ENTRY 10950 20170601 14321095000000001
SUBENT 10950001 20170601 14321095000100001
BIB 13 57 1095000100002
TITLE Absolute measurement of the uranium-235 fission cross 1095000100003
section from 0.2 to 1.2 MeV 1095000100004
AUTHOR (O.A.Wasson, M.M.Meier, K.C.Duval) 1095000100005
INSTITUTE (1USANBS) 1095000100006
REFERENCE (J,NSE,81,196,1982) 1095000100007
(C,79KNOX,,966,1979) 1095000100008
(W,WASSON,198112) 1095000100009
REL-REF (I,,W.P.Poenitz,J,NIM,109,413,1973) 1095000100010
Details of the neutron scintillator (black detector) 1095000100011
(O,10595001,O.A.Wasson,R,ANL-76-90,183,1976) 1095000100012
235U(n,f) cross sections from the same fission chamber1095000100013
FACILITY (VDG,1USANBS) NBS 3-MV Van de Graaff Laboratory 1095000100014
INC-SOURCE (P-LI7) Pulsed protons (1.8 to 3.0 MeV, 5 to 10 ns 1095000100015
wide at a 1-MHz repetition rate) on 7Li. 1095000100016
Neutrons were collimated to cone with half angle of 1095000100017
4.4 deg. 1095000100018
Source was heavily shielded with lithium carbonate 1095000100019
loaded paraffin. 1095000100020
DETECTOR (FISCH) Large-volume multiplated fission ionization 1095000100021
chamber 1095000100022
(SCIN) Large (12.5 cm diam x 19 cm long) NE110 plastic 1095000100023
scintillator ("Black detector") shielded with Pb, 1095000100024
paraffin and Li2CO3. 1095000100025
SAMPLE Plates of fission chamber coated with a nominal 1095000100026
thickness of 100 ug/cm2 uranium oxide on 10x18 cm 1095000100027
area. 1095000100028
Total mass of 235U was measured as 0.1709+/-0.0020 g. 1095000100029
METHOD (TOF) 235U desposit at ~1.3 m from the neutron source 1095000100030
and a neutron flux detector at ~5.9 m from the 1095000100031
neutron source. 1095000100032
CORRECTION Corrections made for 1095000100033
- air transmission, 1095000100034
- deadtime, 1095000100035
- backgrounds in fission chamber and flux monitor, 1095000100036
- collimator in-scattering, 1095000100037
- neutron transmission through edge of collimator, 1095000100038
- scatter from flux monitor shield, 1095000100039
- fission chamber spectrum loss, 1095000100040
- fission fragment absorption in deposits, 1095000100041
- variation of flux monitor efficiency with energy. 1095000100042
ERR-ANALYS (ERR-T) Total uncertainty 1095000100043
(ERR-S) Statistical uncertainty 1095000100044
(ERR-1) Air transmission 1095000100045
(ERR-2) Effective area of collimator 1095000100046
(ERR-3) Black detector spectral fitting and backgrounds1095000100047
(ERR-4) Fission chamber transmission and scattering 1095000100048
(ERR-5) Position of fission chamber (0.3%) 1095000100049
(ERR-6) Position of collimator (0.1%) 1095000100050
(ERR-7) Geometric area of collimator (0.5%) 1095000100051
(ERR-8) 235U mass in fission chamber (1.2%) 1095000100052
(ERR-9) Black detector efficiency calculation (1.0%) 1095000100053
(ERR-10) Fission spectrum extrapolation (0.4%) 1095000100054
(ERR-11) Black detector shield scattering (0.3%) 1095000100055
(ERR-12) Neutron beam non-uniformity (0.3%) 1095000100056
HISTORY (19820111C) 1095000100057
(19820812A) Updated reference 1095000100058
(20170601A) On. Major revision in 002. 1095000100059
ENDBIB 57 0 1095000100060
COMMON 9 6 1095000100061
EN-ERR ERR-5 ERR-6 ERR-7 ERR-8 ERR-9 1095000100062
ERR-10 ERR-11 ERR-12 1095000100063
KEV PER-CENT PER-CENT PER-CENT PER-CENT PER-CENT 1095000100064
PER-CENT PER-CENT PER-CENT 1095000100065
10. 0.3 0.1 0.5 1.2 1.0 1095000100066
0.4 0.3 0.3 1095000100067
ENDCOMMON 6 0 1095000100068
ENDSUBENT 67 0 1095000199999
