23675001 20251218
23675001 20251218
15 124
New insights on fission of 235U induced by high
energy neutrons from a new measurement at nTOF
(A.Manna, E.Pirovano, P.Console Camprini, L.Cosentino,
M.Dietz, Q.Ducasse, P.Finocchiaro, C.Le Naour,
D.Mancusi, C.Massimi, A.Mengoni, R.Nolte, D.Radeck,
L.Tassan-Got, N.Terranova, G.Vannini, A.Ventura,
O.Aberle, V.Alcayne, S.Amaducci, J.Andrzejewski,
L.Audouin, V.Babiano-Suarez, M.Bacak, M.Barbagallo,
S.Bennett, E.Berthoumieux, J.Billowes, D.Bosnar,
A.Brown, M.Busso, M.Caamano, L.Caballero-Ontanaya,
F.Calvino, M.Calviani, D.Cano-Ott, A.Casanovas,
D.M.Castelluccio, F.Cerutti, E.Chiaveri, N.Colonna,
G.Cortes, M.A.Cortes-Giraldo, S.Cristallo, L.A.Damone,
P.J.Davies, M.Diakaki, C.Domingo-Pardo, R.Dressler,
E.Dupont, I.Duran, Z.Eleme, B.Fernandez-Dominguez,
A.Ferrari, V.Furman, K.Goebel, R.Garg,
A.Gawlik-Ramiega, S.Gilardoni, I.F.Goncalves,
E.Gonzalez-Romero, C.Guerrero, F.Gunsing, H.Harada,
S.Heinitz, J.Heyse, D.G.Jenkins, A.Junghans,
F.Kaeppeler, Y.Kadi, A.Kimura, I.Knapova, M.Kokkoris,
Y.Kopatch, M.Krticka, D.Kurtulgil, I.Ladarescu,
C.Lederer-Woods, H.Leeb, J.Lerendegui-Marco,
S.J.Lonsdale, D.Macina, T.Martinez, A.Masi, P.Mastinu,
M.Mastromarco, E.A.Maugeri, A.Mazzone, E.Mendoza,
V.Michalopoulou, P.M.Milazzo, F.Mingrone,
J.Moreno-Soto, A.Musumarra, A.Negret, F.Ogallar,
A.Oprea, N.Patronis, A.Pavlik, J.Perkowski, C.Petrone,
L.Piersanti, I.Porras, J.Praena, J.M.Quesada,
D.Ramos-Doval, T.Rauscher, R.Reifarth, D.Rochman,
C.Rubbia, M.Sabate-Gilarte, A.Saxena, P.Schillebeeckx,
D.Schumann, A.Sekhar, A.G.Smith, N.V.Sosnin, P.Sprung,
A.Stamatopoulos, G.Tagliente, J.L.Tain,
A.Tarifeno-Saldivia, Th.Thomas, P.Torres-Sanchez,
A.Tsinganis, J.Ulrich, S.Urlass, S.Valenta, V.Variale,
P.Vaz, D.Vescovi, V.Vlachoudis, R.Vlastou, A.Wallner,
P.J.Woods, T.Wright, P.Zugec)
(2ITYUBO,2GERPTB,2ITYBOL,2ITYLNS,2UK EDG,2FR PAR,
2FR SAC,2ZZZCER,2GRCTUA,2ITYEFR,2SPNPCM,2ITYCAT,
3POLLOU,2SPNVAL,2AUSATI,2ITYBAU,2UK MAN,3CROZAG,
2UK YRK,2ITYUPG,2SPNSAU,2SPNUPC,2SPNSEU,2ITYOAC,
2SWTPSI,2GRCIOA,2GERFRK,2PRTLFE,2JPNJAE,2ZZZGEL,
2GERZFK,2GERKFK,3CZRCHU,2ITYPAD,2ITYTRI,3RUMBUC,
2SPNGRU,2AUSVIE,2SWTBAS,2UK HFS,3INDTRM,3AULCBR)
(2ITYITY) Consiglio Nazionale delle Ricerche, Bari
(J,PL/B,860,139213,2025)
(I,,E.Pirovano+,J,JINS,18,P11011,2023)
Details on PPFC+RPT measurements
(I,,A.Manna+,J,JINS,18,P04024,2023)
Details on PPAC+RPT measurements
(SYNCY,2ZZZCER) CERN nTOF facility.
