legs subm]g$ 9 a wat]-fill$ pla/ic      
conta9]4 ,see ! photograph  on ! next   
page4 ,! plat=m is locat$ 9 a beam (    
neutrons  emanat+ f a b]yllium t>get #ae
 feet away1 :i* is be+ bomb>d$  by      
deut]ons f a #bb-,me,v cyclotron4 ,!    
purpose ( ! wat] is to  surr\nd ! bones 

9 t "p ( ! subject's skeleton ) a       
neutron  mod]ator equival5t to ! body   
tissue surr\nd+ ! re/ ( 8  skeleton4 7,a
 neutron mod]ator sl[s d[n ! neutrons & 
?us makes  !m m likely to activate !    
calcium 9 ! bones47 ,on ea* side (  !   
pati5t1 !re are two pla/ic conta9]s     
p]man5tly fill$ ) a  solution conta9+ a 
kn[n quantity ( calcium4 ,^! s]ve z     
/&>ds = ! analysis4    ,! beam (        
neutrons is turn$ on = #ce to #dj       
seconds4 ,x is !n  int]rupt$ :ile plat=m
 & pati5t are rotat$ #ahj degrees4 ,!   
irradiation is resum$ s t a uni=m dose (
 neutrons bomb>ds !  pati5t f bo? front 
& back4    ,dur+ ! irradiation y\r      
pati5t receives a dose ( radiation      
equival5t to approximately #aj ord9>y   
*e/ ,x rays & "o ( !  calcium isotopes 9
 8 bones 7calcium-#dh7 is activat$ to   
calcium-#di4  ,! latt] has a half-life (
 only #h4h m9utes & s c\nt+ mu/  beg9   
soon aft] ! irradiation4                
,illu/ration3 ,pati5t      ,a pati5t 9  
position = :ole body irradiation )      

neutrons    g5]at$ by an accel]ator4 ,8 
arms & legs are surr\nd$ by    plexiglas
 conta9]s fill$ ) wat] & 8 head is      
encas$ 9 a    plexiglas helmet4 ,on ei!r
 side ( him are conta9]s1 :i* s]ve z    
/&>ds1 fill$ ) an aque\s solution ( a   
calcium salt4 ,!    pati5t is /&+ on a  
turntable t is rotat$ #ahj degrees aft] 
half ! irradiation is complet$ s t !    
dose ( neutrons is    uni=mly di/ribut$ 
to ! front & ! back ( ! pati5t4         
,illu/ration3 ,pati5t      ,a pati5t 9  
position = :ole-body gamma-ray          
spectrometry4 ,!    detectors are       
sc9tillation cry/als t produce pulses ( 
light    proportional 9 int5sity to !   
en]gy ( ! gamma ray absorb$ 9    !      
cry/al4 ,! pati5t is scann$ f head to   
foot 9 approximately    #ab m9utes at a 
rate t is v>i$ to comp5sate = ! gradual 
decay ( ! calcium-#di radioactivity dur+
 ?is p]iod4 ,ne> !    pati5t's head are 
two calcium /&>d solutions 9 plexiglas  
conta9]s4    ,! pati5t lies d[n 9 a     
padd$ alum9um box &1 only #d m9utes aft]

  ! irradiation is conclud$1 a r+ ( #d  
gamma-ray sc9tillation  detectors#aj    
beg9 to measure ! gamma rays emitt$ by 8
 body4 ,^!  detectors1 :i* are ea* #d   
in*es ?ick & #i in*es 9 diamet]1 pass   
ov] 8 body f head to foot4 ,?is takes   
#ab m9utes & s9ce !  calcium-#di is     
decay+ ) a half-life ( #h4h m9utes1 !   
detectors  are made to scan at a        
gradually decreas+ rate to comp5sate = !
  r$uc$ radioactivity dur+ ! lat] p>ts (
 ! c\nt+ p]iod4 ,!  figure on ! next    
page %[s ! gamma-ray spectrum = !       
pati5t4  ,notice ! peak correspond+ to  
an en]gy ( #c4a ,me,v4 ,because !re are 
small contributions to ?is en]gy peak f 
o!r activat$ products 9  ! body1 repeat 
c\nts are tak5 lat] 7aft] ! calcium-#di 
has  decay$7 s t ^! contributions c be  
measur$ & subtract$4    ,tw5ty m9utes   
aft] ! irradiation p]iod1 !             
radioactivity ( !  calcium /&>ds is     
measur$ by ! same in/rum5t4 ,! ratio ( !
  c\nts f y\r pati5t's body to t ( !    
/&>ds is #j4baj2 ?is  s]ves z an index (

 ! calcium cont5t ( 8 body on ?is day4  
,because ( ! c>e tak5 to make ! analysis
 repeatable1 ?is index is  probably     
accurate to ab\t #a or #b4    ,y\r      
pati5t's disease usually results 9 a    
decrease ( approximately #c  ( ! calcium
 9 8 body p] ye>4 ,?us1 by mak+ ! same  
measurem5t a ye> f n[1 y w be able to   
tell if y\r treatm5t  is a success by   
not+ t ! calcium level 9 y\r pati5t's   
bones  has /opp$ decreas+ at a dang]\s  
rate4      ,9 a ,pla/ics ,plant    ,!   
,problem    ,y are an analytical *emi/  
work+ = a company t makes pla/ic4  ,x is
 #aa3cj a4m4 & y h be5 call$ by ! plant 
sup]9t5d5t  because "s ( ! pla/ic com+ f
 ! plant has be5 %[+ a  yell[i%-br[n    
discoloration4 ,!re seem to be only a   
few possible  reasons = x1 b no easy way
 to tell :i* "o is correct4 ,"o         
possibility is t a copp] tank1 9 :i* !  
pla/ic is prep>$1 is  someh[ be+ corrod$
 by excess acid 9 ! raw mat]ial & m9ute 
quantities ( dissolv$ copp] are         
discolor+ ! pla/ic4 ,y c\ld  prove t ?is

 is ! cause if y c\ld f9d copp] 9 !     
pla/ic1  b ! plant sup]9t5d5t wants !   
answ] imm$iately because a few  h\rs    
delay 9 production w jeop>dize a        
valuable contract1 &  ord9>y *emical    
analysis w\ld take sev]al h\rs4 ,h[ c y 
quickly  det]m9e if !re is copp] pres5t 
9 ! pla/ic8      ,illu/ration3 ,graph3  
8,c\nts p] #ab4e m9utes_/#ej ,ke,v      
*annel0 vs                              
8,*annel no40      ,elem5t              
,c\nts      ,*annel no4    #b4ge ,me,v  
,na-#bd               #ejjj             
#aj    #c4aj ,me,v ,ca-#di              
#cbjj               #af    #c4he ,me,v  
,cl-#ch                #ejj             
#cc    #d4j ,me,v ,ca-#di               
#ajj               #ci                  
7,values e/imat$ f graph7      ,a       
portion ( ! gamma-ray spectrum obta9$   
aft] neutron activation    ( a human    
body4 ,! area 9 ! #c4aj-,me,v peak1 :i* 
is above !    backgr\nd due to sodium & 
*lor9e activities1 is a measure ( !     
quantity ( calcium 9 ! body ( ! subject4

