ENTRY 41501 20080331 41434150100000001 SUBENT 41501001 20080331 41434150100100001 BIB 16 49 4150100100002 TITLE Measurements of delayed neutron yields from thermal 4150100100003 neutron induced fission of 237-Np. 4150100100004 AUTHOR (N.A.Gundorin, K.V.Zhdanova, V.E.Zhuchko,L.B.Pikel'ner,4150100100005 N.V.Rebrova, I.M.Salamatin, V.I.Smirnov, V.I.Furman) 4150100100006 INSTITUTE (4ZZZDUB) 4150100100007 REFERENCE (J,YF,70,(6),1011,200706) Main Reference 4150100100008 (J,PAN,70,(6),975,200706)Engl.translation of YF,70,10114150100100009 REL-REF (N,,S.B.BORZAKOV+,J,AE,79,231,1995) Experiment.method 4150100100010 FACILITY (REAC,4ZZZDUB) Fast pulse reactor IBR-2 4150100100011 Improved (2004 year) exp. setup "Isomer-M" on the 4150100100012 channel 11-B of IBR-2 reactor. 4150100100013 (CHOPS,4ZZZDUB) Bent mirror neutron guide and neutron 4150100100014 cadmium chopper synchronized with reactor neutron 4150100100015 bursts cadmium "ping-pong". 4150100100016 INC-SOURCE (REAC) IBR-2 in pulsed mode, frequency - 5Hz, 4150100100017 peak power - 1300 MVt. 4150100100018 INC-SPECT Neutron beam density at output of neutron guide - 4150100100019 6.E+05 n/s/cm**2. 4150100100020 DETECTOR (D4PI,PROPC) 18 proportional He-3 counters SNM-33 of 4150100100021 32mm diameter, 52cm length, at 2 atm. pressure, 4150100100022 1850 V voltage, installed in plexiglass block of 4150100100023 50*50*70 cm size. 4150100100024 Detector efficiency was defined at experiment with 4150100100025 U-235 sample. EPS(prompt)/EPS(delayed)=0.76+-0.02. 4150100100026 SAMPLE U-235 of about 8mg weight on aluminum foil. 4150100100027 Neptunium oxide NpO2 sample of 60 mm diameter, 23.05 g 4150100100028 mass. Installed in nickel shell inside of hermetic 4150100100029 aluminum container.Weight 40.4 Gram, 237-Np content - 4150100100030 99.999%. U-235 and Pu-239 admixtures less 1.E-06. 4150100100031 MONITOR ((MONIT1)92-U-235(N,F),PR,NU) 4150100100032 From LANDOLT-BOERSTEIN, vol.16. 4150100100033 Low Energy Neutron Physics (Springer). 4150100100034 ((MONIT2)92-U-235(N,F),DL,NU) 4150100100035 ((MONIT3)93-NP-237(N,F),PR,NU) 4150100100036 MONIT-REF ((MONIT2),E.FORT+,J,PNE,41,385,2002) 4150100100037 MONIT3 Reference the same as MONIT1. 4150100100038 METHOD (TOF) 23 m flight path. 4150100100039 CORRECTION Corrections were Made For : 4150100100040 contribution of U-236 and Pu-239 admixtures - 1-2%, 4150100100041 U-233 accumulation due to radioactive decay of Np-237 4150100100042 during the time of 10 years from sample production 4150100100043 - 4 %, 4150100100044 background processes - neptunium fission by fast 4150100100045 neutrons, neutron scattering in sample, background of 4150100100046 experimental hall,fast neutron production in (alpha,n)4150100100047 reaction of oxygen of NpO2 sample - from 20 to 40%. 4150100100048 HISTORY (20070831C) Compiled at CJD. M.M. 4150100100049 (20080331U) 2nd Reference was added. 4150100100050 STATUS (COREL,41366001) 4150100100051 ENDBIB 49 0 4150100100052 COMMON 6 3 4150100100053 MONIT1 MONIT1-ERR MONIT2 MONIT2-ERR MONIT3 MONIT3-ERR 4150100100054 PRT/FIS PRT/FIS PRT/FIS PRT/FIS PRT/FIS PRT/FIS 4150100100055 2.413 0.007 0.01659 0.00035 2.47 0.14 4150100100056 ENDCOMMON 3 0 4150100100057 ENDSUBENT 56 0 4150100199999 SUBENT 41501002 20070831 41414150100200001 BIB 4 5 4150100200002 REACTION (93-NP-237(N,F),DL,NU,,MXW) 4150100200003 ANALYSIS Averaged over three measurements values: 4150100200004 0.0108+-0.0009, 0.0114+-0.0014, 0.0107+-0.0014. 4150100200005 ERR-ANALYS (ERR-T) Total Error 4150100200006 STATUS From the Text of 1st Reference 4150100200007 ENDBIB 5 0 4150100200008 NOCOMMON 0 0 4150100200009 DATA 3 1 4150100200010 EN-MEAN DATA ERR-T 4150100200011 EV PRT/FIS PRT/FIS 4150100200012 0.025 0.0110 0.0009 4150100200013 ENDDATA 3 0 4150100200014 ENDSUBENT 13 0 4150100299999 ENDENTRY 2 0 4150199999999