PHYSICAL REVIEW C 85, 034616 (2012)
Neu on-induced ission c oss sec ion o 245Cm: New esul s om da a aken
a he ime-o - ligh acili y n TOF
M. Cal iani,1,2,*M. H. Meaze,3,†N. Colonna,3J. P aena,4U. Abbondanno,5G. Ae s,6H. Al a ez,7F. Al a ez-Vela de,8
S. And iamonje,2,6J. And zejewski,9P. Assimakopoulos,10,‡L. Audouin,11 G. Badu ek,12 M. Ba bagallo,3P. Baumann,13
F. Beˇ
c ´
aˇ
,14 F. Belloni,5,6B. Be hie ,11 E. Be houmieux,6F. Cal i ˜
no,15 D. Cano-O ,16 R. Capo e,4,17 C. Ca apic¸o,6,18
P. Cennini,2V. Chepel,19 E. Chia e i,2G. Co es,15 A. Cou u e,19 J. Cox,19 M. Dahl o s,2S. Da id,11 I. Dillmann,20
C. Domingo-Pa do,21 W. D idi,6I. Du an,7C. Ele he iadis,22 M. Embid-Segu a,8L. Fe an ,11,‡A. Fe a i,2
R. Fe ei a-Ma ques,23 K. Fujii,5W. Fu man,24 S. Galanopoulos,25 G. Giub one,26 I. Gonc¸al es,18 E. Gonzalez-Rome o,16
A. Go e do ski,27 F. G amegna,1C. Gue e o,16 F. Gunsing,6B. Haas,28 R. Haigh ,29 M. Heil,20 A. He e a-Ma inez,2
M. Igashi a,30 E. Je icha,12 F. K¨
appele ,20 Y. Kadi,2D. Ka adimos,10 D. Ka amanis,10 V. Ke le o ,27 M. Ke eno,13
P. Koehle ,31 V. Kono alo ,27 E. Kossionides,32 M. K iˇ
cka,14 C. Lampoudis,22 C. Lede e ,33 H. Leeb,12 A. Lindo e,23
I. Lopes,23 M. Lozano,4S. Lukic,13 J. Ma ganiec,9S. Ma one,3T. Ma ´
ınez,16 C. Massimi,34 P. Mas inu,1E. Mendoza,8
A. Mengoni,2,17 P. M. Milazzo,5C. Mo eau,5M. Mosconi,20 F. Ne es,23 H. Obe humme ,12 S. O’B ien,19 J. Pancin,6
C. Papach is odoulou,10 C. Papadopoulos,25 C. Pa adela,7N. Pa onis,10 A. Pa lik,33 P. Pa lopoulos,35 L. Pe o ,6M. T. Pigni,12
R. Plag,20 A. Plompen,36 A. Plukis,6A. Poch,15 C. P e el,15 J. Quesada,4T. Rausche ,37 R. Rei a h,21 M. Rose i,38
C. Rubbia,39 G. Rudol ,13 P. Rullhusen,36 J. Salgado,18 C. San os,18 L. Sa chiapone,1,2R. Sa men o,18 I. Sa idis,22
P. Schillebeeckx,36 C. S ephan,11 G. Taglien e,3J. L. Tain,26 L. Tassan-Go ,11 L. Ta o a,18 R. Te lizzi,3G. Vannini,34
V. Va iale,3P. Vaz,18 A. Ven u a,38 D. Villama in,16 M. C. Vincen e,16 V. Vlachoudis,2R. Vlas ou,25 F. Voss,20 S. Wal e ,20
M. Wiesche ,11 and K. Wisshak20
(n TOF Collabo a ion§)
1INFN-Labo a o i Nazionali Legna o and Dipa imen o di Fisica, Uni e si `
a di Pado a, Padua, I aly
2CERN, Gene a, Swi ze land
3INFN-Sezione di Ba i, Ba i, I aly.
4Uni e sidad de Se illa, Se illa, Spain
5Is i u o Nazionale Fisica Nuclea e, T ies e, I aly
6CEA/Saclay-DSM/DAPNIA, Gi -su -Y e e, F ance
7Uni e sidade de San iago de Compos ela, San iago de Compos ela, Spain
8Cen o de In es igaciones Ene ge icas Medioambien ales y Tecnologicas, Mad id, Spain
9Uni e si y o Lodz, Lodz, Poland
10Uni e si y o Ioannina, Ioannina, G eece
11Cen e Na ional de la Reche che Scien i ique/IN2P3-IPN, O say, F ance
12A omins i u de ¨
Os e eichischen Uni e si ¨
a en, Technische Uni e si ¨
a Wien, Vienna, Aus ia
13Cen e Na ional de la Reche che Scien i ique/IN2P3-IReS, S asbou g, F ance
14Cha les Uni e si y, P ague, Czech Republic
15Uni e sidad Poli ecnica de Ca alunya, Ba celona, Spain
16Cen o de In es igaciones Ene ge icas Medioambien ales y Tecnologicas, Mad id, Spain
17Nuclea Da a Sec ion, In e na ional A omic Ene gy Agency, Vienna, Aus ia
18Ins i u o Tecnol´
ogico e Nuclea , Lisbon, Po ugal
19Uni e si y o No e Dame, No e Dame, Indiana 46556, USA
20Ins i u ¨
u Ke nphysik, Ka ls uhe Ins i u e o Technology, Campus No d, Ka ls uhe, Ge many
21GSI Helmhol zzen um ¨
u Schwe ionen o schung GmbH, Da ms ad , Ge many
22A is o le Uni e si y o Thessaloniki, Thessaloniki, G eece
23LIP-Coimb a and Depa amen o de Fisica, Uni e sidade de Coimb a, Coimb a, Po ugal
24Join Ins i u e o Nuclea Resea ch, F ank Labo a o y o Neu on Physics, Dubna, Russia
25Na ional Technical Uni e si y o A hens, A hens, G eece
26Ins i u o de F´
ısica Co puscula , CSIC-Uni e sidad de Valencia, Valencia, Spain
27Ins i u e o Physics and Powe Enginee ing, Obninsk, Russia
28Cen e Na ional de la Reche che Scien i ique/IN2P3-CENBG, Bo deaux, F ance
29Los Alamos Na ional Labo a o y, Los Alamos, New Mexico 87545, USA
30Tokyo Ins i u e o Technology, Tokyo, Japan
31Physics Di ision, Oak Ridge Na ional Labo a o y, Oak Ridge, Tennessee 37831, USA
32NCSR, A hens, G eece
33Facul y o Physics, Uni e si y o Vienna, Vienna, Aus ia
34Dipa imen o di Fisica, Uni e si `
a di Bologna, and Sezione INFN di Bologna, Bologna, I aly
35Pˆ
ole Uni e si ai e L´
eona d de Vinci, Pa is La D´
e ense, F ance
36CEC-JRC-IRMM, Geel, Belgium
034616-1
0556-2813/2012/85(3)/034616(10) ©2012 Ame ican Physical Socie y
M. CALVIANI e al. PHYSICAL REVIEW C 85, 034616 (2012)
37Depa men o Physics, Uni e si y o Basel, Basel, Swi ze land
38ENEA, Bologna, I aly
39Uni e si `
a degli S udi Pa ia, Pa ia, I aly
(Recei ed 15 No embe 2011; published 29 Ma ch 2012)
