Measu emen o he 244Cm and 246Cm neu on-induced cap-
u e c oss sec ions a he n_TOF acili y
V. Alcayne1, A. Kimu a2, E. Mendoza1, D. Cano-O 1, T. Ma ínez1, O. Abe le3,
J. And zejewski4, L. Audouin5, V. Béca es1, M. Bacak3,6,7, M. Ba bagallo3,8, F. Beˇ
c áˇ
9,
G. Bellia10,11, E. Be houmieux7, J. Billowes12, D. Bosna 13, A. B own14, M. Busso8,15,16,
M. Caamaño17, L. Caballe o-On anaya18, F. Cal iño19, M. Cal iani3, A. Casano as19,
F. Ce u i3, Y. H. Chen5, E. Chia e i3,12,20, N. Colonna8, G. Co és19, M. A. Co és-Gi aldo20,
L. Cosen ino10, S. C is allo8,15,21, L. A. Damone8,22, M. Diakaki23,3, M. Die z24, C. Domingo-
Pa do18, R. D essle 25, E. Dupon 7, I. Du án17, Z. Eleme26, B. Fe nández-Domínguez17,
A. Fe a i3, P. Finocchia o10, V. Fu man27, K. Göbel28, A. Gawlik4, S. Gila doni3,
T. Gloda iu29, I. F. Gonçal es30, E. González-Rome o1, C. Gue e o20, F. Gunsing7,
H. Ha ada2, S. Heini z25, J. Heyse31, D. G. Jenkins14, F. Käppele 32, Y. Kadi3, T. Ka abuchi33,
N. Ki el25, I. Knapo a9, M. Kokko is23, Y. Kopa ch27, M. K iˇ
cka9, D. Ku ulgil28,
I. Lada escu18, C. Lede e -Woods24, J. Le endegui-Ma co20, S. Lo Meo34,35, S. J. Lonsdale24,
D. Macina3, A. Manna35,36, A. Masi3, C. Massimi35,36, P. Mas inu37, M. Mas oma co3,
F. Ma eucci38,39, E. A. Mauge i25, A. Mazzone8,40, A. Mengoni34, V. Michalopoulou23,
P. M. Milazzo38, F. Ming one3, A. Musuma a10,11, A. Neg e 29, R. Nol e41, F. Ogálla 42,
A. Op ea29, N. Pa onis26, A. Pa lik43, J. Pe kowski4, L. Pe san i8,15,21, I. Po as42,
J. P aena42, J. M. Quesada20, D. Radeck41, D. Ramos-Do al5, T. Rausche 44,45, R. Rei a h28,
D. Rochman25, M. Saba é-Gila e3,20, A. Saxena46, P. Schillebeeckx31, D. Schumann25,
S. Simone10, A. G. Smi h12, N. V. Sosnin12, A. S ama opoulos23, G. Taglien e8,
J. L. Tain18, T. Talip25, A. Ta i eño-Saldi ia19, L. Tassan-Go 3,23,5, A. Tsinganis3, J. Ul ich25,
S. U lass3,47, S. Valen a9, G. Vannini35,36, V. Va iale8, P. Vaz30, A. Ven u a35, D. Vesco i8,15,
V. Vlachoudis3, R. Vlas ou23, A. Wallne 48, P. J. Woods24, T. W igh 12, and P. Žugec13
1Cen o de In es igaciones Ene gé icas Medioambien ales y Tecnológicas (CIEMAT), Spain
2Japan A omic Ene gy Agency (JAEA), Tokai-mu a, Japan
3Eu opean O ganiza ion o Nuclea Resea ch (CERN), Swi ze land
4Uni e si y o Lodz, Poland
5Ins i u de Physique Nucléai e, CNRS-IN2P3, Uni . Pa is-Sud, Uni e si é Pa is-Saclay, F-91406 O -
say Cedex, F ance
6Technische Uni e si ä Wien, Aus ia
7CEA I u, Uni e si é Pa is-Saclay, F-91191 Gi -su -Y e e, F ance
8Is i u o Nazionale di Fisica Nuclea e, Sezione di Ba i, I aly
9Cha les Uni e si y, P ague, Czech Republic
10INFN Labo a o i Nazionali del Sud, Ca ania, I aly
11Dipa imen o di Fisica e As onomia, Uni e si à di Ca ania, I aly
12Uni e si y o Manches e , Uni ed Kingdom
13Depa men o Physics, Facul y o Science, Uni e si y o Zag eb, Zag eb, C oa ia
14Uni e si y o Yo k, Uni ed Kingdom
