ENTRY 20026 20120708 22322002600000001 SUBENT 20026001 20120708 22322002600100001 BIB 15 61 2002600100002 INSTITUTE (2SWDFOA) 2002600100003 REFERENCE (J,AF,29,45,196501) 2002600100004 AUTHOR (H.Conde,S.Schwarz,N.Starfelt) 2002600100005 TITLE A method for the absolute measurement of fast neutron 2002600100006 flux with a large liquid scintillator 2002600100007 FACILITY (VDG,2SWDFOA) Van de Graaff generator 2002600100008 INC-SOURCE (P-LI7) Pulsed neutron beam, Li7(p,n)Be7 reaction, 2002600100009 Li-metal target 2002600100010 .The neutrons from the source were collimated by a 2002600100011 channel, 40 cm long, through a block of paraffin. 2002600100012 SAMPLE .Li-6 glass containing 5.07 +- 0.08% by weight. The 2002600100013 isotopic enrichment was 95.17 +- 0.02% in Li-6. 2002600100014 Its dimensions were 1.5 inch diameter, and 3/8 inch 2002600100015 thickness. At the same time detector. 2002600100016 METHOD .A Li6-loaded glass scintillator was mounted 2002600100017 in the centre of a liquid scintillator tank and the 2002600100018 number of (n,alpha) reactions in the glass was re- 2002600100019 gistered for a certain integrated neutron flux 2002600100020 which was given by the scintillator tank. 2002600100021 The efficiency of the scintillator tank for an 2002600100022 isotropic neutron flux was well known. For the 2002600100023 collimated beam used here, a lead scatterer was placed2002600100024 in the beam, which acts as a pure isotropic scatterer.2002600100025 (TRN) The fraction of neutrons scattered was 2002600100026 determined by a transmission measurement (the total 2002600100027 cross section is equal to the scattering cross sect.) 2002600100028 in this way the incoming neutron flux can be 2002600100029 absolutely measured. 2002600100030 (TOF) Time-of-flight techniques have been used to 2002600100031 select the primary neutrons and discriminate against 2002600100032 neutrons scattered in the glass, thermalized in the 2002600100033 tank and scattered back in the glass-detector. 2002600100034 DETECTOR (GLASD) Li6-loaded glass scintillator 2002600100035 (STANK) Liquid scintillator tank for neutron flux 2002600100036 measurement by looking at the fraction of the 2002600100037 collimated neutron beam which was scattered by means 2002600100038 of a lead scatterer mounted at the center of the tank 2002600100039 just in front of the glass detector. 2002600100040 .The flux is monitored by a current integrator on the 2002600100041 lithium metal target and by a Li6-I(Eu) scintillator 2002600100042 in a polyethylene sphere. 2002600100043 COMMENT .Value somewhat lower than the value published in 2002600100044 BNL-325. 2002600100045 .Good agreement with the relative measurement of 2002600100046 Schwarz et al, Nucl.Phys.63(1965)593.(See entry 20059)2002600100047 REL-REF (A,20059001,S.Schwarz+,J,NP,63,593,1965) 2002600100048 CORRECTION .Scattering in the scintillator liquid of neutrons 2002600100049 scattered out of the beam increase the number of 2002600100050 neutrons detected by the Li6-glass. The use of time- 2002600100051 of-flight techniques keeps this correction below 0.5%.2002600100052 .Correction for multiple scattering in the glass 2002600100053 detector using a Monte-Carlo technique, 7%. 2002600100054 ERR-ANALYS (DATA-ERR) No information given 2002600100055 STATUS (TABLE) .Data from AF,29,45,1965 2002600100056 HISTORY (19710428T) From NEUDADA file 2002600100057 (19710908E) 2002600100058 (19810121A) G.C. Converted to reaction formalism, error2002600100059 analysis changed. 2002600100060 (19810213E) 2002600100061 (20120708A) SD: Updated to new date formats,lower case.2002600100062 Corrections according last EXFOR rules and Dict. 2002600100063 ENDBIB 61 0 2002600100064 NOCOMMON 0 0 2002600100065 ENDSUBENT 64 0 2002600199999 SUBENT 20026002 20120708 22322002600200001 BIB 1 1 2002600200002 REACTION (3-LI-6(N,T)2-HE-4,,SIG) 2002600200003 ENDBIB 1 0 2002600200004 NOCOMMON 0 0 2002600200005 DATA 4 1 2002600200006 EN EN-RSL DATA DATA-ERR 2002600200007 MEV MEV B B 2002600200008 1.0000E-01 5.0000E-03 6.4000E-01 2.0000E-02 2002600200009 ENDDATA 3 0 2002600200010 ENDSUBENT 9 0 2002600299999 ENDENTRY 2 0 2002699999999