Chandra, B P

Dhoble, S J

Kher, R S

Khokhar, M S K

Nayar, V

English

IACS Institutional Repository

Indian J. Phys. 76A (6). 577-579 (2002)U P  A— un in ternational JournalE f f e c t  of l y o l i im in e s c e n c e  d e c a y  i n  KCI m i c r o c r y s t a l l i n e  p o w d e r  i n  l y o lu m in e s c e n c ed o s i m e t r y  o f  i o n i z a t i o n  r a d ia t i o n sS J D h o b ic * ,  V  N a y a r ' ,  R  S K h e r , B  P  C h an d ra^  and M  S K  K hokh ar'*Kainlu Nehru College, Sakkardaia Square, Nagpur - 440 (K)9, Maharashtra, India 'C.M D P,G College, Bilaspur-49.S 001. Chhatisgarh, India -Govt Autonomous Post-Graduate Science College. Bilaspur 495 001, Chhatisgarh. India T( Ravishankar Shiikla University, Raipur -- 492 010, Chhatisgarh. India ■*G G D Univeisity, Bilsapui -  495 001. Chhatisgarh, IndiaE-mail ‘ sjdhoblc@iediffmail coinKe< e i v e d  4 A p r i l  2 0 0 2 ,  t m c p i e d  / /  S e p t e m h e i  2 0 0 2Uistrac’t The lyolummesceni intensity of gamma irradiated potassium chloride powder ol different particle sizes have been investigated In theiiiLsh range 75-250 pm, the lyoluminescence (LL) peak inlensity increases with increasing particle size Above 2.50 pm and uplo 425 pm. the LL peak inicnsiiy decreases Foi particle si/e greater than 425 pm. the LL peak intensity increases again The LL glow curves show that LL decay limes consist ul (WO components lor all particle sizes The dependence of decay time, especially the longer component on the particle size has been investigated IViiticle SI7X* has no significant effect on the shorter decay component m LL emission A possible explanaiion lor the experimental icsults has been.lULiuptedwords Lyoluminescence, KCI.I'\CS No. 78 60 -bW hen s tro n g ly  e n e rg is e d  a lk a l i  h a lid e  c ry s ta ls  arc  d is s o lv e d  in  liq u id  s o lv e n t ( l i k e  w a te r ) ,  l ig h t  is e m it te d  as a re s u lt o f  le eo m h in a tio n  o f  h y d ra te d  e le c tro n s  w ith  the ho les on the surface  ol l iy s ta llite s . T h is  p h e n o m e n o n  is c a lle d  ly o lu m in e s c e n c e  ( L L )  1 i 1 L a te r  o n , A h n s tro m  [2 ]  an d  A r n ik a r  e t  a l  [ 3 |  a lso  p ro p o sed  ihc m e ch a n ism  o f  L L .  A c c o rd in g ly , the  e lec tro n s  trapped  at an ion  \acan c ic s  in  io n ic  c ry s ta ls  g e l h y d ra te d  on  d is s o lu tio n  and then  icaci w ith  h o le s  fo r m in g  h y d ra te d  a n io n s  in  an e x c ite d  state  which leads  to  th e  e m is s io n .X + e , aqwhere X  =  h a lo g e n  a to m s .T h e  L L  s in g le  o b ta in e d  d u r in g  th e  d is s o lu t io n  o f  p re v io u s ly  •lu id iated  m a te r ia ls  is e x p re s s e d  in  th e  fo rm  o f  a g lo w  c u rv e . These cu rves  b e g in  w ith  a h ig h  p e a k  fo llo w e d  b y  an e x p o n e n tia lly  tlcereasing  in te n s ity . Q u i t e  a  n u m b e r  o f  s tu d ie s  h a v e  b een  i^hdertaken to  u n d e rs ta n d  th e  L L  e m is s io n  [4 ] .  H o w e v e r , theLoricsponding A u tho rs u rv e y  o f lite ra tu re  sh ow s th at the p a rtic le  s ize  stud ies h ave  been  m a in ly  re s tric te d  to o rg a n ic  c o m p o u n d s . T l ie  e ffe c t  o f  p a rtic le  s ize  on L L  fro m  o rg a n ic  phosphors has been  n o ted  by  E t t in g c r [5 ] .  