ENTRY 14667 20201207 14761466700000001
SUBENT 14667001 20201207 14761466700100001
BIB 9 25 1466700100002
TITLE Fission Cross Sections of U235 and U238 for Fast 1466700100003
Neutrons 1466700100004
AUTHOR (N.P.Heydenburg,R.C.Meyer,K.Way) 1466700100005
REFERENCE (R,CF-636,1943) 1466700100006
INSTITUTE (1USACHI) 1466700100007
FACILITY (ACCEL,1USACHI) 1466700100008
DETECTOR (FISCH,IOCH) Two chambers were used. The second 1466700100009
chamber with a larger collector was used for enriched 1466700100010
uranium samples which were one inch in diameter. The 1466700100011
distance between the neutron source and the uranium 1466700100012
sample was increased for the absolute cross-section 1466700100013
determinations. The chambers were cadmium-lined as 1466700100014
shown. A boron-lined ionization chamber, surrounded 1466700100015
by paraffin, was used as a neutron monitor. 1466700100016
SAMPLE Samples of normal uranium of various thicknesses were 1466700100017
used for comparison with the enriched samples. The 1466700100018
235U content of the first two samples was checked by 1466700100019
comparing their UX2 beta ray yield with normal 1466700100020
uranium, after the UX2 content of the samples was in 1466700100021
equilibrium. 1466700100022
CORRECTION The correction for fission absorption was obtained 1466700100023
from an absorption curve, determined with the use of 1466700100024
a number of uniform U3O8 samples of known weight, 1466700100025
prepared by the Bureau of Standards. 1466700100026
HISTORY (20201207C) BP 1466700100027
ENDBIB 25 0 1466700100028
NOCOMMON 0 0 1466700100029
ENDSUBENT 28 0 1466700199999
SUBENT 14667002 20201207 14761466700200001
BIB 6 16 1466700200002
REACTION (92-U-238(N,F),,SIG,,SPA) 1466700200003
INC-SOURCE (D-C12) Cl2(d,n) neutrons of 640 keV maximum energy. 1466700200004
The carbon neutrons were produced by deuteron 1466700200005
bombardment of thick graphite discs. About 99 per 1466700200006
cent of these neutrons are due to the reaction 1466700200007
C12(d,n) for which Q = -.28 MeV. 1466700200008
SAMPLE The measurement was made with a normal U3O8 sample of 1466700200009
11 mm diameter and containing 1.140 mgm of U3O8. 1466700200010
METHOD For determining the absolute fission cross-section, 1466700200011
the distance between the uranium sample and the 1466700200012
graphite target was increased to 2.77 cm (distance to 1466700200013
top surface of graphite). The deuteron energy was 1466700200014
970 keV, giving neutrons of maximum energy 665 keV in 1466700200015
the forward direction. 1466700200016
ERR-ANALYS (DATA-ERR) No details on sources of uncertainties. 1466700200017
STATUS (TABLE) page 5. 1466700200018
ENDBIB 16 0 1466700200019
NOCOMMON 0 0 1466700200020
DATA 3 1 1466700200021
EN-MAX DATA DATA-ERR 1466700200022
KEV MB MB 1466700200023
640.0 18.6 1.1 1466700200024
ENDDATA 3 0 1466700200025
ENDSUBENT 24 0 1466700299999
SUBENT 14667003 20201207 14761466700300001
BIB 8 23 1466700300002
REACTION (92-U-235(N,F),,SIG,,SPA) 1466700300003
INC-SOURCE (D-C12) Cl2(d,n) neutrons of 640 keV maximum energy. 1466700300004
The carbon neutrons were produced by deuteron 1466700300005
bombardment of thick graphite discs. About 99 per 1466700300006
cent of these neutrons are due to the reaction 1466700300007
C12(d,n) for which Q = -.28 MeV. 1466700300008
SAMPLE The measurement was made with a normal U3O8 sample of 1466700300009