The neu on-induced ission c oss sec ion o 245Cm was measu ed a n TOF in a wide ene gy ange and wi h
high esolu ion. The ene gy dependence, measu ed in a single measu emen om 30 meV o 1 MeV neu on
ene gy, has been de e mined wi h 5% accu acy ela i e o he 235U(n, ) c oss sec ion. In o de o educe he
unce ain y on he absolu e alue, he da a ha e been no malized a he mal ene gy o ecen measu emen s
pe o med a ILL and BR1. In he ene gy ange o o e lap, he esul s a e in ai ag eemen wi h some p e ious
measu emen s and con i m, on a e age, he e alua ed c oss sec ion in he ENDF/B-VII.0 da abase, al hough
sizable di e ences a e obse ed o some impo an esonances below 20 eV. A simila beha io is obse ed
ela i e o JENDL/AC-2008, a eac o -o ien ed da abase o ac inides. The new esul s con ibu e o he o e all
imp o emen o he da abases needed o he design o ad anced eac o sys ems and may lead o e inemen s o
ission models o he ac inides.
DOI: 10.1103/PhysRe C.85.034616 PACS numbe (s): 25.85.Ec, 28.65.+a, 27.90.+b
I. INTRODUCTION
T ansu anium elemen s (TRU) such as Np, Pu, Am, and
Cm a e buil up as a esul o mul iple neu on cap u es and
adioac i e decays in all p esen ly ope a ing nuclea eac o s
based on he U/Pu nuclea uel cycle. Some highly adioac i e
iso opes o hese elemen s cons i u e he mos impo an haza d
o nuclea was e managemen . Se e al p oposals ha e been
made in ecen yea s o educe he adio oxici y o nuclea
was e con aining TRU. Clea ly, any kind o sys em designed o
bu n nuclea was e, c i ical o subc i ical, he mal o as , will
need o be loaded wi h uel con aining a la ge ac ion o TRU.
The esponse o hese sys ems (e.g., wi h espec o c i icali y)
in he p esence o TRU is di ec ly linked o he ission c oss
sec ions o hese iso opes. These ission c oss sec ions a e
he e o e key elemen s in assessing he s a egy o be ollowed
in de ailed easibili y s udies and in he enginee ing design o
nuclea was e ansmu a ion sys ems, i.e., Gene a ion IV as
eac o s o ad anced nuclea was e bu ne s [1].
As o mos ansu anium iso opes, he bu nup o 245Cm
elies mos ly on ission eac ions. The compe i ion wi h he
neu on cap u e channel de e mines also he u he buildup
o he hea ie cu ium iso opes and o hea ie elemen s. In
his con ex , accu a e ission c oss sec ions a e equi ed om
he mal neu on ene gies o se e al MeV.
Besides hese applica ions, he ission c oss sec ions o
he Cm iso opes a e also o in e es o imp o ing he
heo e ical desc ip ion o he ission p ocess, pa icula ly o
he sys ema ics o ission ba ie s. Fission c oss sec ions a e
also needed as inpu o ne wo k calcula ions o -p ocess
nucleosyn hesis, whe e he eac ion low may be e mina ed
by spon aneous, β-delayed, and neu on-induced ission o
e y neu on- ich ac inides. Such a ecycling may ha e a
*[email p o ec ed]
†P esen add ess: Depa men o Physics, Uni e si y o Chi agong,
Chi agong, Bangladesh.
‡deceased
§h p://www.ce n.ch/n o
s ong in luence on he inal -p ocess abundances [2,3]. The
neu on-induced ission c oss sec ion o 245Cm p esen la ge
unce ain ies o up o 50% in some ene gy egions, whe eas
sensi i i y analyses o he mos impo an ad anced eac o s
indica e ha accu acies be e han 10% a e needed [4].
Due o he ela i ely high αac i i y, which is ela ed
pa icula ly o he una oidable 244Cm con amina ion o he
sample ma e ial, only a ew measu emen s o he 245Cm(n, )
c oss sec ion ha e been pe o med so a . In 1969 Moo e and
Keywo h [5] epo ed da a om 20 eV o 3 MeV by using a
nuclea explosion as he neu on sou ce. The measu emen
o B owne e al. [6] in 1978 a he 100 MeV elec on
linea accele a o a Law ence Li e mo e Na ional Labo a o y
co e ed he neu on ene gy ange be ween 0.01 and 35 eV.
The sho ligh pa h o 3.6 m esul ed in a poo ene gy
esolu ion bu pe mi ed he use o a low sample mass o a ew
mic og ams o educe he α- ela ed backg ound. Da a aken by
Whi e e al. [7] soon a e wa d a he same acili y ex ended
he ene gy ange up o 63.09 eV, wi h imp o ed esolu ion.
In his measu emen , a 245Cm sample wi h 99% en ichmen
was used. In he egion o o e lap, he wo da a se s di e
signi ican ly in a ious esonances. Recen ly, 245Cm ission
c oss sec ions in he neu on ene gy ange be ween 0.03 eV
and 20 keV ha e been measu ed wi h a lead slowing-down
neu on spec ome e a he Ins i u e o Nuclea Resea ch
o he Russian Academy o Sciences [8]. Finally, he esul s
o a new measu emen pe o med a he GELINA neu on
acili y o Ins i u e o Re e ence Ma e ials and Measu emen s
(IRMM), Geel, Belgium, ha e jus become a ailable [9]. Using
a245Cm sample wi h 98.5% en ichmen and a pai o Si-Au
su ace ba ie de ec o s, high-quali y da a om he mal o
100 eV neu on ene gy we e collec ed a he 9.3 m ligh pa h,
and a new esonance analysis was pe o med.