 ,a comput] may make    ! necess>y      
corrections due to ! backgr\nd 7:i*     
results f    ov]lapp+ ( "p ( ! o!r      
gamma-ray peaks74    ,! ,solution    ,"o
 reason t ord9>y analytical me?ods are s
 sl[1 9 ?is case1  is because ! am\nt ( 
copp] y are look+ = is s small t y  w\ld
 h to dissolve a l>ge am\nt ( pla/ic to 
get en\gh copp] to  measure4 ,y "k t    
ne>ly all ! pla/ic is c>bon1 hydrog51 & 
oxyg5 & t none ( ^! elem5ts are easily  
made radioactive :5  !y are bomb>d$ )   
l[-en]gy neutrons4 ,y look 9 a table to 
see  if copp] is easily activat$4 ,y f9d
 t !re are two /able  isotopes ( copp]  
hav+ atomic weights ( #fc & #fe4 ,ea* ( 
^! is  easily activat$1 giv+ radioactive
 isotopes1 copp]-#fd & copp]-#ff4  ,!   
latt] has a half-life ( ab\t #e m9utes &
 emits gamma rays )  en]gies ( #a4jci   
,me,v1 :i* are easy to measure4    ,9 ! 
rese>* build+ next door1 !re is a small 
reactor t c  irradiate encapsulat$      
samples ) l[-en]gy neutrons at ! rate ( 
a  million million neutrons p] squ>e    

c5timet] p] second 7#aj                 
neutrons_/cm_/sec74 ,y calculate t if y 
irradiate only "o t5? (  a gram ( !     
pla/ic = #aj m9utes1 & if ! pla/ic      
conta9s only  "o "p ( copp] 9 "o million
 p>ts ( pla/ic1 !n at ! end (  !        
irradiation ! radioactive copp] =m$ w be
 emitt+ ov] #djj  gamma rays p] second4 
,!re is a pneumatic tube t c remove !   
irradiat$ sample 9 #bj seconds1 & y     
decide t x w take only a  m9ute or two  
to remove ! sample f its capsule & get x
 into a  gamma-ray c\nt] locat$ ne>by4  
,! c\nt] is a sc9tillation c\nt]  t is  
connect$ to a pulse-height analyz]4     
,if y c\nt = only #aj m9utes y w detect 
ab\t #ajjj gamma rays  ( ! "r en]gy     
7all[+ = ! ineffici5cies ( ! detector   
sy/em74 ,?is s\nds l x %\ld d ! job4 ,b 
does ! good  pla/ic conta9 copp] too8 ,&
 h[ mu* does x take to produce !        
discoloration8    ,y decide to use      
neutron activation analysis & to analyze
 samples (  faulty pla/ic1 normal       
pla/ic1 & a small piece ( copp] foil1   

:i*  y h weigh$ & seal$ 9 a small       
polye?yl5e bag z a /&>d4  ,y\r results  
are %[n 9 ! table bel[4      ,sample    
,c\nts 9 #aj m9utes#aa    #j4a grams    
faulty pla/ic                           
#ajj1jjj    #j4a grams good pla/ic      
#a1jjj    #j4a milligrams ( pure copp]  
#a1jjj1jjj    ,x work$6 ,! faulty pla/ic
 conta9s #ajj times z mu* copp] z !     
good pla/ic1 specifically #ajj p>ts p]  
million4 7,if #j4a milligrams (  pure   
copp] gave #a1jjj1jjj c\nts1 !n ! #j4a  
grams ( faulty pla/ic  conta9s          
7#ajj1jjj_/a1jjj1jjj7  #j4a milligrams  
or #j4ja milligrams (  copp]4 ,?is is "o
 t5 ?\s&? ( ! weight ( ! pla/ic or #j4ja
  or #ajj ppm47 ,y relay ! in=mation to 
! plant sup]9t5d5t  almo/ be=e he f9i%es
 8 lun*4 ,he n[ kn[s :at to d & !       
crisis is ov]4      ,9 a ,museum    ,!  
,problem    ,y are a curator work+ ) !  
anci5t co9 collection ( a l>ge  museum4 
,a donor has j giv5 ! museum a gr\p (   
#ej gold co9s  presumably ab\t #aejj    
ye>s old4 ,aft] mon?s ( c>eful /udy1 y h

  satisfi$ y\rself t mo/ ( ^? co9s are  
g5u9e specim5s (  t p]iod4 ,judg+ f y\r 
exp]i5ce1 y decide t a small gr\p  (    
five are def9ite =g]ies4    ,h[ev]1 !re 
are ?ree o!rs t y suspect are also      
fakes1 b y  are n q c]ta94 ,y "k t bo?  
g5u9e m9t]s & =g]s  (t5 tri$ to save    
money by dilut+ _! gold ) less exp5sive 
metals su* z silv] & copp]4 ,s9ce !     
*ances are slim t !  =g]'s product has !
 same conc5tration ( gold1 silv]1 &     
copp]  z ! g5u9e co9s1 y realize t a    
*emical analysis w\ld help  y decide if 
! d\btful pieces 7 real or fake4    ,an 
accurate *emical analysis w\ld require a
 sample ( su* size t  ! co9 w\ld be ru9$
 z a museum specim54 ,y ne$ an          
analytical  me?od t c be appli$ to an   
inf9itesimal sample4    ,! ,solution    
,y are n a sci5ti/ b y've he>d ab\t     
neutron activation  analysis4 ,!re=e1 y 
contact a radio*emi/ at a local         
univ]sity  :o is an exp]t 9 ?is field4  
,he decides to use a sampl+ te*nique    
develop$ by sci5ti/s at  ,brookhav5     

,national ,laboratory = sampl+ metal    
objects (  ar*aeological int]e/4 ,y     
obta9 f him a set ( #ej qu>tz plates  t 
h be5 gr\nd on "o side4 ,foll[+ 8       
in/ructions1 y  c>efully scrape away a  
small area on ! edge ( ea* co94 ,y !n   
rub ea* fre%ly clean$ area across !     
gr\nd surface ( "o plate  leav+ a m9ute 
/reak ( metal simil> to a p5cil m>k4    
,at ! sci5ti/'s laboratory1 ea* plate is
 c>efully plac$ inside a  qu>tz tube4   
,no attempt is made to weigh ! t9y /reak
 ( metal s9ce  y wi% only to comp>e !   
ratios ( ! metal conc5trations4  ,h[ev]1
 because ! samples make a r bulky       
package1 ! sci5ti/  is conc]n$ ) !      
uni=mity ( ! neutron flux t ea* sample  
w 8see04 ,he !re=e also places 9 ea*    
tube an exactly equal  weight ( a       
gold--silv]--copp] alloy wire 7( kn[n   
proportions7 to act  z a /&>d           
neutron-flux monitor4 ,! tubes are !n   
seal$ & tak5  to a reactor to be        
irradiat$ = #ab h\rs4    ,aft] ! samples
 are remov$ f ! reactor1 ! sci5ti/      

