ENTRY 20640 20060807 21782064000000001 SUBENT 20640001 20060807 21782064000100001 BIB 15 41 2064000100002 INSTITUTE (2UK NPL) 2064000100003 REFERENCE (J,JNE/AB,17,125,196306) 2064000100004 AUTHOR (E.J.Axton) 2064000100005 TITLE -Absolute measurement of the neutron flux density 2064000100006 in the a.E.R.E. Reactor gleep .- 2064000100007 INC-SOURCE (REAC )Sample position of the a.E.R.E. Reactor gleep. 2064000100008 SAMPLE .Foils with thickness less than 0.002 in. 2064000100009 .The manganese foil contained 11 per cent nickel 2064000100010 METHOD (ACTIV) Activity measurements of Au-198 and Mn-56, 2064000100011 Cd-filter method. 2064000100012 (COINC) For Mn-56 the absolute activity was 2064000100013 determined by 4pi-beta-gamma coincidence technique. 2064000100014 DETECTOR (PROPC) 4pi-beta gas flow proportional counter 2064000100015 (NAICR) 1 in. * 1.5 in. NaI(Tl) crystal 2064000100016 ANALYSIS .For calculation of the flux density and the so- 2064000100017 factor of Mn-55 the westcott-formalism has been used 2064000100018 MONITOR (79-AU-197(N,G)79-AU-198,,RI) 2064000100019 Thermal cross section=98.8 B, S0- 2064000100020 factor = 17.3 (it amounts to a resonance integral 2064000100021 of 1558 B including the 1/V-contribution) 2064000100022 .Assumed thermal cross section of manganese = 13.25B 2064000100023 .Assumed g-factors for neutron temperature of 80 deg., 2064000100024 Mn-55 = 1.000 and Au-197 = 1.0086. 2064000100025 COMMENT .The 4pi-beta-gamma coincidence technique is shown 2064000100026 to be suitable for absolute measurement of Mn-56. 2064000100027 STATUS .Taken from j.Nucl. Energy, 17(1963)125. 2064000100028 CORRECTION .For the efficiencies of beta and gamma-detectors, 2064000100029 for gamma-gamma coincidences, for decay scheme, for 2064000100030 internal conversion, for flux depression and for 2064000100031 self-shielding effects. 2064000100032 .For Au-197 an additional correction for the deviation 2064000100033 of the cross section from the 1/V-law in maxwellian 2064000100034 region (increase of the so-factor by 0.027). 2064000100035 ERR-ANALYS .For flux density standard error +- 3 per cent , 2064000100036 systematic error +- 1 per cent, accuracy of the mean 2064000100037 flux density +- 2 per cent. 2064000100038 .For the so-factor of Mn-55 no errors is given. 2064000100039 HISTORY (19760610C) 2064000100040 (19770331E) 2064000100041 (20060807A) Date and reference are corrected. 2064000100042 (20060807U) Last checking has been done. 2064000100043 ENDBIB 41 0 2064000100044 NOCOMMON 0 0 2064000100045 ENDSUBENT 44 0 2064000199999 SUBENT 20640002 20060807 21782064000200001 BIB 2 6 2064000200002 REACTION (25-MN-55(N,G)25-MN-56,,RI,,RNV) 2064000200003 FROM THE GIVEN SO-VALUE OF 2064000200004 0.737 THE RESONANCE INTEGRAL EXCLUDING THE 1/V- 2064000200005 CONTRIBUTION HAS BEEN CALCULATED 2064000200006 HISTORY (19760610C) 2064000200007 (19770331E) 2064000200008 ENDBIB 6 0 2064000200009 NOCOMMON 0 0 2064000200010 DATA 2 1 2064000200011 EN-MIN DATA 2064000200012 EV B 2064000200013 5.0000E-01 8.6000E+00 2064000200014 ENDDATA 3 0 2064000200015 ENDSUBENT 14 0 2064000299999 ENDENTRY 2 0 2064099999999