15Is i u o Nazionale di Fisica Nuclea e, Sezione di Pe ugia, I aly
16Dipa imen o di Fisica e Geologia, Uni e si à di Pe ugia, I aly
17Uni e si y o San iago de Compos ela, Spain
18Ins i u o de Física Co puscula , CSIC - Uni e sidad de Valencia, Spain
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© The Au ho s, published by EDP Sciences. This is an open access a icle dis ibu ed unde he e ms o he C ea i e
Commons A ibu ion License 4.0 (h p://c ea i ecommons.o g/licenses/by/4.0/).
19Uni e si a Poli ècnica de Ca alunya, Spain
20Uni e sidad de Se illa, Spain
21Is i u o Nazionale di As o isica - Osse a o io As onomico di Te amo, I aly
22Dipa imen o di Fisica, Uni e si à degli S udi di Ba i, I aly
23Na ional Technical Uni e si y o A hens, G eece
24School o Physics and As onomy, Uni e si y o Edinbu gh, Uni ed Kingdom
25Paul Sche e Ins i u (PSI), Villingen, Swi ze land
26Uni e si y o Ioannina, G eece
27Join Ins i u e o Nuclea Resea ch (JINR), Dubna, Russia
28Goe he Uni e si y F ank u , Ge many
29Ho ia Hulubei Na ional Ins i u e o Physics and Nuclea Enginee ing, Romania
30Ins i u o Supe io Técnico, Lisbon, Po ugal
31Eu opean Commission, Join Resea ch Cen e, Geel, Re ieseweg 111, B-2440 Geel, Belgium
32Ka ls uhe Ins i u e o Technology, Campus No h, IKP, 76021 Ka ls uhe, Ge many
33Tokyo Ins i u e o Technology, Japan
34Agenzia nazionale pe le nuo e ecnologie (ENEA), Bologna, I aly
35Is i u o Nazionale di Fisica Nuclea e, Sezione di Bologna, I aly
36Dipa imen o di Fisica e As onomia, Uni e si à di Bologna, I aly
37Is i u o Nazionale di Fisica Nuclea e, Sezione di Legna o, I aly
38Is i u o Nazionale di Fisica Nuclea e, Sezione di T ies e, I aly
39Dipa imen o di As onomia, Uni e si à di T ies e, I aly
40Consiglio Nazionale delle Rice che, Ba i, I aly
41Physikalisch-Technische Bundesans al (PTB), Bundesallee 100, 38116 B aunschweig, Ge many
42Uni e si y o G anada, Spain
43Uni e si y o Vienna, Facul y o Physics, Vienna, Aus ia
44Depa men o Physics, Uni e si y o Basel, Swi ze land
45Cen e o As ophysics Resea ch, Uni e si y o He o dshi e, Uni ed Kingdom
46Bhabha A omic Resea ch Cen e (BARC), India
47Helmhol z-Zen um D esden-Rossendo , Ge many
48Aus alian Na ional Uni e si y, Canbe a, Aus alia
Abs ac . The neu on cap u e eac ions o he 244Cm and 246Cm iso opes open
he pa h o he o ma ion o hea ie Cm iso opes and hea ie elemen s such as
Bk and C in a nuclea eac o . In addi ion, bo h iso opes belong o he mino
ac inides wi h a la ge con ibu ion o he decay hea and o he neu on emission
in i adia ed uels. The e a e only wo p e ious 244Cm and 246Cm cap u e c oss
sec ion measu emen s: one in 1969 using a nuclea explosion [1] and he mos
ecen da a measu ed a J-PARC in 2010 [2]. The da a o bo h iso opes a e e y
sca ce due o he di icul ies in pe o ming he measu emen s: high in insic
ac i i y o he samples and limi ed acili ies capable o p o iding iso opically
en iched samples.
