ENTRY 41782 20250702 4178200000001 SUBENT 41782001 20250702 20251001 4178200100001 BIB 9 140 4178200100002 TITLE Delayed neutrons from spontaneous fission of 252Cf 4178200100003 AUTHOR (V.N.Nefedov,A.K.Melnikov,B.I.Starostov) 4178200100004 REFERENCE (C,71VIENNA,,89,1971) 4178200100005 TOF base 3.5, 2.7 m. 4178200100006 INSTITUTE (4RUSNIR) 4178200100007 METHOD (COINC) Delayed coincidences method. 4178200100008 Coincidence between by the instants of 252Cf fissions 4178200100009 and the registration of fission neutrons were recorded4178200100010 by AI-100 and AI-256 multichannel analysers. 4178200100011 DETECTOR (SCIN) Gas scintillation chamber, xenon-filled, 4178200100012 with 252Cf and 235U layers. 4178200100013 CORRECTION Effect due to scattered neutrons was measured by iron4178200100014 ring ( 55 mm internal diameter, 25 x 25 mm thick) to be4178200100015 negligible. 4178200100016 ADD-RES ---------------------------------------------- 4178200100017 . Fig.2 - total 252Cf spont.fission neutron spectrum; 4178200100018 X-scales - time and channel number - linear; 4178200100019 energy - not linear, not logarithmic; 4178200100020 TOF base 3.5 m and 2.7 m; 4178200100021 separate peaks at 0.4, 0.5, 0.7, 1.16, 1.6, 1.95, 4178200100022 2.6, 2.13, 3.3 MeV . 4178200100023 Data of Fig.2 (digitized) 4178200100024 Time, nsec Counts Time, nsec Counts 4178200100025 441.31 4419.1 215.88 13189. 4178200100026 439.19 4455.6 215.16 13410. 4178200100027 437.07 4565.8 211.63 13630. 4178200100028 434.25 4528.5 209.50 13925. 4178200100029 431.43 4638.6 208.78 14109. 4178200100030 427.20 4527.5 207.35 14477. 4178200100031 421.55 4637.2 204.51 14882. 4178200100032 416.61 4710.1 203.09 15102. 4178200100033 413.09 4599.1 201.67 15286. 4178200100034 410.27 4746.0 198.15 15102. 4178200100035 403.91 4818.8 196.02 15285. 4178200100036 398.97 4928.5 194.60 15617. 4178200100037 394.04 4891.0 192.47 15764. 4178200100038 391.92 4853.9 191.05 15984. 4178200100039 389.10 4963.9 189.63 16132. 4178200100040 386.29 4742.5 188.21 16352. 4178200100041 382.76 4815.7 186.08 16684. 4178200100042 380.64 4925.9 182.53 16978. 4178200100043 377.82 4851.8 181.82 17199. 4178200100044 374.99 5072.4 177.59 17087. 4178200100045 373.58 4924.8 175.46 17345. 4178200100046 370.05 5108.5 172.64 17455. 4178200100047 364.40 5181.3 169.82 17381. 4178200100048 359.46 5291.1 167.70 17528. 4178200100049 353.82 5290.3 165.56 17822. 4178200100050 352.40 5547.9 162.05 17638. 4178200100051 348.88 5363.2 159.21 17969. 4178200100052 343.24 5288.7 153.58 17747. 4178200100053 339.71 5361.9 150.77 17562. 4178200100054 336.88 5508.8 148.66 17415. 4178200100055 334.06 5545.2 144.44 17304. 4178200100056 329.82 5655.1 144.46 16935. 4178200100057 326.30 5617.8 142.35 16751. 4178200100058 321.36 5727.5 138.84 16456. 4178200100059 317.82 5874.3 136.76 15829. 4178200100060 314.29 5984.3 133.94 15718. 4178200100061 311.46 6094.4 133.25 15460. 4178200100062 308.64 6241.3 129.05 14797. 4178200100063 305.10 6388.1 126.97 14244. 4178200100064 301.57 6534.9 124.87 13986. 4178200100065 298.75 6387.2 123.49 13396. 4178200100066 296.63 6534.2 120.69 12991. 4178200100067 293.10 6644.2 120.01 12475. 4178200100068 289.57 6791.0 117.22 11996. 4178200100069 287.44 6938.0 115.82 11775. 4178200100070 283.90 7158.5 113.74 11001. 4178200100071 281.78 7268.7 110.95 10559. 4178200100072 278.24 7489.2 109.57 9895.5 4178200100073 275.42 7636.1 108.18 9600.6 4178200100074 272.59 7819.8 105.40 8753.1 4178200100075 270.45 8224.7 104.02 8274.1 4178200100076 267.63 8187.4 101.22 7721.2 4178200100077 264.79 8444.8 100.53 7426.5 4178200100078 261.96 8628.6 97.735 7020.9 4178200100079 261.24 8886.3 95.649 6468.2 4178200100080 257.71 8996.3 94.260 6062.8 4178200100081 255.59 9216.9 91.463 5620.4 4178200100082 253.46 9400.8 90.064 5399.2 4178200100083 251.33 9584.6 87.970 4993.8 4178200100084 249.21 9694.8 85.868 4735.7 4178200100085 247.08 9952.3 83.771 4403.9 4178200100086 245.67 10099. 