ENTRY G0005 20060729 G014G000500000001 SUBENT G0005001 20060729 G014G000500100001 BIB 17 86 G000500100002 TITLE Differential cross sections for the d(g,n) reaction G000500100003 below 10 MeV G000500100004 AUTHOR (Y.Birenbaum,Z.Berant,A.Wolf,S.Kahane,R.Moreh) G000500100005 INSTITUTE (3ISLNEG) G000500100006 REFERENCE (J,PRL,61,(7),810,198808) ang. distribution coeff. at G000500100007 diff. gamma energies are given. graph of ang. G000500100008 distribution for various photon energies are given. G000500100009 (C,84KNOX,,213,198409) graph of ang. distribution at G000500100010 two photon energies are given. G000500100011 SAMPLE the target was a thin-walled glass vial, 4.4 cm in dia.G000500100012 and 5 cm high, filled with high-purity heavy water G000500100013 (D2O), 99.8 per-cent D), placed with its axis G000500100014 perpendicular to the reaction plane. G000500100015 FACILITY (REAC) IRR-2 reactor. G000500100016 INC-SOURCE photo neutron spectra were taken at angles of 30 deg. G000500100017 to 150 deg, in 10 deg. steps, at the following G000500100018 energies: 5970, 7279, and 7639 keV from the Fe(n,g) G000500100019 source; 6837, 8533, and 8999 keV from the Ni(n,g) G000500100020 source; and 7939, 8498, and 8884 keV from the Cr(n,g) G000500100021 source. G000500100022 INC-SPECT highly monochromatic gamma lines (delta e approx. G000500100023 20 eV) were obtained from thermal-neutron capture G000500100024 in metallic disk of Fe, Ni, and Cr, placed near the G000500100025 core of the IRR-2 reactor. Typical intensities for G000500100026 the strong gamma lines were about 10**6 photons/ G000500100027 cm**2 * s. G000500100028 ANALYSIS The neutron yields at the various angles were G000500100029 normalized for the running time and the average photon G000500100030 flux during each run. G000500100031 Absolute differential cross sections were obtained G000500100032 from the measured angular distributions. G000500100033 DETECTOR He-3 spectrometer, having a typical resolution of G000500100034 60 - keV FWHM for 3 - MeV neutrons. G000500100035 PART-DET (N) G000500100036 ERR-ANALYS (ERR-S) the errors quoted in angular dist. coeff. G000500100037 in the c.m. system include only the statistical G000500100038 uncertainties. G000500100039 (ERR-SYS) systematic errors, such as may result from G000500100040 uncertainties in the calculated relative efficiency G000500100041 and multiple scattering contribution, and from G000500100042 uncertainties in the photon flux normalization and G000500100043 in the absolute cross sections, were estimated to be G000500100044 less than 6 percent. G000500100045 -the photons were collimated and neutron filtered G000500100046 in a tangential beam port, and a parallel beam, G000500100047 with an angular divergence less than 1 deg., was G000500100048 obtained at the target position. G000500100049 -the dimensions of the target were selected on the G000500100050 basis of a monte carlo calculation which evaluated G000500100051 the effect of neutron multiple scattering on the G000500100052 peak areas. This was found to be less than 1 percent, G000500100053 reflecting the high resolution of the present system. G000500100054 -the experimental setup was tested for systematic G000500100055 asymmetries by measuring the angular distribution of G000500100056 neutron groups emitted from known isolated resonances, G000500100057 which, due to their defined spin and parity, should G000500100058 be symmetric around 90 deg. the system was found to G000500100059 be symmetric to within +- 3 percent. G000500100060 -because of the angular energy variation of the G000500100061 emitted neutrons (i.e., fo E(gamma) = 9 MeV, G000500100062 E(n)(40 deg.) - E(n)(140 deg) approx. 