We ha e measu ed bo h neu on cap u e c oss sec ions a he n_TOF Expe i-
men al A ea 2 (EAR-2) wi h h ee C6D6de ec o s and also a A ea 1 (EAR-1)
wi h he TAC. P elimina y esul s assessing he quali y and limi a ions (back-
g ound sub ac ion, measu emen echnique and coun ing s a is ics) o his new
expe imen al da ase s a e p esen ed and discussed.
1 In oduc ion
Accu a e neu on cap u e c oss sec ion da a o mino ac inides (MAs) a e equi ed o es i-
ma e he p oduc ion and ansmu a ion a es o MAs in ligh -wa e eac o s (LWR) wi h a
high bu nup, c i ical as eac o s like Gen-IV sys ems and o he inno a i e de ices such as
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accele a o d i en sys ems (ADS) [3]. The 244Cm (T1/2=18.1 yea s) and 246Cm (T1/2=4730
yea s) iso opes a e among he mos impo an MAs due o he di icul ies in hei ansmu a-
ion and hei con ibu ion o he adio oxici y o he i adia ed nuclea uels. In pa icula ,
e en a e h ee yea s o cooling, 244Cm sha es nea ly 50% o he o al ac inide decay hea in
i adia ed eac o uels wi h a high bu nup. In addi ion, bo h o hem a e in he pa h o he
c ea ion o any hea ie Cm iso opes and hea ie elemen s like Bk and C .
Only wo p e ious cap u e measu emen s we e done be o e he n_TOF measu emen s. The
i s one, done in 1969 [1], used he neu ons p oduced in an unde -g ound nuclea explo-
sion. The 244Cm (n,γ) c oss sec ion was measu ed in a ange om 20 eV o 1 keV and o
he 246Cm(n,γ) om 20 eV o 400 eV. The second cap u e measu emen was pe o med in
2010 wi h a la ge co e age Ge-a ay in he Accu a e Neu on Nucleus Reac ion Measu e-
men Ins umen (ANNRI) a J-PARC [2]. In his second measu emen he da a ob ained o
bo h iso opes ange om 2 eV o 300 eV. The esonance analysis was done up o 30 eV. The
sca ci y o he a ailable da a and he many expe imen al challenges in ol ed in he wo p e-
ious measu emen s mo i a ed an addi ional measu emen unde di e en condi ions, i.e., in
a di e en acili y, wi h di e en de ec o s and moni o s and wi h a di e en me hodology.
2 Expe imen
The same samples used a J-PARC ha e been measu ed a n_TOF. In his acili y, he neu on
beam is gene a ed h ough spalla ion o 20 GeV/c p o ons, which a e ex ac ed in pulses om
he CERN P o on Synch o on and impinging on a lead a ge . The pulses ha e a nominal
in ensi y o 7×1012 p o ons and a ime sp ead o 7 ns ( ms). The neu ons a el along wo
beam lines owa ds he wo expe imen al a eas along : EAR-1 ligh leng h o 185 m [4]
(ho izon al) and EAR-2 ligh leng h o 19 m [5] ( e ical). The neu on lux is la ge in he
EAR-2 and he ene gy esolu ion is be e in he EAR-1.
