ENTRY 23159 20120731 22332315900000001
SUBENT 23159001 20120731 22332315900100001
BIB 12 55 2315900100002
AUTHOR (S.Oberstedt, A.Oberstedt, E.Birgersson,I.Fabry, 2315900100003
F.-J.Hambsch, N.Kornilov, G.Loevestam,A.Tudora) 2315900100004
TITLE First results on the neutron-induced fission cross 2315900100005
section of 231-Pa for incident neutron energies 2315900100006
En > 17 MeV . 2315900100007
INSTITUTE (2ZZZGEL) S.Oberstedt,I.Fabry,F.-J.Hambsch, 2315900100008
G.Loevestam, N.Kornilov . 2315900100009
(2SWDSWD) A.Oberstedt, Dept.of Natural Sciences, 2315900100010
Oerebro University, Sweden 2315900100011
(3RUMBUU) A.Tudora 2315900100012
REFERENCE (J,ANE,43,26,2012) Data Table. 2315900100013
#doi:10.1016/j.anucene.2011.12.023 2315900100014
FACILITY (VDG,2ZZZGEL) 2315900100015
MONITOR (93-NP-237(N,F),,SIG) 2315900100016
METHOD (TOF) 2315900100017
DETECTOR (FISCH) Frisch-gridded fission chamber . 2315900100018
(SCIN) Three NE213 scintillation detectors employing 2315900100019
the pulse-shape discrimination technique for efficient 2315900100020
neutron/gamma-ray separation were placed at 0, 30, 60 2315900100021
degrees relative to the deuteron beam axis and 4.598 m 2315900100022
away from the neutron source and used to measure energy2315900100023
distributions from the neutron source at En = 16, 19, 2315900100024
20,21 MeV. Neutron spectra at 0degree, corrected for 2315900100025
pulse-height dependent efficiency, were used for the 2315900100026
neutron background correction and are shown in Fig.3 2315900100027
of J,ANE,43,26,2012. 2315900100028
The efficiency calibration of the neutron detectors was2315900100029
performed with a 252Cf spontaneous fission source (see 2315900100030
REL-REF of N.Kornilov+). 2315900100031
SAMPLE Pa-231 sample was obtained by means of spray-painting.2315900100032
Original diameter 28 mm was reduced by collimator to 2315900100033
6 mm, effective mass determined by alpha-spectrometry 2315900100034
53.4+-1.3 microgram. 2315900100035
Np-237 sample of 28 mm diameter, mass 182.2 microgram 2315900100036
+- 1.7%, isotopic purity 99.9 %, with negligible 2315900100037
fractions of 238U and 238Pu of less than 2E-7 and 4E-8,2315900100038
respectively. 2315900100039
Protactinium sample was mounted on one side of the 2315900100040
chamber together with a well-characterized 237Np sample2315900100041
in back-to-back geometry. 2315900100042
The distance between sample and neutron source - 60 mm.2315900100043
REL-REF (N,,C.Budtz-Joergensen+,J,NIM/A,258,209,1987) 2315900100044
Details of Frisch-grid fission chamber construction. 2315900100045
(M,,N.V.Kornilov+,J,NIM/A,599,226,2009) 2315900100046
Efficiency calibration details. 2315900100047
CORRECTION Fraction of fission fragments,which are absorbed in the2315900100048
sample due to neutron momentum transfer - estimated 2315900100049
particle leakage amounts to (2.4 +-0.6)% at En = 21MeV.2315900100050
Without any significant error (smaller than 1.5%) 2315900100051
authors assume that, due to considerable energy loss in2315900100052
the target at large emission angles, about half of the 2315900100053
events escape detection. 2315900100054
For alpha-particles pile-up. 2315900100055
For dead time - < 4.%. 2315900100056
HISTORY (20120731C) M.M. 2315900100057