The limi ed amoun o da a and he disc epancies be ween
hem a e e lec ed by he e alua ions in he majo c oss-sec ion
lib a ies, ENDF/B-VII.0 [10], JEFF-3.1 [11], and JENDL-3.3
[12]. The c oss sec ions in hese lib a ies a e all essen ially
based on he same e alua ion [13], which elied on he
da a o B owne e al. [6] up o 20 eV and on he da a
034616-2
NEUTRON-INDUCED FISSION CROSS SECTION OF ... PHYSICAL REVIEW C 85, 034616 (2012)
o Moo e and Keywo h [5] a highe ene gy. A di e en
app oach was used in JENDL-4 [14], as well as in he special
pu pose ile JENDL/AC-2008 [15], a specialized e sion o
JENDL con aining only da a on ac inides needed o ad anced
eac o echnology (since he wo iles a e equi alen o
ac inides, in he ollowing we will only e e o he la e ).
In JENDL/AC-2008, he e alua ion o he ission c oss sec ion
o 245Cm below 20 eV was modi ied o be e ep oduce
he he mal c oss sec ion and he esul s om ime-o - ligh
measu emen s including he da a o Whi e e al. [7], which
we e no conside ed in Re . [13].
The disc epancies be ween he a ious expe imen al esul s
and he e alua ed c oss sec ions a e a majo p oblem o
he new applica ions, which equi e unce ain ies below 10%.
Fu he expe imen al da a a e he e o e necessa y o imp o e
he accu acy o he (n, ) c oss sec ion o 245Cm. To his pu pose,
a measu emen was pe o med a he neu on acili y n TOF a
CERN, aking ad an age o he wide neu on ene gy ange, o
he high esolu ion, and o he high ins an aneous lux o his
spalla ion neu on sou ce [16]. This las p ope y makes he
nTOF acili y pa icula ly con enien o measu emen s o
adioac i e iso opes since i minimizes he backg ound ela ed
o he na u al adioac i i y o he samples.
The expe imen al se up used o he measu emen is
desc ibed in Sec. II. The esul ing c oss sec ions, which we e
ob ained simul aneously om nea he mal ene gies (30 meV)
up o 1 MeV, a e p esen ed in Sec. III, compa ed o p e ious
da a and o majo e alua ed da a lib a ies. In Sec. IV he
R-ma ix analysis o he esonances is discussed, and he
esul s a e compa ed wi h p e ious e alua ions.
II. EXPERIMENTAL SETUP AND DATA ANALYSIS
The expe imen al se up is based on he ission ioniza ion
chambe desc ibed in Re . [17]. The signals we e eco ded wi h
a lash analog- o-digi al con e e (ADC) [18] and analyzed o
ex ac he neu on ime o ligh as well as he ene gy deposi ed
by he ission agmen s in he de ec o . The ou cu ium
samples used in he expe imen we e p o ided by he Ins i u e
o Physics and Powe Enginee ing, Obninsk, and by he Join
Ins i u e o Nuclea Resea ch, Dubna. Thin laye s o CmO2
we e p epa ed on 100-μm- hick Al backings by he pain ing
echnique [19]. The masses and αac i i ies a e lis ed in Table I.
As o all o he samples in he measu emen , he diame e o
he Cm samples was 8 cm o ma ch he diame e o he neu on
beam used in he ission p og am a n TOF. The iso opic
composi ion was measu ed by αspec oscopy, showing a
6% con amina ion o 244Cm. Because o i s sho hal -li e o
18 y , his iso ope is esponsible o he la ge sample ac i i ies
be ween 60 and 100 MBq. I also con ibu es signi ican ly o
he ission backg ound due o i s mo e han 200 imes highe
a e o spon aneous ission. Figu e 1shows he ampli ude
dis ibu ion o he digi ized signals. The α-pa icle and ission
backg ound we e de e mined in uns wi hou he neu on
beam. The wo la ge s uc u es a low ampli ude a e due o
αpa icles om he na u al adioac i i y o he sample and o
hei pileup, while he con ibu ion o he spon aneous ission
o 244Cm is isible in he no-beam uns a all ampli udes.
TABLE I. Cha ac e is ics o he CmO2samples used in he
measu emen s discussed in his wo k. The o e all ac i i y o he
samples is mos ly due o he 244Cm con amina ion.
Sample Mass (mg) Unce ain y (%) Ac i i y (MBq)
1 0.367 1.3 66.1
2 0.538 1.2 96.9
3 0.407 1.3 73.3
4 0.399 1.3 71.9
Because o he la ge αbackg ound and αpileup a a he
high h eshold had o be chosen o he pulse-heigh dis i-
bu ion. The alue ha maximizes he ission- o-backg ound
a io was ound a ound channel 80. Simula ions o he
ission agmen ene gy deposi ion in he gas ( o de ails, see
Re . [20]) indica e ha he de ec ion e iciency ob ained wi h
his h eshold is app oxima ely 50%.
Apa om he loss o s a is ics, he la ge backg ound and
he high h eshold p e en he de e mina ion o he de ec ion
e iciency and o he expe imen al e ec s (such as he dead-
ime co ec ion) wi h su icien accu acy. Fo his eason, an
absolu e no maliza ion could no be pe o med o he p esen
da a se . A di e en app oach, desc ibed below, had o be
ollowed in o de o ex ac accu a e ission c oss sec ions.
As illus a ed in Fig. 1, e en he high alue o he h eshold
is no su icien o ully ejec he α-pa icle backg ound.
Fu he mo e, he backg ound om spon aneous ission has
o be accu a ely de e mined. To minimize he s a is ical un-
ce ain ies, his ime-independen esidual backg ound, which
was measu ed wi hou he neu on beam, was ans o med
in o le ha gy scale and i ed wi h he exponen ial ela ion
ea+bE, wi h he pa ame e bbeing ixed o he alue o
-1.15129 expec ed om he ime- o-le ha gy con e sion. Wi h
Ampli ude (ch.)
0 20 40 60 80 100 120 140 160 180 200
Coun s
1
10
2
10
3
10
4
10 Cm
245
Cm backg ound
245
U
235
FIG. 1. (Colo online) Ampli ude dis ibu ion o signals eco ded
in he ission ioniza ion chambe wi h he neu on beam [ ed (ligh
g ey) solid line] and du ing backg ound uns wi h no beam [ ed (ligh
g ey) dashed line]. The s uc u es a low ampli udes a e p oduced by
αpa icles and by α-pa icle pileup. These backg ounds a e missing
in he ampli ude dis ibu ion o 235U (shown as a black solid line o
compa ison). The e ical dashed line a channel 80 ep esen s he
h eshold used in he analysis.