A n  im p o r ta n t  fa c to r  is the f ra c t io n  o f  e n e rg y  d e p o s ite d  in s u rro u n d in g  a ir  as c o m p a re d  w ith  e n erg y  im p a rte d  to  the so lid  R e c e n t stud ies ha ve  been  rep o rte d  by B a lo g u n  and  A d e s a n m i [6 ] s h o w in g  that d is s o lu tio n  c u rv e , lig h t y ie ld , dose  response c u rv e  and  s ta b ility  o f  L L  response are  p a rtic le  s ize -  d e p e n d e n t in  the case o f  m a n n o s e . R es u lts  s h o w e d  lo w e r  y ie ld  fo r  f in e r  p a rt ic le  s ize  as fo u n d  in  e a r lie r  resu lts  rep o rte d  by  E tlin g e r  |5 | .  A n o th e r  fa c to r e x p la in in g  p a rtic le  s ize -d ep e n d en c e  m ig h t be in s e n s itiv e  s u rfa ce  la yers . A c c o rd in g  to  A h n s lro m |2 ] ,  su rfa ce  e ffe c ts  an d  th e re fo re  p a rt ic le  s ize  w i l l  be an im p o rta n t  p a ra m e te r in  L L  fro m  in o rg a n ic  phosphors  as it w as  in o rg an ics . L e lie v re  and A d o lf !  [7 ]  sh ow  an o p tim u m  p a rtic le  sizx o f  -  8 0  p m  fo r  N a C l  an d  a lso  di.scuss the d is s o lu tio n  as a fu n c tio n  o f  the  g ra in  s ize . F o r  th e  d e v e lo p m e n t  o f  L L  d o s im e tr ic  m a te r ia l  in v e s tig a tio n  o f  d if fe re n t  p a ra m e te rs  are  req u ired  such as dens ity  o f  c o lo u r  ce n tres , ra te  o f  d is s o lu tio n  o f  th e  s a m p le , te m p e ra tu re©20021ACS578 S J Phohle, V Nayan R S Klier, B P Chandra and M S K Khokharo l s o lu t io n  an d  th e  m ass o f  the  d is s o lv e d  s a m p le . O u t  o f ,  these  d is s o lu t io n  ra le  o f  th e  s a m p le  is d c p c n d c n i on  th e  p a r t ic le  sisr.c o f  th e  p o w d e r .  T h e r e f o r e  in  th e  p re s e n t  w o r k ,  w e  h a v e  in v e s tig a te d  the d e p e n d e n c e  o f  L L  in te n s ity  on th e  p a rt ic le  s ize  o f  K C l  p o w d e r  w ith  w a te r  as s o lv e n t. vSince d e c a y  t im e  is an  im p o rta n t p a ra m e te r  fo r  L L  d o s im e try , it w o u ld  be in s tru c tiv e  to  sec w h e th e r  L L  d e c a y  t im e  e x p e r im e n ts  w ith  K C l  p o w d e r  o f  d if fe re n t  p a r t ic le  s i /c s  w o u ld  in d ic a te  the d e p e n d e n c e  o f  d e c a y  l im e  on the p a rt ic le  s i /c  o f  m ic ro c ry s ta ls .K C l  c ry s ta ls  w e re  g ro w n  by s lo w  c o o lin g  o f  m e lt . S in g le  c ry s ta ls  w e re  c ru s h e d  an d  p a rt ic le s  o l the d e s ire d  s i /c  w e re  o b ta in e d  u s in g  test s ie v e s . T h e  s a m p le s  w e re  e x p o s e d  to  y -ra y s  fro m  so u rc e  at a d o s e  ra te  o f  0 .2 8 0 6  x 10*  ^ G y /h r .  