c>efully  breaks op5 ea* ( ! qu>tz tubes
 & places ! sample & !  /&>d piece (    
wire 9 sep>ate numb]$ pla/ic capsules ) 
lids4  ,= an accurate comp>ison1 ea*    
capsule is prep>$ 9 ! same mann]4  ,ab\t
 #d h\rs aft] ! samples are remov$ f !  
reactor1 he beg9s  ! radioactivity      
measurem5ts4    ,! sample capsules are  
load$ into an automatic sample-*ang+    
me*anism t places ea* "o into an        
id5tical position above a  li?ium-drift$
 g]manium detector4 7,see ! *apt] beg9n+
 on page  #ai47 ,gamma-ray spectra are  
collect$ all day1 fir/ f a sample1 !n  f
 its accompany+ /&>d4 ,ea* c\nt takes #b
 m9utes1 & #c  m9utes are requir$ betwe5
 c\nts = data pr9t\t & sample  *ang+4 ,a
 typical gamma-ray spectrum looks l ! "o
 9 ! figure  on ! next page4 ,notice t  
only gold 7gold-#aih7 & copp]           
7copp]-#fd7 %[ up 9 ?is %ort c\nt+ "t4  
,lat] on1 radioactivity  f silv]        
7silv]-#aajm7 c be measur$ us+ a long]  
c\nt+  "t4 ,?is c be done because :ile !
 activation products f copp]  & gold h  

relatively %ort half-lives 7#ab4h h\rs &
 #b4g days1  respectively71 t f silv]   
has a half-life ( #bgj days4 ,to        
increase  ! s5sitivity ( ! analysis =   
silv]1 ! sci5ti/ repackages &           
re-irradiates ! samples & wires = #ajj  
h\rs4 ,silv]-#aajm is "o  ( two         
radioactive isotopes ( silv] t h ! same 
mass4 ,9  ?is case1 "o has a high] en]gy
 ?an ! o!r & decays 9 a  diff]5t way4   
,?is is kn[n z an isom]ic /ate & x      
occurs = _m  o!r elem5ts z well z =     
silv]4     ,illu/ration3 ,graph3 8,c\nts
 9 "o m9ute p] #c4a ,ke,v *annel0 vs    
8,*annel0      ,elem5t                  
,c\nts    ,*annel numb]    #j4aeh ,ms,v 
,au-#aii            #fjj                
#dj    #j4dab ,me,v ,au-#aih            
#hjj               #abj    #j4eaa ,me,v 
,cu-#fd              #ej                
#aej    #j4fgf ,me,v ,au-#aih           
#dj               #bje                  
7,values e/imat$ f graph7      ,!       
spectrum obta9$ f a /reak ( metal on a  
qu>tz plate aft] a    #c-;h\r exposure  

to neutrons 9 a reactor & a #f-;h\r     
delay be=e    c\nt+4 ,! activation      
products ( gold & copp] are obvi\sly    
pres5t & are easily measur$ 9 only #a   
m9ute4    ,illu/ration3 ,graph3 8,c\nts 
p] #ajj m9utes p] #c4b ,ke,v *annel0 vs 
8,*annel numb]0              ,en]gy     
,c\nts         ,*annel ,numb]           
#j4dde ,me,v                   #bcj     
#acj         #j4feg ,me,v               
#abjj                    #aij           
#j4fhg ,me,v                   #agj     
#bjj         #j4gae ,me,v               
#bbj                    #bbj            
#j4gfj ,me,v                   #bcj     
#bbe         #j4hbj ,me,v               
#fj                    #bej             
#j4hhd ,me,v                   #ejj     
#bfj         #j4icg ,me,v               
#aij                    #bhj            
7,values are e/imat$ f graph7      ,!   
spectrum obta9$ f ! same /reak ( metal  
aft] re-exposure    to neutrons = #ajj  
h\rs & a delay ( approximately #b mon?s 
be=e    c\nt+4 ,activation products f   

gold & copp] h decay$ away    & !       
gamma-ray spectrum ( silv]-#aajm is n[  
obs]v$4 ,9 ?is    case ! sample is clos]
 to ! detector ?an = ! e>li]            
measurem5t & ! measurem5t takes #ajj    
m9utes4    ,two mon?s lat]1 ! sci5ti/   
repeats ! proc$ure ( c\nt+ !  samples & 
/&>ds1 except t ?is "t ! pla/ic capsules
 are  clos] to ! detector1 ea* c\nt is =
 #ajj m9utes1 & ! sample  *ang] op]ates 
= ab\t a week4 ,a typical spectrum looks
 l t 9  ! figure on page #ci4    ,!     
sci5ti/ c n[ compute ratios = ! ?ree    
elem5ts 9 ea*  sample & comp>e !m ) !   
/&>d1 b he decides t a  comput] c\ld d x
 fa/] & ) few] errors4 ,! data collect$ 
dur+ ! two s]ies ( c\nts are !re=e s5t  
to a data process+  c5t] :]e1 9 a matt] 
( m9utes1 a comput] does ! foll[+ =  ea*
 ( #ej samples3      #a4 ,f9ds !        
#j4daa-,me,v gamma-ray peak = gold-#aih4
      #b4 ,det]m9es ! total c\nts 9 !   
peak4      #c4 ,repeats ! process = !   
correspond+ wire /&>d4      #d4         
,corrects ! total c\nt = ! wire = !     

small am\nt (    radioactive decay t    
occurr$ 9 ! few m9utes betwe5 ! sample  
c\nt & ! /&>d c\nt4      #e4 ,computes !
 ratio3 total c\nt = sample_/total c\nt 
=    /&>d 7correct$7      #f4 ,repeats  
all ! above = ! #j4eaa-,me,v gamma ray =
 copp]-#fd &    79 ! long] c\nts7 = !   
#j4feh-,me,v gamma ray = silv]-#aaj4    
#g4 ,computes ! ratios3 sample to /&>d  
7= copp]7_/sample to    /&>d 7= gold7 & 
sample to /&>d 7= silv]7_/sample to     
/&>d 7= gold74      #h4 ,tabulates &    
pr9ts ! ratios f\nd 9 ,/ep #g4          
,illu/ration3 ,graph3 ,numb] ( co9s at  
indicat$ ratios vs4                     
,copp]_/gold ratio      ,radioactivity  
ratios = #ej 8gold0 co9s4 ,above are !  
silv] to gold    ratios4 ,!re are two   
gr\ps ( g5u9e co9s4 ,five kn[n =g]ies   
%[ consid]ably high] ratios ?an ! g5u9e 
co9s4 ,two ( !    suspect co9s also %[  
high ratios b ! ?ird1 suspect ,a1 %[s a 
ratio t falls into "o ( ! g5u9e gr\ps4  
,bel[ are ! copp]    to gold ratios4    
,aga9 !re are two gr\ps ( g5u9e co9s4   