034616-3
M. CALVIANI e al. PHYSICAL REVIEW C 85, 034616 (2012)
he pa ame e ade e mined by he i , he abo e exp ession
was hen used o backg ound sub ac ion. A co ec ion o he
dead ime ( ela ed o he o e lap o wo consecu i e signals
as de ined in Re . [17]) was applied o accoun o possible
dis o ions in he ene gy dependence o he measu ed c oss
sec ion. Howe e , gi en he small coun a e abo e he chosen
h eshold, he co ec ions a e less han 1% in he in es iga ed
ene gy ange.
The con ibu ion o he 244Cm(n, ) eac ion o he measu ed
ission yield was no sub ac ed below 500 keV neu on
ene gy because i was es ima ed o be less han 1%. No
co ec ion was applied o he sel -shielding e ec , which is
less han 0.1% e en o he bigges esonances. Conside ing all
sou ces o sys ema ic unce ain ies, he absolu e c oss sec ion
is cha ac e ized by unce ain ies o ∼5% in he in es iga ed
ene gy ange.
III. NORMALIZATION AND RESULTS
Thec osssec iono he245Cm(n, ) eac ion was de e mined
ela i e o he 235U e e ence sample, which was moun ed in
he same ission chambe . The p ocedu e used in he analysis
o he e e ence sample is desc ibed in de ail in Re . [20].
As men ioned be o e, he high h eshold applied on he
pulse-heigh dis ibu ion o he 245Cm samples leads o a
de ec ion e iciency which is subs an ially di e en om ha
o he 235U e e ence sample. An a emp o de e mine he
di e ence by means o Mon e Ca lo simula ions was aban-
doned because he co ec ion ac o depends on he ampli ude-
o-ene gy calib a ion, which could no be accu a ely de ined
due o he s ong in luence o he α-pa icle backg ound.
Acco dingly, he e iciency co ec ion became oo la ge o
mee he in ended accu acy o less han 10%. The al e na i e
app oach was o use he he mal c oss sec ion o no maliza-
ion. A ho ough examina ion o he ecommended he mal
c oss sec ions showed ha ea lie expe imen al da a di e ed
by up o 30%. The ecommended alue in ENDF/B-VII.0 o
2142 b is based on he measu emen o B owne e al. [6], which
ag ees wi hin unce ain ies wi h he esul s o Re s. [21,22]
bu is la ge han epo ed in o he measu emen s [23–25].
The JENDL/AC-2008 da abase ecommends a lowe he mal
c oss sec ion o 2054 b, which is based on he combined
expe imen al esul s o Re s. [6] and [24]. Al hough he
ecommended alues di e only by 5%, he la ge disc epancy
be ween he expe imen al esul s sugges s ha hey a e s ill
unce ain by mo e han 10%.
The e o e, he p esen da a ha e been no malized o he
he mal c oss sec ion epo ed in wo ecen measu emen s
by Le ou neau e al. [26], who ob ained a alue o 1943 ±
65 b in a measu emen a he Ins i u Laue-Lange in (ILL)
high- lux eac o , G enoble, F ance, and by Popescu e al. [27],
who ob ained 1951 ±18s a ±81sys b in a measu emen a
he BR1 eac o o he S udiecen um oo Ke nene gie -
Cen e d’E ude de l’´
ene gie Nucl´
eai e (SCK·CEN), Mol,
Belgium. In iew o he excellen ag eemen be ween bo h
esul s, he weigh ed a e age o 1946 ±51 b has been adop ed
o no maliza ion. Since he n TOF da a s a a 30 meV and
do no ex end down o 25 meV, an ex apola ion has been used
Neu on Ene gy (eV)
-1
10 1
)eV (ba n E
σ
100
150
200
250
300
350 n_TOF
Whi e 1979
B owne 1978
ENDF/B-VII.0
JENDL/AC-2008
FIG. 2. (Colo online) Ene gy-weigh ed neu on-induced ission
c oss sec ion o 245Cm om he mal ene gy o 1 eV. The n TOF
esul s (black do s), no malized o ecen he mal c oss-sec ion
measu emen s, a e compa ed wi h p e ious da a and wi h wo
e alua ed da a se s.
below 40 meV, simila o he one desc ibed in Re . [20]. We
no e ha he c oss sec ion de e mined in his way can easily
be scaled i an imp o ed alue o he he mal c oss sec ion
becomes a ailable.
Figu e 2shows he ene gy-weigh ed c oss sec ion om
he mal ene gy up o 1 eV. The esul s o he p esen wo k
a e compa ed wi h p e ious da a and wi h he e alua ed
c oss sec ions in ENDF/B-VII.0 and JENDL/AC-2008. In his
egion, he wo p e ious measu emen s [6,7] show a di e en
end, wi h he bigges di e ence o ∼20% close o he he mal
ene gy. The n TOF da a a e in e media e be ween he wo
measu emen s below 100 meV bu a e in easonable ag eemen
wi h da a o Whi e e al. [7] abo e ha ene gy.
The compa ison wi h e alua ions shows some in e es ing
ea u es. The p esen esul s a e no well ep oduced ei he by
ENDF/B-VII.0 o by JENDL/AC-2008 (which, by he way,
does no ep oduce any o he p e ious esul s ei he ). In
pa icula , he e alua ed c oss sec ion in bo h da abases shows
a simila ene gy dependence bu di e s in he absolu e c oss
sec ion by app oxima ely 20% up o 200 meV. Ano he poin
o no e is ha bo h e alua ions o e es ima e he impo ance o
he i s esonance a 0.9 eV.
Figu e 3shows he n TOF esul s in he ange be ween
1 and 10 eV, compa ed wi h p e ious da a and e alua ions.
P e ious esul s in his ange show some disc epancies, wi h
a highe c oss sec ion gene ally obse ed in he da a o Whi e
e al. [7], pa icula ly o he 7.5 eV esonance. The n TOF
da a a e in easonable ag eemen wi h his da a se , excep o
he wo bigges esonances. The shoulde on he igh wing
o he esonance a 2 eV, which does no seem e iden in he
da a o B owne e al. [6], is ins ead con i med by he p esen
esul s.
