ENTRY 23527 20190603 22802352700000001 SUBENT 23527001 20190603 22802352700100001 BIB 11 46 2352700100002 TITLE A measurement of the variation of the ratio of fission2352700100003 to absorption in U235 brtween 1 eV and 100 eV incident 2352700100004 neutron energy 2352700100005 AUTHOR (E.R.Collins,T.M.Kavanegh,J.E.Lynn) 2352700100006 REFERENCE (R,NRDC-117,1959) 2352700100007 INSTITUTE (2UK HAR) 2352700100008 FACILITY (LINAC,2UK HAR) Linear electron accelerator. 2352700100009 At 400 pulses/sec. 2352700100010 INC-SPECT Slow neutrons . Energy < 0.045 eV . 2352700100011 Neutron beam was monitored by counting neutrons 2352700100012 scatterired from lead block at the entrance to the 2352700100013 final collimator tube. 2352700100014 SAMPLE U-235 metal disc of 3.1 inch diameter, 0.2 inch 2352700100015 thickness, on a Al frame. 2352700100016 U-235 - 92.7%, U-238 - 7.24 %, Al - 0.017%, 2352700100017 Ni - 0.05%, Si - 0.0085%, Fe - 0.032 %, Cr - 0.003 %, 2352700100018 W - 0.01 %, Mo-0.0225%, B - 0.0005% . U-234 (~1.%) 2352700100019 included in U-238 content. 2352700100020 DETECTOR (SCIN) Scintillating plastic detectors, 4.5 cm long, 2352700100021 4.5 cm diameter, viewed by EMI type 6099D 2352700100022 photopultiplier. Datectors were placed on either side 2352700100023 of the sample. 2352700100024 (BF3) For transmission measurement. Detection 2352700100025 efficiency proportional to SQRT(E) within 1 % down 2352700100026 to 1.2 eV. 4% deviation at 0.1 eV. 2352700100027 (BF3) For scattering measurement. 2352700100028 Annual ring of 10-BF(3) counters, sample in the center 2352700100029 of ring. Efficiency is proportional to SQRT(E). 2352700100030 Measuremet with and without B4C sleeve surrounding 2352700100031 the sample. 2352700100032 METHOD (TOF,COINC) Flight path 7.36 . Fission events as 2352700100033 function of time-of-flight. Coincidences from pair 2352700100034 detectors.Resolution 0.1 microsec. 2352700100035 Fission detection efficiency in calibrated Pu-240 2352700100036 SF source was measured to be ~1%. 2352700100037 Tested by U and Cd samples. 2352700100038 (TRN) Thransmission was measured by three 10-BF(3) 2352700100039 counters replaced the sample. 2352700100040 .Lead sample was used to count scattered neutrons. 2352700100041 Resolution 0.22microsec/m at scattering measurement, 2352700100042 0.29 microsec/m at transmission and fission 2352700100043 measurements. 2352700100044 CORRECTION For overlap neutrons from previous pulse < 10.% . 2352700100045 For backgraund measured when beam was swiched off 2352700100046 < 2.%. 2352700100047 HISTORY (20190604C) M.M. 2352700100048 ENDBIB 46 0 2352700100049 NOCOMMON 0 0 2352700100050 ENDSUBENT 49 0 2352700199999 SUBENT 23527002 20190604 22802352700200001 BIB 6 15 2352700200002 REACTION 1(92-U-235(N,0),,EN) 2352700200003 2(92-U-235(N,F),,WID) 2352700200004 REL-REF (A,,D.J.Hughes+,R,BNL-325,1958) 2nd edition. 2352700200005 (D,,F.J.Shore+,J,PR,112,191,1958) 2352700200006 Disagree due to effect of resolution. 2352700200007 ANALYSIS (SLA) Derived by single-level Breit-Wigner formula (7) 2352700200008 ETA=NU*(GANNAfis/(GAMMAfis+GAMMAgamm)) 2352700200009 from measured ETA assuming that NU and gamma-width do 2352700200010 not fluctuate from resonance to resonance. 2352700200011 FLAG (1.) These estimates of the fission widths are 2352700200012 probably in error on account of neglect ot the effect 2352700200013 of resolution ( authors' comment). 2352700200014 ERR-ANALYS (DATA-ERR) Type of uncertainty is not explained in the 2352700200015 article. 2352700200016 STATUS (TABLE) Table 1 of rep. NRDC-117,1959 2352700200017 ENDBIB 15 0 2352700200018 NOCOMMON 0 0 2352700200019 DATA 4 16 2352700200020 DATA 1DATA 2DATA-ERR 2FLAG 2352700200021 EV MILLI-EV MILLI-EV NO-DIM 2352700200022 1.15 150. 30. 2352700200023 2.07 24. 3. 2352700200024 3.18 150. 35. 2352700200025 3.67 75. 15. 2352700200026 4.95 7. 1. 1. 2352700200027 5.60 77. 17. 2352700200028 6.45 24. 3. 1. 2352700200029 7.20 33. 3. 2352700200030 8.85 67. 4. 2352700200031 9.25 150. 26. 1. 2352700200032 12.0 13. 2. 2352700200033 12.6 35. 5. 2352700200034 15.8 49. 10. 1. 2352700200035 16.7 28. 6. 1. 2352700200036 19.8 54. 10. 2352700200037 24.2 39. 10. 2352700200038 ENDDATA 18 0 2352700200039 ENDSUBENT 38 0 2352700299999 SUBENT 23527003 20190604 22802352700300001 BIB 3 5 2352700300002 REACTION 1(92-U-235(N,0),,EN) 2352700300003 2(92-U-235(N,F),,WID) 2352700300004 3(92-U-235(N,EL),,WID) 2352700300005 ANALYSIS Derived from measured ETA assuming interfering. 2352700300006 STATUS (TABLE) Text page 8 of rep. NRDC-117,1959 2352700300007 ENDBIB 5 0 2352700300008 NOCOMMON 0 0 2352700300009 DATA 3 2 2352700300010 DATA 1DATA-APRX 2DATA-APRX 3 2352700300011 EV MILLI-EV MILLI-EV 2352700300012 3.18 150. 0.028 2352700300013 3.68 74. 0.053 2352700300014 ENDDATA 4 0 2352700300015 ENDSUBENT 14 0 2352700399999 ENDENTRY 3 0 2352799999999