Protons (7 to 8.5E+12 protons/pulse, pulse width of
7 nsec) were accelerated to 20 GeV/c with repetition
rate of 0.8 Hz at maximum.
(SPALL) 1E+6 neutrons/pulse were produced in a Pb
spallation target coupled to water moderators.
The diameter of the neutron beam at sample position
is 2 cm.
(EN-RSL-HW) Half of bin width
Two 235U (92.699(5)%) and eight 235U (99.933(14)%)
enriched samples mounted in PPFC and PPAC.
Two polyethylene sheets for n-p scattering measurement.
(TOF) Flight path of 185 m
(EDE) for separation of (n,p) events form (n,d), (n,t)
and (n,a) events
Corrected for 12C(n,p) events by an additional
measurement using graphite samples
(1-H-1(N,EL)1-H-1,,DA,P)
n-p scattering cross section in the centre-of-mass
system for proton at 20 and 25 deg in the laboratory
system in LA150 library (VL40 wave analysis energy
dependent phase-shift solution of Arndt above 26 MeV)
interpolated by MCNP
+----------------------------------------------------+
Tlab (MeV) sigma,cm (mb/sr)
theta,lab=20.0 deg theta,lab=25.0 deg
------------------------------------------------------
20.0 151.1773 143.0919
25.0 119.6774 112.3854
30.0 98.2831 91.4940
35.0 82.9424 76.5152
40.0 71.5839 65.3763
45.0 62.8253 56.8485
50.0 55.9827 50.1418
55.0 50.5020 44.8111
60.0 46.0731 40.4603
65.0 42.4019 36.9134
70.0 39.3703 33.9688
75.0 36.8074 31.5020
80.0 34.6420 29.4214
85.0 32.7947 27.6482
90.0 31.2097 26.1335
95.0 29.8372 24.8245
100.0 28.6440 23.6949
110.0 26.6841 21.8386
120.0 25.1544 20.3961
130.0 23.9333 19.2479
140.0 22.9368 18.3085
150.0 22.1063 17.5243
160.0 21.3968 16.8537
170.0 20.7786 16.2632
180.0 20.2285 15.7369
190.0 19.7309 15.2568
200.0 19.2700 14.8089
210.0 18.8391 14.3918
220.0 18.4333 13.9956
230.0 18.0407 13.6170
240.0 17.6676 13.2522
250.0 17.3040 12.8977
260.0 16.9518 12.5551
270.0 16.6048 12.2189
280.0 16.2674 11.8915
290.0 15.9355 11.5723
300.0 15.6067 11.2609
310.0 15.2859 10.9539
320.0 14.9683 10.6510
330.0 14.6563 10.3578
340.0 14.3475 10.0676
350.0 14.0429 9.7806
+----------------------------------------------------+
(,R.A.Arndt,S,NEANDC-305,39,1991)
(APRVD) Proofread by Elisa Pirovano and Alice Manna
(2025-12-23)
(20251218R) Data received from Elisa Pirovano
(20251218C) On+ED
ENDBIB 124 0
NOCOMMON
ENDSUBENT 127 0
23675002 20251218
6 128
1(92-U-235(N,F),,SIG) PPFC+3S-RPT dataset
2(92-U-235(N,F),,SIG) PPAC+MSRPT dataset
1.PPFC+3S-RPT dataset
(FISCH) Parallel Plate Fission Chamber (PPFC)
containing eight 235U samples (42 mm diam., 264 to
338 ug/cm2 determined by alpha counting),
for measurement up to 145 MeV.