Figu e 4shows he n TOF esul s compa ed wi h p e ious
da a and e alua ions be ween 10 and 17 eV. In his egion
he esul s o B owne e al. [6] su e om he poo ene gy
esolu ion o ha measu emen . Fo he 11.5 eV esonance
he n TOF da a all be ween he wo p e ious measu emen s,
034616-4
NEUTRON-INDUCED FISSION CROSS SECTION OF ... PHYSICAL REVIEW C 85, 034616 (2012)
Neu on Ene gy (eV)
12345678910
(ba n)
σ
10
2
10
3
10
n_TOF
Whi e 1979
B owne 1978
ENDF/B-VII.0
JENDL/AC-2008
FIG. 3. (Colo online) The p esen 245Cm(n, ) c oss sec ions o
his wo k compa ed wi h p e ious da a and e alua ions in he ene gy
ange om 1 o 10 eV.
while he da a o Re . [6] a e comple ely uled ou a highe
ene gies by he n TOF esul s. Apa om a sys ema ic shi
in he esonance ene gies, good ag eemen is obse ed again
wi h he esul s o Whi e e al. [7].
The la ge disc epancy be ween p e ious esul s is clea ly
e lec ed in he di e ence be ween he e alua ions. In his
egion, ENDF/B-VII.0 s ongly unde es ima es he esonance
s eng hs, while JENDL/AC-2008 o e es ima es hem sligh ly.
Fu he mo e, he double in ENDF/B-VII.0 da a a ound 15 eV
is clea ly excluded by he p esen esul s. A p elimina y
esonance analysis shows ha he n TOF esonance s eng hs
a e 14% lowe han hose in Re . [7], on a e age.
Fo neu on ene gies abo e 20 eV, da a om Moo e
and Keywo h [5] a e also a ailable. In gene al, he n TOF
esul s a e in e y good ag eemen wi h his las da a se ,
which was ob ained wi h a collima ed neu on beam om a
nuclea explosion (Fig. 5). The ag eemen wi h he da a o
Whi e e al. [7] is also easonable. In his ene gy ange he
e alua ed c oss sec ions a e essen ially based on he esul s o
Moo e and Keywo h [5]. Consequen ly, hey gene ally
Neu on Ene gy (eV)
10 11 12 13 14 15 16 17
(ba n)
σ
0
50
100
150
200
250
300
350
400
450
n_TOF
Whi e 1979
B owne 1978
ENDF/B-VII.0
JENDL/AC-2008
FIG. 4. (Colo online) The 245Cm(n, ) c oss sec ion o his wo k
be ween 10 and 17 eV neu on ene gy, compa ed wi h wo p e ious
da a se s and wi h e alua ions.
Neu on Ene gy (eV)
20 25 30 35 40 45 50
(ba n)
σ
0
50
100
150
200
250
300
350
400
450 n_TOF
Whi e 1979
B owne 1978
Moo e and Keywo h 1971
ENDF/B-VII.0
JENDL/AC-2008
FIG. 5. (Colo online) The 245Cm(n, )c osssec iono hiswo k
be ween 20 and 50 eV neu on ene gy compa ed wi h p e ious
measu emen s and wi h he ENDF/B-VII.0 and JENDL/AC-2008
e alua ions. The e is almos pe ec ag eemen be ween he p esen
esul s and he da a o Re . [5].
adequa ely ep oduce he c oss sec ion measu ed a n TOF
as well.
The good ag eemen be ween he n TOF esul s and he
da a in Re . [5] is also con i med a highe ene gy, as
illus a ed in Fig. 6. Because o he simila ene gy esolu ion
he esonance s uc u es a e pe ec ly ma ched all he way
up o 1 keV. The e alua ions ollow he esonance s uc u es
o he da a below 100 eV, which can be conside ed as he
cu en limi o he esol ed esonance egion (RRR) in he
e alua ed c oss-sec ion lib a ies. As discussed in Re . [20]
o he 233U(n, ) eac ion, he obse ed s uc u es could be in
some cases mul iple s o esonances, pa icula ly o neu on
ene gies abo e a ew hund ed eV.
An impo an con i ma ion o he eliabili y o he p esen
esul s is p o ided by he compa ison wi h he da a ecen ly
ob ained by Se o e al. a GELINA [9], shown in Fig. 7 om
he mal o 100 eV neu on ene gy. Apa om he di e ence
Neu on Ene gy (eV)
70 80 90 100 110 120
(ba n)
σ
0
50
100
150
200
250
300 n_TOF
Moo e and Keywo h 1971
ENDF/B-VII.0
JENDL/AC-2008
FIG. 6. (Colo online) The 245Cm(n, ) c oss sec ion in he neu on
ene gy ange om 70 o 120 eV. In his egion, only one p e ious
da a se was a ailable.
034616-5

M. CALVIANI e al. PHYSICAL REVIEW C 85, 034616 (2012)
Neu on Ene gy (eV)
-1
10 1 10 2
10
(ba n)
σ
10
2
10
3
10
n_TOF
Se o e al. 2011
FIG. 7. (Colo online) The p esen 245Cm(n, ) c oss sec ion om
he mal o 100 eV neu on ene gy compa ed wi h ecen esul s a
GELINA [9].
below 1 eV, which is s ill wi hin he sys ema ic unce ain y o
bo h da a se s, and small disc epancies in he alleys o he i s
ew esonances, he e is a good ag eemen o all esonances,
hus con i ming he high le el o con idence o he ea u es
desc ibed abo e.
The p esen high- esolu ion da a in combina ion wi h he
esul s o Se o e al. [9] and wi h he da a o Moo e and
Keywo h [5] may pe mi he ex ac ion o new and mo e
accu a e esonance (o pseudo esonance) pa ame e s and he
ex ension o he esonance egion well abo e he cu en limi
o oughly 300 eV (see Sec. IV). Such an imp o emen in
he knowledge o he esonan beha io o he c oss sec ion is
impo an o accu a e calcula ions o sel -shielding e ec s in
uel elemen s, pa icula ly in Gene a ion IV as eac o s. A
he same ime, he da a could p o ide mo e in o ma ion on he
a e age le el densi y and o he undamen al nuclea physics
p ope ies, leading o e inemen s o ission models o he
ac inides.