7,! same    co9s make up ! two gr\ps "h 
z above47 ,! five kn[n =g]ies    aga9 %[
 high] ratios ?an ! g5u9e ones & aga9 ! 
same two    suspects appe> to be =g]ies4
 ,suspect ,a1 h[ev]1 %[s a ratio        
simil> to "o gr\p ( ! g5u9e specim5s4   
,"o !re=e concludes    t suspect ,a is  
g5u9e & t ,b & ,c are n4    ,= example1 
suppose = sample #a !re are #bj1jjj     
c\nts 9 !  #j4dab-,me,v peak 7gold71    
#aij c\nts 9 ! #j4eaa-,me,v peak        
7copp]71 &  #dej c\nts 9 ! #j4fed-,me,v 
peak 7silv]74 ,suppose also t /&>d  #a  
yield$ #aj1jjj1 #ejj1 & #djj c\nts = ^! 
?ree peaks 7correct$  = decay71         
respectively4 ,!n ! ratio = gold w\ld be
  7#bj1jjj_/aj1jjj7  #b4jj1 ! ratio =   
copp] w\ld be 7#aij_/ejj7  #j4chj1  & ! 
ratio = silv] w\ld be 7#dej_/djj7       
#a4ac4    ,f9ally1 ! activity ratio (   
copp] to gold w\ld be 7#j4chj_/b4jj7    
#j4aij1 & ! activity ratio ( silv] to   
gold w\ld be 7#a4ac_/b4jj7   #j4efe4    
,because ea* sample 0 irradiat$ ) an    
id5tical /&>d1 &  c\nt$ 9 an id5tical   

arrangem5t1 ! la/ two ratios w be !     
same = diff]5t samples if1 & only if1 ! 
conc5trations ( gold1  silv]1 & copp] 9 
^? samples are 9 id5tical proportions4  
,?is  w be true no matt] :]e 9 ! reactor
 or = h[ long !  irradiation took place4
    ,n[ ! sci5ti/ pres5ts ! data to y4  
,y imm$iately see t 7a7  ! good co9s    
fall into two gr\ps1 "o ) a silv] to    
gold activity  ratio ( approximately    
#j4ef & a copp] to gold ratio (         
approximately  #j4bj & a second gr\p )  
^! ratios approximately #j4ea & #j4ah2  
7b7 ! co9s y 7 c]ta9 7 =g]ies h di/9ctly
 high]  ratios rang+ f #j4fj to #j4fe = 
silv] to gold & f #j4bc to  #j4cj =     
copp] to gold2 & 7c7 ( ! ?ree suspect$  
co9s1 two h  ratios t fall into ! range 
( ! kn[n =g]ies1 b "o1 )  ratios (      
#j4eeb & #j4aih1 is probably g5u9e4     
,y pres5t ! result to ! museum director 
9 ! =m ( a graph  7see ! figure on page 
#da7 & a few weeks lat]1 #dc co9s are   
add$ to  ! p]man5t exhibits ( ! museum1 
:ile #g are disc>d$4      ,9 a          

,crim9ology ,laboratory    ,! ,problem  
,y are a sci5ti/ work+ 9 ! crim9ology   
laboratory ( a l>ge  metropolitan city4 
,a detective br+s y a m9ute sample (    
pa9t tak5  f ! clo?+ ( a hit-&-run      
victim4 ,he has a suspect ^:  automobile
 pa9t seems to mat* t sample4 ,! suspect
 0 f\nd 9  8 p>k$ automobile1 n f> f !  
sc5e ( ! accid5t4 ,he seems  to fit !   
description giv5 by two witnesses1 & he 
is extremely  n]v\s4 ,y scrape a small  
sample ( pa9t f a rec5tly damag$ area  (
 ! suspect's c>1 &1 7) ! aid ( a        
microscope7 f9d t !  pigm5t cont5t seems
 to be ! same z t tak5 f ! victim's     
clo?+4 ,b1 are !y really f ! same pa9t8 
,! ,solution    ,y "k t pa9t1 l almo/   
ev]y?+ else1 conta9s v small  quantities
 ( impurities t are pres5t only by      
accid5t & d n  affect its prop]ties z a 
useful mat]ial4 ,! trace impurities1 z  
!y are call$1 w v>y f bat* to bat* ( !  
same pa9t4 ,v  r>ely w a mat* be obta9$ 
9 bo? type & conc5tration ( trace       
impurities 9 two samples if !y are n f !

 same bat*4    ,by measur+ a suffici5t  
numb] ( diff]5t elem5ts1 ! probability  
( accid5tally mat*+ two samples c be z  
r>e z ! duplication  ( f+]pr9ts 9 two   
individuals4 ,mat*+ ( trace impurities  
is  (t5 call$ a 8f+]pr9t0 me?od4    ,)  
neutron activation analysis1 y c obta9 !
 8f+]pr9ts0 (  ! two samples to see if  
!y mat*4 ,al?\gh ?is k9d ( evid5ce may  
be difficult to use z pro( 9 c\rt1 a    
positive mat* w let !  detective "k t he
 is on ! "r track4 ,also1 ! suspect     
might  confess if he is confront$ ) !   
evid5ce & realizes t he is  8caught04   
,on ! o!r h&1 a mismat* w cle> ! suspect
  completely & ! detective w "k to look 
else:]e = !  crim9al4    ,y seal ea*    
sample 9 a t9y polye?yl5e bag ab\t  in* 
squ>e4 ,"o  sample is tak5 f ! victim's 
clo?+ & ! second1 ab\t !  same size z ! 
fir/1 tak5 f ! damag$ area ( !          
automobile4  ,9 prep>+ ^! samples1 y    
h&le all ! mat]ials ) clean  =ceps      
because y realize t ! mo/ m9ute dirt f  
y\r f+]s  w be detect$ 9 ! analysis4    

,! two bags are irradiat$ toge!r = #a   
h\r 9 a ne>by reactor &  #b h\rs lat] y 
beg9 c\nt+ ! samples ) a                
high-resolution1                        
li?ium-drift$-g]manium1 gamma-ray       
spectromet]4 ,?is w give y a  mat* 7or  
mismat*7 = elem5ts t yield radioisotopes
 ( fairly  %ort half-life su* z         
manganese 7#b4ef h\rs71 copp] 7#ab4h    
h\rs71  sodium 7#ae h\rs71 ars5ic 7#bg4g
 h\rs71 etc4 ,y plan on 8c\nt+0 !       
samples aga9 lat] on1 if ! fir/ c\nts   
mat*1 s t y c *eck  on radioisotopes )  
long] half-lives su* z iron 7#de days71 
*romium  7#bg days71 silv] 7#bgj days71 
cobalt 7#e ye>s71 etc4    ,! two        
gamma-ray spectra y obta9 look l ^? 9 ! 
figure on  ! opposite page4 ,! gamma    
rays f ! irradiat$ pa9t tak5 f  !       
victim's clo?+ indicate ! pres5ce ( !   
common elem5ts  sodium1 potassium1 &    
copp]1 b gold1 lan?anum1 & europium are 
also conspicu\sly pres5t4 ,! gamma rays 
f ! o!r sample also  reveal sodium1     
potassium1 & gold b 9 r diff]5t         

proportions4  ,m /rik+ is ! abs5ce (    
copp] & ! two r>e e>?s1 & !  pres5ce (  
manganese & ars5ic1 :i* 7 n indicat$ 9 !
 fir/  sample4    ,! pa9t samples       
def9itely d n mat*4 ,!re=e1 y in=m !    
detective t 8 suspect is innoc5t aft]   
all4 ,y've solv$ y\r  problem1 b he /ill
 has 84 ,p]haps ! same te*nique w       
provide  positive pro( :5 he f9ds ! real
 culprit4      ,illu/ration3 ,graph3    
8,c\nts_/#aj m9 p] #c4c ,ke,v *annel    
7arbitr>y                       scale70 
vs 8,*annel numb]0      ,elem5t         
,*annel numb]    4#abb ,me,v ,eu        
7,europium7                             
#ce    4#cbh ,me,v ,la 7,lan?anum7      
#ie    4#cdd ,me,v ,eu                  
#if    4#dab ,me,v ,au 7,gold7          
#aaj    4#dhf ,me,v ,la                 
#abj    4#eaa ,me,v ,cu 7,copp]7        
#ade    4#hae ,me,v ,la                 
#bdj    4#hcg ,me,v ,eu                 
#bde    4#ifa ,me,v ,eu                 
#bij    #a4cg ,me,v ,na 7,sodium7       
#daj    #a4ec ,me,v ,k 7,potassium7     