The samples ha e been measu ed in bo h expe imen al a eas. The measu emen in EAR-2
has been done wi h h ee C6D6de ec o s and he To al Ene gy De ec ion (TED) [6] echnique,
and he measu emen in EAR-1 wi h he n_TOF To al Abso p ion Calo ime e (TAC) [7],
designed o de ec he comple e γ- ay cascade. Measu ing in bo h expe imen al a eas wi h
di e en de ec o s and echniques will allow o c osscheck esul s and, p esumably, o educe
he inal unce ain ies.
The a ge s used o he expe imen consis in wo samples o 244Cm and one o 246Cm.
The e we e 0.4 mg o 244Cm in each o he 244Cm samples and 1.1 mg o 246Cm in he 246Cm
sample. The iso opic abundances o he di e en ac inides a e p esen ed in Table 1.
Table 1. Iso opic composi ion (% a oms) o he 244Cm and 246Cm samples.
244Cm sample 246Cm sample
244Cm 60.3±1.1 20.3±0.5
245Cm 2.4±0.3 1.1±0.3
246Cm 6.3±0.6 57.7±1.5
247Cm - 2.8±0.4
248Cm - 8.8±0.2
240Pu 31.0±0.6 9.3±0.2
2.1 Measu emen a he EAR-2
The h ee C6D6de ec o s we e placed a 5 cm om he sample and pe pendicula o he
beam. In addi ion, h ee addi ional de ec o s we e used o moni o ing he beam. Two o
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hem measu ed he in ensi y o he p o on beam. The hi d one was he SiMon [8], an a ay
o ou silicon de ec o s acing a hin en iched li hium luo ide oil, o moni o ing he neu on
beam.
To ob ain accu a e weigh ing unc ions equi ed o he PHWT [9] echnique, a e y
de ailed desc ip ion o he expe imen al se -up has been implemen ed in he Gean 4 oolki
[10]. The simula ed esponse unc ions ha e been alida ed wi h expe imen al da a ob ained
wi h se e al calib a ion sou ces ( 133Ba, 137Cs, 60Co, 88Y, AmBe and CmC). The geome y
implemen ed in Gean 4 and one o he simula ed esponse unc ions a e shown in Figu e 1.
The da a ob ained a n_TOF a e p ocessed wi h he Pulse Shape Analysis (PSA) ou ine [11].
(MeV)
dep
E
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
coun s/second/BinWid h
1000
2000
3000
4000
5000
6000
MC
Exp-Backg ound
Figu e 1. Geome y o he EAR-2 se up as implemen ed in Gean 4 (le ). Compa ison be ween simu-
la ed (MC) and expe imen al esponse unc ion o an 88Y sou ce ( igh ).
The esul s o he i s a e s o ed in ROOT iles [12]: signal ampli udes, signal a eas, imes,
e c.. Also he con e sion om ime-o - ligh o neu on ene gy is done.
Accu a e ampli ude- o-ene gy calib a ions and gain s abili y checks we e pe o med on
a weekly basis o he h ee C6D6de ec o s using 133Ba, 137Cs, 60Co, 88Y, AmBe and CmC
calib a ion sou ces. Small gain shi s ( 8%) a e obse ed and co ec ed as a unc ion o ime.
The o al numbe o coun s as a unc ion o neu on ene gy measu ed wi h he Cm samples
in place a e shown in Figu e 2. Also shown a e he es ima ed o al backg ound, he beam
ela ed backg ound, and he no-beam ela ed backg ound. These backg ounds ha e been
ob ained om dedica ed measu emen s.
A p elimina y bu a he comple e analysis o he da a measu ed a he EAR-2 has been
pe o med and wo p elimina y cap u e yields (no backg ound sub ac ed) ha e been ob-
ained, one o he 244Cm samples and he o he o he 246Cm sample. Bo h yields (no
backg ound sub ac ed) a e p esen ed in Figu e 3 oge he wi h he yields ob ained om he
JEFF-3.3 [13] c oss sec ions wi h he expe imen al backg ound and he cha ac e is ics o he
EAR-2 neu on beam (neu on lux + esolu ion unc ion)[14]. The ela i e di e ences be-
ween he expe imen al and he e alua ed yields (in %) a e shown a he bo om o each panel,
in eg a ed o each esonance. The esul s ha e been no malized o he i s la ge esonance
o 240Pu a 1 eV.
