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Centre d’Etudes Nucléaires Bordeaux-GradignanCENBG

2

Overview of the surrogate method

Principle of the surrogate nuclear reactions method and its limitations

(3He,x) as a surrogate : modeling and uncertainties

- Cm, Pa isotope measurements

- 175Lu measurement

Summary

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3

Consist

of a transfer

of one or few nucleonsfrom

the projectile to the target

(stripping) or vice versa (pick

up)

Under the condition

:

Surrogate

nuclear

reaction

method

The transfer

reaction

)b, a( yNyxAxZN

AZ YX

projectile aThe trasfer

reaction

barrier coulombVEproj

ejectile b

Indirect measurement

of cross sections

The Absolute

Surrogate

Technique (the transfer

reaction) was

first suggested

by Cramer and Brittin 1970 to overcome

the problem

associated

with

neutron induced

cross sections on short-lived

targets.

-

Many of these nuclei are too difficult to produce with currently

available experimental techniques

-

too

short lived

to serve as targets

in present-day

set-ups.Huge radio toxicities:(strong neutron and alpha emitters)e. g. 0.12·109 bq/g for 242Cm


4

RECENTLY, interest has been renewed …

Nucleosynthesis

process Neutron-capture reactions on neutron-rich nuclei : s and r-process

Nuclear Astrophysics

Reactor designs & waste management

Transmutation of Minor Actinides produced in U/Pu

cycle

In transmutation the intention is

to convert

the MAs

into

fission products.

Nuclear data needs for Thorium/Uranium fuel cycle innovative fuel cycle for GEN IV reactors

used

to obtain

cross sections for neutron-induced

fission for various

protactinium and thorium nuclei

CENBG (2000)

In the world …

USA (LLNL, LBNL, …)Japan (ASRC-JAEA)India (BARC)…


5




- Cm,Pa isotope measurements

- 175Lu measurement

Summary

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6

An alternative solution exists… : transfer reactions

+ b ←

Y + a

Surrogate reaction

Measured

a

n + AX

H.C. Britt et al.

(Los Alamos 1970…!!)

Y

b

)()(1nn

ACN EPE

Microscopic optical model calculation (BIII), TALYS

A+1X* A+1X*

nAX

gs

A+1X*

Bn

E*,J

P

(E*,J)

Neutron-induced reaction

)( nA

nE

tnN

XA

bCNCN

CN NNwhereEEN

ENEP

*)(*)(*)(

*)(


7

Neutron-induced reaction Surrogate reaction

),(),()( ),(),()( 1111

JEPJEEJEPJEE nJ

nA

nA

CNnJ

nA

nA

CN

1) Ewing-Weisskopf

limit : (E* > Bn+2.5MeV)

)1),(( )()()( )(),( 11

Jn

Ann

ACNn

Ann JEEPEEEPJEP

2)

are quite similar in neutron-induced and surrogate reaction),( ),( 11 JEandJE nA

nA

A+1X*

E*,J

Y + a b +

A+1X*n + AX

A+1X*

J

population mismatchThe surrogate

acceptance

limits

P

(E*,J)


8




- Cm,Pa isotope measurements

- 175Lu measurement

Summary

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9

242Cm 244Cm243Cm

245Cm

243Am

+n +n+n

3He

242Am( 3He,p)

( 3He,d)( 3He,t)

( 3He,α)

Curium isotopes and Americium produced by transfer reactions 243Am(3He,=[p,d,t,α])

Fission cross section of minor actinidesCm isotopes

T1/2

=7370 y

Performed @ Tandem-Orsay/ 24 MeV

/ 50nAe/2005

One experiment

provides

a simultaneousmeasurement

of (n,f) reactions.

G. Kessedjian PhD thesis, Univ Bordaux 1, 2008


10

Carbon

foil75µg/cm²

243Am152µg/cm²=6mm

*)(*)(*)(

*)(EEN

ENEP

eje

eje

eje

cos21* ejeprojprojejeejeejeejejprojprojrecoil

ejeproj EmEmEmEmm

EQEE

3He beam

*EejeE

eje

E - E

%7.0 4keV 150at low excitation energy

243Am(3He,d)244Cm

208Pb(3He,d)209Bi208Pb(3He,)207Pb


11

*)(*)(*)(

*)(EEN

ENEP

eje

eje

3He beam

E - E

=fission fragment

15 Solar

cells

)90()0(,,

4*)( int W

WfEfission

- Geometry

simulation - 252Cf measurements

(46±1)%

252Cf measurements-Coincidences

Cell-Silicon

detector(96±1)%

In beam

ejetile-frag-fragcoincidences

measurementsW(0°)/W(90°)=1.47±0.17for E*=7.5 MeV 243Am(3He,t)