#dee    #a4fj ,me,v ,la                 
#dge                          7*annel   
numb]s e/imat$7      ,illu/ration3      
,graph3 8,c\nts_/#aj m9 p] #c4c ,ke,v   
*annel 7arbitr>y                        
scale70 vs 8,*annel numb]0      ,elem5t 
,*annel numb]    #j4dab ,me,v ,au       
7,gold7                                 
#aaj    #j4eaa ,me,v ,na                
#ade    #j4eei ,me,v ,z 7,ars5ic7       
#afj    #j4feg ,me,v ,z                 
#aie    #j4hdg ,me,v ,mn 7,manganese7   
#bej    #a4ba ,me,v ,z                  
#cgj    #a4cg ,me,v ,na 7,sodium7       
#daj    #a4ec ,me,v ,k 7,potassium7     
#dee                          7*annel   
numb]s e/imat$7      ,gamma-ray spectra 
( two samples ( pa9t4 ,^! two spectra   
are    obvi\sly diff]5t &1 !re=e1 c\ld n
 h come f ! same    s\rce4              
,,summ+ ,,up3 ,,:at ,,lies ,,ahead      
,^! five situations are int5d$ to %[ :y 
neutron activation  analysis is us$1 :5 
x c be appli$1 & h[ x works4    ,9 !    
real _w1 !re are (t5 _m reasons :y ?is  

k9d (  analysis is us$4 ,z 9 !          
situations describ$ "h1 x may be !  only
 workable me?od4 ,sometimes !re may be a
 *oice ( me?ods1 b  activation analysis 
is us$ because x has c]ta9 peculi>      
advantages  or because x happ5s to be ! 
mo/ conv5i5t4 ,!re are o!r times1       
h[ev]1 :5 o!r analytical me?ods c & %\ld
 be us$4 ,su*  situations arise :5 !    
elem5t s\ght is n easily activat$1 or   
:5 a satisfactory alt]native me?od exi/s
 t is m economical or  m conv5i5t4 ,!   
po9ts to rememb] ab\t ! use ( activation
  analysis are t3      #a4 ,9 _m cases1 
no elaborate sample prep>ation proc$ure 
is    requir$4      #b4 ,= _m elem5ts1 x
 is ! mo/ s5sitive analytical te*nique  
kn[n4    ,! div]sity ( applications 9   
:i* activation analysis is us$ is       
enorm\s & w probably cont9ue to be4 ,!  
examples giv5 "h  repres5t only a t9y   
fraction ( circum/ances 9 :i* ! me?od   
has  be5 us$4 ,consid] t x has be5 us$  
successfully3      #a4 ,9 ! microscopic 
_w ( biology & m$ic9e2      #b4 ,=      

meteorites arriv+ f ! va/ rea*es (      
space2      #c4 ,9 ! production l9es (  
consum] products2      #d4 ,= preci\s   
samples ( moon rocks2      #e4 ,9 ! mo/ 
8d[n-to-e>?0 bus9ess ( hunt+ = new m9]al
    s\rces2      #f4 ,= explor+ ! causes
 ( ,napoleon's dea? ne>ly #aej ye>s     
e>li] 7see photograph on next page74    
,today1 !re is virtually no    field (  
sci5ce & te*nology t is unt\*$ by ?is   
me?od4    ,! illu/rations ( proc$ures   
us$ 9 ! situations describ$ 9  ?is      
booklet are typical ( "s 9 use today4   
,!re are _m o!r  situations t require   
/ill o!r te*niques4 ,"o ( ! mo/  excit+1
 :i* w be us$ ) increas+ frequ5cy 9 !   
future1  involves ! use ( comput]s4 ,x  
has be5 %[n t data collect$ by          
high-resolution gamma-ray spectromet]s c
 be 8f$0 directly to a  comput]4 ,!     
comput] c be programm$ to id5tify unkn[n
 compon5ts  & to det]m9e ! conc5trations
 ( elem5ts ( int]e/ to !  analy/4 ,x is 
entirely possible to include corrections
 = radioactive  decay1 possible         

int]f]5ces f o!r elem5ts pres5t1 & _m   
o!r factors4 ,x appe>s q likely t ! k9ds
 ( analyses  describ$ "h 7z well z o!rs7
 may som$ay be accompli%$               
automatically1 ) f> small] *ances =     
error & probably m  economically4       
,illu/ration3 ,hair sample      ,samples
 ( ,napoleon's hair4 ,neutron activation
 analysis ( ^! hairs    reveal$ t he _h 
be5 poison$ ) ars5ic4 7,he di$1 h[ev]1  
n f ars5ic poison+1 b f acute m]cury    
intoxication47    ,o!r new] te*niques t 
may f9d increas$ usage 9 ! future are   
exemplifi$ by ! me?od = activation      
analysis ( ! :ole human  body4 ,! use ( 
neutrons produc$ by nucle> ma*9es 7su* z
  cyclotrons or o!r p>ticle accel]ators7
 or produc$ by compact1  portable       
isotopic s\rces w make neutron          
activation analysis ev5  m v]satile4    
,isotopic s\rces produce neutrons z !   
result ( a  nucle> reaction4 ,"o su*    
reaction uses alpha p>ticles emitt$ by  
polonium-#baj 7or "s o!r alpha emitt]7  
to bomb>d ! elem5t  b]yllium4 ,a diff]5t

 k9d ( isotopic s\rce is ! man-made     
radioisotope cali=nium-#beb t decays by 
fission+ 7splitt+7  spontane\sly &      
produces neutrons 9 ! process4 7,"o     
milligram (  cali=nium-#beb w           
spontane\sly produce ov] #aj neutrons p]
  second47 ,:ile cali=nium-#beb is q    
exp5sive at pres5t1 x is  likely t      
production co/s w be significantly r$uc$
 9 !  future4    ,) comput]s1 m conv5i5t
 radiation s\rces1 & cont9u+            
improvem5ts 9 ! te*nology ( gamma-ray   
detectors & nucle>  electronics1 neutron
 activation analysis w become m & m a   
r\t9e tool ( ! analy/4                  
,,app5dix      ,calculation ( ars5ic    
conc5tration ) no /&>d = comp>ison4     
#a4 ,det]m9ation ( ars5ic-#gf activity  
produc$ f #a microgram (  ars5ic at ! "t
 x comes out ( ! reactor4    ,we use !  
equation f page #ab3                    
,a  ,n 7#a - e-t7    :]e ,n is ! numb] (
 t>get atoms4 7,"o microgram ( ars5ic   
conta9s 7#aj-f gram_/#ge grams p]       
mole#ab7  #f4jb  #aj atoms p]  mole :i* 