ENDBIB 55 0 2315900100058
NOCOMMON 0 0 2315900100059
ENDSUBENT 58 0 2315900199999
SUBENT 23159002 20120731 22332315900200001
BIB 5 19 2315900200002
REACTION (91-PA-231(N,F),,SIG) 2315900200003
INC-SOURCE (P-T) For reliability check of the experimental set-up,2315900200004
author switched from a deuteron beam to protons in 2315900200005
order to produce neutrons with energies En = 1.95 and 2315900200006
2.95 MeV. Practically the same fission cross-sections 2315900200007
were measured as published by S.Oberstedt+(2005), 2315900200008
which gives evidence for the reproducibility of present2315900200009
results. 2315900200010
REL-REF (A,22910002,S.Oberstedt+,J,ANE,32,1867,2005) 2315900200011
ERR-ANALYS (ERR-T) Total uncertainty include 2315900200012
- the uncertainties in the obtained number of fission 2315900200013
events for 231Pa and 237Np, which comprises both the 2315900200014
statistical as well as the systematic errors, 2315900200015
(MONIT-ERR) the uncertainty in fission cross-section of2315900200016
the reference isotope 237Np, 2315900200017
- the ones of the effective sample masses, 2315900200018
- the uncertainty related to the low-energy neutron 2315900200019
background. 2315900200020
STATUS (TABLE) Table 1 of J,ANE,43,26,2012 . 2315900200021
ENDBIB 19 0 2315900200022
COMMON 1 3 2315900200023
MONIT-ERR 2315900200024
B 2315900200025
0.03 2315900200026
ENDCOMMON 3 0 2315900200027
DATA 6 3 2315900200028
EN EN-RSL-HW DATA -ERR-T +ERR-T MONIT 2315900200029
MEV MEV B B B B 2315900200030
1.95 0.08 1.15 0.08 0.08 1.67 2315900200031
1.95 0.08 1.04 0.04 0.04 1.67 2315900200032
2.95 0.06 1.00 0.04 0.04 1.63 2315900200033
ENDDATA 5 0 2315900200034
ENDSUBENT 33 0 2315900299999
SUBENT 23159003 20120731 22332315900300001
BIB 6 26 2315900300002
REACTION 1(91-PA-231(N,F),,SIG) 2315900300003
2(91-PA-231(N,F),,SIG) 2315900300004
INC-SOURCE (D-T) Quasi monoenergetic neutrons. 2315900300005
Corresponding energy spread of the neutron beams, 2315900300006
calculated with the computer code EnergySet ( see 2315900300007
G.Loevestam, Program to calculate accelerator setting 2315900300008
and neutron yield data for the IRMM VdG laboratory, 2315900300009
IRMM internal report GE/NP/2/2002/06/20.2002), are 2315900300010
given as the difference between maximum and mean 2315900300011
neutron energy. 2315900300012
CORRECTION Two different neutron-background evaluations : 2315900300013
1 -neutron background correction using the activation 2315900300014
data from A.Fessler et al. (2000), 2315900300015
2 -using the neutron beam profiles measured in the frame2315900300016
of the cross-section measurements. 2315900300017
REL-REF 1(R,,A.Fessler+,J,NSE,134,171,2000) 2315900300018
ERR-ANALYS (ERR-T) Total uncertainty include 2315900300019
- the uncertainties in the obtained number of fission 2315900300020
events for 231Pa and 237Np, which comprises both the 2315900300021
statistical as well as the systematic errors, 2315900300022
(MONIT-ERR) the uncertainty in fission cross-section of2315900300023
the reference isotope 237Np, 2315900300024
- the ones of the effective sample masses, 2315900300025
- the uncertainty related to the low-energy neutron 2315900300026
background. 2315900300027
STATUS (TABLE) Table 1 of J,ANE,43,26,2012 . 2315900300028
ENDBIB 26 0 2315900300029
