Lawangar, R D

Pawar, S H

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TL glow peak intensity in phosphors 219Kunz K. iS. 1057 Numprical Avalijfiiti (McGraM’ Hill, Now Y<nk) p. 20-1.Maclson ]\1. M. & Pook ,1. M. 1071 Atomic J)a ta2 , 171.MrCalla T. R. 1967 Introduction to Numerical Methods and Fortuui Proiframminq (Jnhu Wilcw, New York) jj. 226.Thomas L. A: Bowman TVl. R. 1971 rJ Atmoa, Terra. J*hna. 36. J i l l ,  M21.Von Busch F. & Dunn (k H. 1972 J ,  Chent. /diifs. 56. 19)26.Van Asselt N. 1\ K. B., iMnas 5, (k & Bos 197  ^ (diem Idujs l^dt 24. 555; 197-1 Chew. Phtja..5, 429.Zaro R. N. Fashion .T. K. 196:1 Dinv. Calilonna Rmhalmn Lah. Uopuri No. UFUT.-lOSSl(unjmbliHlied).Indian J .  Phya. 51A, 219-221 (1977)Dependence of a TL glow peak intensity on irradiation dose in CaS: Pd phosphorsK .  L). L a w a n ( U R  a n d  S .  H .  F a  w a r  Fhyalcfi Dp'parlmp.nl, Sh/ivaji Utiwraih/, Kolhapur-4M\{)iU[Jiccei/mcl I? Ftbrniiry 1077)Traps ill a phosphor, whicli st.f)io Iho jiarb oi' al)sorb('(l j ‘nnliat ioiiand giv(^  ris(‘ to phoiioinc n^a like phosplioros(‘oiu*(' d(uray, thormr‘luiniii(\sc(me,(^  and the r^mally stirnulati^d oonrlurtiviby. am cithei* created during iiTadiation ur present prior to irradiation of tlu'i phosplior. However the information about tliis (^ uji be obtained by the study (>l \''ariation of TL gk>w jieak intensity with irradiation dose. Such studi(‘s aJso provider tlu^  infoimation about, tlu^  typos of defects l es- ponsible for glow peaks. Tn this not(‘ wt^  rep«)i t (be study of dose dopeiid(9iee of TL glow peak intensity made on C!a)S phosphors aetivat.ed Avitb varying eon- eentraticTi of Pd.Ca»S phorphors containing varying eoneentration of Pd weie pi*epared )>y the method of thermal reduction of piiritied gypsum as followcal by Bliawalkar ik Malhotra (1969). The sam]iJes studied contained 0.5, O.J, 0.025, 0.0025 and 0.00 wt. % Pd. The oxporimental set-iij) and procedure lollowod in reeoi'ding the gloAv curves were as described earlier (Lawaiigar A Narlikar 1975a). I lie. ex('ita- tion soiir(^ e used was a ulfraviohd. source aHucIi (anit-tcRl predominantly tlu^  3(>50A Hg doublet . Ea(;h time sample was excited for a different period of time and a glow curve was locorded. IHio heating rate? employc'd was 0.46 K/»S.Figure 1 shoves a build-up cutA^ e for a sample containing 0.025 Avt.% Pd. All the samples exhibit single gloAV^ peak in tlu^  tyomperature range ol dOO K to 410'^K and the peak position was at about 350^K. T1 the lattices vacancie acting as electron traps exist prior to irradiation, the filling obey the relation (Mitelitdl et al 19C1)lit n^ [l—osy (-<1^)1 ••• ^9220 R . D. X/awangar and S. H. Pawar1. Viu'i i i l  m n  o f  ^ l o w  po t i k  j n l cMi s i l y  u i M i  ox<’ i t a l i o i i  i n n oKig. 2. P lo t o f  log [l —(/r//^)] voi'iSUH oxo ita tio n  tim o.Charge-sym m etric potentials and the hypertriton  221where yit is the density of filled traps pej- cubic; centinjetei at time i, is the total number of traps per cubic centimetei’ and m is the time coustaut. The equation (1) can bo put up in the formln\}-{ntln^)] — -tjw . (2)Thus a plot of h i[ l—(//y/»„)] vcwrus / is a straight line haviiig slo]>e equal to l/^ ». A plot of In — versus t for a sampb’* containing 0.025 wt. % IM is shown infigure 2 and is obtained by assuming tliat the peak intensity after irradiation I'or time f is proportional to the tilled traps and 7?^  is given by the ])lateau I<'\'‘el Is of i]\o buildup curve (Pawar & Nailikar 1974). From figure 2 it may be seen that the plot, is nearly a straight line. Tlie graphs obtaincKl for other samples ai e also found to be almost linear. Thus these results indirati  ^ that t.he tra])s in the present s^ s^tern of phosphors exist prior to irradiation and are lattice^  va(*ancies. The values of 7//, calenlatcd from the slopes (.f the st r aight, lines aie praethally same for all samples. This suggests that the ty j^cs of defects a(*thig as electron traps are of the same nature. These defects, as earlier investigation hnfl shown, are likely to lx* the sulphur vaeaneios (haAvangar Nailikar 1975b).R eferencelUia-walkar J_). li. 6c Malliotrn. R. Indian J .  f \n r  Appl. Idujs. 7, Milt LiiAViiijgar II. JJ. Niirlikar A. V. l})7r>a r/. Ljunincficcmc H,Ijiiwanger It. D. cV Narlikur A. V. 1U75I) J .  Mater. Sci, 10, 1251.Mitoholl P. V., Wicgtiijcl D- A. & SinolnHiowski D. 11. 1901 Phys. Prv. 121, -484.I’avvar 8. II. & Nailikar* A. V. 1974 .J. Lamwr^rnnee 9, 52Indian J .  Fhys. 51A, 221-223 (1977)Charge-symmetric potentials and the hypertritonH Roy Choudhury and V. P. (IautamDrpartntcnt of Thfioretmd Physics Jndiay Assocdalioic for the (juJtivaiiori of Science, (kilcuita-lOO^ KVI (deceived 22 Fehrudry 1977, revised 30 March 1977)A choice of suitable potentials has been made lor the AN eharge-symmotrie j)arameters of Herndon and Tang to yield a reasonable valm3 lor A-separation energy in a'^ H.Recently two papers (Schick 1975, Gibson & Lehman 1975) have appeared regarding the A-binding (^a) obtained from two sets of A-nuclcon poten­tials (model A and model B) derived from the low-('norgy-parameters of Nagels, at al (1972). According to the analysis of Schick (1975) both, model A and model

Dependence of a Tl Glow Peak Intensity on Irradiation Dose in CaS: Pd Phosphors

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Dependence of a Tl Glow Peak Intensity on Irradiation Dose in CaS: Pd Phosphors

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