(TELES,SCIN,SCIN) Recoil proton telescope
Triple-stage RPT (3S-RPT) at 25 deg
2.PPAC+MSRPT dataset
(PPAC) Parallel Plate Avalanche Counter containing
two 235U samples (80 mm diam., 263 ug/cm2 and
282 ug/cm2)
(TELES,SCIN,SCIN) Recoil proton telescope
. Multi-stage RPT (MS-RPTL) at 25 deg
. Multi-stage RPT (MS-RPTH) at 20 deg
* By Alice Manna and Elisa Pirovano (2025-12-04):
1.PPFC+3S-RPT dataset
The cross section obtained with PPFC and 3S-RPT. In
this detection system, the recoil proton telescope
was at a proton emission angle theta,p of 25 deg.
In this case, the measured fission cross section is
proportional to the differential proton emission
cross section dsigma/dOmega,p at theta,p) in the
laboratory frame.
Therefore, it is possible to re-normalized it in
case of change of the neutron-proton elastic
scattering cross section at the corresponding neutron
scattering angle.
2.PPAC+MSRPT dataset
The cross section obtained with PPAC and MS-RPTL and
MS-RPTH. In this detection system two recoil proton
telescopes were used, positioned at 25 deg and 20 deg,
respectively.
In this case the normalization is not straightforward,
therefore we are proposing a method (outlined in ????)
for the re-normalization.
2(MISC) [w(20 deg)*phi(20 deg)]/[w(25 deg)*phi(25 deg)]
(ERR-T) Total uncertainty
(ERR-S) Statistical uncertainty
(ERR-SYS) Total systematic uncertainty
(ERR-2) Systematic uncertainty correlated between PPFC
and PPAC datasets:
. Isotopic composition of the PE samples (H/C ratio)
1.5%
. Areal density of the PE samples, correlated
component, depending on the sample used for each
energy interval
0.2%-0.8%
. Areal density of the C samples, correlated component,
depending on the sample
0.3%-1.1%
. Beam profile
0.5%
. Beam transmission through PPFC, PPAC, energy
dependent
0.2%-0.5%
1(ERR-1) PPFC/3S-RPT systematic uncertainty uncorrelated
with PPAC/MSR-RPTs systematic uncertainty:
. Isotopic composition of the uranium targets of the
PPFC
0.0014%
. Mass of the uranium targets of the PPFC
0.2%
. Correction on the effective areal density of the
uranium targets of the PPFC
0.6%
. Areal density of the PE samples, uncorrelated
component for the 3S-RPT, depending on the RPT
configuration used for each energy interval
0%-0.4%
. Areal density of the C samples, uncorrelated
component for the 3S-RPT, depending on the RPT
configuration
0%-0.9%
. PPFC detection efficiency: zero-bias efficiency,
weak energy dependence
1.0%-1.2%
. PPFC detection efficiency: extrapolation below
threshold
2.9%
. PPFC dead-time correction, energy dependent
0.04%-0.2%
. 3S-RPT angle
0.1%-0.6%
. 3S-RPT distance
0.8%
. 3S-RPT effective solid angle (area of the dEz
detector)
0.4%-0.7%
. 3S-RPT dead-time correction
0.6%-0.9%
. 3S-RPT: event selection in the dE-E
0.2%-0.4%
. 3S-RPT: efficiency calculation fit
2.4%
