ENTRY 30420 20090310 31353042000000001 SUBENT 30420001 20090310 31353042000100001 BIB 15 45 3042000100002 INSTITUTE (3INDTRM) 3042000100003 REFERENCE (J,ANE,4,135,197703) 3042000100004 (J,ANS,24,456,197611) short note. 3042000100005 AUTHOR (R.Chawla) 3042000100006 TITLE A method for the direct measurement of relative capture3042000100007 rates in Th-232, U-238 containing lattices. 3042000100008 FACILITY (REAC,3INDTRM) Apsara reactor's thermal column at the 3042000100009 Bhabha Atomic Research Centre, Trombay. 3042000100010 INC-SOURCE (REAC) 3042000100011 INC-SPECT Maxwellian neutron spectrum, with the cadmium ratio for3042000100012 gold being measured to be larger than 10**4. 3042000100013 SAMPLE Thorium and uranium metal foils of the diameter,12.5 mm3042000100014 and the thicknesses between 0.12 and 0.25 mm. 3042000100015 .Np-237,Am-243 used were of about 0.05 micro-Curie with3042000100016 deposited diameters of 12.5mm, 0.5mm thick stainless 3042000100017 steel. 3042000100018 METHOD Direct measurement of the neutron capture rate for 3042000100019 232Th relative to that for 238U, with simultaneous use 3042000100020 of Np-237 and 243Am as the long-lived and 3042000100021 alpha-emitting parents of Pa-233 and of Np-239, 3042000100022 respectively. See the decay chains, 3042000100023 Np-237(alpha-emitter) 3042000100024 ' (downward) 3042000100025 Th232 + n --- Th-233 --(B-)-- 'Pa-233' --(B-)-- U-233 3042000100026 U-238 + n --- U-239 --(B-)-- 'Np-239' --(B-)-- Pu-2393042000100027 ' (upward) 3042000100028 Am-243(alpha-emitter) 3042000100029 DETECTOR (GELI) 60 cc, coaxial Ge(Li) detector. 3042000100030 .Low geometry alpha counter. 3042000100031 DECAY-DATA (90-TH-233,22.MIN,B-) 3042000100032 (91-PA-233,27.0D,DG,312.) 3042000100033 (92-U-239,23.MIN,B-) 3042000100034 (93-NP-239,2.35D,DG,278.) 3042000100035 (93-NP-237,2.E+6YR,A) Long-lived alpha emitter to 233Pa3042000100036 (95-AM-243-G,8.E+3YR,A) 3042000100037 PART-DET (DG) Decay gammas. 312 keV photopeak from Pa-233 and 3042000100038 278 keV photopeak from Np-239. 3042000100039 COMMENT Average corrected value of (1.182+-0.005) was obtained 3042000100040 for the ratio of the strength of alpha sources 3042000100041 (Np-237)/(Am-243). 3042000100042 STATUS (TABLE) Data from Annals of Nuclear Energy,4(1977)135. 3042000100043 (APRVD) Approved by author, 78/03/28 3042000100044 HISTORY (19771026C) KO. 3042000100045 (19780406U) KO.-'Aprvd' added.- 3042000100046 (20090310A) SD:Updated to new date formats,lower case. 3042000100047 ENDBIB 45 0 3042000100048 NOCOMMON 0 0 3042000100049 ENDSUBENT 48 0 3042000199999 SUBENT 30420002 20090310 31353042000200001 BIB 2 19 3042000200002 REACTION ((90-TH-232(N,G)90-TH-233,,SIG,,MXW)/ 3042000200003 (92-U-235(N,G)92-U-236,,SIG,,MXW)) 3042000200004 ERR-ANALYS (ERR-T) Total error is given. 3042000200005 (ERR-SYS) Systematic 3042000200006 Source of error(%) is, 3042000200007 -systematic- net systematic error = 0.5 3042000200008 1.effects of uncertainties in decay constants 0.3 3042000200009 2.impurity corrections in alpha counting(sources) 0.2 3042000200010 3.rel.Self-absorp. Correct'n in gamma counts(foils)0.2 3042000200011 4.nat.Activity+fiss.-Prod. Effects in g-counting 0.2 3042000200012 5.relative flux perturbation correct'n for foils 0.2 3042000200013 (ERR-S) Statistical error. 3042000200014 Source of error(%) is, 3042000200015 -statistical- net statistical error = 0.8 3042000200016 1.statistics of relat. Alpha-counting(sources) 0.4 3042000200017 2.statistics of relat. Gamma-counting 3042000200018 (foils and sources) 0.6 3042000200019 3.relative foil weights 0.3,3042000200020 and total error is +-0.9%. 3042000200021 ENDBIB 19 0 3042000200022 COMMON 2 3 3042000200023 ERR-SYS ERR-S 3042000200024 PER-CENT PER-CENT 3042000200025 0.5 0.8 3042000200026 ENDCOMMON 3 0 3042000200027 DATA 3 1 3042000200028 EN-DUMMY DATA ERR-T 3042000200029 EV NO-DIM NO-DIM 3042000200030 2.5300E-02 2.7250E+00 2.5000E-02 3042000200031 ENDDATA 3 0 3042000200032 ENDSUBENT 31 0 3042000299999 ENDENTRY 2 0 3042099999999