600 keV), a G000500100063 correction was introduced to take into account the G000500100064 change of the detector efficiency with energy. this G000500100065 was done with use of a relative efficiency curve, G000500100066 obtained from a Monte Carlo calculation for the He-3 G000500100067 spectrometer, at the present geometry. The calculation G000500100068 was tested against a measurement of the relative G000500100069 efficiency for neutron energies of 0.1 to 2.77 MeV, G000500100070 and was found to reproduce the experimental efficiency G000500100071 to within 5 percent. G000500100072 MONITOR (1-H-2(G,N)1-H-1,,SIG) absolute diff. cross sections G000500100073 were obtained from the measured angular distributions G000500100074 by using the results of a previous measurement G000500100075 MONIT-REF (,Birenbaum+,J,PR/C,32,1825,1985) in which G000500100076 the total D(g,n) cross section was obtained with an G000500100077 accuracy generally better than 3 percent. G000500100078 -at energies not studied by the above measurement by G000500100079 Y.Birenbaum et. al, an interpolation was made using a G000500100080 smooth exponential function which reproduced the G000500100081 exp. cross sections to within 0.5 percent. G000500100082 COMMENT the results were found to be in good agreement with G000500100083 theory. G000500100084 STATUS (TABLE) data taken from table 1 of Physical Review G000500100085 Letters. vol. 61, no. 7, p. 810, 15 aug. 1988. G000500100086 HISTORY (19881205C) TMK. G000500100087 (20060728A) BIB section updated G000500100088 ENDBIB 86 0 G000500100089 COMMON 1 3 G000500100090 ERR-SYS G000500100091 PER-CENT G000500100092 6.0 G000500100093 ENDCOMMON 3 0 G000500100094 ENDSUBENT 93 0 G000500199999 SUBENT G0005002 20060729 G014G000500200001 BIB 1 1 G000500200002 REACTION (1-H-2(G,N)1-H-1,,DA,,LEG) G000500200003 ENDBIB 1 0 G000500200004 NOCOMMON 0 0 G000500200005 DATA 4 32 G000500200006 NUMBER-CM EN DATA-CM ERR-S G000500200007 NO-DIM KEV MB/SR MB/SR G000500200008 0. 5970. 172. 8. G000500200009 0. 6837. 157. 7. G000500200010 0. 7279. 149. 2. G000500200011 0. 7639. 144. 3. G000500200012 0. 7939. 139. 3. G000500200013 0. 8498. 131. 2. G000500200014 0. 8533. 130. 3. G000500200015 0. 8884. 126. 2. G000500200016 1. 5970. -25.8 12.0 G000500200017 1. 6837. -12.5 7.8 G000500200018 1. 7279. -7.5 10.5 G000500200019 1. 7639. -14.4 5.7 G000500200020 1. 7939. -12.5 9.7 G000500200021 1. 8498. -7.9 10.5 G000500200022 1. 8533. -17.0 10.4 G000500200023 1. 8884. -8.8 5.0 G000500200024 2. 5970. -156.3 12.0 G000500200025 2. 6837. -139.3 9.4 G000500200026 2. 7279. -132.9 9.0 G000500200027 2. 7639. -126.4 9.3 G000500200028 2. 7939. -102.9 8.3 G000500200029 2. 8498. -106.2 11.8 G000500200030 2. 8533. -126.6 1.3 G000500200031 2. 8884. -106.8 5.0 G000500200032 3. 5970. -20.6 15.5 G000500200033 3. 6837. -25.0 12.5 G000500200034 3. 7279. -1.5 14.9 G000500200035 3. 7639. -2.9 11.5 G000500200036 3. 7939. -22.3 8.3 G000500200037 3. 8498. -14.4 10.5 G000500200038 3. 8533. -6.5 13.1 G000500200039 3. 8884. -16.3 5.0 G000500200040 ENDDATA 34 0 G000500200041 ENDSUBENT 40 0 G000500299999 ENDENTRY 2 0 G000599999999