Neu on Ene gy (eV)
3
10 4
10 5
10 6
10
(ba n)
σ
1
10
n_TOF
Moo e and Keywo h 1971
I anin 1997
Fu so 1997
ENDF/B-VII.0
JENDL/AC-2008
FIG. 8. (Colo online) The 245Cm(n, ) c oss sec ion in he un-
esol ed esonance egion om 1 keV o 1 MeV neu on ene gy,
compa ed wi h he da a o Re s. [5,28,29] and wi h he e alua ed da a
se s o ENDF/B-VII.0 and JENDL/AC-2008.
In he un esol ed esonance egion (URR), he n TOF da a
a e compa ed in Fig. 8wi h hose om Re . [5]aswellas
wi h da a om Fu so e al. [28] and I anin e al. [29].
Up o 100 keV he e is a ai ly good ag eemen wi h all
da a se s. A ound 100 keV, howe e , he da a o Moo e and
Keywo h [5] show a kink, which om ha poin on gi es ise
o sys ema ically highe c oss sec ions. This beha io is no
obse ed in he o he wo da a se s, no is i con i med by he
nTOF da a, sugges ing ha i could be due o an expe imen al
a i ac in he esul s o Re . [5]. The c oss sec ion in he URR
a e lis ed in Table II wi h s a is ical unce ain ies.
The compa ison wi h e alua ions shows ela i ely good
ag eemen wi h ENDF/B-VII.0 and JENDL/AC-2008 in he
un esol ed ene gy ange, wi h a sligh p e e ence o he
o me . Because he e alua ed c oss sec ions a e based up o
∼200 keV on ew da a se s, he n TOF esul s a e ce ainly
use ul o imp o ing he e alua ed da a.
A mo e quan i a i e compa ison be ween he n TOF da a,
p e ious esul s, and e alua ions can be pe o med by means
o he esonance in eg al R:
Rn, =E2
E1
σn, (E)
EdE.
The calcula ed in eg als o di e en ene gy egions a e
summa ized in Table III. Because only he p esen da a co e
he en i e ene gy ange om he mal o 1 MeV, he compa ison
wi h p e ious esul s is limi ed o es ic ed ene gy egions.
F om he mal up o 500 meV, he in eg a ed c oss sec ion o
he p esen wo k alls in be ween he alues ob ained om
p e ious esul s and e alua ions. In he 0.5–20 eV ange, he
c oss sec ions measu ed a n TOF a e 5% and 13% lowe
han hose epo ed in Re s. [6] and [7], espec i ely. The i s
di e ence is wi hin he sys ema ic unce ain y o he p esen
da a, while he second is clea ly la ge . The di e ence be ween
he n TOF esul s and hose o Re . [9] is 7%, s ill wi hin he
quo ed sys ema ic unce ain ies.
The bes ag eemen is clea ly be ween he in eg a ed c oss
sec ions ob ained a n TOF and he da a o Re . [5] all he way
om 20 eV o 1 MeV. I should be no ed, howe e , ha a
leas o he 1 keV o 1 MeV neu on ene gy ange, he good
ag eemen on he in eg a ed c oss sec ion masks a sligh ly
di e en end, wi h he da a o Moo e and Keywo h being
lowe a lowe ene gies and sligh ly highe abo e 100 keV (as
shown in Fig. 8).
Compa ed o he esonance in eg als calcula ed om he
e alua ed c oss sec ions, he n TOF alues exhibi di e ences
o 6% and 10% below 20 eV wi h espec o ENDF/B-VII.0 and
JENDL/AC-2008, espec i ely. Abo e 20 eV, he e is excellen
ag eemen be ween he p esen esul s and he e alua ed c oss
sec ion om bo h da abases. While a maximum de ia ion
o only 3% is obse ed wi h espec o ENDF/B-VII.0, he
in eg als ob ained wi h he da a o JENDL/AC-2008 di e
by mo e han 5% om he n TOF esul s abo e 1 keV. In
summa y, a e ision o he e alua ed nuclea da a lib a ies o
he 245Cm(n, ) eac ion is equi ed, pa icula ly below 1 eV
and o he i s ew esonances.
034616-6
NEUTRON-INDUCED FISSION CROSS SECTION OF ... PHYSICAL REVIEW C 85, 034616 (2012)
TABLE II. The ission c oss sec ion o 245Cm in he un esol ed
esonance egion and ela ed s a is ical e o s.
Neu on ene gy (eV) C oss sec ion (b) S a is ical e o (b)
1063.66 13.93 0.45
1195.36 12.19 0.41
1287.85 10.58 0.38
1400.87 11.70 0.39
1570.50 9.74 0.36
1706.18 9.96 0.36
1923.46 8.58 0.35
2122.47 9.19 0.37
2342.46 7.50 0.35
2576.31 7.80 0.34
2795.27 6.74 0.31
3107.68 6.96 0.31
3501.25 7.41 0.33
3777.14 6.45 0.30
4232.62 5.78 0.29
4703.75 5.97 0.29
5162.61 6.32 0.29
5745.91 5.51 0.28
6324.99 5.80 0.28
6985.03 5.52 0.27
7847.29 4.83 0.26
8652.87 4.47 0.24
9575.98 4.92 0.25
10869.95 4.78 0.23
11708.53 3.84 0.20
12853.26 4.04 0.21
14430.83 3.55 0.20
15848.10 3.42 0.19
17900.63 3.82 0.20
19474.75 3.38 0.19
21583.58 3.35 0.17
23889.99 3.29 0.17
26342.24 3.20 0.17
29019.74 3.13 0.18
31773.03 3.33 0.17
35686.11 3.12 0.20
39475.11 2.96 0.16
43428.28 2.79 0.15
48006.45 2.68 0.14
53947.00 2.54 0.13
59648.49 2.45 0.13
66310.60 2.62 0.12
72698.75 2.18 0.11
80520.91 2.04 0.11
89155.20 2.25 0.13
99204.58 2.24 0.11
109248.50 2.29 0.11
120405.10 2.00 0.09
133804.00 2.17 0.09
147564.20 2.01 0.10
163490.77 1.95 0.09
178981.00 1.96 0.08
198498.80 1.99 0.08
219652.20 1.84 0.08
242099.91 2.02 0.07
266399.41 1.92 0.07
TABLE II. (Con inued.)