11 mm diameter and containing 1.140 mgm of U3O8. 1466700300010
METHOD For determining the absolute fission cross-section, 1466700300011
the distance between the uranium sample and the 1466700300012
graphite target was increased to 2.77 cm (distance to 1466700300013
top surface of graphite). The deuteron energy was 1466700300014
970 keV, giving neutrons of maximum energy 665 keV in 1466700300015
the forward direction. 1466700300016
ANALYSIS To obtain the cross section for U235 for C12 neutrons, 1466700300017
the natural value must be multiplied by 140 and by 1466700300018
.505 the fraction of fissions due C12 neutrons for 1466700300019
ordinary uranium. Dr. Way has made a more detailed 1466700300020
calculation of correction for the above data and 1466700300021
finds 235U cross section of 1.10 b. 1466700300022
ERR-ANALYS (DATA-ERR) No details on sources of uncertainties. 1466700300023
FLAG (1.) Corrected value. 1466700300024
STATUS (TABLE) page 5. 1466700300025
ENDBIB 23 0 1466700300026
NOCOMMON 0 0 1466700300027
DATA 4 2 1466700300028
EN-MAX DATA DATA-ERR FLAG 1466700300029
KEV B B NO-DIM 1466700300030
640.0 1.36 0.08 1466700300031
640.0 1.10 1. 1466700300032
ENDDATA 4 0 1466700300033
ENDSUBENT 32 0 1466700399999
SUBENT 14667004 20201207 14761466700400001
BIB 7 20 1466700400002
REACTION (92-U-235(N,F),,SIG,,SPA) 1466700400003
INC-SOURCE (D-C12) Cl2(d,n) neutrons of 640 keV maximum energy. 1466700400004
The carbon neutrons were produced by deuteron 1466700400005
bombardment of thick graphite discs. About 99 per 1466700400006
cent of these neutrons are due to the reaction 1466700400007
C12(d,n) for which Q = -.28 MeV. 1466700400008
SAMPLE Enriched sample Mg-XVII-B-1. This sample is 1466700400009
advantageous for getting sigma 235U because the 1466700400010
corrections for the fast neutrons from 13C and the 1466700400011
deuterium contamination will be small amounting to 1466700400012
only 5 per cent of the total number of fissions 1466700400013
observed. 1466700400014
ANALYSIS For a distance between sample and target of 5.35 cm, 1466700400015
8.7x10-3 fissions/mu were observed, using for the 1466700400016
neutron yield Q(15 degrees) = 15.2x10**6 neutrons/mu, 1466700400017
for a deuteron energy of 963 keV. Detailed 1466700400018
calculation by Dr. Way yields 1.20 b. 1466700400019
ERR-ANALYS (DATA-ERR) No details on sources of uncertainties. 1466700400020
FLAG (1.) Corrected value. 1466700400021
STATUS (TABLE) page 6. 1466700400022
ENDBIB 20 0 1466700400023
NOCOMMON 0 0 1466700400024
DATA 4 2 1466700400025
EN-MAX DATA DATA-ERR FLAG 1466700400026
KEV B B NO-DIM 1466700400027
640.0 1.52 0.07 1466700400028
640.0 1.20 1. 1466700400029
ENDDATA 4 0 1466700400030
ENDSUBENT 29 0 1466700499999
SUBENT 14667005 20201207 14761466700500001
BIB 5 12 1466700500002
REACTION (92-U-238(N,F),,SIG,,SPA) 1466700500003
INC-SOURCE (D-D) D(d,n) neutrons of maximum energy 3.95 MeV. 1466700500004
D3PO4 targets were used for most of this work. 1466700500005
SAMPLE All the data were taken with a U3O8 sample of weight 1466700500006
1.140 mg, diameter l1 mm. 1466700500007
METHOD Two absolute measurements have been made on the 1466700500008
fission cross-section for D-D neutrons in the forward 1466700500009
direction for normal uranium. From the value of the 1466700500010
observed fissions/mu, using the D3PO4 target and 1466700500011
