A new method of production and study of the most exotic neutron rich - - PowerPoint PPT Presentation

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A new method of production and study of the most exotic neutron rich - - PowerPoint PPT Presentation

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A new method of production and study of the most exotic neutron rich nuclei J.N. Wilson, IPN Orsay 1 2 Exoticity 3 Spontaneous Fission 252 Cf(SF), 248 Cm(SF) (Gammasphere, Euroball) Exoticity 4 Spontaneous Fission 252 Cf(SF), 248 Cm(SF)

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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

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Exoticity Spontaneous Fission

252Cf(SF), 248Cm(SF)

(Gammasphere, Euroball)

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Exoticity Spontaneous Fission

252Cf(SF), 248Cm(SF)

(Gammasphere, Euroball) Fission induced by thermal neutrons

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

(EXILL Exogam@ILL)

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Exoticity Spontaneous Fission

252Cf(SF), 248Cm(SF)

(Gammasphere, Euroball) 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)

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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)

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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)

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5-10 cm 1-3 cm Sample Fluxes typically 106 n/cm2/s 109 n/s Typically over 99% of neutrons ‘’wasted’’ Wasted neutrons contribute to the room background

7Li(p,n)

d(d,n) d(9Be,n)

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5-10 cm 1-3 cm Sample Fluxes typically 106 n/cm2/s 109 n/s Typically over 99% of neutrons ‘’wasted’’ Wasted neutrons contribute to the room background Placement of gamma detectors impossible without heavy shielding

7Li(p,n)

d(d,n) d(9Be,n)

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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
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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

Sample

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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

Sample

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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

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)

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Precision spectroscopy of fast neutron induced reactions

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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

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3 weeks of beam time: ~ 3 × 109 events with Mγ >= 3 Ge singles rates ~ 8kHz

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Time (ns) Energy (keV)

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Time (ns) Energy (keV)

Prompt fission gamma rays

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gate

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mercredi 16 septembre 2015

Fission Fragment Isomers (10ns - 10µs)

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TIPS – Tagging Isomer PartnerS

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TIPS – Tagging Isomer PartnerS

99mMo 139Sn*

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Time (ns) Energy (keV)

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Time (ns) Energy (keV) 400 ns

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T1/2 ~ 170 ns

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134Te: 6+ isomer 164 ns

2+ → 0+

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36 134Te 164 ns 133I 170ns 132Te 145 ns 135Te 0.5 µs 136Xe 2.9 µs 138Ba 0.8 μs

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134Te 164 ns

2+ → 0+

133I 170ns 132Te 145 ns 135Te 0.5 µs 136Xe 2.9 µs 138Ba 0.8 μs

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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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mercredi 16 septembre 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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mercredi 16 septembre 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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mercredi 16 septembre 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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mercredi 16 septembre 2015

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Total Fission Rate > 150 kHz at 100nA 7Li UO2 bar

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mercredi 16 septembre 2015

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mercredi 16 septembre 2015

Ebeam=13.5 MeV

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Liquang Geometry simulation Gas target fluxes EDEN detector

7Li

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Liquang Geometry simulation Gas target fluxes EDEN detector E=15 MeV

7Li

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Liquang Geometry simulation Gas target fluxes EDEN detector

7Li

E=14.5 MeV

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Liquang Geometry simulation Gas target fluxes EDEN detector

7Li

E=14 MeV

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Liquang Geometry simulation Gas target fluxes EDEN detector

7Li

E=13.5 MeV

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Liquang Geometry simulation Gas target fluxes EDEN detector

7Li

E=13 MeV