ENTRY 23132 20130110 22342313200000001
SUBENT 23132001 20130110 22342313200100001
BIB 17 197 2313200100002
TITLE Resonance parameters for 197Au + n below 200 eV 2313200100003
AUTHOR (C.Massimi, A.Borella, S.Kopecky, C.Lamboudis, 2313200100004
M.C.Moxon, P.Schillebeeckx, G.Vannini) 2313200100005
INSTITUTE (2ITYUBO,2ZZZGEL) 2313200100006
(2UK UK ) Hyde Copse, Marchan,3 United Kingdom 2313200100007
REFERENCE (J,NC/B,125,517,2010) 2313200100008
#doi:10.1393/ncb/i2010-10847-9 2313200100009
(J,KPS,59,1689,2011) Same Res.Par. at 4.9 eV given 2313200100010
REL-REF (I,,M.Flaska+,J,NIM/A,531,392,2004) 2313200100011
Description of the accelerator and its neutron 2313200100012
producing target 2313200100013
(I,,C.Coceva+,R,IRMM-06,1996) 2313200100014
IRMM internal report GE/R/ND/06/96 2313200100015
1(I,,S.Kopecky+,J,NP/A,773,173,2006) 2313200100016
Detailed description of the exp. setup for 2313200100017
transmission measurements. 2313200100018
2(I,,A.Borella+,J,NIM/A,577,636,2007) 2313200100019
Description of the method and of the calculation of 2313200100020
weighting function 2313200100021
SAMPLE Temperature at the sample position was continuously 2313200100022
monitored. The average temperature was used in the 2313200100023
resonance shape analysis to account for Doppler effect.2313200100024
1 Samples of thickness 2313200100025
- 10.0 microm (5.861E-5 at/b), 2313200100026
20.0 microm (1.163E-4 at/b), 2313200100027
50.0 microm(2.906E-4 at/b) 2313200100028
using 50 Hz frequency and natural Cd filter to prevent 2313200100029
overlapping between neutron bunches; 2313200100030
- 3.0 mm (1.757E-2 at/b) using 800 Hz frequency and 2313200100031
B-10 filter to prevent overlapping between neutron 2313200100032
bunches. 2313200100033
2 At 12.5 m flight path (and 50 Hz frequency) - samples 2313200100034
of thickness 0.5 mm (3.097E-3 at/b) using Co,Bi,Na 2313200100035
filters for background, with and without natural Cd 2313200100036
filter to prevent overlapping between neutron bunches. 2313200100037
At 30 m flight path: 2313200100038
- 50 Hz frequency and natural Cd filter to prevent 2313200100039
overlapping, samples of thickness 2313200100040
1.0mm(6.007E-3 at/b) using Na filter for background, 2313200100041
0.5mm(3.097E-3 at/b) using W,Co,Na filters for 2313200100042
background, 2313200100043
0.5 mm (3.097E-3 at/b), 0.1 mm (5.945E-4 at/b), 2313200100044
50.0 microm (2.906E-4at/b), 10.0 microm (5.861E-5at/b),2313200100045
5.0 microm (2.772 at/b) using Na filter for background;2313200100046
- 800 Hz frequency and B-10 filter to prevent 2313200100047
overlapping, samples of thickness 2313200100048
1.0mm (6.07E-3at/b), 0.5 mm(3.097E-3 at/b), 2313200100049
0.1 mm (5.940E-4 at/b); 2313200100050
0.1 mm (5.940E-4 at/b) using Na filter for background; 2313200100051
0.1 mm (5.940E-4 at/b) using S filter for background. 2313200100052
3 0.1 mm thick Au foil was placed at a 7 m distance from2313200100053
the neutron producing target. The areal density of the 2313200100054
Au filter (5.886E-4 at/b) was similar compared to the 2313200100055
one of the capture sample (5.945E-4 at/b). 2313200100056
FACILITY (LINAC,2ZZZGEL) GELINA at IRMM . 2313200100057
INC-SOURCE (PHOTO) Pulsed white neutron source. Electron pulses 2313200100058
(max.repetition rate 800 Hz, peak current up to 12 A 2313200100059
in 10 ns time interval) are accelerated up to 150 MeV. 2313200100060
Post-acceleration magnet compresses electron bunches 2313200100061
to width < 1 ns (peak current 120 A). 2313200100062
Electrons generate bremsstrahlung in rotating uranium 2313200100063
target - neutrons were mainly produced by gamma,n and 2313200100064
gamma,f reactions. 2313200100065
Water-filled Be containers as moderators. 2313200100066