2(ERR-1) PPAC/MS-RPTs systematic uncertainty
uncorrelated with PPFC/3S-RPT systematic uncertainty:
. Mass of the uranium samples of the PPAC
1.0%
. Areal density of the PE samples, uncorrelated
component for the MS-RPTs, depending on the sample
used for each energy interval
0.0%-0.3%
. Areal density of the C samples, uncorrelated
component for the MS-RPTs, depending on the sample
0%-0.5%
. PPAC: reconstruction of the fission fragments
trajectories
0.4%
. PPAC efficiency calculation fit, energy dependent
2.0%-2.7%
. PPAC anisotropy correction, energy dependent
0%-1.2%
. MS-RPT position, depending on the RPT configuration
0.9%-1.2%
. MS-RPT signal reconstruction, depending on the RPT
detectors included in the analysis of each energy
interval
0.5%-1.8%
. MS-RPT: events selection in the dE-E matrix,
depending on the RPT detectors included in the
analysis
2.0%-5.0%
. MS-RPT dead-time correction, depending on the RPT
detectors included in the analysis
1.0%-2.0%
(TABLE,,A.Manna+,J,PL/B,860,139213,2025)
ENDBIB 128 0
NOCOMMON
EN EN-RSL-HW DATA 1 ERR-T 1 ERR-S 1 ERR-SYS 1 ERR-1 1 DATA 2 ERR-T 2 ERR-S 2 ERR-SYS 2 ERR-1 2 ERR-2 MISC 2
MEV MEV MB MB MB MB PER-CENT MB MB MB MB PER-CENT PER-CENT NO-DIM
10.63 0.63 1795. 147. 88. 117. 6.5 0.000
11.95 0.70 1768. 137. 73. 116. 6.5 0.000
13.44 0.79 1887. 142. 71. 123. 6.5 0.000
15.12 0.89 2040. 152. 73. 133. 6.5 0.000
17.01 1.00 2094. 153. 69. 137. 6.5 0.000
19.14 1.13 1982. 140. 52. 130. 6.5 0.000
21.86 1.60 2112. 147. 50. 138. 6.5 0.000
25.30 1.85 2134. 149. 53. 140. 6.5 0.000
29.22 0.71 2175. 125. 76. 99. 4.5
30.68 0.75 2131. 121. 73. 97. 4.5
32.21 0.79 2158. 123. 74. 98. 4.5
33.82 0.83 2174. 113. 51. 101. 4.6
35.51 0.87 2087. 108. 49. 97. 4.6
37.29 0.91 2105. 110. 51. 97. 4.6
39.16 0.95 1987. 105. 50. 92. 4.1 2007. 102. 62. 81. 3.4 2.1 0.000
41.12 1.01 1968. 105. 51. 91. 4.1 1991. 104. 67. 80. 3.4 2.1 0.000
43.17 1.05 1962. 106. 54. 91. 4.1 1925. 102. 66. 77. 3.4 2.1 0.000
45.33 1.11 2025. 104. 43. 94. 4.1 1972. 104. 67. 79. 3.4 2.1 0.000
47.59 1.16 2034. 105. 47. 94. 4.1 1874. 101. 67. 75. 3.4 2.1 0.000
49.97 1.22 1880. 98. 45. 87. 4.1 1916. 103. 68. 77. 3.4 2.1 0.000
52.73 1.54 1946. 100. 43. 90. 4.2 1826. 94. 62. 71. 3.4 1.9 0.000
55.89 1.63 1894. 99. 45. 88. 4.2 1847. 90. 53. 72. 3.4 1.9 0.000
59.25 1.73 1870. 99. 48. 87. 4.2 1797. 88. 53. 70. 3.4 1.9 0.000
62.80 1.83 1829. 99. 51. 85. 4.2 1800. 89. 54. 71. 3.4 1.9 0.000
66.57 1.94 1805. 100. 53. 84. 4.2 1744. 87. 54. 68. 3.4 1.9 0.000
70.57 2.06 1769. 99. 55. 83. 4.3 1697. 85. 54. 66. 3.4 1.9 0.000
74.80 2.18 1717. 99. 58. 80. 4.3 1696. 86. 55. 66. 3.4 1.9 0.000
79.28 2.31 1761. 103. 63. 82. 4.3 1642. 84. 54. 64. 3.4 1.9 0.000
84.04 2.45 1697. 101. 62. 79. 4.3 1671. 81. 48. 65. 3.4 1.9 2.180
89.09 2.60 1685. 105. 70. 79. 4.3 1632. 79. 46. 64. 3.4 1.9 5.072
94.43 2.75 1586. 100. 66. 74. 4.3 1627. 79. 47. 64. 3.4 1.9 6.778
