ENTRY 14706 20210510 14861470600000001 SUBENT 14706001 20210510 14861470600100001 BIB 7 13 1470600100002 TITLE Scattering Cross-section for Thermal Neutrons 1470600100003 AUTHOR (E.Bragdon) 1470600100004 REFERENCE (R,CP-1827,10,1944), NSR keynumber 1944BRZZ. 1470600100005 INSTITUTE (1USACHI) 1470600100006 FACILITY (REAC,1USAANL) 1470600100007 CORRECTION Corrections for geometrical size of sample, for 1470600100008 absorption, and for multiple scattering can be made 1470600100009 by obtaining the slope at zero thickness of an 1470600100010 intensity vs sample thickness curve. Such intensity 1470600100011 curves made with materials of known cross sections 1470600100012 make it possible to calculate the corrections for 1470600100013 samples of unknown scattering cross sections. 1470600100014 HISTORY (20210510C) BP 1470600100015 ENDBIB 13 0 1470600100016 COMMON 1 3 1470600100017 EN-DUMMY 1470600100018 EV 1470600100019 0.0253 1470600100020 ENDCOMMON 3 0 1470600100021 ENDSUBENT 20 0 1470600199999 SUBENT 14706002 20210510 14861470600200001 BIB 5 11 1470600200002 REACTION (13-AL-27(N,EL)13-AL-27,,SIG,,SPA) 1470600200003 METHOD The scattering material is placed in layers inside an 1470600200004 inverted Cd cup in such a way that neutrons moving 1470600200005 upwards from the graphite of a thermal column are 1470600200006 scattered backwards from the scatterer and strike an 1470600200007 In foil protected by Cd from a direct beam. The 1470600200008 scattering cross section of a material is determined 1470600200009 by comparing its back-scattering to that of graphite. 1470600200010 ERR-ANALYS (DATA-ERR) No details on sources of uncertainties. 1470600200011 MONITOR (6-C-0(N,EL)6-C-0,,SIG,,SPA) Graphite. 1470600200012 STATUS (TABLE) page 10. 1470600200013 ENDBIB 11 0 1470600200014 COMMON 1 3 1470600200015 MONIT 1470600200016 B 1470600200017 4.8 1470600200018 ENDCOMMON 3 0 1470600200019 DATA 2 1 1470600200020 DATA DATA-ERR 1470600200021 B B 1470600200022 1.33 0.2 1470600200023 ENDDATA 3 0 1470600200024 ENDSUBENT 23 0 1470600299999 SUBENT 14706003 20210510 14861470600300001 BIB 5 11 1470600300002 REACTION (26-FE-0(N,EL)26-FE-0,,SIG,,SPA) 1470600300003 METHOD The scattering material is placed in layers inside an 1470600300004 inverted Cd cup in such a way that neutrons moving 1470600300005 upwards from the graphite of a thermal column are 1470600300006 scattered backwards from the scatterer and strike an 1470600300007 In foil protected by Cd from a direct beam. The 1470600300008 scattering cross section of a material is determined 1470600300009 by comparing its back-scattering to that of graphite. 1470600300010 ERR-ANALYS (DATA-ERR) No details on sources of uncertainties. 1470600300011 MONITOR (6-C-0(N,EL)6-C-0,,SIG,,SPA) Graphite. 1470600300012 STATUS (TABLE) page 10. 1470600300013 ENDBIB 11 0 1470600300014 COMMON 1 3 1470600300015 MONIT 1470600300016 B 1470600300017 4.8 1470600300018 ENDCOMMON 3 0 1470600300019 DATA 2 1 1470600300020 DATA DATA-ERR 1470600300021 B B 1470600300022 10.9 0.2 1470600300023 ENDDATA 3 0 1470600300024 ENDSUBENT 23 0 1470600399999 SUBENT 14706004 20210510 14861470600400001 BIB 5 11 1470600400002 REACTION (28-NI-0(N,EL)28-NI-0,,SIG,,SPA) 1470600400003 METHOD The scattering material is placed in layers inside an 1470600400004 inverted Cd cup in such a way that neutrons moving 1470600400005 upwards from the graphite of a thermal column are 1470600400006 scattered backwards from the scatterer and strike an 1470600400007 In foil protected by Cd from a direct beam. The 1470600400008 scattering cross section of a material is determined 1470600400009 by comparing its back-scattering to that of graphite. 1470600400010 ERR-ANALYS (DATA-ERR) No details on sources of uncertainties. 