INC-SPECT Direct - fast neutron spectrum with very good time 2313200100067
resolution. 2313200100068
Moderated - slow neutron spectrum at reduced energy 2313200100069
resolution. 2313200100070
METHOD (TOF) 0.5 ns resolution. 2313200100071
1(TRN) Neutron detectors were placed at 49.345+-0.006 m 2313200100072
distance from neutron producing target. Samples were 2313200100073
placed almost halfway between detector and neutron 2313200100074
producing target. Angle between the flight path and 2313200100075
the normal to the moderator was -9 deg. 2313200100076
(FNB) Sample changer was also used to place black 2313200100077
resonance filters (i.e. S, Na, Co, W, and Ag) for 2313200100078
background determination applying the black resonance 2313200100079
technique. All measurements have been performed 2313200100080
with at least one fixed black resonance filter in beam.2313200100081
The background level at 4.9 eV for a sample out 2313200100082
measurement was < 1% and about 10% for measurements 2313200100083
with a 10 microm thick Au sample in the beam. 2313200100084
30mm diameter neutron beam at the sample position. 2313200100085
(PHD) Pulse-height window selects the alpha-peak of 2313200100086
Li-6(n,alpha) reaction to distinguish a neutron event 2313200100087
from background events. 2313200100088
2 Capture measurements at nominal flight path distances 2313200100089
of 12.5 m, 30 m , 60 m (angle between the flight path 2313200100090
and the normal to the moderator is 18, 0 and 9 degrees,2313200100091
respectively).Moderated neutron beam was collimated to 2313200100092
75 mm diameter at the sample position. 2313200100093
At about 1m from the sample a shielding of boron-oxide 2313200100094
and paraffin together with a 10 cm thick lead wall, 2313200100095
was placed to reduce the background. 2313200100096
Pulse height weighting technique was used to create 2313200100097
detector response proportional to the energy of the 2313200100098
registered gamma. 2313200100099
3 Self-indication measurements at 30 m flight path using2313200100100
the same setup as for capture measurements. 2313200100101
Au filter (squared metal disc 21.7x22.0 cm, areal 2313200100102
density of 5.886*10-4 atoms/barn,nominal thickness 2313200100103
0.11 mm) was placed at the beginning of the neutron 2313200100104
beam pipe, far from the measurement station. 2313200100105
PART-DET 1(N) 2313200100106
2(G) 2313200100107
DETECTOR Response function was investigated using MONTE Carlo 2313200100108
calculation - REL-REFs of M.Flaska+, C.Coceva+. 2313200100109
Fe-56(n,gamma) capture measurements at 60 m Flight Path2313200100110
(A.Borella+, Int.Workshop on P&T and ADS Development, 2313200100111
SCK*CEN, Mol, Belgium, 6-8 October,2003) - to validate 2313200100112
resolution function. 2313200100113
1(BF3) BF3 proportional counters - to monitor 2313200100114
output and stability of the accelerator and to 2313200100115
normalize the sample-in and sample-out measurements to 2313200100116
the same total neutron intensity. 2313200100117
(GLASD) Li-glass scintillator (NE 912), enriched to 95%2313200100118
in Li-6 of 1/4 inch (6.35mm) thickness, 4 inch(101.6mm)2313200100119
diameter, viewed by a photo-multiplier. 2313200100120
Background as a function of TOF was derived by black 2313200100121
resonance technique. 2313200100122
2(SCIN) C6D6 liquid scintillator array. Each detector 2313200100123
was positioned at an angle of 125 degrees with respect 2313200100124
to the direction of the neutron beam. 2313200100125
Each scintillator was coupled to a quartz windowed 2313200100126
(boron free) photomultiplier. 2313200100127
Threshold for the deposited energy of the detection 2313200100128