F o r  m e a s u r in g  L L  in te n s ity , a s m a ll q u a n tity  o f  c o lo u re d  p o w d e r  w as  p la c e d  in  a h ig h ly  tra n s p a re n t g lass  tu b e  w h ic h  w as  p la c e d  c lo s e  to  the p h o to m u lt ip l ie r  tu b e  k e p t in  a lig h t t ig h t b o x  T h e  b o x  had  a c irc u la r  h o le  on  th e  lo p  s u rfa c e  th ro u g h  w h ic h  a s y r in g e  w as  in s e rte d  to  in je c t  the s o lu t io n  in to  the g lass tu b e . T h e  in te n s ity  o f  lig h t e m it te d  d u r in g  d is s o lu t io n  w a s  d e te c te d  b y  the p h o to m u lt ip l ie i  tu b e  (H m a m a ls u  R 1 3 0 7 )  w h o s e  o u tp u t  w as  c o n n e c te d  to  an X - Y  re c o rd e r. F o r  a ll m e a s u re m e n ts , c .c  o f  d is t i l le d  w a te r  w a s  a d d e d  to  5 0  m g  o l the s a m p le  T h e  e x p e r im e n ts  h a v e  b een  c a r r ie d  fo r  e ig h t  d if fe re n t  p a rt ic le  s izes. A l l  these m e a s u re m e n ts  h a v e  b een  re p e a te d  .several t im e s  in  id e n tic a l e x p e r im e n ta l c o n d it io n s  to  en su re  re p ro d u c ib i l i ty .iM g u re  I s h o w s  the ty p ic a l L I .  g lo w  c u rv e s  lo r  K C l  p o w d e r  e x p o s e d  to y -ra y s  o l 7 x 10  ^ G y  dose  fo r  d if le r e n l  p a rt ic le  si/.es . T h e  F ig u re  1 s h o w s  th a t w h e n  y - ir ra d ia te d  m ic ro c ry s ta ls  are  di.sso lvcd in a f ix e d  v o lu m e  (.^ c . c . ) o l d is t ille d  w ate r, in i t ia l ly  the L I .  in te n s ity  inc reases  w ith  lim e , a tta in s  a m a x im u m  v a lu e  1^^^ at a p a rt ic u la r  t im e  then  it decreases  and f in a lly  d is ap p e ars . W id th  o l the L L  g lo w  p e a k s  in c re a s e s  w ith  in c re a s in g  p a r t ic le  s ize  o f  K C l p o w d e r  d u e  to rate  o f  d is s o lu tio n  o f  m ic m c ry s la ll in c  pow der- in  the  s o lv e n t. W i t h  in c re a s in g  p a r t ic le  s ize  o f  m ic ro c ry s ta l l in e  p o w d e r, the I - L  p e a k  in te n s ity  in c re a s e s  d u e  to  the  fo rm a t io n  o f  r a d io ly s is  p ro d u c ts  d u r in g  y -ra y  ir ra d ia t io n , but a b o v e  2 5 0  p m25s ize  o f  th e  K C l  p o w d e r, the  L L  in te n s ity  d e crea ses  and  then b e c o m e s  c o n s ta n t. T h e  v a r ia t io n  o f  L L  p e a k  in te n s ity  in  Figure  2  (c u rv e  a ) , s h o w s  th a t a b o v e  2 5 0  \ in \  s ize  o f  m ic ro c ry s ia llin c  p o w d e r  o f  K C l ,  th e  L L  in te n s ity  m a y  v a ry  w ith  rad io lys is  p ro d u c ts  as w e ll  as b y  th e  d is s o lu t io n  ra te . A b o v e  4 0 0  p m , L l .  in te n s ity  b e c o m e s  a p p r o x im a te ly  c o n s ta n t d u e  to  increasing  ra d io ly s is  p ro d u c ts  an d  d e c re a s in g  d is s o lu t io n  ra le  in  w a te r as a s o lv e n t.F ig u re  2  (c u rv e  b )  s h o w s  th e  v a r ia t io n  o f  t^ ^^  w ith  p a rtic le  si/c  o f  K C l  p o w d e r  w ith  w a te r  as s o lv e n t. V a lu e  o f  increases w ith  p a rt ic le  s ize  o f  K C l  p o w d e r. T h e  in c re a s in g  o rd e r  o f  the curve  w ith  the  p a r t ic le  s iz e  is d u e  to  re c o m b in a t io n  o f  rad io lysrs  p ro d u c ts  w h ic h  is m u c h  m o re  in  th e  s u rfa c e  o f  m ic ro c ry s ia llm c  p o w d e r.Figiire 2. VaiiLiiion in LL glow peak hcight.s (1 ) (cuive a) ami iiiuc i (curve h) with piirlicle