ENTRY 40141 20210319 41954014100000001 SUBENT 40141001 20210319 41954014100100001 BIB 9 32 4014100100002 TITLE Average number of prompt neutrons in spontaneous 4014100100003 fission of Fm-256 4014100100004 AUTHOR (M.Dakovskii,Yu.A.Lazarev,Yu.Ts.Oganesyan) 4014100100005 INSTITUTE (4ZZZDUB) 4014100100006 REFERENCE (J,SNP,16,641,1973) Engl.translation of: 4014100100007 (J,YF,16,1167,1972) Issue 6. 4014100100008 (R,JINR-P15-6218,1976) Preprint. 4014100100009 FACILITY (CYCLO,4ZZZDUB) Fm-256 was synthesized in the internal 4014100100010 Ne-22 (130 MeV ion energy, about 6E+13 prt/sec 4014100100011 intensity) ion beam of U-300 cyclotron by reaction 4014100100012 U-238(Ne-22,p3n)Md-256 -> E.C.(90.%,HL=1.33hr -> Fm-2564014100100013 which cross-section is about 2.E-33 cm**2. 4014100100014 METHOD (COINC) The coincidences between the impulses from 4014100100015 neutron detectors and fission fragment detectors. 4014100100016 DETECTOR (COIN,LONGC,SIBAR) Long counter for recording of 4014100100017 neutrons; consists of 36 He-3 counters placed into 4014100100018 plexiglas block. For recording of fission fragments 4014100100019 the surface-barrier Si(Au) detectors were used. 4014100100020 The efficiency of fission-neutron registration 4014100100021 determined for Cm-244 was 48.5%; 4014100100022 background < 0.001 n/fis. 4014100100023 ERR-ANALYS Background due to spontaneous fission of Cf-246 and 4014100100024 Fm-252 (presented in investigated source) can not 4014100100025 introduce an error > 0.1 % in measured NU. 4014100100026 HISTORY (19730322C) Compiled at the centre 4014100100027 (19860506U) Some corrections made 4014100100028 (19861009U) One extra reaction line added 4014100100029 (20150316A) M.M. Refs. J,SNP,16,641,1973; 4014100100030 J,YF,16,(6),1167,1972 were added. 4014100100031 BIB information was updated. NO-DIM -> PRT/FIS for NU .4014100100032 Subents 003,004 were added. 4014100100033 (20210319U) Minor correction of free text. 4014100100034 ENDBIB 32 0 4014100100035 NOCOMMON 0 0 4014100100036 ENDSUBENT 35 0 4014100199999 SUBENT 40141002 20210319 41954014100200001 BIB 8 18 4014100200002 REACTION 1(100-FM-256(0,F),PR,NU) 4014100200003 2((100-FM-256(0,F),PR,NU)/(96-CM-244(0,F),PR,NU)) 4014100200004 ANALYSIS Time distribution of registered fission events agrees 4014100200005 with FM-256 half-life 2.62 hr (97% spon.fission) 4014100200006 MONITOR 1(96-CM-244(0,F),PR,NU) Average prompt neutron number 4014100200007 for spontaneous fission of Fm-256 is defined relative 4014100200008 to average prompt neutron number for Cm-244 spontaneous4014100200009 fission using the source of 13 fis/min intensity. 4014100200010 MONIT-REF (,A.H.Jaffey+,J,NP/A,145,1,1970) 4014100200011 MISC-COL (MISC1) Variance for Fm-256 fis. neutrons multiplicity,4014100200012 width of NU distribution 1.48+-0.22 prt/fis. 4014100200013 (MISC2) Variance for Cm-244 fis. neutrons multiplicity,4014100200014 (SIGnu)**2, (prt/fis)**2 . 4014100200015 ERR-ANALYS (ERR-S) Statistical error. 4014100200016 STATUS (TABLE) Table II of Sov.Nucl.Phys.,v.16,p.641,1973 -NU.4014100200017 Text, page 642 for ratio and MISC data. 4014100200018 HISTORY (20210219U) DECAY-DATA were moved in free text of 4014100200019 ANALYSIS. 4014100200020 ENDBIB 18 0 4014100200021 COMMON 2 3 4014100200022 MONIT MONIT-ERR 4014100200023 PRT/FIS PRT/FIS 4014100200024 2.69 0.02 4014100200025 ENDCOMMON 3 0 4014100200026 DATA 8 1 4014100200027 DATA 1ERR-S 1DATA 2ERR-S 2MISC1 MISC1-ERR 4014100200028 MISC2 MISC2-ERR 4014100200029 PRT/FIS PRT/FIS NO-DIM NO-DIM SEE TEXT SEE TEXT 4014100200030 SEE TEXT SEE TEXT 4014100200031 3.73 0.18 1.387 0.066 2.19 0.66 4014100200032 1.33 0.08 4014100200033 ENDDATA 6 0 4014100200034 ENDSUBENT 33 0 4014100299999 SUBENT 40141003 20210319 41954014100300001 BIB 3 6 4014100300002 REACTION (100-FM-256(0,F),PR/NUM,NU,,REL) 4014100300003 Total number of events 204. 4014100300004 Distributions of multiplicities of registered neutrons4014100300005 number of events. 4014100300006 STATUS (TABLE) Table I of Sov.Nucl.Phys.,v.16,p.641,1973. 4014100300007 HISTORY (20150316C) M.M. Subent was added. 4014100300008 ENDBIB 6 0 4014100300009 NOCOMMON 0 0 4014100300010 DATA 2 8 4014100300011 PART-OUT DATA 4014100300012 NO-DIM ARB-UNITS 4014100300013 0. 27. 4014100300014 1. 65. 4014100300015 2. 58. 4014100300016 3. 36. 4014100300017 4. 14. 4014100300018 5. 4. 4014100300019 6. 0. 4014100300020 7. 0. 4014100300021 ENDDATA 10 0 4014100300022 ENDSUBENT 21 0 4014100399999 SUBENT 40141004 20210319 41954014100400001 BIB 3 6 4014100400002 REACTION (96-CM-244(0,F),PR/NUM,NU,,REL) 4014100400003 Total number of events 7169. 4014100400004 Distributions of multiplicities of registered neutrons4014100400005 number of events. 4014100400006 STATUS (TABLE) Table I of Sov.Nucl.Phys.,v.16,p.641,1973. 4014100400007 HISTORY (20150316C) M.M. Subent was added. 4014100400008 ENDBIB 6 0 4014100400009 NOCOMMON 0 0 4014100400010 DATA 2 8 4014100400011 PART-OUT DATA 4014100400012 NO-DIM ARB-UNITS 4014100400013 0. 1645. 4014100400014 1. 2745. 4014100400015 2. 1991. 4014100400016 3. 640. 4014100400017 4. 137. 4014100400018 5. 137. 4014100400019 6. 11. 4014100400020 7. 0. 4014100400021 ENDDATA 10 0 4014100400022 ENDSUBENT 21 0 4014100499999 ENDENTRY 4 0 4014199999999