a new method of production and study of the most exotic neutron … · 2015-09-28 · 16...

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A new method of production and study of the most

exotic neutron rich nuclei

J.N. Wilson, IPN Orsay

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Exoticity

4

Exoticity

Spontaneous Fission 252Cf(SF), 248Cm(SF)

(Gammasphere, Euroball)

5

Exoticity



Fission induced by

thermal neutrons 235U(nth,f) 241Pu(nth,f)

(EXILL Exogam@ILL)

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Exoticity



Fission induced by

thermal neutrons 235U(nth,f) 241Pu(nth,f)

(EXILL Exogam@ILL)

Fission induced by fast

1.5 MeV neutrons 238U(n,f), 232Th(n,f)

(LICORNE @ IPN Orsay)

7

5-10 cm

1-3 cm

Sample

Fluxes typically

106 n/cm2/s

109 n/s

7Li(p,n)

d(d,n)

d(9Be,n)

8

5-10 cm

1-3 cm

Sample

Fluxes typically

106 n/cm2/s

109 n/s

Typically over 99% of neutrons ‘’wasted’’

7Li(p,n)

d(d,n)

d(9Be,n)

9

5-10 cm

1-3 cm

Sample

Fluxes typically

106 n/cm2/s

109 n/s


Wasted neutrons contribute to the room background

7Li(p,n)

d(d,n)

d(9Be,n)

10

5-10 cm

1-3 cm

Sample

Fluxes typically

106 n/cm2/s

109 n/s


Wasted neutrons contribute to the room background

Placement of gamma detectors impossible without heavy shielding

7Li(p,n)

d(d,n)

d(9Be,n)

11

n

n

n

n

H target

100nA 7Li

13-17 MeV

Lithium Inverse Cinematiques ORsay NEutron source

p(7Li,7Be)n reaction in inverse kinematics

Focused source of fast neutrons between 0.5 and 4 MeV

12

n

n

n

n

H target

100nA 7Li

13-17 MeV




Sample

13

n

n

n

n

H target

100nA 7Li

13-17 MeV




Sample

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n

n

n

n

H target

100nA 7Li

13-17 MeV




γ

γ

Sample

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Hydrogen gas cells

H2 pressure and

flow control system

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“Comparative measurement of prompt fission gamma-ray emission from fast

neutron induced fission of 235U and 238U”

M. Lebois, J.N. Wilson, et al., Phys. Rev. C Rapid Communication

In press (2015)

“Development of a kinematically focused neutron source with the p(7Li,n)7Be

inverse reaction”

M.Lebois, J.N. Wilson et al., Nucl. Instrum. Meth. A 735 145 (2014)

“Experimental studies of prompt fission neutron spectra”

Alix Sardet, CEA/DAM/DIF Bruyeres-le-chatel, Ph.D thesis, 2 Oct. (2015)

17 Precision spectroscopy of fast neutron induced reactions

18

mercredi 16 septembre

2015

Evolution and collectivity development

in the vicinity of 78Ni

Shape coexistence

and collectivity

around N=60

Neutron-rich nuclei around and

beyond 132Sn

Spectroscopy of neutron-rich

fragments of 40<Z<50

Physics Cases

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Total Fission Rate > 150 kHz at 100nA 7Li

Uranium metal target

(ITU Karlsruhe)

3cm

21 3 weeks of beam time: ~ 3 × 109 events with Mγ >= 3

Ge singles rates

~ 8kHz

22 Time (ns)

En

erg

y (

keV

)

23 Time (ns)

En

erg

y (

keV

)

Prompt fission gamma rays

25

gate

28


2015

Fission Fragment Isomers (10ns - 10µs)

29

mercredi 16 septembre 2015

TIPS – Tagging Isomer PartnerS

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mercredi 16 septembre 2015

TIPS – Tagging Isomer PartnerS

99mMo

139Sn*

31 Time (ns)

En

erg

y (

keV

)

32 Time (ns)

En

erg

y (

keV

)

400 ns

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T1/2 ~ 170 ns

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134Te: 6+ isomer 164 ns

2+ → 0+

36

13

4Te 1

64 n

s

13

3I 170ns

13

2Te 1

45 n

s

13

5Te 0

.5 µ

s

13

6X

e 2

.9 µ

s

13

8B

a 0

.8 μ

s

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134Te 164 ns

2+ → 0+

13

3I 170ns

13

2Te 1

45 n

s

13

5Te 0

.5 µ

s

13

6X

e 2

.9 µ

s

13

8B

a 0

.8 μ

s

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To be continued …

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• 238U(n,f) or 232Th(n,f) reactions can be used to study neutron

rich fission fragments for the first time (LICORNE@IPNO)

• Cold fission (En ~ 1.5 MeV produced with 7Li beam)

• Simultaneous production & study of hundreds of exotic nuclei

• Excellent selectivity of fission fragments and their partners

via isomer tagging from ~50 ns – few μs (TIPS)

Conclusions

• Hybrid Ge/LaBr3 array to get lifetime information (ν-ball)