si/c ol K(J with walcr used as sol vein, exposed lo y-do.se =  1  \  It)' Ci> ,F ig u re  3 (c u rv e  a ) s h o w s  th at ih c  to ta l L L  intcn.siiy d , i  in c re a s e s  w ith  p a r t ic le  s ize  u p lo  30(J p m  ll  m a y  be due lu in c reas in g  s ize  o l m ic ro c ry s la llin c  p o w d e r  b e in g  d isso lved  which in c reas es  the ra le  o f  re c o m b in a t io n  o f  r a d io ly s is  products  uplo 3(X ) p m  s ize , l y  d ecreases w ith  fu r th e r  in c reas e  in p a rtic le  s i/c  ol m ic ro c ry s ta l fro m  3 0 0  to  4 0 0  p m . A b o v e  3 0 0  p m , the rale ol ra d io ly s is  p ro d u c t inc reases , w h ile  ra te  o f  d is .so lu lion  dccicascspanicle size with waier used as solvent, exposed to y-dosc = 7 x 1(V Gy Particle s i i t s  • (i) 0-75 gm, (ii) 75-150 gni. ('<0 150-180 gm. (IV) 180-212 gin, (V) 212-250 gm. (vi) 250-300 gm, (vii) 355-425 gm and (viii) 425-850 gmF ig u re  3. Variation m total L L  intensity  L  (curve  a) and decay mne t (curve b) with part icle size of  KCl with  water  used as solvent, exposed to y-dose = 7 x 10' Gy.Effect of lyoluminescence decay in KCI microcrystalline powder etc 579y\hove 4 0 0  s ize  o f  m ic r o c r y s la l l in e  o f  K C I .  ^  increases dueii) increase th e  ra d io ly s is  p ro d u c ts  d u r in g  y - ir ra d ia t io n , w h ile  in  this re g io n , d is s o lu tio n  ra le  d e crea ses  d u e  to  increase  o f  p a n ic le  si/c. T h e  in c re a s in g  r a le  o f  b y  ra d io ly s is  p ro d u c ts  is m o re  as com pared to  th e  d e c re a s e  b y  d is s o lu t io n  ra te , th en  f in a l res u lts  ol I j. m a y  in c reas e  a b o v e  4 0 0  ^tm s ize  o f  m ic n x :ry s la lin c  p o w d er.f ig u r e  4  s h o w s  th e  p lo t o f  lo g  1 o f  K C I  p o w d e r w ith  tim e . T h e  value o f  lo g  I  is in c re a s in g  w ith  p a rt ic le  s ize  as m o re  q u a n tity  o f  ilic p o w d e r  is g e ll in g  d is s o lv e d . T h e  s lo p e  o f  th e  c u rv e  b e tw e e n  loj: I and d is s o lu t io n  l im e  is d e c re a s in g  w ith  in c re a s in g  p a rt ic le  si/c. b e c a u s e  la rg e r  s ize d  g ra in s  d is s o lv e  s lo w ly . T h is  s lo p e  indicates th e  s ta b i l i ty  in  th e  ra te  o f  fo r m a t io n  o f  ra d io ly s is  pinducls an d  d is s o lu tio n  o f  g ra in s  fo r the K C I  p o w d e r. T h e re fo re ,  decay tim e  o f  L L  in te n s ity  is o n e  o f  the im p o r ia n l la c to rs  fo r  L L  j iA in ic try .I'l u^rL- 4. Flol ol log I vcl.siis I (I >im) ol KCI miLiovr>slnllinc powder II I (liUiTenl pnmdc si/cs 0 0 - 7 * '  pm D  7S -  LSO pm. A 150 -  ixw pm , IKl) -  212 pm. ♦♦ 212-250 pm. -  250 ^00 pm . ^ 15S - 425 pm ,  ^ 425 S50 pmA lte r  a t ta in in g  th e  L L  p e a k  at m a x im u m  in te n s ity  ( Im ) ,  the  dci. .\v o l L L  in te n s ity  d e p e n d s  on  th e  n a tu re  o t p a rtic le s  (F ig u re  Liirvc b ). D e c a y  t iir ie  in c re a s e s  u p lo  4 ( k  , m  (hen  sa tu ra tes  at hiplicr p a rt ic le  s i /c  o f  K C I  p o w d e r  (a b o v e  4(K) | im ) .  