81.667 4182.6 4178200100087 243.54 10246. 79.557 4071.8 4178200100088 241.41 10504. 76.039 3923.9 4178200100089 237.87 10872. 71.811 3849.7 4178200100090 235.73 11240. 67.584 3775.4 4178200100091 233.60 11571. 64.054 3848.5 4178200100092 230.79 11423. 61.224 4032.3 4178200100093 229.37 11570. 59.784 4584.5 4178200100094 227.24 11754. 58.310 5762.9 4178200100095 225.82 11975. 56.859 6536.2 4178200100096 223.70 12122. 54.060 6130.6 4178200100097 221.57 12343. 52.040 4325.6 4178200100098 219.43 12784. 50.033 2299.6 4178200100099 217.31 12858. 4178200100100 Comment of compiler M.M.: 4178200100101 Fit of Energy (MeV) dependence from time (nsec) : 4178200100102 Energy = 4178200100103 -0.06127 + 28.79584*time + 60902.36178*(1/time)**2 4178200100104 was done by digitized energy scale dependence from 4178200100105 time: 4178200100106 Time, nsec Energy, MeV 4178200100107 357.61 0.5 4178200100108 325.87 0.6 4178200100109 301.90 0.7 4178200100110 283.56 0.8 4178200100111 267.34 0.9 4178200100112 253.94 1.0 4178200100113 230.67 1.2 4178200100114 206.69 1.5 4178200100115 178.48 2.0 4178200100116 160.15 2.5 4178200100117 146.04 3.0 4178200100118 126.30 4.0 4178200100119 118.54 4.5 4178200100120 ---------------------------------------------- 4178200100121 . Fig.4 - distribution of delayed coincidences of 4178200100122 252Cf - 235U fragments, 4178200100123 X-scale - channel number - linear, 4178200100124 delayed coincidences, details in Subent 002. 4178200100125 ---------------------------------------------- 4178200100126 . Fig.6 - distribution of delayed coincidences of 4178200100127 252Cf fragments; 4178200100128 X-scales - time and channel number - linear; 4178200100129 combination of 13-mm thick silver strip and 50 x 50 mm4178200100130 plastic scintillator and gas scintillation chamber; 4178200100131 separate peaks at 2., 7., 20., 30., 80. nsec. 4178200100132 ---------------------------------------------- 4178200100133 . Emission times for various energy groups of delayed 4178200100134 neutrons were calculated using smooth spectrum 4178200100135 of Fig.2 (Table 1) 4178200100136 # Energy,MeV Emission time, s 4178200100137 1 0.5 5 - 10 4178200100138 2 0.7 5 - 10 4178200100139 3 1.16 2 - 3 4178200100140 4 1.6 7 - 8 4178200100141 HISTORY (20250702C) M.M. 4178200100142 ENDBIB 140 0 4178200100143 NOCOMMON 0 0 4178200100144 ENDSUBENT 143 0 4178200199999 SUBENT 41782002 20250701 20251001 4178200200001 BIB 6 11 4178200200002 REACTION (98-CF-252(0,F),DL/GRP,NU) 4178200200003 SAMPLE . 252Cf layer on Al backing of 0.5 mm thickness and 4178200200004 20 mm diameter. Activity 4.E+4 fis/sec. 4178200200005 . U-235 metallic layer of 95 % enrichment, 0.025 mm 4178200200006 thickness, 24 mm diameter. 4178200200007 ANALYSIS Expanding the delayed coincidence curve ( Fig.4 ) by 4178200200008 various exponents. 4178200200009 MISC-COL (MISC) Emission time, nanosec 4178200200010 ERR-ANALYS (DATA-ERR) Type of uncertainty is not explained in the 4178200200011 article. 4178200200012 STATUS (TABLE,,V.N.Nefedov,C,71VIENNA,,89,1971) Table II 4178200200013 ENDBIB 11 0 4178200200014 NOCOMMON 0 0 4178200200015 DATA 5 3 4178200200016 GRP-NUM DATA DATA-ERR MISC MISC-ERR 4178200200017 NO-DIM PC/FIS PC/FIS NSEC NSEC 4178200200018 1. 2.7 0.4 2.3 0.5 4178200200019 2. 0.6 0.1 7.3 1. 4178200200020 3. 0.2 0.03 30. 2. 4178200200021 ENDDATA 5 0 4178200200022 ENDSUBENT 21 0 4178200299999 ENDENTRY 2 0 4178299999999