ENTRY 21520 20071001 21872152000000001 SUBENT 21520001 20071001 21872152000100001 BIB 13 73 2152000100002 INSTITUTE (2ZZZISP) Authors, 2152000100003 (2FR SAC) Experimental site. 2152000100004 (2FR CAD) Last author. 2152000100005 REFERENCE (C,65SALZBURG,1,255,196503) 2152000100006 AUTHOR (G.Fraysse,A.Prosdocimi) 2152000100007 TITLE -Fission cross section measurement of U-235 and 2152000100008 Pu-239 for low energy neutrons.- 2152000100009 FACILITY (SPECC,2FR SAC) Crystal spectrometer ( Three orien- 2152000100010 tations used), 2152000100011 (REAC,2FR SAC) El-3 reactor in saclay, 18 mw power. 2152000100012 INC-SOURCE (REAC) Reactor neutrons. 2152000100013 SAMPLE .Boron foils deposited by electron bombardment under 2152000100014 vacuum on aluminium backings weighted before their 2152000100015 removal from the vacuum system. Elemental boron was 2152000100016 used, containing 19.81 at. Percent of B-10. However 2152000100017 the preparation of the foil may enrich the foil in 2152000100018 B-10 to about 20.3 at.Perc. This effect has not been 2152000100019 checked and is one of the main sources of error of 2152000100020 the experiment. Two layers are used - 3.329e+18 2152000100021 atoms/cm**2, and 4.183e+18 atoms/cm**2. 2152000100022 .Fissile foil preparation fully described in nucl. 2152000100023 Instr. Meth 21(1963)161. Plastic foils of about 25 2152000100024 micrograms/cm**2 are metallized with an evaporated 2152000100025 aluminium layer to reduce strongly the light 2152000100026 transmission. Fissile layers deposited by electro- 2152000100027 spraying of an acetate uranium or plutonium solution. 2152000100028 In U-layer, composed of a mixture of U-O2(CH3COO)2 and2152000100029 U-O2(CH3COO)3, 2/3 of the total weight was fissile 2152000100030 material. More details in Table 1 of reference. 2152000100031 METHOD (STTA) Comparison of fission foils with natural boron 2152000100032 foils at 3 energies. The 2200 m/sec value is 2152000100033 obtained by fitting the cross section shape to 2152000100034 these 3 data points. 2152000100035 DETECTOR (IOCH ) Gridded pulse ionization chamber for 2152000100036 the boron counting in a 2*pi geometry. It was 2152000100037 filled with a mixture of 95% argon and 5% C-O(2) at 2152000100038 580 mm Hg. 2152000100039 (SOLST) A solid state detector in low geometry 2152000100040 (0.01 of 2*pi) for counting the fission fragments 2152000100041 the energy resolution was about 2 percent, 1 cm**2 2152000100042 sensitive area, resistivity 450 Ohm*cm, 30 volt 2152000100043 bias. 2152000100044 (COIN,SCIN,SCIN) At the energy of 0.275 eV, the 2152000100045 fission fragments are counted with two xenon 2152000100046 filled scintillators detecting the two coincident 2152000100047 fragments in a 4*pi geometry. Pressure 1.5 atm., 2152000100048 Energy resolution about 20 percent. The xenon gas 2152000100049 was purified by circulation over a calcium purifier 2152000100050 heated at 400 deg C. 2152000100051 CORRECTION .Presence in the neutron beam of neutrons with 2152000100052 harmonic wave-lengths (ff-counting and B-counting) 2152000100053 .Background noise (B-counting) 2152000100054 .Dead time (FF counting, B- counting, fission foil 2152000100055 Alpha counting). 2152000100056 .Geometrical efficiency (FF counting, B- counting, 2152000100057 fission foil alpha-counting) 2152000100058 .Discrimination and selfabsorption (alpha spectra) 2152000100059 .Backscattering (ff-counting, B-counting, fission 2152000100060 foil alpha counting) 2152000100061 .Isotopic composition (fission foils) 2152000100062 .Alpha pile up (Pu- measurements) 2152000100063 .Different neutron flux upon target and monitor. 2152000100064 .Neutron beam profile. 2152000100065 ERR-ANALYS (ERR-T) The total error given includes all the errors, 2152000100066 except those due to the uncertainties in the 2152000100067 isotopic composition and chemical purity of the 2152000100068 boron foils. 2152000100069 STATUS (NDD) Data taken from NEUDADA. 