In  F ig u re  2 ,b o th  the c u rv e s  a rc  o f  in c re a s in g  o rd e r  w ith  in c re a s in g  s ize  o f  p a r t ic le s  d u e  to  d e c re a s in g  d is s o lu t io n  o f  m ic r o c r y s ta l l in e  p o w d e r  in  w a te r. T h e  a re a  b e tw e e n  b o th  th e  cu rv e s  in d ic a te  the  re c o m b in a tio n  o f  h y d ra te d  e le c tro n  and h o le  in  the su rfa ce  o f  m ic r o c r y s ta l l in e  p o w d e r  a n d  r e c o m b in a t io n  o f  r a d io ly s is  p ro d u c ts  d u r in g  d is s o lu t io n . T h is  d if fe re n c e  is v e ry  m u c h  a ttc c iin g  the en erg y  ab so rp tio n  by  m ic ro cry 's la llin c  p o w d e r  d u rin g  y -ray  irra d ia tio n , the L L  in tensity  Ix 'in g  not d ire c lly  re la ted  to a b so rb ed  dose o f  p o w d e r. I ’h c rc fo rc , f ix e d  rang e  o f  p a rtic le  s ize  (m a x im u m  v a r ia tio n  5 0  | jm )  m a y  be p e rm is s ib le  fo r  K C I  p o w d e r  to  be used as ly o lu m in e s c e n c e  d o s im e try  o l io n i /a t io n  ra d ia tio n s . T h e  L L  o f  a lk a li h a lid e  crys ta ls  dep en d s on d iffe re n t  p a ra m e te rs  such as ra d ia t io n  do.se, d e n s ity  o f  c o lo u r  cen tres , ra te  o f  d is .so lu lio n , te m p e ra tu re  o f  the s o lu tio n , m ass o f  the d is s o lv e d  sa m p le , typ e  o f  the im p u r ity  present, p H  o f  the so lvent and ty p e  t i f  the  s a m p le . A m o n g  th e m , the m o s t im p o r la n t  p a ra m e te r  is p a rtic le  s ize  o f  the L I . phosphor.F ro m  the resu lts  p re s e n te d  a b o v e , it m a y  be c o n c lu d e d  that the ly o lu m m e .s c c n c c  in te n s ity  ca n n o t he d iie c t ly  c o rre la te d  to the ra d io ly s is  p ro d u c t (c o lo u r  c e n tre  c o n c e n tra t io n )  o r the  d is s o lu tio n  ra le  but d e p en d s  on b o th  fac tors  s im u lta n e o u s ly . S u c h  stu d ies  w o u ld  be h e lp fu l in p ro v id in g  in fo rm a tio n  fo r  ly o lu m in e s c e n c e  d o s im e try  .m d b e tte r  in s ig h t in to  the k in e tic s  o f  re a c tio n s  re s p o n s ib le  fo r  L L  e m is s io n . I t  w o u ld  d e lim lc ly  add to  o u r  k n o w le d g e  o f  d e fe c t  in te ra c tio n s  in g e n era l and  p a rt ic u la r ly  in .solids.R eferences[I] E W'lcdemann ami C .Schinidl A/j// P h \ \  56 210(1895)12| A Ahnslmm Ar/f/ ( ' I f c n i  S k u k I  19 ^0()(l9f)5)| t |  H .1 Arnikai, V K Deo and A S Cniarc ./ t h u v . V o o m i  42 65 (1972)|4 |  G T Reynolds ./ I a u u i h  54 43 (1992)[5] K V Eltinpei and K J Pmle I n i  J A m > l  H a d i a i  h o t  33 I I 15(1982)[6] r  A Baogun and C A Adesanmi A/>/)/ HiuU n o iu l  Is in  40(3) 243 (1989)[7] B Lclievrc and J P Adloll J dv  / '/iva 25 789 (1964)

Effect of Lyoluminescence Decay in KCl Microcrystalline Powder in Lyoluminescence Dosimetry of Ionization Radiations

http://arxiv.iacs.res.in:8080/jspui/bitstream/10821/7520/1/Effect%20of%20Lyoluminescence%20Decay%20in%20KCI%20Microcrystalline_S%20J%20Dhoble.pdf

Effect of Lyoluminescence Decay in KCl Microcrystalline Powder in Lyoluminescence Dosimetry of Ionization Radiations

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