100.10 2.92 1569. 107. 79. 72. 4.2 1707. 82. 48. 67. 3.4 1.9 5.915
106.62 3.61 1591. 127. 105. 72. 4.2 1602. 77. 44. 63. 3.5 1.7 12.657
114.08 3.86 1516. 125. 104. 69. 4.2 1540. 75. 44. 61. 3.6 1.7 13.809
122.06 4.13 1498. 135. 116. 68. 4.2 1528. 75. 45. 61. 3.6 1.7 4.796
130.61 4.42 1454. 122. 102. 66. 4.2 1523. 76. 46. 61. 3.6 1.7 4.143
139.75 4.72 1498. 131. 111. 69. 4.2 1442. 72. 43. 58. 3.6 1.7 2.360
149.53 5.06 1519. 75. 44. 61. 4.0 4.163
161.55 6.96 1535. 74. 41. 62. 4.0 3.959
176.08 7.58 1396. 70. 40. 57. 4.1 3.600
191.93 8.27 1505. 75. 43. 62. 4.1 3.540
209.20 9.01 1523. 78. 46. 63. 4.2 3.545
228.03 9.82 1448. 75. 45. 60. 4.2 3.531
248.56 10.71 1453. 75. 46. 60. 4.1 1.940
270.93 11.67 1407. 74. 46. 58. 4.1 1.804
295.31 12.72 1579. 84. 53. 65. 4.1 2.162
321.88 13.86 1378. 75. 48. 57. 4.2 1.886
350.85 15.11 1501. 83. 54. 63. 4.2 2.069
384.26 18.30 1620. 90. 59. 68. 4.2 1.941
422.69 20.13 1481. 84. 55. 63. 4.2 2.074
ENDDATA
ENDSUBENT 289 0
23675003 20251218
6 30
(92-U-235(N,F),,SIG,,AV)
Weighted average of PPFC/3SRPT and PPAC/MSRPT datasets
Weights used to calculated the weighted mean
(MISC1) w(PPFC/3S-RPT)
(MISC2) w(PPAC/MS-RPTL)
(DATA-ERR) The uncertainty results from the procedure
to calculate the weighted average.
* By Alice Manna and Elisa Pirovano (2025-12-04):
The final cross section obtained as weighted average
of the two independent results (in which we have a
contribution from both the neutron-proton elastic
scattering differential cross section).
This data set contains the weights used to calculate
the weighted mean, which makes it possible to
re-calculate the weighted mean of the re-normalized
fission cross sections measured with the two
experimental configurations PPFC/3S-RPT and
PPAC/MS-RPTL(H).
As discussed in E.Pirovano et al. "Absolute cross
section for neutron-induced fission of 235U in the
energy range from 10 MeV to 400 MeV" (to be published
in Phys.Rev.C and arXiv), these two data sets are
partially correlated, as the same polyethylene
samples and beam intensity monitors were employed.
However, a small re-normalization of the differential
neutron-proton scattering cross section will not
effect the stated relative uncertainty of the final
fission cross section.
(TABLE,,A.Manna+,J,PL/B,860,139213,2025)
(DEP,23675002) Datasets from PPFC/3SRPT and PPAC/MSRPT
ENDBIB 30 0
NOCOMMON
EN EN-RSL-HW DATA DATA-ERR MISC1 MISC2
MEV MEV MB MB NO-DIM NO-DIM
10.63 0.63 1795. 147. 0. 1.
11.95 0.70 1768. 137. 0. 1.
13.44 0.79 1887. 142. 0. 1.
15.12 0.89 2040. 152. 0. 1.
17.01 1.00 2094. 153. 0. 1.
19.14 1.13 1982. 140. 0. 1.
21.86 1.60 2112. 147. 0. 1.
25.30 1.85 2134. 149. 0. 1.
29.22 0.71 2175. 125. 1. 0.
30.68 0.75 2131. 121. 1. 0.
32.21 0.79 2158. 123. 1. 0.
33.82 0.83 2174. 113. 1. 0.
35.51 0.87 2087. 108. 1. 0.
37.29 0.91 2105. 110. 1. 0.