is #h  #aj atoms ( ars5ic47     is !    
neutron flux4 7,?is w\ld be kn[n to !   
reactor op]ator4 ,x  is usually measur$ 
by ins]t+ mat]ials ( kn[n composition & 
measur+ _! activation4 ,9 ?is case1     
#aj neutrons p] squ>e  c5timet] p]      
second47     is ! activation cross      
section4 7,neutron cross sections h be5 
measur$ & tabulat$ by sci5ti/s4 ,= !    
activation ( ars5ic-#ge  to ars5ic-#gf1 
! cross section is kn[n to be #d4b      
#aj-bd squ>e  c5timet]47     is !       
dis9tegration con/ant = ars5ic-#gf4     
7,"h1   7ln  #bac_/t179 h\rs72 t1 !     
half-life = ars5ic-#gf1 is #bf4f  h\rs s
   7#j4fic_/bf4f7  #j4jbf47    t is ! "t
 ( ! irradiation4 7,"h t is #ab h\rs47  
,!re=e3 ,a1 ! activity ( ars5ic-#gf1    
#h  #aj  #aj  #d4b  #aj-bd  7#a -       
e-#j4jbf  #ab7      7,note3 e is a      
physical con/ant1 #b4ga7       #i  #aj  
dis9tegrations p] second p] microgram   
#b4 ,det]m9ation ( activity ( ars5ic    
measur$ 9 ! sample &  correct$ back to !
 "t ( removal f ! reactor4    ,we use ! 

equation3                            ,a 
7,r7_/7,e  ,f7 et    :]e ,r is ! measur$
 c\nt rate4 7,9 ?is case1 ,r is ! numb] 
(  c\nts p] second obs]v$ 9 !           
#j4eei-,me,v gamma-ray peak1 :i* is     
#ecjj c\nts 9 #bj m9utes or #d4d c\nts  
p] second47    ,e is ! effici5cy ( !    
detector4 7,9 ?is case1 x is ! numb] (  
c\nts obs]v$ 9 ! #j4eei peak = ea*      
#j4eei-,me,v gamma ray emitt$  by a     
radioactive mat]ial at ! sample di/ance4
 ,?is is kn[n = !  detector be+ us$ by  
mak+ o!r measurem5ts &1 = ! set-up  us$ 
"h1 is #j4jaj47    ,f is ! av]age numb] 
( #j4eei-,me,v gamma rays emitt$ 9 ea*  
dis9tegration ( ars5ic-#gf4 7,?is c be  
d$uc$ f ! decay s*eme  ( ars5ic-#gf4    
,see ! decay s*eme = manganese-#ef on   
page #ac4 ,9 !  decay ( ars5ic-#gf !    
numb] ( #j4eei-,me,v gamma rays emitt$  
p]  dis9tegration is approximately      
#j4da47     is ! dis9tegration con/ant =
 ars5ic-#gf4 7#j4jbf1 see page #di47    
t is ! decay "t4 7,?is is ! numb] ( h\rs
 f ! "t !  sample 0 remov$ f ! reactor  

to ! "t x 0 c\nt$1 or #e  h\rs47        
,!re=e1 ,a1 ! activity ( ars5ic-#gf     
produc$ 9 ! sample at !  "t ( removal f 
! reactor1           7#d4d c\nts p]     
second7_/7#j4jaj  #j4da7 e#j4jbf  #e    
h\rs                        #abjj       
dis9tegrations p] second    #c4         
,calculation ( ars5ic conc5tration 9 !  
sample4    ,we use ! equation3          
,conc5tration 9 p>ts p] million         
7,a7_/7,a  ,w7 #aj    :]e ,a & ,a 7     
det]m9$ above & ,w is ! weight ( sample 
analyz$ or #cjj micrograms 7#j4jjjc     
gram74    ,!re=e ! conc5tration is      
7#abjj7_/7i  #aj  #cjj7  #aj  #dd p>ts  
p] million4                             
,,footnotes      #a,!re are exceptions4 
,= a few elem5ts !re are no /able       
nuclei4      ,9 "s cases1 !re are o!r   
diff]5ces t make c]ta9 atoms            
radioactive4    #b,^! gamma rays 7call$ 
prompt gamma rays because !y are        
in/antane\sly produc$ :5 ! neutron is   
captur$7 c also be      us$ = analysis &
 sometimes are1 b we w n be discuss+    

?is      type ( analysis 9 ?is booklet4 
#c,s5sitivity 9 ?is case means h[ small 
an am\nt ( an unkn[n      elem5t c be   
detect$4    #d,nuclide is a g5]al t]m   
applicable to all atomic =ms ( elem5ts4 
,:]eas isotopes are ! v>i\s =ms ( a s+le
 elem5t 7h5ce      are a family (       
nuclides7 & all h ! same atomic numb] & 
numb] ( protons1 nuclides comprise all !
 isotopic =ms ( all      ! elem5ts4     
#e,! half-life ( a radioactive nuclide  
is ! "t x takes = half      ! nuclei 9 a
 l>ge sample to und]go decay4 ,note t   
aft] half      ( !m are gone1 a second  
half-life p]iod w r$uce !      rema9d]  
by "o half1 leav+ "o qu>t] ( ! orig9al  
numb]4    #f,! dis9tegration con/ant is 
relat$ to ! half-life1 ,t1 by      !    
expression3   natural log>i?m (         
#b_/;half-life1 or                      
7ln #b7_/7,t7  7#j4fic7_/7,t7    #g,!   
detector effici5cy is ! ratio ( ! numb] 
( gamma rays      detect$ to ! numb]    
emitt$ by ! sample4    #h;,a deut]on is 
! nucleus ( a heavy hydrog5 7deut]ium7  

atom &      consi/s ( "o neutron & "o   
proton4    #i,n all nucle> reactors are 
appropriate = ?is "w4 ,= example1       
reactors design$ = electric p[]         
production d n h !      means built into
 !m = ins]t+ & remov+ small samples = a 
8%ort0 p]iod ( irradiation4    #aj;,a   
sc9tillation detector is a cry/all9e    
device1 usually sodium      iodide      
conta9+ a small am\nt ( ?allium1 :i* has
 ! prop]ty      ( emitt+ light :5 en]gy 
is absorb$ f nucle> radiation4          
#aa;,aft] a #aj-m9ute irradiation & a   
#c-m9ute delay be=e c\nt+1      correct$
 = decay to a common "t4    #ab,"o mole 
is ! atomic weight ( an atom or molecule
 express$ 9      grams1 or ! weight (   
#f4jb  #aj atoms or molecules p] mole4  
#acln #b is ! natural log>i?m ( #b4     
,,read+ ,,li/      ,g5]al ,in=mation    
,ab\t ,nucle> ,sci5ce      ,secrets ( ! 
,nucleus1 ,joseph ,s4 ,lev+]1           
,mc,graw-,hill ,book    ,company1 ,new  
,york1 #aifg1 #abg pp41 #j4ej4          
,work+ ,) ,atoms1 ,otto ,r4 ,fris*1     

