ENTRY L0265 20201209 L045L026500000001 SUBENT L0265001 20201209 L045L026500100001 BIB 10 15 L026500100002 TITLE On the Photodisintegration of Beryllium and Deuterium L026500100003 AUTHOR (F.E.Myers,L.C.Van Atta) L026500100004 REFERENCE (J,PR,61,19,1942) L026500100005 #doi:10.1103/physrev.61.19 L026500100006 INSTITUTE (1USAMIT) L026500100007 FACILITY (ACCEL,1USAMIT) Electron accelerator. L026500100008 INC-SOURCE (THRDT) X-rays. L026500100009 DETECTOR (BF3,GEMUC) L026500100010 METHOD The essential features of the experiment are the use L026500100011 of high voltage x-ray to produce the disintegrations L026500100012 and a boron-trifluoride filled proportional counter L026500100013 to detect the resulting neutrons. L026500100014 COMMENT Compiler's comment: The present day threshold values L026500100015 are 1.66 MeV and 2.2 MeV for 9Be and 2H, respectively. L026500100016 HISTORY (20201209C) BP L026500100017 ENDBIB 15 0 L026500100018 NOCOMMON 0 0 L026500100019 ENDSUBENT 18 0 L026500199999 SUBENT L0265002 20201209 L045L026500200001 BIB 3 12 L026500200002 REACTION ((4-BE-9(G,N)4-BE-8,,SIG)//(1-H-2(G,N)1-H-1,,SIG)) L026500200003 ANALYSIS Reaction thresholds were measured in the present L026500200004 work: High voltage x-rays have been used to L026500200005 redetermine the thresholds for the L026500200006 photodisintegration of beryllium and deuterium nuclei, L026500200007 giving 1.627+-0.010 MeV and 2.183+-0.012 MeV, L026500200008 respectively. The cross section ratio was deduced by L026500200009 comparing neutron counting rates 15 keV above the L026500200010 reaction thresholds. Therefore, the beryllium cross L026500200011 section energy was 1.642 MeV and deuterium cross L026500200012 section energy is 2.198 MeV. L026500200013 STATUS (TABLE) page 21. L026500200014 ENDBIB 12 0 L026500200015 NOCOMMON 0 0 L026500200016 DATA 3 1 L026500200017 EN-NM EN-DN DATA-APRX L026500200018 MEV MEV NO-DIM L026500200019 1.642 2.198 10.0 L026500200020 ENDDATA 3 0 L026500200021 ENDSUBENT 20 0 L026500299999 SUBENT L0265003 20201209 L045L026500300001 BIB 3 9 L026500300002 REACTION (1-H-2(G,N)1-H-1,,SIG) L026500300003 ANALYSIS For quantum energies ranging from 0 to 0.25 MeV above L026500300004 threshold or 2.183-2.433 X-ray energy. With even less L026500300005 precision it is possible to estimate the order of L026500300006 magnitude of the total cross section: reasonable L026500300007 guesses as to the effective number of quanta and the L026500300008 sensitivity of neutron detection lead to a value of L026500300009 about 10**(-28) cm2. L026500300010 STATUS (TABLE) page 22. L026500300011 ENDBIB 9 0 L026500300012 NOCOMMON 0 0 L026500300013 DATA 3 1 L026500300014 EN-MIN EN-MAX DATA-APRX L026500300015 MEV MEV MB L026500300016 2.183 2.433 0.1 L026500300017 ENDDATA 3 0 L026500300018 ENDSUBENT 17 0 L026500399999 ENDENTRY 3 0 L026599999999