NOCOMMON 0 0 2315900300030
DATA 9 12 2315900300031
EN EN-RSL-HW DATA 1-ERR-T 1+ERR-T 1DATA 22315900300032
ERR-T 2MONIT MONIT-ERR 2315900300033
MEV MEV B B B B 2315900300034
B B B 2315900300035
15.0 0.7 1.54 0.15 0.15 1.51 2315900300036
0.20 2.24 0.04 2315900300037
15.3 0.8 1.55 0.15 0.15 1.51 2315900300038
0.20 2.26 0.05 2315900300039
15.9 0.8 1.62 0.15 0.15 1.58 2315900300040
0.21 2.27 0.05 2315900300041
17.2 0.6 1.71 0.17 0.24 1.61 2315900300042
0.22 2.28 0.05 2315900300043
17.2 0.6 1.62 0.17 0.22 1.52 2315900300044
0.21 2.28 0.05 2315900300045
17.7 0.6 1.68 0.18 0.26 1.58 2315900300046
0.21 2.28 0.05 2315900300047
18.3 0.5 1.62 0.18 0.28 1.51 2315900300048
0.20 2.27 0.05 2315900300049
18.8 0.5 1.61 0.18 0.32 1.49 2315900300050
0.20 2.27 0.05 2315900300051
19.3 0.5 1.60 0.19 0.37 1.53 2315900300052
0.21 2.27 0.05 2315900300053
19.8 0.5 1.63 0.20 0.45 1.69 2315900300054
0.23 2.27 0.05 2315900300055
20.4 0.5 1.65 0.22 0.52 1.52 2315900300056
0.20 2.29 0.05 2315900300057
20.9 0.5 1.79 0.26 0.75 1.54 2315900300058
0.21 2.31 0.05 2315900300059
ENDDATA 28 0 2315900300060
ENDSUBENT 59 0 2315900399999
SUBENT 23159004 20120731 22332315900400001
BIB 5 19 2315900400002
REACTION (91-PA-231(N,F),,SIG) 2315900400003
ANALYSIS Fission cross-section and its total uncertainty are 2315900400004
calculated individually for both ways of data 2315900400005
treatment, and then averaged - weighted by their 2315900400006
individual uncertainties. 2315900400007
ERR-ANALYS (ERR-T) Total uncertainty include 2315900400008
- the uncertainties in the obtained number of fission 2315900400009
events for 231Pa and 237Np, which comprises both the 2315900400010
statistical as well as the systematic errors, 2315900400011
(MONIT-ERR) the uncertainty in fission cross-section of2315900400012
the reference isotope 237Np, 2315900400013
- the ones of the effective sample masses, 2315900400014
- the uncertainty related to the low-energy neutron 2315900400015
background. 2315900400016
REL-REF (A,21731003,O.Birgul+,J,RCA,11,108,1969) 2315900400017
(D,10929002,S.Plattard+,J,PRL,46,633,1981) 2315900400018
STATUS (TABLE) Table 1 of J,ANE,43,26,2012 . 2315900400019
(DEP,23159003) Average of two treatments given in 2315900400020
Subent 003. 2315900400021
ENDBIB 19 0 2315900400022
NOCOMMON 0 0 2315900400023
DATA 7 12 2315900400024
EN EN-RSL-HW DATA -ERR-T +ERR-T MONIT 2315900400025
MONIT-ERR 2315900400026
MEV MEV B B B B 2315900400027
B 2315900400028
15.0 0.7 1.52 0.18 0.18 2.24 2315900400029
0.04 2315900400030
15.3 0.8 1.54 0.18 0.18 2.26 2315900400031
0.05 2315900400032
15.9 0.8 1.61 0.18 0.19 2.27 2315900400033
0.05 2315900400034
17.2 0.6 1.66 0.20 0.23 2.28 2315900400035
0.05 2315900400036
17.2 0.6 1.57 0.19 0.21 2.28 2315900400037
0.05 2315900400038
17.7 0.6 1.63 0.20 0.24 2.28 2315900400039
0.05 2315900400040
18.3 0.5 1.56 0.19 0.25 2.27 2315900400041
0.05 2315900400042
18.8 0.5 1.54 0.19 0.27 2.27 2315900400043
0.05 2315900400044
19.3 0.5 1.56 0.20 0.30 2.27 2315900400045
0.05 2315900400046
19.8 0.5 1.67 0.22 0.35 2.27 2315900400047
0.05 2315900400048
20.4 0.5 1.56 0.21 0.40 2.29 2315900400049
0.05 2315900400050
20.9 0.5 1.61 0.23 0.55 2.31 2315900400051
0.05 2315900400052
ENDDATA 28 0 2315900400053
ENDSUBENT 52 0 2315900499999
ENDENTRY 4 0 2315999999999