,basic ,books1 ,inc41 ,publi%]s1    ,new
 ,york1 #aife1 #if pp41 #c4ej4      ,!  
,atom & ,its ,nucleus1 ,george ,gam[1   
,pr5tice-,hall1 ,inc41    ,englewood    
,cliffs1 ,new ,j]sey1 #aifa1 #aec pp41  
#a4ie4      ,inside ! ,nucleus1 ,irv+   
,adl]1 ,! ,john ,day ,company1 ,inc41   
,new    ,york1 #aifc1 #aib pp41 #d4ie4  
,radioisotopes & ,radiation1 ,john ,h4  
,lawr5ce1 ,b]n>d ,man[itz1 &    ,b5jam9 
,s4 ,loeb1 ,dov] ,publications1 ,inc41  
,new ,york1 #aifd1 #aca pp41    #b4ej4  
,s\rcebook on ,atomic ,en]gy 7?ird      
edition71 ,samuel ,glas/one1 ,van       
,no/r& ,re9hold ,company1 ,new ,york1   
#aifg1 #hhc pp41 #ae4jj4      ,!        
,semiconductor ,revolution 9 ,nucle>    
,radiation ,c\nt+1 ,j4 ,m4    ,holl&] & 
,i4 ,p]lman1 ,sci5ce1 #aed3 #hd 7,octob]
 #g1 #aiff74      ,ab\t ,activation     
,analysis    ,popul> ,level             
,neutron ,activation ,analysis1 ,v9c5t  
,p4 ,gu9n1 ,int]national ,sci5ce    &   
,te*nology1 ,prototype ,issue1 #gd      
7#aifa74      ,di/ribution ( ,ars5ic 9  

,napoleon's ,hair1 ,hamilton ,smi?1 ,/5 
,=%ufvud1 & ,&]s ,wass51 ,nature1 #aid3 
#gbe 7,may #bf1 #aifb74      ,nucle>    
,activation ,analysis1 ,ri*>d ,e4       
,wa9]di & ,norman ,p4 ,du,beau1         
,sci5ce1 #aci3 #ajbg 7,m>* #ae1 #aifc74 
,neutron ,activation ,analysis1 ,w4 ,h4 
,wahl & ,h4 ,h4 ,kram]1 ,sci5tific      
,am]ican1 #fh3 #baj 7,april #aifg74     
,te*nical ,level      ,activation       
,analysis ,h&book1 ,rob]t ,c4 ,ko*1     
,academic ,press1 ,inc41    ,new ,york1 
#aifj1 #bai pp41 #h4jj4      ,neutron   
,activation ,exp]im5ts 9 ,radio*emi/ry1 
,k4 ,s4 ,vorres1    ,j\rnal ( ,*emical  
,education1 #cg3 #cia 7,augu/ #aifj74   
,radioactivation ,analysis1 ,h4 ,j4 ,m4 
,b[5 & ,e4 ,gibbons1 ,ox=d    ,univ]sity
 ,press1 ,london1 ,engl&1 #aifc1 #bie   
pp41 #h4jj4      ,neutron ,irradiation &
 ,activation ,analysis1 ,d5is ,taylor1  
,van    ,no/r& ,re9hold ,company1 ,new  
,york1 #aifd1 #ahe pp41 #h4ie4          
,guide to ,activation ,analysis1        
,william ,a4 ,lyon 7,ed471 ,van ,no/r&  

,re9hold ,company1 ,new ,york1 #aifd1   
#ahf pp41 #e4ie4      ,advances 9       
,activation ,analysis1 ,volume #a1 ,j4  
,m4 ,a4 ,l5ihan & ,s4    ,j4 ,?omson    
7,eds471 ,academic ,press1 ,inc41 ,new  
,york1 #aifi1 #bcc pp41    #i4ej4       
,activation ,analysis2 ,pr9ciples &     
,applications1 ,j4 ,m4 ,a4 ,l5ihan    & 
,s4 ,j4 ,?omson 7,eds471 ,academic      
,press1 ,inc41 ,new ,york1 #aife1 #baa  
pp41 #h4ej4      ,mod]n ,tr5ds 9        
,activation ,analysis1 ,volumes #a & #b1
 ,j4 ,r4 ,de,voe    & ,p4 ,d4 ,la,fleur 
7,eds471 ,national ,bureau ( ,/&>ds     
,special    ,publication ,numb] #cab1   
,u4 ,s4 ,gov]nm5t ,pr9t+ ,(fice1        
,wa%+ton1    ,d4 ,c41 #aifi1 #bjje pp41 
#h4ej4      ,pott]y ,analysis by        
,neutron ,activation1 ,i4 ,p]lman & ,f4 
,ass>o1    ,ar*aeometry1 #aa3 #ba       
7#aifi74    ,bibliographies             
,activation ,analysis3 ,a ,bibliography1
 ,g4 ,j4 ,lutz1 ,r4 ,j4 ,bor5i1 ,r4 ,s4 
,maddock1 & ,w4 ,w4 ,me9ke 7,eds471     
,national ,bureau ( ,/&>ds    ,te*nical 

,note #dfg1 ,u4 ,s4 ,gov]nm5t ,pr9t+    
,(fice1 ,wa%+ton1 ,d4    ,c41 #aifi1    
#h4ej4      ,=5sic ,sci5ce3 ,a          
,bibliography ( ,activation ,analysis   
,pap]s1 ,g4    ,j4 ,lutz 7,ed471        
,national ,bureau ( ,/&>ds ,te*nical    
,note #eai1 ,u4 ,s4    ,gov]nm5t ,pr9t+ 
,(fice1 ,wa%+ton1 ,d4 ,c41 #aigj1 #j4ej4
      ,det]m9ation ( ,light ,elem5ts 9  
,metals3 ,a ,bibliography (             
,activation ,analysis ,pap]s1 ,g4 ,j4   
,lutz 7,ed471 ,national ,bureau (       
,/&>ds ,te*nical ,note #ebd1 ,u4 ,s4    
,gov]nm5t ,pr9t+ ,(fice1    ,wa%+ton1   
,d4 ,c41 #aigj1 #j4ge4      ,pollution  
,analysis3 ,a ,bibliography ( !         
,lit]ature ( ,activation    ,analysis   
,pap]s1 ,g4 ,j4 ,lutz 7,ed471 ,u4 ,s4   
,gov]nm5t ,pr9t+ ,(fice1    #aiga1      
#j4de4      #ad-,me,v ,neutron ,g5]ators
 9 ,activation ,analysis3 ,a            
,bibliography1 ,g4    ,j4 ,lutz 7,ed471 
,u4 ,s4 ,gov]nm5t ,pr9t+ ,(fice1 #aiga1 
#a4jj4      ,oceanography3 ,a           
,bibliography ( ,select$ ,activation    