Neu on ene gy (eV) C oss sec ion (b) S a is ical e o (b)
294989.00 1.82 0.07
319148.50 1.88 0.07
354762.69 1.70 0.06
388847.09 1.70 0.06
431067.00 1.68 0.07
469301.91 1.70 0.06
524493.50 1.67 0.05
566595.00 1.51 0.05
632016.81 1.47 0.05
702688.63 1.62 0.05
761827.88 1.53 0.04
841674.31 1.73 0.05
915319.13 1.54 0.06
971360.81 1.50 0.06
IV. R-MATRIX ANALYSIS
In all e alua ed da a lib a ies he esol ed esonance egion
ex ends up o 100 eV. In he ENDF/B-VII.0 e alua ion, which
is based on he wo k by Maslo e al. [13], he esonance
pa ame e s a e ex ac ed om he da a by B owne e al. [6]
om 0.01 o 20 eV and by Moo e and Keywo h [5] om40 o
100 eV and om he combina ion o bo h da a se s in be ween.
JEFF-3.1 and JENDL-3.3 use he ENDF/B-VII.0 e alua ion
and con ain he e o e iden ical esonance pa ame e s. In
JENDL/AC-2008, he pa ame e s o le els below 20 eV we e
ins ead e alua ed on he basis o all h ee p e ious da a se s
(Re s. [5–7]) by using he mul ile el B ei -Wigne o malism.
Abo e 21 eV, esonance ene gies and pa ial wid hs a e
adop ed om he e alua ion o Maslo and a e he e o e
iden ical o he alues in ENDF/B-VII.0.
The p esen da a indica e ha ENDF/B-VII.0 and
JENDL/AC-2008 need some e ision, pa icula ly in he
he mal egion and o he h ee majo esonances below 20 eV.
Fu he mo e, he high esolu ion o he n TOF beam allows
one o ex end he esonance analysis abo e he uppe limi o
he RRR in all cu en e alua ions.
Fo hese easons an R-ma ix analysis o he p esen da a
has been pe o med wi h he Bayesian code SAMMY [30]in he
mul ile el B ei -Wigne o malism. Co ec ions o he ene gy
esolu ion o he neu on beam and o Dopple b oadening
due o he he mal mo ion o he a ge nuclei we e aken in o
accoun in he i . The Dopple b oadening was modeled by a
ee gas a 300 K. The e ec o he po en ial sca e ing was
conside ed by using a adius o 9.52 m [13]. The backg ound
was assumed o be ze o, while he no maliza ion was ixed
o 1. Following he choice in Re s. [5], [6], and [13], all
esonances we e conside ed o be o s-wa e ype. We no e
ha , as claimed in bo h e alua ions, he a e age le el spacing
is oo small o iden i y all indi idual esonances in he RRR and
ha he obse ed s uc u es could be indi idual le els as well
as agg ega es o esonances (so-called pseudo esonances).
This is pa icula ly he case o neu on ene gies abo e a
ew ens o eV. In ENDF/B-VII.0, 88 posi i e and 3 nega i e
034616-7
M. CALVIANI e al. PHYSICAL REVIEW C 85, 034616 (2012)
TABLE III. The esonance in eg al (in ba ns) calcula ed o di e en ene gy egions om he n TOF da a, compa ed wi h he p edic ions
o wo majo da abases and wi h p e ious esul s. The quo ed unce ain ies e e only o he s a is ical e o s. Fo Whi e e al. [7] unce ain ies
a e no a ailable.
Neu on ene gy n TOF JENDL/AC-2008 ENDF/B-VII.0 B owne e al. [6]Whi ee al. [7] Moo e and O. Se o e al. [9]
Keywo h [5]
0.025–0.5 eV 2305.2±2.2 2267 2447 2468.2±7.5 2163.6 2709.5±10.8
0.5–20 eV 573.4±1.0 641 608 602.1±3.6 651.2 615.9±1.4
20–100 eV 109.2±0.4 108 108 108.6±0.3 103.3±0.5
0.1–1 keV 54.9±0.352 56 54.3±0.249±0.5
1keV o1MeV 28.3±0.2 26.5 27.7 27.8±0.2
0.5 eV o 1 MeV 765.8±1.2 827 798
ene gy esonances we e assumed, while in JENDL/AC-2008,
86 posi i e esonances we e complemen ed wi h only one
esonance a nega i e ene gy.
The n TOF da a we e i ed by lea ing he esonance ene gy
and  always ee in he i , while γwas kep ixed due o i s
negligible impac . Because he i o a ission esonance alone
does no gene ally allow one o de e mine also he neu on
wid h, nshould be kep ixed, o each esonance, o he alue
de e mined in p e ious e alua ions. Howe e , in se e al cases,
mos ly below 20 eV, i was no possible o i he esonance
wi hou changing n.
The esonance pa ame e s in JENDL/AC-2008 we e
adop ed as ini ial alues in he esonance i s below 100 eV.
Abo e his ene gy, a bi a ily chosen ini ial alues o  and
nha e been le ee o a y in he i . The same spin (J=4)
was assigned o all new esonances. The e o e, he esonance
i s abo e 100 eV can only p o ide accu a e alues o he
ission ke nels and no o he indi idual esonance pa ame e s.
The SAMMY i s om he mal up o 100 eV a e p esen ed
in Figs. 9and 10. The imp o emen ela i e o he mos ecen
e alua ions in ENDF/B-VII.0 and JENDL/AC-2008 is e iden ,
Neu on Ene gy (eV)
0 2 4 6 8 10 12 14 16
(ba n)
σ
0
200
400
600
800
1000
1200
n_TOF
SAMMY
FIG. 9. (Colo online) Fi o he n TOFda aup o16eVneu on
ene gy. The esonance pa ame e s o JENDL/AC-2008 we e assumed
as ini ial alues. The i was pe o med lea ing Enand  ee o a y.
Fo some esonances, nwas also conside ed a ee pa ame e , and a
ew esonances we e added in his ene gy ange o imp o e he i .
pa icula ly o he s ong esonances below 20 eV (see, o
compa ison, Figs. 2–6). To ep oduce he n TOF da a i was in
some cases necessa y o add new esonances and/o o change
he esonance spins. Fo example, a new le el a 3.5 eV (wi h
spin 4) was included o ep oduce he ail o he 2 eV esonance.
In he p esen analysis, a o al o 90 esonances (excluding he
nega i e one) we e coun ed below 100 eV, co esponding o
an a e age le el spacing o 1.11 eV.
The p esen R-ma ix analysis demons a es he need o
a e ision o he cu en esonance pa ame e s, pa icula ly
below 20 eV. This is clea ly demons a ed in Fig. 11 by he
a io o he ission ke nels ob ained om he p esen da a and
om he pa ame e s gi en in he e alua ed da a lib a ies. While
he ke nels ag ee wi hin 5% abo e 30 eV, hanks o he high
accu acy o he nuclea explosion da a o Moo e and Keywo h
[5], disc epancies o up o 50% a e seen a lowe ene gies,
which need o be p ope ly co ec ed.