12

Carbon

foil75µg/cm² 243Am

152µg/cm²=6mm

*)(*)(*)(

*)(EEN

ENEP

eje

eje

3He beam

E - E

pdt

3He

%1.0%1.0

)%01.0(85,99purity isotopichigh need

244

241

243

CmAmAm

atoms...light other target

impuritiesof presence16 oxydeO

backingtarget 1312 CandC

*Ehigh at reactionsn evaporatio-fusion

theofon contributi

),3(backing same

12 HeC


13

),( 312243 pHebackingCAm

),( 312 pHebackingC

),( 312243 dHebackingCAm

),( 312 dHebackingC

*)(*)(*)( ENfENEN CarboneejeNeje

Ameje


14

*)(*)(*)( ENfENEN CarboneejeNeje

Ameje

*)(*)(*)(*)( tcontaminensingles, ENENfENEN Carbone

ejeNejeAmeje

Introduces-

Systematic

uncertainties-

correlations


15

*)(*)(*)(

*)(EEN

ENEP

eje

eje

= fission fragment

=

cascade

( light nuclei

don’t

contribute)

( light nuclei

should

contribute)

)()()( 1nn

ACNn

A EPEE

10%


16

242Cm(n,f) T1/2 =163 d 243Cm(n,f) T1/2 =29.1 y241Am(n,f) T1/2 =432.6 y

5,4737 1,9098 10,9368 10 3,5599 2,6342

5,6887 1,9931 11,0162 10 3,5685 2,9383

5,9032 1,9241 11,2231 10 3,6832 3,521

6,1182 1,9072 11,3531 10 3,7615 3,8158

6,3332 1,8681 11,2154 10 3,8635 3,2258

Neutron f uncertainties

energy (barn) total (f) CN statistical systematic

(MeV) (%) (%) (%) (%)

0,1027 0,4459 16,8828 10 13,3595 2,5184

0,3172 0,703 14,3968 10 9,6983 3,4626

0,5322 1,2634 12,6495 10 7,0897 3,056

SEND TO EXFOR 23076

Backgroud

subtractionand

fission detector efficiency


17

231Pa 233Pa232Pa

234Pa

232Th

+n +n +n

3He

231Th

( 3He, pf and p)

( 3He,d)( 3He,t)

( 3He,α)

Protactinium and thorium isotopes produced

by transfer

reactions

232Th(3He,x=[p,d,t,α])

Capture cross section of the Th/U fuel cycle nucleiPa isotopes


/ 50nAe / 2000&2002


18

M. Petit, et al.

Nucl. Phys. A 735, 345-371 (2004)

Derived

233Pa(n,n’) et 233Pa(n,) using

a local

statistical

Hauser-Feschbach

model

Modeling

Energie neutron (MeV)0,0 0,2 0,4 0,6 0,8 1,0

(n,) (barns)

0,0

0,5

1,0

1,5

2,0

2,5Petit et al.endf 6.8jendl 3.3nos résultats

Equivalent233Pa(n,)234Pa

S. Boyer et al. Nucl. Phys. A775 (2006) 175

Unfortunately there is no neutron-induced data for comparison.

equivalent 233Pa(n,f)234Pa


19

4 C6 D6 Scintillators

2 E-E

6 Ge

New set-up


/ 15nAe/ Feb 2010

Validation of the Transfer réaction

with existing (n,) data

Validation of the surrogate method for capture reactions in the rare earth nuclei

174Yb (3He,p) 176Lu as a surrogate reaction 175Lu(n,)176Lu

Efficiency

determined with MCNP simulations and validated with a set

of -calibrations and nuclear reactions.

C6

D6

detectors

*)(*)(*)(

*)(EEN

ENEP

eje

eje


20

Next

Step

: Surrogate

method

applied

to the actinide regionA 238U target

is

now

available

(from

GSI)238U(d, p) 239U is

planned

for 2011 at

OCL OSLO

0

0,2

0,4

0,6

0,8

1

1,2

5,5 6 6,5 7 7,5 8

Excitation energie / MeV

norm

aliz

ed p

roba

bilit

y

this workprob_500175Lu(n,g)

p

pc N

NEP )(

Normalized

to 1

176Lu*

Sn

= 6,29 MeV

E*,J

175Lu*

n

C6

D6

in coincidence

with

E-E

TALYS

Preliminary

resultsThe decay

probability

P

calculated

with

Talys

is

compared

to themeasured

probability

deduced

from

the (3He,p) transfert reaction

:

- in Fig.1

the extracted

P

from

(3He,p) is

overestimated

by a factor 3.The red

curve

is

obtained

as the blue

one but with

a threshold

of 500 keV

on the C6D6

detectors (in order

to eliminate

the (n,n’) contamination below

500 keV

excitation energy).