,analysis    ,lit]ature1 ,g4 ,j4 ,lutz  
7,ed471 ,u4 ,s4 ,gov]nm5t ,pr9t+ ,(fice1
    ,wa%+ton1 ,d4 ,c41 #aiga1 #j4ej4    
,,motion ,,pictures    ,available = loan
 )\t *>ge f ! ,,us]da-,,tic ,film       
,libr>y1 ,p4  ,o4 ,box #fb1 ,oak ,ridge1
 ,,tn #cghcj4      ,! ,nucle> ,witness3 
,activation ,analysis 9 ,crime          
,inve/igation1 #bh    m9utes1 color1    
#aiff4 ,?is film illu/rates !           
application (    activation analysis to 
! inve/igation ( crim9al cases involv+  
murd]1 burgl>y1 & n>cotics p$dl+4       
,nucle> ,f+]pr9t+ ( ,anci5t ,pott]y1 #bj
 m9utes1 color1 #aigj4    ,animat$      
sequ5ces are us$ to expla9 sev]al ( !   
analytical    te*niques4 ,"p ( ! film   
%[s h[ ! rese>* is actually done    9 ! 
laboratory4      ,! ,atomic ,f+]pr9t1   
#ab m9utes1 color1 #aifd4 ,! pr9ciples (
    neutron activation analysis are     
expla9$ & ! ma*9es us$ 9    ?is "w are  
%[n4 ,"s ( its applications 9 crime     
detection1    geology & soil sci5ce1    
analysis ( art & ar*aeological objects1 

oil ref9+1 agriculture1 electronics1    
biology & m$ic9e1 & !    space sci5ces  
are illu/rat$4      ,neutron ,activation
 ,analysis1 #dj m9utes1 color1 #aifd4   
,?is film    describes ! nature1        
pot5tialities1 & applications ( neutron 
activation analysis4 ,! k9ds ( neutron  
s\rces us$ & !    c\nt+ te*niques are   
%[n4 ,examples ( applications 9 crime   
detection1 geology & geo*emi/ry1        
agriculture1 m$ic9e1 !    petroleum &   
*emical indu/ries1 & ! semiconductor    
indu/ry are    %[n4                     
,photo ,cr$its    ,cov]                 
,f$]al ,bureau ( ,inve/igation    #b    
,smi?sonian ,in/itution    #cj  #ca     
,univ]sity ,hospital1 ,univ]sity (      
,wa%+ton    #dg               ,dr4 ,/5  
,=%ufvud                                
,illu/ration3 ,b]n>d ,keis*      ,!     
,au?or    ,dr4 ,b]n>d ,keis* receiv$ 8  
,b4,s4 degree f ,r5ssela] ,polyte*nic   
,in/itute & 8 ,ph4,d4 f ,wa%+ton        
,univ]sity4 ,he is n[ a ,s5ior  ,fell[  
at ! ,c>negie-,mellon ,in/itute (       

,rese>* at ,c>negie-,mellon  ,univ]sity 
9 ,pittsburgh4 ,he is pres5tly engag$ 9 
a project t  deals ) ! applications (   
nucle> te*nology to art id5tification4  
,?is is sponsor$ by ! ,national ,gall]y 
( ,art & 9 ! pa/ has  also receiv$      
support f ! ,u4 ,s4 ,atomic ,en]gy      
,commission & !  ,national ,sci5ce      
,f\ndation4 ,previ\sly he 0 a nucle>    
rese>*  *emi/ ) ! ,phillips ,petroleum  
,company & s5ior sci5ti/ at !  ,nucle>  
,sci5ce & ,eng9e]+ ,corporation4 ,he has
 contribut$ articles  on art            
au!ntication to a numb] ( j\rnals4 ,=   
,,erda1 9 addition to  ?is booklet1 he  
has writt5 ,! ,my/]i\s ,box3 ,nucle>    
,sci5ce &  ,art1 ,lo/ ,worlds3 ,nucle>  
,sci5ce & ,ar*aeology1 & ,secrets (  !  
,pa/3 ,nucle> ,en]gy ,applications 9    
,art & ,ar*aeology4                     
,a ^w ab\t ,,erda4444      ,! mission ( 
! ,u4 ,s4 ,en]gy ,rese>*  ,developm5t   
,adm9i/ration  7,,erda7 is to develop   
all en]gy s\rces1 to make ! ,nation     
basically  self-suffici5t 9 en]gy1 & to 

protect public heal? & welf>e &  !      
environm5t4 ,,erda programs are divid$  
into six major categories3              
,,cons]vation ,,( ,,en]gy--,m effici5t  
use ( exi/+ en]gy s\rces1  developm5t ( 
alt]nate fuels & eng9es = automobiles to
 r$uce  dep5d5ce on petroleum1 &        
elim9ation ( wa/eful habits ( en]gy     
consumption4     ,,fossil               
,,en]gy--,expansion ( coal production & 
! developm5t (  te*nologies = conv]t+   
coal to syn!tic gas & liquid fuels1     
improvem5t ( oil drill+ me?ods & (      
te*niques = conv]t+  %ale deposits to   
usable oil4     ,,sol>1 ,,geo!rmal1 ,,& 
,,advanc$ ,,en]gy ,,sy/ems--,rese>* on  
sol>  en]gy to heat1 cool1 & ev5tually  
electrify build+s1 on conv]sion  (      
und]gr\nd heat s\rces to gas &          
electricity1 & on fusion  reactors = !  
g5]ation ( electricity4     ,,environm5t
 ,,& ,,safety--,inve/igation ( heal?1   
safety1 &  environm5tal effects ( !     
developm5t ( en]gy te*nologies1 &       
rese>* on managem5t ( wa/es f en]gy     

production4     ,,nucle> ,,en]gy--,exp&+
 m$ical1 indu/rial & rese>* applications
  & upgrad+ reactor te*nologies = !     
g5]ation ( electricity1  p>ticul>ly us+ 
! bre$] concept4     ,,national         
,,security--,production & adm9i/ration (
 nucle> mat]ials  s]v+ bo? civilian &   
milit>y ne$s4    ,,erda programs are    
c>ri$ out by contract & coop]ation )    
indu/ry1  univ]sity communities1 & o!r  
gov]nm5t ag5cies4 ,= m  in=mation1 write
 to ,,us]da-,te*nical ,in=mation ,c5t]1 
,p4 ,o4 ,box #fb1  ,oak ,ridge1         
,t5nessee #cghcj4                       
,illu/ration3 ,,erda ,seal              
,unit$ ,/ates               ,en]gy      
,rese>* & ,developm5t ,adm9i/ration     
,(fice ( ,public ,affairs               
,wa%+ton1 ,d4,c4 #bjede                 
,transcrib]'s ,notes      --,reta9$     
publication in=mation f ! pr9t$ edition3
 ?is e,book    is public-doma9 9 !      
c\ntry ( publication4    --,:]e         
possible1 ,,utf sup]script & subscript  
numb]s are us$2 "s    e-read] fonts may 

n support ^! *>act]s4    --,9 ! text    
v]sion only1 text 9 italics is delimit$ 
by    und]scores4    --,9 ! text v]sion 
only1 sup]script text is prec$$ by c>et 
&    delimit$ by brackets4    --,9 !    
text v]sion only1 subscript$ text is    
prec$$ by und]score    & delimit$ by    
brackets4    --,9 ! text v]sion only1   
add$ a brief label to ea* illu/ration2  
& = graphs1 provid$ tabul> summ>ies ( ! 
data :]e possible4