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Neu on ene gy(eV)
2−
10 1−
10 1 10 2
10
Coun s
4
10
5
10 Cm sample
244
Beam bkg.
No beam bkg.
To al bkg.
Neu on ene gy(eV)
2−
10 1−
10 1 10 2
10
Coun s
4
10
5
10
Cm sample
246
Beam bkg.
No beam bkg.
To al bkg.
Figu e 2. To al numbe o coun s (750 bins pe decade) and es ima ed backg ounds egis e ed in he
244Cm (le ) and 246Cm ( igh ) EAR-2 measu emen s.
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(eV)
n
E
1 2 3 4 5 6 7 8 9 10
Cap u e Yield + bkg
0.05
0.1
0.15
0.2
0.25
0.3
0.35
Expe imen al Yield To al Sammy Yield
)γPu-240 (n, )γCm-244 (n,
)γCm-246 (n, Cm-244 (n, )
Cm - 1000 bins pe decade
244
1 2 3 4 5 6 7 8 9 10
2−
1.5−
1−
0.5−
0
0.5
1
1.5
2
(eV)
n
E
1 2 3 4 5 6 7 8 9 10
Cap u e Yield + bkg
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
0.2
Expe imen al Yield To al Sammy Yield
)γPu-240 (n, )γCm-244 (n,
)γCm-246 (n, Cm-244 (n, )
Cm-245 (n, ) Cm-247 (n, )
)γCm-248 (n, )γAm-243 (n,
Cm sample - 1000 bins pe decade
246
1 2 3 4 5 6 7 8 9 10
15−
10−
5−
0
5
10
15
(eV)
n
E
10 20 30 40 50 60 70
Cap u e Yield + bkg
14
16
18
20
22
24
26
28
3−
10×
Expe imen al Yield To al Sammy Yield
)γPu-240 (n, )γCm-244 (n,
)γCm-246 (n, Cm-244 (n, )
Cm - 1000 bins pe decade
244
10 20 30 40 50 60 70
50−
40−
30−
20−
10−
0
10
20
30
40
50
(eV)
n
E
10 20 30 40 50 60 70
Cap u e Yield + bkg
12
14
16
18
20
3−
10×
Expe imen al Yield To al Sammy Yield
)γPu-240 (n, )γCm-244 (n,
)γCm-246 (n, Cm-244 (n, )
Cm-245 (n, ) Cm-247 (n, )
)γCm-248 (n, )γAm-243 (n,
Expe imen al Yield To al Sammy Yield
)γPu-240 (n, )γCm-244 (n,
)γCm-246 (n, Cm-244 (n, )
Cm-245 (n, ) Cm-247 (n, )
)γCm-248 (n, )γAm-243 (n,
Cm sample - 1000 bins pe decade
246
10 20 30 40 50 60 70
15−
10−
5−
0
5
10
15
(eV)
n
E
80 100 120 140 160 180 200
Cap u e Yield + bkg
11
12
13
14
15
16
17
18
19
20
3−
10×
Expe imen al Yield To al Sammy Yield
)γPu-240 (n, )γCm-244 (n,
)γCm-246 (n, Cm-244 (n, )
Cm - 750 bins pe decade
244
80 100 120 140 160 180 200
60−
40−
20−
0
20
40
60
(eV)
n
E
80 100 120 140 160 180 200
Cap u e Yield + bkg
10
12
14
16
18
3−
10×
Expe imen al Yield To al Sammy Yield
)γPu-240 (n, )γCm-244 (n,
)γCm-246 (n, Cm-244 (n, )
Cm-245 (n, ) Cm-247 (n, )
)γCm-248 (n, )γAm-243 (n,
Expe imen al Yield To al Sammy Yield
)γPu-240 (n, )γCm-244 (n,
)γCm-246 (n, Cm-244 (n, )
Cm-245 (n, ) Cm-247 (n, )
)γCm-248 (n, )γAm-243 (n,
Cm sample - 750 bins pe decade
246
80 100 120 140 160 180 200
60−
40−
20−
0
20
40
60
Figu e 3. P elimina y expe imen al yields (no backg ound sub ac ed) o he measu ed 244Cm (le )
and 246Cm ( igh ) samples. Toge he wi h he expe imen al da a poin s, we show an es ima ion o he
con ibu ion o he cap u e and ission eac ions in each iso ope p esen in he samples. These con ibu-
ions ha e been ob ained using he SAMMY compu e code o calcula e he eac ion yields aking in o
accoun he expe imen al condi ions such as Dopple and esolu ion b oadening, and aking he eac ion
c oss sec ions om JEFF-3.3. The esul ing yields we e hen no malized o i he expe imen al esul s
and added o he backg ound, ob ained om dedica ed measu emen s.
