ENTRY 13847 20020812 00001384700000001 SUBENT 13847001 20020812 00001384700100001 BIB 14 36 1384700100002 INSTITUTE (1USAGA) 1384700100003 REFERENCE (J,NSE,12,190,1962) 1384700100004 AUTHOR (W.M.Lopez,J.R.Beyster) 1384700100005 TITLE Measurement of Neutron Diffusion Parameters in Water 1384700100006 by the Pulsed Neutron Method 1384700100007 FACILITY (LINAC) Electron linear accelerator. 1384700100008 INC-SOURCE (PHOTO). Pb or W target. 1384700100009 SAMPLE Large and small rectangular water samples with values 1384700100010 of the geometrical buckling from 0.014 cm**(-2) to 1384700100011 0.59 cm**(-2). 1384700100012 METHOD Pulsed neutron method applied to measure the time- 1384700100013 dependent flux distributions as a function of 1384700100014 geometrical size. 1384700100015 Thermal absorption cross section of hydrogen inferred 1384700100016 from theoretical fit to the measured data. 1384700100017 DETECTOR (FISCH) Small fission counter placed in an external 1384700100018 position for dimension <5 in. and at the center of the1384700100019 large samples. Two fission counters used for the 1384700100020 large-geometry measurements. 1384700100021 ANALYSIS Neutron mean lifetimes measured for a variety of 1384700100022 sample sizes and fitted to the diffusion-theory 1384700100023 representation by the method of least squares. 1384700100024 Fourier analysis applied for time-dependent spatial 1384700100025 distribution of thermalized neutrons to separate 1384700100026 fundamental mode decay from higher modes in large 1384700100027 geometries. Spatial distribution assumed 1384700100028 approximately separable in x,y, and z at some time 1384700100029 after initial pulse of fast neutrons. 1384700100030 CORRECTION Raw data corrected for coincidence losses and 1384700100031 normalized to constant source intensity. 1384700100032 Flight-time and container-reflection effects taken 1384700100033 into account. 1384700100034 ERR-ANALYS (DATA-ERR) RMS error of the uncertainties estimated 1384700100035 from the least squares procedure. 1384700100036 STATUS Data taken from reference text. 1384700100037 HISTORY (20020731C) IS 1384700100038 ENDBIB 36 0 1384700100039 COMMON 1 3 1384700100040 TEMP 1384700100041 DEG-C 1384700100042 26.7 1384700100043 ENDCOMMON 3 0 1384700100044 ENDSUBENT 43 0 1384700199999 SUBENT 13847002 20020923 00001384700200001 BIB 1 1 1384700200002 REACTION (1-H-1(N,G)1-H-2,,SIG,,MXW,DERIV) 1384700200003 ENDBIB 1 0 1384700200004 NOCOMMON 0 0 1384700200005 DATA 3 1 1384700200006 EN-DUMMY DATA DATA-ERR 1384700200007 EV MB MB 1384700200008 0.0253 325. 2. 1384700200009 ENDDATA 3 0 1384700200010 ENDSUBENT 9 0 1384700299999 ENDENTRY 2 0 1384799999999