The good ene gy esolu ion o he n TOF neu on beam
allows one o obse e esonances, o pseudo esonances, o
neu on ene gies e en abo e 100 eV, he limi o cu en
e alua ions. A p elimina y analysis indica es ha he ange
could be easonably ex ended up o a ound 300 eV wi h p esen
s a is ics. Figu e 12 shows a en a i e i pe o med in he
Neu on Ene gy (eV)
20 30 40 50 60 70 80 90 100
(ba n)
σ
0
100
200
300
400
500
600 n_TOF
SAMMY
FIG. 10. (Colo online) Fi o he n TOF da a om 20 o 100 eV
neu on ene gy. The s a egy o he i was he same as o he i s
showninFig.9.
034616-8
NEUTRON-INDUCED FISSION CROSS SECTION OF ... PHYSICAL REVIEW C 85, 034616 (2012)
Neu on Ene gy (eV)
0 20406080100
Ke nel a io
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
1.3
1.4
1.5
n_TOF/(JENDL/AC-2008)
n_TOF/(ENDF/B-VII.0)
FIG. 11. (Colo online) Ra io o he esonance ke nels de e mined
in his wo k and hose de e mined om he esonance pa ame e s
o he wo mos ecen e alua ions. Abo e 20 eV he esonance
pa ame e s in ENDF/B-VII.0 and JEND/AC-2008 coincide, and so
does he a io.
egion be ween 100 and 200 eV neu on ene gy. In his ange,
a o al o 55 le els we e ound o be su icien o ep oduce he
obse ed esonance s uc u es.
V. CONCLUSIONS
The neu on-induced ission c oss sec ion o 245Cm has
been measu ed a n TOF om 30 meV o 1 MeV neu on
ene gy. Such a wide ene gy ange is co e ed he e in a single
measu emen . The ene gy dependence o he c oss sec ion
could be de e mined wi h an unce ain y close o 3%. Howe e ,
i was no possible o ob ain he absolu e no maliza ion wi h
compa able accu acy because o he high h eshold needed
o educing he la ge αbackg ound. The e o e, he da a ha e
been eno malized o he weigh ed a e age o he he mal
c oss sec ion de e mined in wo ecen measu emen s. The
combina ion o he unce ain ies o backg ound sub ac ion,
no maliza ion, and lux shape esul s in an o e all sys ema ic
unce ain y a ound 5% in he whole ene gy ange. F om
he mal ene gies o 0.1 eV he n TOF da a all, on a e age, in
be ween he only wo p e ious ime-o - ligh measu emen s,
while hey clea ly ule ou one o hese in he egion abo e
10 eV. F om 50 eV up o 10 keV, he p esen esul s a e in
Neu on Ene gy (eV)
100 120 140 160 180 200
(ba n)
σ
0
50
100
150
200
250
n_TOF
SAMMY
FIG. 12. (Colo online) Fi o he n TOF da a om 100 o 200 eV
neu on ene gy. In his ene gy ange no esonance analysis exis ed
o da e. The ini ial pa ame e s o En,n, , and he spin we e
a bi a ily chosen.
ag eemen wi h he only high- esolu ion da a exis ing p io
o his wo k [5], while a highe ene gies a sligh ly di e en
ene gy dependence is obse ed ela i e o p e ious measu e-
men s.
Compa ed o he e alua ed c oss sec ions in he da a
lib a ies ENDF/B-VII.0 and JENDL/AC-2008, he e is ea-
sonably good ag eemen , i.e., wi hin ±5%, o he esonance
in eg als. Howe e , la ge di e ences exis o some esonances
below 20 eV as well as o he end in he un esol ed
esonance egion. A p elimina y esonance analysis shows
ha he esonance pa ame e s could be subs an ially imp o ed
and ha he RRR could be ex ended o signi ican ly highe
ene gies. Acco dingly, a e ision o he e alua ed ission c oss
sec ion o 245Cm is equi ed, pa icula ly o he esol ed
esonance egion.
ACKNOWLEDGMENTS
This wo k was suppo ed by he Eu opean Commission’s
5 h F amewo k P og amme unde Con ac No. FIKW-CT-
2000-00107 (n TOF-ND-ADS P ojec ) and by he 7 h F ame-
wo k P og amme unde he ANDES p ojec , G an Ag eemen
No. 249671.
[1] M. Sal a o es, Nuclea Ene gy Agency, Repo No.
NEA/WPEC-26, 2008.
[2] I. V. Pano , E. Kolbe, B. P ei e , T. Rausche , K.-L. K a z, and
F.-K. Thielemann, Nucl. Phys. A 747, 633 (2005).
[3] J. Beun e al.,Phys.Re .C77, 035804 (2008).
[4] G. Alibe i e al.,Ann. Nucl. Ene gy 33, 700 (2006).
[5] M. S. Moo e and G. A. Keywo h, Phys.Re .C3, 1656 (1971).
[6]J.C.B ownee al., Nucl. Sci. Eng. 65, 166 (1978).
[7] R. M. Whi e e al.,inP oceedings o he In e na ional
Con e ence on Nuclea C oss Sec ions o Technology, edi ed
by J. L. Fowle , C. H. Johnson, and C. D. Bowman (Uni e si y
o Tennessee, Knox ille, TN, USA, 1980), p. 496.
[8] A. A. Aleksee e al.,A . Ene gy 106, 133 (2009).
[9] O. Se o , C. Wagemans, S. Ve mo e and J. Van Gils, J. Ko ean
Phys. Soc. 59, 1896 (2011).
[10] M. B. Chadwick, P. Obloˇ
zinsk´
y, M. He man e al.,Nucl. Da a
Shee s 107, 2931 (2006).
[11] The JEFF 3.1 Nuclea Da a Lib a y, edi ed by A. Koning,
R. Fo es , M. Kelle , R. Mills, H. Hen iksson, and Y. Rugama,
JEFF Repo No. 21, NEA Rep. No. 6190 (Nuclea Ene gy
Agency, Pa is, 2006).
[12] K. Shiba a e al.,J. Nucl. Sci. Technol. 39, 1125 (2002).
[13] V. M. Maslo , E. Sh. Sukho i skij, Yu. V. Po odzinskij, A. B.
Klepa skij, and G. B. Mo o ogskij, E alua ion o Neu on Da a
034616-9