applying the corrections the cross section was 1466700500012
extracted. 1466700500013
STATUS (TABLE) page 8. 1466700500014
ENDBIB 12 0 1466700500015
NOCOMMON 0 0 1466700500016
DATA 2 1 1466700500017
EN-MAX DATA 1466700500018
MEV B 1466700500019
3.95 0.69 1466700500020
ENDDATA 3 0 1466700500021
ENDSUBENT 20 0 1466700599999
SUBENT 14667006 20201207 14761466700600001
BIB 5 19 1466700600002
REACTION ((92-U-235(N,F),,SIG,,SPA)/(92-U-238(N,F),,SIG,,SPA)) 1466700600003
INC-SOURCE (D-D) D(d,n) neutrons of maximum energy 3.95 MeV. 1466700600004
D3PO4 targets were used for most of this work. 1466700600005
SAMPLE MgXVII-B-6, TX-22 sample. 1466700600006
METHOD The distance between the deuterium target and the 1466700600007
sample was 4.17 cm for the above measurements. A 1466700600008
number of additional 235 enriched and normal uranium 1466700600009
were received from Berkeley. These were used to 1466700600010
obtain more data on sigma 235U/sigma 238U for 3.95 1466700600011
MeV neutrons. A special chamber was constructed for 1466700600012
comparing two samples simultaneously. This was a 1466700600013
double ionization chamber with the two samples 1466700600014
mounted back to back on the high voltage plate. The 1466700600015
two samples were about 1 mm apart and measurements 1466700600016
were made with a distance of 5 cm between target and 1466700600017
sample. Bach chamber was connected to a separate 1466700600018
amplifier and counter. Comparisons were made on three 1466700600019
sets of samples for 3.95 MeV neutrons. 1466700600020
STATUS (TABLE) Table 4, page 7. 1466700600021
ENDBIB 19 0 1466700600022
NOCOMMON 0 0 1466700600023
DATA 2 1 1466700600024
EN-MAX DATA 1466700600025
MEV NO-DIM 1466700600026
3.95 2.54 1466700600027
ENDDATA 3 0 1466700600028
ENDSUBENT 27 0 1466700699999
SUBENT 14667007 20201207 14761466700700001
BIB 5 19 1466700700002
REACTION ((92-U-235(N,F),,SIG,,SPA)/(92-U-238(N,F),,SIG,,SPA)) 1466700700003
INC-SOURCE (D-D) D(d,n) neutrons of maximum energy 3.95 MeV. 1466700700004
D3PO4 targets were used for most of this work. 1466700700005
SAMPLE MgXVII-B-5, TX-18 sample. 1466700700006
METHOD The distance between the deuterium target and the 1466700700007
sample was 4.17 cm for the above measurements. A 1466700700008
number of additional 235 enriched and normal uranium 1466700700009
were received from Berkeley. These were used to 1466700700010
obtain more data on sigma 235U/sigma 238U for 3.95 1466700700011
MeV neutrons. A special chamber was constructed for 1466700700012
comparing two samples simultaneously. This was a 1466700700013
double ionization chamber with the two samples 1466700700014
mounted back to back on the high voltage plate. The 1466700700015
two samples were about 1 mm apart and measurements 1466700700016
were made with a distance of 5 cm between target and 1466700700017
sample. Bach chamber was connected to a separate 1466700700018
amplifier and counter. Comparisons were made on three 1466700700019
sets of samples for 3.95 MeV neutrons. 1466700700020
STATUS (TABLE) Table 4, page 7. 1466700700021
ENDBIB 19 0 1466700700022
NOCOMMON 0 0 1466700700023
DATA 2 1 1466700700024
EN-MAX DATA 1466700700025
MEV NO-DIM 1466700700026
3.95 2.36 1466700700027
ENDDATA 3 0 1466700700028
ENDSUBENT 27 0 1466700799999
SUBENT 14667008 20201207 14761466700800001
BIB 5 19 1466700800002
REACTION ((92-U-235(N,F),,SIG,,SPA)/(92-U-238(N,F),,SIG,,SPA)) 1466700800003