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2.2 Measu emen a he EAR-1
The measu emen in EAR-1 was pe o med wi h he TAC, which is an a ay o 40 BaF2
c ys als designed o de ec he ull cap u e γ- ay cascades. The da a analysis is ongoing and
i will ollow simila p ocedu es han he ones pe o med in p e ious TAC expe imen s [15]
[16]. Signals a e g ouped in o TAC e en s wi h a 20 ns coincidence window, and cu s in o al
deposi ed ene gy and de ec ion mul iplici y allow o imp o e he signal o backg ound a io.
The o al numbe o coun s as a unc ion o neu on ene gy measu ed wi h he 244Cm
samples in place a e shown in Figu e 4, oge he wi h he es ima ed backg ounds. The be e
ene gy esolu ion and smalle ins an aneous neu on luence in EAR-1 esul s in a na owe
esonan s uc u e and a la ge con ibu ion o he no-beam ela ed backg ound.
Neu on ene gy(eV)
1 10 2
10
Coun s
2
10
3
10
4
10 Cm sample
244
Beam bkg.
No beam bkg.
To al bkg.
Figu e 4. To al numbe o coun s (1000 bins pe decade) and es ima ed backg ounds egis e ed in he
244Cm EAR-1 measu emen .
3 Conclusions
The cap u e c oss sec ions o 244Cm and 246Cm a e equi ed o es ima e he p oduc ion and
ansmu a ion a es o MAs in LWR and also o new eac o ypes. The e a e only wo
p e ious cap u e measu emen s o hese wo iso opes, bo h o hem wi h many expe imen-
al di icul ies.The e o e, a new measu emen has been pe o med a n_TOF using he wo
expe imen al a eas and p elimina y cap u e yields ha e been ob ained.
Re e ences
[1] M. S. Moo e e . al., Phys. Re . C, 3, 1656 (1971)
[2] A. Kimu a e . al., Jou . Nucl. Sc. Tech. 49, 708 (2012)
[3] G. Alibe i e . al., , Ann. Nucl. Ene . 33, 700 (2006)
[4] C. Gue e o e al., Eu . Phys. J. A 49, 27 (2013)
[5] C. Weiss e al., Nucl. Ins um. Me h. A 799, 90 (2015)
[6] R.L. Macklin and J.H. Gibbons,Phys. Re . 159, 1007 (1967)
[7] C.Gue e o e al., Nucl. Ins um. Me h. A 608, 424 (2009)
[8] S. Ma one e al., Nucl. Ins um. Me h. A 517, 389 (2004)
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[9] Abondano e al., Nucl. Ins um. Me h. A 521, 454 (2004)
[10] S. Agos inelli e al., Nucl. Ins um. Me h. A 506, 250 (2003)
[11] P. Žugec e al., Nucl. Ins um. Me h. A 812, 134 (2016)
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