ENTRY 14700 20210420 14831470000000001 SUBENT 14700001 20210420 14831470000100001 BIB 10 45 1470000100002 TITLE Scattering of Slow Neutrons. II 1470000100003 AUTHOR (A.C.G.Mitchell,E.J.Murphy,M.D.Whitaker) 1470000100004 REFERENCE (J,PR,50,133,1936) 1470000100005 #doi:10.1103/PhysRev.50.133 1470000100006 REL-REF (I,,A.C.G.Mitchell+,J,PR,48,653,1935) Experimental 1470000100007 apparatus. 1470000100008 INSTITUTE (1USANYU) 1470000100009 INC-SOURCE (RA-BE) 1470000100010 DETECTOR (GEMUC) The detectors were thin sheets of the metals 1470000100011 Ag, Rh and In of dimensions 6 by 10 cm. After 1470000100012 irradiation the detectors were assayed with a 1470000100013 Geiger-Muller tube. 1470000100014 METHOD A cylindrical block of paraffin, 15 cm in diameter 1470000100015 and 17 cm high, contained a Ra-Be bulb located on the 1470000100016 axis 6 cm from the top surface. The thin detectors 1470000100017 were placed on top of the paraffin cylinder and the 1470000100018 scatterer, usually blocks of metal the same size as 1470000100019 the detector, were placed on top of the detector. In 1470000100020 some cases a sheet of Cd metal, containing 0.218 1470000100021 g/cm2, was interposed between the paraffin and the 1470000100022 detector. This served as a filter to cut out neutrons 1470000100023 of the C group. After irradiation for a given length 1470000100024 of time the detectors were placed around a 1470000100025 Geiger-Muller tube counter and the activity obtained 1470000100026 with the help of a thyratron "scale of two" recording 1470000100027 system. An activity measurement was used to derive 1470000100028 the scattering cross sections. 1470000100029 ANALYSIS Percentage of scattered neutrons was measured (n/n0). 1470000100030 This quantity is related to a combination of single 1470000100031 scattering (sigmas) and capture cross (sigmac) 1470000100032 sections as n/n0 = (N*a*sigmas/(2*N*b*(sigmas+sigmac)) 1470000100033 *[1-exp(-2*N*b*(sigmas +sigmac)*x)], where N is the 1470000100034 number of atoms/cm2 of the scatterer, and a and b 1470000100035 quantities which come in because of the solid angles 1470000100036 involved. The quantity N*(sigmas+sigmac) is the usual 1470000100037 absorption coefficient, and the factor 2 arises since 1470000100038 the neutrons traverse the scatterer twice. The 1470000100039 calculation does show, however, that the slope of the 1470000100040 curve for small thicknesses is proportional to 1470000100041 N*sigmas, and the saturation value is governed by 1470000100042 sigmas/(sigmas+sigmac). Thus the relative scattering 1470000100043 cross section can be obtained and some idea as to the 1470000100044 ratio of scattering cross section to total cross 1470000100045 section. 