• Fission tagging with gamma calorimeter or ionisation chamber

Perspectives

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• Construction of a hybrid Ge + LaBr3 array @ IPN Orsay

• Goal: to approach 10% total gamma photopeak efficiency

• LOI (2015) signed by 43 scientists from 17 different institutions

• Run for > 2 months using the 238U(n,f) and 232Th(n,f) reactions

• Workshop planned for early 2016 to physics cases

A hybrid LaBr3-Ge array for fast timing spectroscopic studies

at the IPN Orsay

ν-ball

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J. N. Wilson1, M. Lebois1 ,Q. Liqiang1, R. Shearman2,3, I. Matea1, S. Oberstedt4 , A. Oberstedt5, 6

R. J. Carroll2, P. H. Regan1,2, P. Amador-Celdran7, D. L. Bleuel8, J. A. Briz9, W. N. Catford1

D. Doherty10, R. Eloirdi7, G. Georgiev11 , A. Gottardo3, K. Hadynske-Klek12 , K. Hauschild11

V. Ingeberg12 , J. Ljungvall11 , A. Lopez-Martens 3 , G. Lorusso2, R. Lozeva13 , P. Marini14

Th. Materna15, L. Mathieu14 ,S. Panebianco10 , Zs. Podolyák1 , A. Porta9 , K. Resynkina11 , S. J. Rose12 , E.Sahin12 ,S. Siem12 , A. G. Smith16 , G. Tveten12, D. Verney3 , N. Warr17 , F. Zesier12

and M. Zielinska10

1Institut de Physique Nucléaire d’Orsay, 91406 Orsay Cedex, France 2Department of Physics, University of Surrey, Guildford, GU2 7XH, UK 3National Physical Laboratory, Teddington, Middlesex, TW11 0LW, UK

4Institute for Reference Materials and Measurements, 2440 Geel, Belgium 5Fundamental Physics, Chalmers University of Technology, 41296 Goteborg, Sweden

6CEA/DAM Ile-de-France, 91297 Arpajon Cedex, France 7Institute for Transuranium Elements (ITU), Postfach 2340, 76125 Karlsruhe, Germany

8Lawrence Livermore National Laboratory, Livermore, California 94551, USA 9Subatech, CNRS/IN2P3, University Nantes, EMN, Nantes, France

10IRFU, CEA Saclay, 91191 Gif-sur-Yvette, France 11CSNSM Orsay, 91405 Orsay, France

12Department of Physics, University of Oslo, Blindern, N-0316 Oslo, Norway 13Institut Pluridisciplinaire Hubert Curien, Université de Strasbourg, 23 rue du Loess F-67037 Strasbourg, France

14CENBG, Université de Bordeaux, CNRS/IN2P3,Chemin du Solarium, B.P. 120, 33175 Gradignan, France 15 IRFU, CEA Saclay, 91191 Gif-sur-Yvette, France

16 Department of Physics and Astronomy, The University of Manchester, Manchester M13 9PL, UK 17 IKP, University of Koln, Koln,Germany

Collaborators

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2015

101Sn

99In 100In

98Cd (190 ns)

102Sn (720 ns)

101In

99Cd 100Cd (60 ns)

M. Gorska et al., “98Cd – The two proton

hole spectrum in 100Sn”, Phys. Rev. Lett.

79 2415 (1997)

M. Lipoglavsek et al., “Polarization

charge in 102Sn”. Phys. Lett B 440,

246 (1998)

R.M. Clark and J.N. Wilson et al.

“Yrast and near yrast excitations

up to high spin in 100Cd”,

Phys. Rev. C61 044311 (2000)

N=50

Z=50 100Sn

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FISSION events

(n,n’)

Intrisic activity

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LICORNE

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Fission becomes more symmetric with increasing En

LICORNE

NFS

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2015

7Li p n 7Be

Maximum fluxes ~108 n/s/steradian

28µm

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56Fe Neutron Capture and Scattering Cross Sections

- Capture

- Elastic Scattering

- Inelastic Scattering

Thermal Energies Fast Energies

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2015

Eγ

log10 t (ns)

-8

-4

-7

-6

-5

Delayed γ’s

Prompt γ’s

-9

10 ns – 10 μs

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2ns

400 ns

• Average time between fission events is ~100 us

fission

event

• Effective time window 10 ns – 10 μs? Or longer?

….

Event time structure

LICORNE pulsed

neutron beam

delayed

gamma

delayed

gamma

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2015

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Total Fission Rate > 150 kHz at 100nA 7Li

UO2 bar

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2015

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2015

Ebeam=13.5 MeV

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Liquang Geometry simulation

Gas target fluxes

EDEN detector

7Li

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Gas target fluxes

EDEN detector

E=15 MeV

7Li

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Gas target fluxes

EDEN detector

7Li

E=14.5 MeV

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Gas target fluxes

EDEN detector

7Li

E=14 MeV

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Gas target fluxes

EDEN detector

7Li

E=13.5 MeV

64


Gas target fluxes

EDEN detector

7Li

E=13 MeV

a new method of production and study of the most exotic neutron … · 2015-09-28 · 16...

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