SUBENT 10950002 20170601 14321095000200001
BIB 4 8 1095000200002
REACTION (92-U-235(N,F),,SIG,,AV) 1095000200003
FLAG (1.) Aluminum collimator used 1095000200004
(2.) Brass collimator used 1095000200005
STATUS Values except for energy dependent systematic 1095000200006
uncertainties are coincide with those in Table II of 1095000200007
Nucl.Sci.Eng.81(1982)196. 1095000200008
(APRVD) Approved by O.A.Wasson, 1982/2/23 1095000200009
HISTORY (20170601A) On. ERR-S: 1.6% -> 1.5% at 236 to 285 keV. 1095000200010
ENDBIB 8 0 1095000200011
NOCOMMON 0 0 1095000200012
DATA 10 37 1095000200013
EN-MIN EN-MAX DATA ERR-T ERR-S ERR-1 1095000200014
ERR-2 ERR-3 ERR-4 FLAG 1095000200015
KEV KEV B PER-CENT PER-CENT PER-CENT 1095000200016
PER-CENT PER-CENT PER-CENT NO-DIM 1095000200017
217. 272. 1.285 2.7 1.6 0.7 1095000200018
0.3 1.0 0.2 1. 1095000200019
236. 285. 1.241 2.7 1.5 0.7 1095000200020
0.4 1.0 0.2 1. 1095000200021
265. 313. 1.281 3.6 1.7 0.7 1095000200022
0.3 2.4 0.3 2. 1095000200023
290. 333. 1.202 2.6 1.5 0.7 1095000200024
0.2 0.9 0.3 1. 1095000200025
325. 368. 1.210 2.5 1.4 0.7 1095000200026
0.3 0.6 0.2 1. 1095000200027
352. 403. 1.252 2.4 1.2 0.4 1095000200028
0.2 0.8 0.2 2. 1095000200029
369. 406. 1.209 2.4 1.3 0.7 1095000200030
0.2 0.5 0.2 1. 1095000200031
401. 428. 1.212 2.4 1.2 1.0 1095000200032
0.2 0.4 0.2 1. 1095000200033
451. 488. 1.123 2.4 1.1 1.0 1095000200034
0.2 0.4 0.2 1. 1095000200035
456. 497. 1.148 2.3 1.0 0.5 1095000200036
0.2 0.7 0.2 2. 1095000200037
482. 531. 1.107 2.2 1.1 0.7 1095000200038
0.2 0.4 0.2 1. 1095000200039
492. 556. 1.139 2.2 0.9 0.6 1095000200040
0.2 0.7 0.2 2. 1095000200041
520. 567. 1.127 2.1 0.9 0.6 1095000200042
0.2 0.4 0.2 1. 1095000200043
545. 595. 1.115 2.3 1.0 0.6 1095000200044
0.2 0.7 0.2 2. 1095000200045
563. 612. 1.094 2.1 0.9 0.5 1095000200046
0.2 0.4 0.2 1. 1095000200047
600. 650. 1.111 2.2 0.8 0.5 1095000200048
0.3 0.9 0.2 2. 1095000200049
600. 652. 1.121 2.2 1.0 0.5 1095000200050
0.3 0.4 0.2 1. 1095000200051
649. 696. 1.097 2.2 1.0 0.5 1095000200052
0.3 0.4 0.2 1. 1095000200053
667. 729. 1.115 2.3 1.1 0.5 1095000200054
0.3 0.7 0.2 2. 1095000200055
686. 738. 1.100 2.2 1.0 0.5 1095000200056
0.2 0.4 0.2 1. 1095000200057
726. 778. 1.125 2.2 1.0 0.5 1095000200058
0.2 0.4 0.2 1. 1095000200059
757. 818. 1.120 2.2 1.0 0.4 1095000200060
0.2 0.5 0.2 1. 1095000200061
787. 821. 1.097 2.3 1.1 0.4 1095000200062
0.2 0.7 0.2 2. 1095000200063
802. 860. 1.139 2.2 1.0 0.4 1095000200064
0.2 0.5 0.2 1. 1095000200065
835. 875. 1.111 2.2 0.9 0.4 1095000200066
0.2 0.7 0.2 2. 1095000200067
840. 898. 1.103 2.2 1.0 0.4 1095000200068
0.2 0.5 0.2 1. 1095000200069
876. 939. 1.135 2.2 1.0 0.4 1095000200070
0.2 0.6 0.3 1. 1095000200071
905. 955. 1.179 2.3 1.1 0.5 1095000200072
0.2 0.7 0.3 2. 1095000200073
905. 990. 1.170 2.3 1.1 0.5 1095000200074
0.2 0.6 0.3 1. 1095000200075
972. 1016. 1.200 2.3 0.9 1.0 1095000200076
0.2 0.6 0.2 1. 1095000200077
1010. 1060. 1.200 2.3 1.0 0.6 1095000200078
0.2 0.7 0.2 2. 1095000200079
1030. 1070. 1.205 2.2 0.9 0.5 1095000200080
0.2 0.7 0.2 1. 1095000200081
1070. 1120. 1.175 2.3 1.0 0.9 1095000200082
0.2 0.6 0.2 2. 1095000200083
1079. 1120. 1.200 2.3 1.0 0.6 1095000200084
0.2 0.7 0.2 1. 1095000200085
1127. 1170. 1.180 2.3 1.0 0.7 1095000200086
0.2 0.7 0.2 1. 1095000200087
1136. 1191. 1.193 2.3 1.1 0.7 1095000200088
0.2 0.6 0.2 2. 1095000200089
1174. 1218. 1.179 2.3 1.2 0.6 1095000200090
0.2 0.7 0.2 1. 1095000200091
ENDDATA 78 0 1095000200092
ENDSUBENT 91 0 1095000299999
ENDENTRY 2 0 1095099999999