1470000100046 HISTORY (20210420C) BP 1470000100047 ENDBIB 45 0 1470000100048 COMMON 1 3 1470000100049 EN-DUMMY 1470000100050 EV 1470000100051 0.0253 1470000100052 ENDCOMMON 3 0 1470000100053 ENDSUBENT 52 0 1470000199999 SUBENT 14700002 20210420 14831470000200001 BIB 2 2 1470000200002 REACTION (6-C-0(N,EL)6-C-0,,SIG) 1470000200003 STATUS (TABLE) Table II, page 135. 1470000200004 ENDBIB 2 0 1470000200005 NOCOMMON 0 0 1470000200006 DATA 1 1 1470000200007 DATA 1470000200008 B 1470000200009 3.4 1470000200010 ENDDATA 3 0 1470000200011 ENDSUBENT 10 0 1470000299999 SUBENT 14700003 20210420 14831470000300001 BIB 2 2 1470000300002 REACTION (12-MG-0(N,EL)12-MG-0,,SIG) 1470000300003 STATUS (TABLE) Table II, page 135. 1470000300004 ENDBIB 2 0 1470000300005 NOCOMMON 0 0 1470000300006 DATA 1 1 1470000300007 DATA 1470000300008 B 1470000300009 3.0 1470000300010 ENDDATA 3 0 1470000300011 ENDSUBENT 10 0 1470000399999 SUBENT 14700004 20210420 14831470000400001 BIB 2 2 1470000400002 REACTION (13-AL-27(N,EL)13-AL-27,,SIG) 1470000400003 STATUS (TABLE) Table II, page 135. 1470000400004 ENDBIB 2 0 1470000400005 NOCOMMON 0 0 1470000400006 DATA 1 1 1470000400007 DATA 1470000400008 B 1470000400009 1.0 1470000400010 ENDDATA 3 0 1470000400011 ENDSUBENT 10 0 1470000499999 SUBENT 14700005 20210420 14831470000500001 BIB 2 2 1470000500002 REACTION (16-S-0(N,EL)16-S-0,,SIG) 1470000500003 STATUS (TABLE) Table II, page 135. 1470000500004 ENDBIB 2 0 1470000500005 NOCOMMON 0 0 1470000500006 DATA 1 1 1470000500007 DATA 1470000500008 B 1470000500009 0.9 1470000500010 ENDDATA 3 0 1470000500011 ENDSUBENT 10 0 1470000599999 SUBENT 14700006 20210420 14831470000600001 BIB 2 2 1470000600002 REACTION (24-CR-0(N,EL)24-CR-0,,SIG) 1470000600003 STATUS (TABLE) Table II, page 135. 1470000600004 ENDBIB 2 0 1470000600005 NOCOMMON 0 0 1470000600006 DATA 1 1 1470000600007 DATA 1470000600008 B 1470000600009 1.4 1470000600010 ENDDATA 3 0 1470000600011 ENDSUBENT 10 0 1470000699999 SUBENT 14700007 20210420 14831470000700001 BIB 2 2 1470000700002 REACTION (25-MN-55(N,EL)25-MN-55,,SIG) 1470000700003 STATUS (TABLE) Table II, page 135. 1470000700004 ENDBIB 2 0 1470000700005 NOCOMMON 0 0 1470000700006 DATA 1 1 1470000700007 DATA 1470000700008 B 1470000700009 2.2 1470000700010 ENDDATA 3 0 1470000700011 ENDSUBENT 10 0 1470000799999 SUBENT 14700008 20210420 14831470000800001 BIB 2 2 1470000800002 REACTION (26-FE-0(N,EL)26-FE-0,,SIG) 1470000800003 STATUS (TABLE) Table II, page 135. 1470000800004 ENDBIB 2 0 1470000800005 NOCOMMON 0 0 1470000800006 DATA 1 1 1470000800007 DATA 1470000800008 B 1470000800009 10.6 1470000800010 ENDDATA 3 0 1470000800011 ENDSUBENT 10 0 1470000899999 SUBENT 14700009 20210420 14831470000900001 BIB 2 2 1470000900002 REACTION (28-NI-0(N,EL)28-NI-0,,SIG) 1470000900003 STATUS (TABLE) Table II, page 135. 