2152000100070 HISTORY (19800422T) G.C. 2152000100071 (19800429E) 2152000100072 (20070926A) Date is corrected. DATA-ERR To ERR=T , 2152000100073 units in SAN 004 changed - SM 2152000100074 (20071001U) Last corrections have been done. 2152000100075 ENDBIB 73 0 2152000100076 NOCOMMON 0 0 2152000100077 ENDSUBENT 76 0 2152000199999 SUBENT 21520002 20071001 21872152000200001 BIB 2 2 2152000200002 REACTION (92-U-235(N,F),,SIG) 2152000200003 MONITOR (5-B-0(N,A),,SIG) A0+A1 particles from B-10 2152000200004 ENDBIB 2 0 2152000200005 NOCOMMON 0 0 2152000200006 DATA 6 2 2152000200007 EN-NRM EN EN-RSL DATA ERR-T MONIT 2152000200008 MILLI-EV MILLI-EV MILLI-EV B B B 2152000200009 3.22E+01 3.216E+01 4.E-02 5.12E+02 1.1E+01 6.74E+022152000200010 6.26E+01 6.26E+01 1.E-01 3.43E+02 9. 4.83E+022152000200011 ENDDATA 4 0 2152000200012 ENDSUBENT 11 0 2152000299999 SUBENT 21520003 19800429 00002152000300001 BIB 4 6 2152000300002 REACTION (94-PU-239(N,F),,SIG) 2152000300003 MONITOR (5-B-0(N,A),,SIG) A0+A1 PARTICLES 2152000300004 FROM B-10. 2152000300005 STATUS (SPSDD,21780003) 2152000300006 HISTORY (800422T) G.C. 2152000300007 (800429E) 2152000300008 ENDBIB 6 0 2152000300009 NOCOMMON 0 0 2152000300010 NODATA 0 0 2152000300011 ENDSUBENT 10 0 2152000399999 SUBENT 21520004 20071001 21872152000400001 BIB 2 3 2152000400002 REACTION ((94-PU-239(N,F),,SIG)/(92-U-235(N,F),,SIG)) 2152000400003 HISTORY (20070930A) RATIO to DATA, ARB-UNITS to NO-DIM 2152000400004 changed 2152000400005 ENDBIB 3 0 2152000400006 NOCOMMON 0 0 2152000400007 DATA 4 2 2152000400008 EN EN-RSL DATA ERR-T 2152000400009 MILLI-EV MILLI-EV NO-DIM NO-DIM 2152000400010 3.216E+01 4.E-02 1.309 2.3E-02 2152000400011 6.260E+01 1.E-01 1.533 3.7E-02 2152000400012 ENDDATA 4 0 2152000400013 ENDSUBENT 12 0 2152000499999 SUBENT 21520005 20071001 21872152000500001 BIB 4 4 2152000500002 REACTION (94-PU-239(N,F),,SIG) 2152000500003 MONITOR (92-U-235(N,F),,SIG) 2152000500004 STATUS (DEP,21520004) 2152000500005 HISTORY (20070930U) MONIT Heading moved to COL.4 2152000500006 ENDBIB 4 0 2152000500007 NOCOMMON 0 0 2152000500008 DATA 5 2 2152000500009 EN EN-RSL DATA ERR-T MONIT 2152000500010 MILLI-EV MILLI-EV B B B 2152000500011 3.216E+01 4.E-02 6.58E+02 1.2E+01 5.03E+02 2152000500012 6.260E+01 1.E-01 5.15E+02 1.2E+01 3.36E+02 2152000500013 ENDDATA 4 0 2152000500014 ENDSUBENT 13 0 2152000599999 SUBENT 21520006 20071001 21872152000600001 BIB 3 5 2152000600002 REACTION (92-U-235(N,F),,SIG) 2200 m/sec value obtained 2152000600003 from a fit to the sigma(F)/sigma(B(N,a)) data 2152000600004 of the world recommended shape. 2152000600005 MONITOR (5-B-0(N,A),,SIG) A0+a1 particles from B-10 2152000600006 HISTORY (20070930U) MONIT Heading moved to COL.4 2152000600007 ENDBIB 5 0 2152000600008 NOCOMMON 0 0 2152000600009 DATA 5 1 2152000600010 EN DATA ERR-T MONIT MONIT-ERR 2152000600011 EV B B B B 2152000600012 2.53E-02 5.82E+02 1.E+01 7.61E+02 2. 2152000600013 ENDDATA 3 0 2152000600014 ENDSUBENT 13 0 2152000699999 SUBENT 21520007 20071001 21872152000700001 BIB 3 5 2152000700002 REACTION (94-PU-239(N,F),,SIG) 2200 m/sec value obtained 2152000700003 by fitting to the sigma(F)/sigma(B(N,a)) data 2152000700004 the world recommended shape. 2152000700005 MONITOR (5-B-0(N,A),,SIG) A0+A1 particles from B-10. 2152000700006 HISTORY (20070930U) MONIT Heading moved to COL.4 2152000700007 ENDBIB 5 0 2152000700008 NOCOMMON 0 0 2152000700009 DATA 5 1 2152000700010 EN DATA ERR-T MONIT MONIT-ERR 2152000700011 EV B B B B 2152000700012 2.53E-02 7.4E+02 1.E+01 7.61E+02 2. 2152000700013 ENDDATA 3 0 2152000700014 ENDSUBENT 13 0 2152000799999 SUBENT 21520008 20071001 21872152000800001 BIB 3 3 2152000800002 REACTION (94-PU-239(N,F),,SIG) 2200 m/sec value. 2152000800003 MONITOR (92-U-235(N,F),,SIG) 2200 m/sec value. 2152000800004 HISTORY (20070930U) MONIT Heading moved to COL.4 2152000800005 ENDBIB 3 0 2152000800006 NOCOMMON 0 0 2152000800007 DATA 4 1 2152000800008 EN DATA ERR-T MONIT 2152000800009 EV B B B 2152000800010 2.53E-02 7.37E+02 9. 5.77E+02 2152000800011 ENDDATA 3 0 2152000800012 ENDSUBENT 11 0 2152000899999 SUBENT 21520009 20071001 21872152000900001 BIB 1 3 2152000900002 REACTION (94-PU-239(N,F),,SIG) 2200 m/sec, mean value 2152000900003 from two determinations, viz. 1.With U-235 2152000900004 as monitor, and 2.With B-10 as monitor. 2152000900005 ENDBIB 3 0 2152000900006 NOCOMMON 0 0 2152000900007 DATA 3 1 2152000900008 EN DATA ERR-T 2152000900009 EV B B 2152000900010 2.53E-02 7.38E+02 7. 2152000900011 ENDDATA 3 0 2152000900012 ENDSUBENT 11 0 2152000999999 ENDENTRY 9 0 2152099999999