ENTRY 23527 20190604 228023527 0 1 SUBENT 23527001 20190603 228023527 1 1 BIB 11 46 23527 1 2 TITLE A measurement of the variation of the ratio of fission23527 1 3 to absorption in U235 brtween 1 eV and 100 eV incident 23527 1 4 neutron energy 23527 1 5 AUTHOR (E.R.Collins,T.M.Kavanegh,J.E.Lynn) 23527 1 6 REFERENCE (R,NRDC-117,1959) 23527 1 7 INSTITUTE (2UK HAR) 23527 1 8 FACILITY (LINAC,2UK HAR) Linear electron accelerator. 23527 1 9 At 400 pulses/sec. 23527 1 10 INC-SPECT Slow neutrons . Energy < 0.045 eV . 23527 1 11 Neutron beam was monitored by counting neutrons 23527 1 12 scatterired from lead block at the entrance to the 23527 1 13 final collimator tube. 23527 1 14 SAMPLE U-235 metal disc of 3.1 inch diameter, 0.2 inch 23527 1 15 thickness, on a Al frame. 23527 1 16 U-235 - 92.7%, U-238 - 7.24 %, Al - 0.017%, 23527 1 17 Ni - 0.05%, Si - 0.0085%, Fe - 0.032 %, Cr - 0.003 %, 23527 1 18 W - 0.01 %, Mo-0.0225%, B - 0.0005% . U-234 (~1.%) 23527 1 19 included in U-238 content. 23527 1 20 DETECTOR (SCIN) Scintillating plastic detectors, 4.5 cm long, 23527 1 21 4.5 cm diameter, viewed by EMI type 6099D 23527 1 22 photopultiplier. Datectors were placed on either side 23527 1 23 of the sample. 23527 1 24 (BF3) For transmission measurement. Detection 23527 1 25 efficiency proportional to SQRT(E) within 1 % down 23527 1 26 to 1.2 eV. 4% deviation at 0.1 eV. 23527 1 27 (BF3) For scattering measurement. 23527 1 28 Annual ring of 10-BF(3) counters, sample in the center 23527 1 29 of ring. Efficiency is proportional to SQRT(E). 23527 1 30 Measuremet with and without B4C sleeve surrounding 23527 1 31 the sample. 23527 1 32 METHOD (TOF,COINC) Flight path 7.36 . Fission events as 23527 1 33 function of time-of-flight. Coincidences from pair 23527 1 34 detectors.Resolution 0.1 microsec. 23527 1 35 Fission detection efficiency in calibrated Pu-240 23527 1 36 SF source was measured to be ~1%. 23527 1 37 Tested by U and Cd samples. 23527 1 38 (TRN) Thransmission was measured by three 10-BF(3) 23527 1 39 counters replaced the sample. 23527 1 40 .Lead sample was used to count scattered neutrons. 23527 1 41 Resolution 0.22microsec/m at scattering measurement, 23527 1 42 0.29 microsec/m at transmission and fission 23527 1 43 measurements. 23527 1 44 CORRECTION For overlap neutrons from previous pulse < 10.% . 23527 1 45 For backgraund measured when beam was swiched off 23527 1 46 < 2.%. 23527 1 47 HISTORY (20190604C) M.M. 23527 1 48 ENDBIB 46 0 23527 1 49 NOCOMMON 0 0 23527 1 50 ENDSUBENT 49 0 23527 199999 SUBENT 23527002 20190604 228023527 2 1 BIB 6 15 23527 2 2 REACTION 1(92-U-235(N,0),,EN) 23527 2 3 2(92-U-235(N,F),,WID) 23527 2 4 REL-REF (A,,D.J.Hughes+,R,BNL-325,1958) 2nd edition. 23527 2 5 (D,,F.J.Shore+,J,PR,112,191,1958) 23527 2 6 Disagree due to effect of resolution. 23527 2 7 ANALYSIS (SLA) Derived by single-level Breit-Wigner formula (7) 23527 2 8 ETA=NU*(GANNAfis/(GAMMAfis+GAMMAgamm)) 23527 2 9 from measured ETA assuming that NU and gamma-width do 23527 2 10 not fluctuate from resonance to resonance. 23527 2 11 FLAG (1.) These estimates of the fission widths are 23527 2 12 probably in error on account of neglect ot the effect 23527 2 13 of resolution ( authors' comment). 23527 2 14 ERR-ANALYS (DATA-ERR) Type of uncertainty is not explained in the 23527 2 15 article. 23527 2 16 STATUS (TABLE) Table 1 of rep. NRDC-117,1959 23527 2 17 ENDBIB 15 0 23527 2 18 NOCOMMON 0 0 23527 2 19 DATA 4 16 23527 2 20 DATA 1DATA 2DATA-ERR 2FLAG 23527 2 21 EV MILLI-EV MILLI-EV NO-DIM 23527 2 22 1.15 150. 30. 23527 2 23 2.07 24. 3. 23527 2 24 3.18 150. 35. 23527 2 25 3.67 75. 15. 23527 2 26 4.95 7. 1. 1. 23527 2 27 5.60 77. 17. 23527 2 28 6.45 24. 3. 1. 23527 2 29 7.20 33. 3. 23527 2 30 8.85 67. 4. 23527 2 31 9.25 150. 26. 1. 23527 2 32 12.0 13. 2. 23527 2 33 12.6 35. 5. 23527 2 34 15.8 49. 10. 1. 23527 2 35 16.7 28. 6. 1. 23527 2 36 19.8 54. 10. 23527 2 37 24.2 39. 10. 23527 2 38 ENDDATA 18 0 23527 2 39 ENDSUBENT 38 0 23527 299999 SUBENT 23527003 20190604 228023527 3 1 BIB 3 5 23527 3 2 REACTION 1(92-U-235(N,0),,EN) 23527 3 3 2(92-U-235(N,F),,WID) 23527 3 4 3(92-U-235(N,EL),,WID) 23527 3 5 ANALYSIS Derived from measured ETA assuming interfering. 23527 3 6 STATUS (TABLE) Text page 8 of rep. NRDC-117,1959 23527 3 7 ENDBIB 5 0 23527 3 8 NOCOMMON 0 0 23527 3 9 DATA 3 2 23527 3 10 DATA 1DATA-APRX 2DATA-APRX 3 23527 3 11 EV MILLI-EV MILLI-EV 23527 3 12 3.18 150. 0.028 23527 3 13 3.68 74. 0.053 23527 3 14 ENDDATA 4 0 23527 3 15 ENDSUBENT 14 0 23527 399999 ENDENTRY 3 0 2352799999999