1470000900004 ENDBIB 2 0 1470000900005 NOCOMMON 0 0 1470000900006 DATA 1 1 1470000900007 DATA 1470000900008 B 1470000900009 18.0 1470000900010 ENDDATA 3 0 1470000900011 ENDSUBENT 10 0 1470000999999 SUBENT 14700010 20210420 14831470001000001 BIB 2 2 1470001000002 REACTION (29-CU-0(N,EL)29-CU-0,,SIG) 1470001000003 STATUS (TABLE) Table II, page 135. 1470001000004 ENDBIB 2 0 1470001000005 NOCOMMON 0 0 1470001000006 DATA 1 1 1470001000007 DATA 1470001000008 B 1470001000009 8.3 1470001000010 ENDDATA 3 0 1470001000011 ENDSUBENT 10 0 1470001099999 SUBENT 14700011 20210420 14831470001100001 BIB 2 2 1470001100002 REACTION (30-ZN-0(N,EL)30-ZN-0,,SIG) 1470001100003 STATUS (TABLE) Table II, page 135. 1470001100004 ENDBIB 2 0 1470001100005 NOCOMMON 0 0 1470001100006 DATA 1 1 1470001100007 DATA 1470001100008 B 1470001100009 3.7 1470001100010 ENDDATA 3 0 1470001100011 ENDSUBENT 10 0 1470001199999 SUBENT 14700012 20210420 14831470001200001 BIB 2 2 1470001200002 REACTION (47-AG-0(N,EL)47-AG-0,,SIG) 1470001200003 STATUS (TABLE) Table II, page 135. 1470001200004 ENDBIB 2 0 1470001200005 NOCOMMON 0 0 1470001200006 DATA 1 1 1470001200007 DATA 1470001200008 B 1470001200009 6.3 1470001200010 ENDDATA 3 0 1470001200011 ENDSUBENT 10 0 1470001299999 SUBENT 14700013 20210420 14831470001300001 BIB 2 2 1470001300002 REACTION (48-CD-0(N,EL)48-CD-0,,SIG) 1470001300003 STATUS (TABLE) Table II, page 135. 1470001300004 ENDBIB 2 0 1470001300005 NOCOMMON 0 0 1470001300006 DATA 1 1 1470001300007 DATA-APRX 1470001300008 B 1470001300009 1.2 1470001300010 ENDDATA 3 0 1470001300011 ENDSUBENT 10 0 1470001399999 SUBENT 14700014 20210420 14831470001400001 BIB 2 2 1470001400002 REACTION (50-SN-0(N,EL)50-SN-0,,SIG) 1470001400003 STATUS (TABLE) Table II, page 135. 1470001400004 ENDBIB 2 0 1470001400005 NOCOMMON 0 0 1470001400006 DATA 1 1 1470001400007 DATA 1470001400008 B 1470001400009 4.1 1470001400010 ENDDATA 3 0 1470001400011 ENDSUBENT 10 0 1470001499999 SUBENT 14700015 20210420 14831470001500001 BIB 2 2 1470001500002 REACTION (80-HG-0(N,EL)80-HG-0,,SIG) 1470001500003 STATUS (TABLE) Table II, page 135. 1470001500004 ENDBIB 2 0 1470001500005 NOCOMMON 0 0 1470001500006 DATA 1 1 1470001500007 DATA 1470001500008 B 1470001500009 4.7 1470001500010 ENDDATA 3 0 1470001500011 ENDSUBENT 10 0 1470001599999 SUBENT 14700016 20210420 14831470001600001 BIB 2 2 1470001600002 REACTION (82-PB-0(N,EL)82-PB-0,,SIG) 1470001600003 STATUS (TABLE) Table II, page 135. 1470001600004 ENDBIB 2 0 1470001600005 NOCOMMON 0 0 1470001600006 DATA 1 1 1470001600007 DATA 1470001600008 B 1470001600009 7.7 1470001600010 ENDDATA 3 0 1470001600011 ENDSUBENT 10 0 1470001699999 SUBENT 14700017 20210420 14831470001700001 BIB 2 2 1470001700002 REACTION (83-BI-209(N,EL)83-BI-209,,SIG) 1470001700003 STATUS (TABLE) Table II, page 135. 1470001700004 ENDBIB 2 0 1470001700005 NOCOMMON 0 0 1470001700006 DATA 1 1 1470001700007 DATA 1470001700008 B 1470001700009 10.2 1470001700010 ENDDATA 3 0 1470001700011 ENDSUBENT 10 0 1470001799999 ENDENTRY 17 0 1470099999999