system at 12.5 m, 30 m, and 60 m was set to 200 keV, 2313200100129
150 keV and 150 keV, respectively. 2313200100130
Linearity and resolution of the C6D6 detectors were 2313200100131
monitored on a weekly basis by measurements of the 2313200100132
2.6 MeV gamma-ray from the Th-232 decay chain. 2313200100133
(IOCH) B-10 Frisch gridded ionization chambers placed 2313200100134
at 80 cm before the capture sample -to monitor shape of2313200100135
neutron spectrum. Double chamber was used with cathode 2313200100136
loaded with two back-to-back layers of about 2313200100137
40 microg/cm2 B-10, effective diameter of 84 mm, 2313200100138
evaporated on a 30 microm thick aluminum backing. 2313200100139
Chambers were operated with continuous flow of mixture 2313200100140
of argon (90%) + methane (10%) at atmospheric pressure.2313200100141
ANALYSIS To derive the transmission and the capture yield from 2313200100142
the raw TOF spectra the data reduction package AGS 2313200100143
(Analysis of Geel Spectra) developed at the IRMM was 2313200100144
used - C.Bastian, AGS,"set of UNIX commands for neutron2313200100145
data reduction", Proc.Int.Conf. on Neutron Research and2313200100146
Industry, Crete, Greece, 1996, Ed. G.Vourvopoulos, 2313200100147
SPIE - International Society for Optical Engineering, 2313200100148
Vol. 2867, 611, 1997 : 2313200100149
AGS code controls the most important spectra 2313200100150
manipulations: dead time correction, background fitting2313200100151
and subtraction and normalization; performs full 2313200100152
propagation of uncertainties, starting from the 2313200100153
uncorrelated uncertainties due to counting statistic; 2313200100154
includes complete covariance matrix accounting for both2313200100155
uncorrelated and correlated uncertainty components. 2313200100156
Resonance shape analysis code REFIT is used to 2313200100157
parameterize the data in terms of resonance parameters.2313200100158
The code is based on the Reich-Moore approximation of 2313200100159
the R-matrix formalism and accounts for self-shielding,2313200100160
multiple scattering and Doppler effects, the resolution2313200100161
of the spectrometer, neutron sensitivity of the capture2313200100162
detection system and attenuation of gamma-rays in 2313200100163
sample. 2313200100164
Normalization of capture yields and self-indication 2313200100165
data was done by means of the saturated resonance 2313200100166
technique applied to the 4.9-eV Au resonance. 2313200100167
For capture measurements with thin samples the 2313200100168
normalization was derived from nearby resonances, 2313200100169
for which the resonance parameters were determined 2313200100170
from the thick sample data. 2313200100171
MONITOR (5-B-10(N,A)3-LI-7,,SIG) C-s were used to drive 2313200100172
(5-B-10(N,TOT),,SIG) capture yields. 2313200100173
CORRECTION For dead-time - maximum correction for neutron energies2313200100174
below 500 eV was 2%. 2313200100175
In capture measurement for the flux measurements the 2313200100176
dead time was 3500 ns, with a maximum dead-time 2313200100177
correction less than 1% at the two stations. The dead 2313200100178
time for the capture measurement systems was 2800 ns. 2313200100179
For the measurements at the 12.5m and 30m station 2313200100180
maximum dead-time corrections were < 20% and 5%, 2313200100181
respectively. 2313200100182
For the attenuation in the exit window of ionization 2313200100183
chamber and the attenuation due to the 80 cm air 2313200100184
between ionization chamber and target. 2313200100185
For background. In transmission measurement 2313200100186
- for sample-out < 1%, 2313200100187
- for sample-in up to 10% at 4.9 eV . 2313200100188
In capture measurement time-dependent background was 2313200100189