INC-SOURCE (D-D) D(d,n) neutrons of maximum energy 3.95 MeV. 1466700800004
D3PO4 targets were used for most of this work. 1466700800005
SAMPLE MgXVII-B-4, TX-18 sample. 1466700800006
METHOD The distance between the deuterium target and the 1466700800007
sample was 4.17 cm for the above measurements. A 1466700800008
number of additional 235 enriched and normal uranium 1466700800009
were received from Berkeley. These were used to 1466700800010
obtain more data on sigma 235U/sigma 238U for 3.95 1466700800011
MeV neutrons. A special chamber was constructed for 1466700800012
comparing two samples simultaneously. This was a 1466700800013
double ionization chamber with the two samples 1466700800014
mounted back to back on the high voltage plate. The 1466700800015
two samples were about 1 mm apart and measurements 1466700800016
were made with a distance of 5 cm between target and 1466700800017
sample. Bach chamber was connected to a separate 1466700800018
amplifier and counter. Comparisons were made on three 1466700800019
sets of samples for 3.95 MeV neutrons. 1466700800020
STATUS (TABLE) Table 4, page 7. 1466700800021
ENDBIB 19 0 1466700800022
NOCOMMON 0 0 1466700800023
DATA 2 1 1466700800024
EN-MAX DATA 1466700800025
MEV NO-DIM 1466700800026
3.95 2.21 1466700800027
ENDDATA 3 0 1466700800028
ENDSUBENT 27 0 1466700899999
SUBENT 14667009 20201207 14761466700900001
BIB 5 12 1466700900002
REACTION ((92-U-235(N,F),,SIG)/(92-U-238(N,F),,SIG)) 1466700900003
INC-SOURCE (D-D) D(d,n) neutrons of maximum energy 3.95 MeV. 1466700900004
Neutrons at 90 deg with energy 2.7 MeV. 1466700900005
D3PO4 targets were used for most of this work. 1466700900006
SAMPLE MgXVII-B-6, TX-22 sample. 1466700900007
METHOD Neutrons at 90 degrees, En=2.7 MeV, distance target 1466700900008
to sample 5 cm. A special chamber was constructed for 1466700900009
comparing two samples simultaneously. This was a 1466700900010
double ionization chamber with the two samples 1466700900011
mounted back to back on the high voltage plate. The 1466700900012
two samples were about 1 mm apart. 1466700900013
STATUS (TABLE) Table 4, page 7. 1466700900014
ENDBIB 12 0 1466700900015
NOCOMMON 0 0 1466700900016
DATA 2 1 1466700900017
EN DATA 1466700900018
MEV NO-DIM 1466700900019
2.7 2.98 1466700900020
ENDDATA 3 0 1466700900021
ENDSUBENT 20 0 1466700999999
SUBENT 14667010 20201207 14761466701000001
BIB 5 12 1466701000002
REACTION ((92-U-235(N,F),,SIG)/(92-U-238(N,F),,SIG)) 1466701000003
INC-SOURCE (D-D) D(d,n) neutrons of maximum energy 3.95 MeV. 1466701000004
Neutrons at 135 deg with energy 2.1 MeV. 1466701000005
D3PO4 targets were used for most of this work. 1466701000006
SAMPLE MgXVII-B-6, TX-22 sample. 1466701000007
METHOD Neutrons at 135 degrees, En=2.1 MeV, distance target 1466701000008
to sample 10 cm. A special chamber was constructed for 1466701000009
comparing two samples simultaneously. This was a 1466701000010
double ionization chamber with the two samples 1466701000011
mounted back to back on the high voltage plate. The 1466701000012
two samples were about 1 mm apart. 1466701000013
STATUS (TABLE) Table 4, page 7. 1466701000014
ENDBIB 12 0 1466701000015
NOCOMMON 0 0 1466701000016
DATA 2 1 1466701000017
EN DATA 1466701000018
MEV NO-DIM 1466701000019
2.1 2.95 1466701000020
ENDDATA 3 0 1466701000021
ENDSUBENT 20 0 1466701099999
ENDENTRY 10 0 1466799999999