- the compound elastic

probability

dominate

in the case of a neutron inducedreaction

(70% just

above

the neutron energy

separation

Sn (Talys

calculation))

- large differences

observed

here

for P

could

be

explained

by angularmomentum

J

mismatch

of the populated

states in the two

reactions.113 keV

Number

of compound nucleus decaying

by

Number

of compound nucleus formed


21

Motivations

How to overcome experimental difficulties for Actinides (n,f) ,(n,)

(3He,x) as a surrogate :

- Pa,Cm measurements

- 175Lu measurement

Summary

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Centre d’Etude Nucléaire Bordeaux-GradignanCENBG


22

� Surrogate

reaction

technique allows

us to use a more readily

obtainable

target.

� Allows

us to expand

our

measurement

abilities

into

previously

inaccessibleregions

of the periodic

chart.

� Designed

correctly

one experiment

provides

a simultaneous

measurementof (n,γ), (n,2n) and (n,f) covering

a surrogate

neutron energy

range from

about 0 to 20 MeV.

�uncertainties

are minimised

with

high

isotope purity

target

and less

impurities

� 238U(d, p)239U to bentchmark

the (n,) cross section in the actinides mass region.

� need

for DWBA calculations

(differentiel

cross section, J

distributions)

Summary and perspectives…


23

Surrogate

method

applied

to Minor

actinide collaboration

M. Aiche1), G. Boutoux1) , B. Jurado1), G. Barreau1), N. Capellan 1) , I. Companis 1) ,S. Czajkowski1) , D. Dassie1), B. Haas1) ,L. Mathieu 1) , E. Bauge 2) , J.M. Daugas 2) , T. Faul

2) , L. Gaudefroy 2) , V. Meot 2) , P. Morel 2)

, N. Pillet 2) , O. Roig 2), J. Taieb 2), O. Serot 3), F. Gunsing 4), L. Tassan-Got 5) , J.T. Burke 6) and X. Derkx 7) .

1) CENBG, Chemin du Solarium B.P. 120, 33175 Gradignan, France2) CEA DPTA/SPN, F-91297 Arpajon, France3) CEA-Cadarache, DEN/DER/SPRC/LEPh, 13108 Saint Paul lez Durance, France4) CEA Saclay, DSM/IRFU/SPhN, 91191 Gif-sur-Yvette cedex, France5) Institut

de Physique Nucléaire, 15 rue Georges Clemenceau, 91406 ORSAY, France6) LLNA, US Department of Energy, Livermore, California 94551, USA.7) GANIL, Bld

Henri Becquerel B.P. 55027, 14076 CAEN Cedex

05, France8) Horia

Hulubei

NIPNE, P. O. Box MG-6, 077125 Bucharest-Magurele, Romania


24

176Lu*

Sn

= 6,29 MeV

E*,J

175Lu*

174Yb (3He,p)

n’

Ig a m m a = f c t ( E * )

0

2 0 0

4 0 0

6 0 0

8 0 0

1 0 0 0

1 2 0 0

1 4 0 0

1 6 0 0

1 8 0 0

3 0 0 4 0 0 5 0 0 6 0 0 7 0 0 8 0 0 9 0 0E * ( 1 0 k e V / c a n a l )

Ig

3 4 3 k e V ( 1 7 5 L u )7 0 k e V ( 1 7 6 L u )1 9 2 . 2 k e V ( 1 7 6 L u )

Sn=6,29 MeV

Ge in coincidence

with

E-E


25

are quite similar in neutron-induced and surrogate reaction

),(),()( 1

JEPJEEP nJ

nA

n

),(1 JEnA

Spin distribution of the compound nucleus 176Lu for :En=100 keV

, 1 MeV

and

2 MeV

Calculations-solid line, extracted from TALYS code-dotted line, extracted from FRESCO DWBA code

174Yb (3He,p) 176Lu as a surrogate reaction 175Lu(n,)176Lu

Theoretical studies

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