monitored during runs having only the sample holder in 2313200100190
the neutron beam; additional 0.5 mm thick Pb-208 sample2313200100191
measurement was done to estimate the background due to 2313200100192
scattered neutrons. 2313200100193
ERR-ANALYS1(ERR-1,,0.5) Uncertainty of normalization factor in 2313200100194
transmission measurement 2313200100195
HISTORY (20110719C) M.M. 2313200100196
Request of data of all resonances was sent to 2313200100197
Cristian Massimi - massimi@bo.infn.it 2011-07-28. 2313200100198
(20130110U) On. MONIT=4.9 eV deleted. 2313200100199
ENDBIB 197 0 2313200100200
NOCOMMON 0 0 2313200100201
ENDSUBENT 200 0 2313200199999
SUBENT 23132002 20110719 22282313200200001
BIB 6 18 2313200200002
REACTION 1(79-AU-197(N,0),,EN) Resonance energy. 2313200200003
2(79-AU-197(N,EL),,WID) Neutron width. 2313200200004
3(79-AU-197(N,G),,WID) Gamma width. 2313200200005
ANALYSIS (MLA) REFIT code, based on the Reich-Moore 2313200200006
approximation of the multi-level R-matrix formalism, 2313200200007
was used to calculate the resonance parameters 2313200200008
performing a simultaneous fit of several data sets. 2313200200009
Adjusted parameters: energy, neutron and radiation 2313200200010
width.Resonance energy was determined from transmission2313200200011
data at 49.34 m, where the time-energy calibration was 2313200200012
adjusted to the U-238 resonance at 6.673 +- 0.001 eV. 2313200200013
REL-REF (A,,R.C.Block+,C,94GATLIN,81,1994) Agree within 1%. 2313200200014
ERR-ANALYS (ERR-S) Statistical uncertainty. 2313200200015
STATUS (TABLE) Text, page 526 of J,NC/B,125,517,2010. 2313200200016
Text, last page of J,KPS,58,(1061),2011. 2313200200017
COMMENT This work was supported by the European Commission 2313200200018
within the Sixth Framework Program through I3-EFNUDAT 2313200200019
,EURATOM contract No. 036434. 2313200200020
ENDBIB 18 0 2313200200021
NOCOMMON 0 0 2313200200022
DATA 8 1 2313200200023
DATA 1ERR-S 1DATA 2ERR-S 2DATA 3ERR-S 32313200200024
PARITY SPIN J 2313200200025
EV EV MILLI-EV MILLI-EV MILLI-EV MILLI-EV 2313200200026
NO-DIM NO-DIM 2313200200027
4.8995 0.0002 14.96 0.02 121.4 0.3 2313200200028
+1. 2. 2313200200029
ENDDATA 6 0 2313200200030
ENDSUBENT 29 0 2313200299999
SUBENT 23132003 20110719 22282313200300001
BIB 3 10 2313200300002
REACTION (79-AU-197(N,G),,WID/STR) Capture kernel. 2313200300003
REL-REF (A,14086002,R.C.Block+,C,94GATLIN,1,81,1994) RPI 2313200300004
(A,23067001,Massimi+,J,PR/C,81,044616,2010) n TOF 2313200300005
Deviations on average by 2% and 1%,respectively. 2313200300006
Maximum deviation is less than 5% 2313200300007
STATUS (UNOBT) Request for the data was sent 28-07-2011 to 2313200300008
Cristian Massimi - massimi@bo.infn.it . 2313200300009
Data are on Fig.3 of J,KPS,58,(1061),2011 2313200300010
and on Fig.1 of J,NC/B,125,517,2010 2313200300011
as ratios to kernels measured at RPI and n TOF. 2313200300012
ENDBIB 10 0 2313200300013
NOCOMMON 0 0 2313200300014
NODATA 0 0 2313200300015
ENDSUBENT 14 0 2313200399999
SUBENT 23132004 20130110 22342313200400001
BIB 4 8 2313200400002
REACTION 1(79-AU-197(N,TOT),,TRN) Transmission 2313200400003
2(79-AU-197(N,G)79-AU-198,,RYL) Capture yield 2313200400004
3(79-AU-197(N,G)79-AU-198,,SIF) Self-indication 2313200400005
ADD-RES (COMP) Comparison with REFIT code calculations 2313200400006
STATUS (UNOBT) Fig.2 of Nuovo.Cim.B125(2010)517 2313200400007
Transmission, capture yield and self-indication 2313200400008
yields for 5, 10, 20, and 100 um thick samples 2313200400009
HISTORY (20130110A) On. REACTION: ,TRN,,RYL -> ,RYL 2313200400010
ENDBIB 8 0 2313200400011
NOCOMMON 0 0 2313200400012
NODATA 0 0 2313200400013
ENDSUBENT 12 0 2313200499999
ENDENTRY 4 0 2313299999999