ENTRY 30781 20220202 32073078100000001
SUBENT 30781001 20220202 32073078100100001
BIB 19 92 3078100100002
TITLE Neutron capture cross section measurement of 232Th in 3078100100003
the energy range of 400-950 keV 3078100100004
AUTHOR (R.P.Anand, H.M.Jain, S.Kailas, S.K.Gupta, 3078100100005
V.S.Ramamurthy) 3078100100006
INSTITUTE (3INDTRM) 3078100100007
REFERENCE (J,ANE,16,87,1989) 3078100100008
((J,RE,93,189,1986)=(C,85SANTA,1,525,1985)) 3078100100009
Prelim. of the ANE article 3078100100010
FACILITY (VDG,3INDTRM) 5.5 MeV accelerator 3078100100011
SAMPLE - The Th-oxide target in form of discs (~14 mm diam., 3078100100012
2 mm thick). 3078100100013
- Two thin Au foils (0.013 mm thick, ~14 mm diam.) 3078100100014
INC-SOURCE (P-LI7) 3078100100015
DETECTOR (GELI) 100 cm3 3078100100016
METHOD (ACTIV) 3078100100017
- Activation method was employed in which the gammas 3078100100018
emitted from the decay of the Th-233 were measured. 3078100100019
- The cross sections were measured relative to the 3078100100020
neutron capture cross sections of Au-197. 3078100100021
ANALYSIS The photopeak area of 459 keV g-ray was extracted with 3078100100022
the computer code SAMPO, which fits each gamma-ray 3078100100023
with Gaussian + two exponentials. 3078100100024
The fitting parameters for the code were determined by 3078100100025
using standard monoenerg. gamma-sources. 3078100100026
MONITOR ((MONIT1)(90-TH-232(N,G)90-TH-233,,SIG,,MXW)/ 3078100100027
(79-AU-197(N,G)79-AU-198,,SIG,,MXW)) 3078100100028
The ratio of the capture cross section of Th and Au at 3078100100029
thermal neutron energy was used as monitor. 3078100100030
The values of the thermal neutron capture cross section3078100100031
used were: 7.40 +/- 0.08 barn for Th-232 3078100100032
98.8 +/- 0.3 barn for Au-197 3078100100033
((MONIT2)79-AU-197(N,G)79-AU-198,,SIG) 3078100100034
MONIT-REF ((MONIT1),,R,BNL-325,(1),1973) 3078100100035
((MONIT2),,R,IAEA-227,1983) 3078100100036
The capture cross sections of 197-Au in the keV 3078100100037
energy range were taken from standard cross sections 3078100100038
recommended by IAEA. 3078100100039
DECAY-DATA (90-TH-233,22.3MIN,DG,459.) 3078100100040
DECAY-MON (79-AU-198-G,2.7D,DG,412.) 3078100100041
CORRECTION Measured cross sections were corrected for: 3078100100042
1. Multiple scattering and self-shielding effects: 3078100100043
--------------------------------------------------- 3078100100044
En (keV) C1 C2 3078100100045
--------------------------------------------------- 3078100100046
Thermal maxw 0.97230 1.0562 3078100100047
425 0.99995 1.0295 3078100100048
480 0.99995 1.0305 3078100100049
535 0.99995 1.0310 3078100100050
590 0.99995 1.0313 3078100100051
615 0.99995 1.0316 3078100100052
645 0.99996 1.0319 3078100100053
690 0.99996 1.0321 3078100100054
740 0.99996 1.0325 3078100100055
845 0.99996 1.0333 3078100100056
950 0.99997 1.0338 3078100100057
------------ -------------------------------------- 3078100100058
C1: Self-shielding + multiple scattering correction 3078100100059
factor for Al-foils 3078100100060
C2: Multiple scattering correction factor for Th- 3078100100061
pellet 3078100100062
2. The effect of the variation of neutron flux as a 3078100100063
function of time was taken into consideration. 3078100100064
This correction factor was found to be less than 6%.3078100100065
3. Second group of neutrons due Ep > 2.4 MeV the 3078100100066
estimated error due to this corr < +/- 1%. 3078100100067
4. The average energy and the spread of the neutron 3078100100068
beam for Li target thickness. The neutron spread 3078100100069
due this was calcu. to be varying from +/-15 to 3078100100070
+/- 25 keV 3078100100071
5. The energy spread due to the angular spread of 3078100100072
neutrons. This was estimated to be about +/- 17 keV.3078100100073
ERR-ANALYS (ERR-T) Overall uncertainty was estimated (5-6%) 3078100100074
(ERR-S,1.,4.) The statistical and fitting error in the 3078100100075
determining the photopeak areas of the 459 and 412 keV3078100100076
gammas by SAMPO: (2-4%) for keV 3078100100077
(<1%)for thermal 3078100100078
(ERR-1,,2.) The uncertainty due the self-shielding and 3078100100079
multiple scattering (<2%) 3078100100080
(ERR-2,,1.) The uncertainty on the thermal capture 3078100100081
cross sections of 232-Th and 197-Au: (<1%) 3078100100082
CRITIQUE The present measurements are in good agreement with the3078100100083
other recent measurements and deviations are within 3078100100084
experimental errors up to En=740keV. 3078100100085
STATUS (TABLE) Table 2 of Ann. Nucl. Energy, 16 (1989) 87 3078100100086
HISTORY (19880411C) TMK 3078100100087
(19890412A) VOF.-Complete revision. 3078100100088
(20090725A) SD: Updated to new date formats,lower case.3078100100089
Units and data in COMMON section were corrected, 3078100100090
energy was added. Cosmetic changes and codes for 3078100100091
partial uncertainties were added. 3078100100092
(20120703U) On. ANALYSIS: Code AREA deleted 3078100100093
(20220202A) VT ERR-ANALYS: corrected 3078100100094
ENDBIB 92 0 3078100100095
COMMON 2 3 3078100100096
EN-NRM MONIT1 3078100100097
EV NO-DIM 3078100100098
0.0253 0.0749 3078100100099
ENDCOMMON 3 0 3078100100100
ENDSUBENT 99 0 3078100199999
SUBENT 30781002 20220202 32073078100200001
BIB 1 1 3078100200002
REACTION (90-TH-232(N,G)90-TH-233,,SIG) 3078100200003
ENDBIB 1 0 3078100200004
NOCOMMON 0 0 3078100200005
DATA 5 10 3078100200006
EN EN-RSL DATA ERR-T MONIT2 3078100200007
KEV KEV MB MB MB 3078100200008
425. 35. 150. 8. 151.4 3078100200009
480. 35. 151. 8. 138. 3078100200010
535. 35. 166. 9. 127. 3078100200011
590. 35. 160. 9. 118. 3078100200012
615. 45. 150. 8. 115. 3078100200013
645. 35. 167. 9. 108.8 3078100200014
690. 45. 164. 9. 102.4 3078100200015
740. 45. 170. 9. 96.4 3078100200016
845. 45. 175. 9. 87.6 3078100200017
950. 45. 162. 9. 84.2 3078100200018
ENDDATA 12 0 3078100200019
ENDSUBENT 18 0 3078100299999
ENDENTRY 2 0 3078199999999