39.16 0.95 1997. 79. 0.4828 0.5172
41.12 1.01 1980. 80. 0.4966 0.5034
43.17 1.05 1943. 79. 0.4793 0.5207
45.33 1.11 1999. 79. 0.5068 0.4932
47.59 1.16 1951. 79. 0.4816 0.5184
49.97 1.22 1897. 77. 0.5256 0.4744
52.73 1.54 1882. 73. 0.4703 0.5297
55.89 1.63 1868. 71. 0.4463 0.5537
59.25 1.73 1828. 70. 0.4314 0.5686
62.80 1.83 1813. 71. 0.4375 0.5625
66.57 1.94 1770. 70. 0.4248 0.5752
70.57 2.06 1727. 69. 0.4169 0.5831
74.80 2.18 1705. 69. 0.4206 0.5794
79.28 2.31 1688. 69. 0.3887 0.6113
84.04 2.45 1681. 67. 0.3769 0.6231
89.09 2.60 1650. 67. 0.3408 0.6592
94.43 2.75 1612. 65. 0.3686 0.6314
100.10 2.92 1658. 69. 0.3513 0.6487
106.62 3.61 1599. 68. 0.2514 0.7486
114.08 3.86 1534. 66. 0.2504 0.7496
122.06 4.13 1521. 67. 0.221 0.779
130.61 4.42 1505. 66. 0.2628 0.7372
139.75 4.72 1454. 65. 0.2177 0.7823
149.53 5.06 1519. 75. 0. 1.
161.55 6.96 1535. 74. 0. 1.
176.08 7.58 1396. 70. 0. 1.
191.93 8.27 1505. 75. 0. 1.
209.20 9.01 1523. 78. 0. 1.
228.03 9.82 1448. 75. 0. 1.
248.56 10.71 1453. 75. 0. 1.
270.93 11.67 1407. 74. 0. 1.
295.31 12.72 1579. 84. 0. 1.
321.88 13.86 1378. 75. 0. 1.
350.85 15.11 1501. 83. 0. 1.
384.26 18.30 1620. 90. 0. 1.
422.69 20.13 1481. 84. 0. 1.
ENDDATA
ENDSUBENT 87 0
23675004 20251218
4 8
(92-U-235(N,F),,SIG,,AV,DERIV)
Averaged data processed by smoothing filter.
The smoothed data starts from 149 MeV, below this
energy the averaged cross section is reported.
(DATA-ERR) The uncertainty on the smoothed data
results from the fitting procedure.
(TABLE,,A.Manna+,J,PL/B,860,139213,2025) U5vsnp-smo
(DEP,23675003) Averaged cross section
ENDBIB 8 0
NOCOMMON
EN EN-RSL-HW DATA DATA-ERR
MEV MEV MB MB
10.63 0.63 1795. 147.
11.95 0.70 1768. 137.
13.44 0.79 1887. 142.
15.12 0.89 2040. 152.
17.01 1.00 2094. 153.
19.14 1.13 1982. 140.
21.86 1.60 2112. 147.
25.30 1.85 2134. 149.
29.22 0.71 2175. 125.
30.68 0.75 2131. 121.
32.21 0.79 2158. 123.
33.82 0.83 2174. 113.
35.51 0.87 2087. 108.
37.29 0.91 2105. 110.
39.16 0.95 1997. 79.
41.12 1.01 1980. 80.
43.17 1.05 1943. 79.
45.33 1.11 1999. 79.
47.59 1.16 1951. 79.
49.97 1.22 1897. 77.
52.73 1.54 1882. 73.
55.89 1.63 1868. 71.
59.25 1.73 1828. 70.
62.80 1.83 1813. 71.
66.57 1.94 1770. 70.
70.57 2.06 1727. 69.
74.80 2.18 1705. 69.
79.28 2.31 1688. 69.
84.04 2.45 1681. 67.
89.09 2.60 1650. 67.
94.43 2.75 1612. 65.
100.10 2.92 1658. 69.
106.62 3.61 1599. 68.
114.08 3.86 1534. 66.
122.06 4.13 1521. 67.
130.61 4.42 1505. 66.
139.75 4.72 1454. 65.
149.53 5.06 1498. 21.
161.55 6.96 1486. 22.
176.08 7.58 1475. 22.
191.93 8.27 1468. 22.
209.20 9.01 1464. 22.
228.03 9.82 1464. 23.
248.56 10.71 1466. 24.
270.93 11.67 1470. 26.
295.31 12.72 1475. 29.
321.88 13.86 1480. 31.
350.85 15.11 1485. 32.
384.26 18.30 1489. 37.
422.69 20.13 1490. 55.
ENDDATA
ENDSUBENT 65 0
ENDENTRY