1470600400011 MONITOR (6-C-0(N,EL)6-C-0,,SIG,,SPA) Graphite. 1470600400012 STATUS (TABLE) page 10. 1470600400013 ENDBIB 11 0 1470600400014 COMMON 1 3 1470600400015 MONIT 1470600400016 B 1470600400017 4.8 1470600400018 ENDCOMMON 3 0 1470600400019 DATA 2 1 1470600400020 DATA DATA-ERR 1470600400021 B B 1470600400022 15.9 0.3 1470600400023 ENDDATA 3 0 1470600400024 ENDSUBENT 23 0 1470600499999 SUBENT 14706005 20210510 14861470600500001 BIB 5 11 1470600500002 REACTION (29-CU-0(N,EL)29-CU-0,,SIG,,SPA) 1470600500003 METHOD The scattering material is placed in layers inside an 1470600500004 inverted Cd cup in such a way that neutrons moving 1470600500005 upwards from the graphite of a thermal column are 1470600500006 scattered backwards from the scatterer and strike an 1470600500007 In foil protected by Cd from a direct beam. The 1470600500008 scattering cross section of a material is determined 1470600500009 by comparing its back-scattering to that of graphite. 1470600500010 ERR-ANALYS (DATA-ERR) No details on sources of uncertainties. 1470600500011 MONITOR (6-C-0(N,EL)6-C-0,,SIG,,SPA) Graphite. 1470600500012 STATUS (TABLE) page 10. 1470600500013 ENDBIB 11 0 1470600500014 COMMON 1 3 1470600500015 MONIT 1470600500016 B 1470600500017 4.8 1470600500018 ENDCOMMON 3 0 1470600500019 DATA 2 1 1470600500020 DATA DATA-ERR 1470600500021 B B 1470600500022 6.9 0.1 1470600500023 ENDDATA 3 0 1470600500024 ENDSUBENT 23 0 1470600599999 SUBENT 14706006 20210510 14861470600600001 BIB 5 11 1470600600002 REACTION (82-PB-0(N,EL)82-PB-0,,SIG,,SPA) 1470600600003 METHOD The scattering material is placed in layers inside an 1470600600004 inverted Cd cup in such a way that neutrons moving 1470600600005 upwards from the graphite of a thermal column are 1470600600006 scattered backwards from the scatterer and strike an 1470600600007 In foil protected by Cd from a direct beam. The 1470600600008 scattering cross section of a material is determined 1470600600009 by comparing its back-scattering to that of graphite. 1470600600010 ERR-ANALYS (DATA-ERR) No details on sources of uncertainties. 1470600600011 MONITOR (6-C-0(N,EL)6-C-0,,SIG,,SPA) Graphite. 1470600600012 STATUS (TABLE) page 10. 1470600600013 ENDBIB 11 0 1470600600014 COMMON 1 3 1470600600015 MONIT 1470600600016 B 1470600600017 4.8 1470600600018 ENDCOMMON 3 0 1470600600019 DATA 2 1 1470600600020 DATA DATA-ERR 1470600600021 B B 1470600600022 10.8 0.2 1470600600023 ENDDATA 3 0 1470600600024 ENDSUBENT 23 0 1470600699999 SUBENT 14706007 20210510 14861470600700001 BIB 6 15 1470600700002 REACTION (76-OS-0(N,EL)76-OS-0,,SIG,,SPA) 1470600700003 METHOD The scattering cross section of one strong absorber 1470600700004 was measured, however that of Cd. The scattering of 1470600700005 Cd causes a background count in the apparatus and 1470600700006 this background with several auxiliary measurements 1470600700007 gives the background scattering of Cd. 1470600700008 ANALYSIS The scattering intensity from a Cd sheet cannot be 1470600700009 compared directly with that from a graphite sheet 1470600700010 because the former is infinitely thick. The ratio 1470600700011 between the back-scattering intensity can be 1470600700012 calculated approximately, however, and Os for Cd 1470600700013 obtained. 1470600700014 ERR-ANALYS (DATA-ERR) Calculational uncertainty, not experimental.1470600700015 MONITOR (48-CD-0(N,EL)48-CD-0,,SIG,,SPA) 1470600700016 STATUS (TABLE) page 11. 1470600700017 ENDBIB 15 0 1470600700018 NOCOMMON 0 0 1470600700019 DATA 2 1 1470600700020 DATA-APRX DATA-ERR 1470600700021 B B 1470600700022 6.0 1.0 1470600700023 ENDDATA 3 0 1470600700024 ENDSUBENT 23 0 1470600799999 ENDENTRY 7 0 1470699999999