Research activities of ATOMKI at former LSF IReS

Strasbourg

High-spin statesJ Timár, ATOMKI, Debrecen

Prague 2007

Roots of the ATOMKI high-spin group – IReS collaboration

Personal links with labs building EG and EB A Algora, BM Nyakó, D Sohler, J Timár, L Zolnai:

PhD, postdoc or other positions in Liverpool, Grenoble, Stockholm, and Legnaro for periods from a few months to a few years

Developement of the DIAMANT charged-particle detector array for use with EB

J Gál, Gy Hegyesi, K Juhász, G Kalinka, J Molnár, BM Nyakó:

Prague 2007

CENBG (Bordeaux) – ATOMKI (Debrecen) – University of Napoli collaboration

Main topics and results of our research activity at IReS Octupole vibration in a SD nucleus (2 experiments, EG +EB) 190Hg Band termination at A~100 (1 experiment, EG) 102,103Pd, 100,101,102Rh, 98,99,100Ru, Band termination at A~130 (2 experiments, EB) 132Ce, 128La, 132La N~Z nuclei at A~100 (5 experiments, EB) 93Pd, 95Ag, 98Cd Chiral bands at A~100 (1 experiment, EB+DIAM) 105,106Rh, 102Ru Search for hyperdeformation (2 experiments, EB+DIAM) 126Ba,118Te, 124Cs, 125Cs, 124Xe

Prague 2007

In collaboration with other EWON and non-EWON labs >50 pulications

Octupole vibration is expected in nuclei where sp orbitals withΔl=3 and ΔJ=3 are close to the Fermi surface

Rotational bands built on octupole vibration were known for several nuclei. However, no SD rotational bands built on any kind of vibrationwas known.

Octupole vibration in the SD 190Hg (Eurogam)

190HgSD

A Wilson et al., Phys. Rev. C54 (1996) 559

RPA calculations predicted octupole vibration in SD bands near 190Hg. Experimental signature: strong E1 transitions between the SD bands.

Experiment with Eurogam 2

Reaction: 160Gd + 34S at 153 MeV~ 4x108 quadruple- and higher-fold events

Linking transitions were established

Prague 2007

Octupole vibration in the SD 190Hg (Euroball)

Experiment with Euroball IV

Reaction: 160Gd + 34S at 156 MeV~ 2x109 triple- and higher-fold eventsMultipolarity of linking transitions: E1

First example of SD bands built on collective vibration

4 papers, 3 conference proceedings

A Korichi et al., Phys. Rev. Lett. 86 (2001) 2746

Prague 2007

Band termination at A~100

Z

N

PdRhRu

Band termination was predicted also for nuclei around100Ru at around spin 30 by CNS calcs.

Experiment with Eurogam 2

Reaction: 70Zn + 36S at 130 MeV~ 6x108 triple- and higher-fold eventsNew high-spin bands for severalPd, Rh, and Ru nuclei

102Pd

J.Gizon et al., Phys. Lett. B410 (1997) 95

Prague 2007

Band termination at A~100 – results•First observation of band termination in the A~100 mass region

•Termination of several bands based on valence-particle and core excited intrinsic configurations in 102,103Pd, 101,102Rh, and 98,99,100Ru

•The observed band terminations correspond to a new type: rigid rotation-like band termination

•On the basis of the properties of the observed terminating states we proposed a larger value for the energy spacing between the neutron d5/2 and g7/2 orbitals

8 papers, and4 conference proceedings

Prague 2007

Chiral bands in the A~100 mass region

Ag

Rh

Tc

N

Z

Ferm

i lev

els

prot

on g

9/2

neut

ron

h 11/2

Vaman et al., Phys. Rev. Lett. 92 (2004)032501.

104Rh

Triaxial core + two valence quasiparticlesOne is a particle type, the other is a hole type

Mutually perpendicular angular momenta

Prague 2007

S. Frauendorf, J. Meng, Nucl. Phys. A 617 (1997) 131.

Chiral doublet band structures in 105,106Rh

3 papers + 3 conference proceedings

Chiral bands in the A~100 mass region – results with EUROBALL

J.Timár et al., Phys. Lett. B598 (2004) 178

Experiment: EUROBALL + DIAMANT at Vivitron IreS96Zr(13C,p3n)105Rh fusion-evaporation reaction

Beam energies of 51 MeV and 58 MeV~ 2x109 triple- and higher-fold events

~ 5x107 belonged to 105Rh

First composite chiral structure in this region

Prague 2007

Search for hyperdeformation around 126Ba (HLHD experiment)

Prague 2007

Experiment with Euroball + Diamant

Reaction: 64Ni + 64Ni at 255 and 261 MeV2 x 2 weeks

~ 6x109 quadruple- and higher-fold events

Extreme deformations @ high spins

No HD band is observed up to now

K. Pomorski, J. Dudek, Phys. Rev. C67, 044316 (2003).LSD calcs.

ND: 2 papers, 2 conf. proc.,HD: 4 conference proceedings

Search for hyperdeformation around 126Ba (HLHD experiment)

FOLD

28+h

26+h

24+h

22+h

Eγx – Eγy

4 x 52 keV

Rotational Plane (width = 3x2 keV) Data: 261 MeV – 255 MeV

-400 -200 0 200 400

Cuts taken on 3D Rotational Plane: Eγx + Eγy - 2 Eγz = δ

Results from 'xn'-type data RPM analysis Preliminary results from 'particle xn'-type data:

Prague 2007

B. Herskind et al., Acta Phys. Pol. B 38, 1421 (2007)

The DIAMANT R&D collaboration

Objectives of the Collaboration: Objectives of the Collaboration: Upgrading of DIAMANT --> Exploitation in experiments Upgrading of DIAMANT --> Exploitation in experiments

Contributions of the collaborating partners:Contributions of the collaborating partners:

Bordeaux Debrecen Napoli

Design: Mechanics Detector+Preamps + VXI Electronics

Financing: 8 VXI Cards 5 VXI Cards CsI Detectors +pin-diodesPreamps

Total cost of upgrading:Total cost of upgrading: ~40 k~40 k€€

MSI - ATOMKI

(Stockholm) (Debrecen)

1989 – 1994

CENBG - Italian

(Bordeaux) (Napoli)

Late '80s – present

1992 – 1999: informal,

2000 – 2004: MTA-CNRS

Participants

Prague 2007

The DIAMANT ancillary detectorDIAMANT: a high-granularity, 4π detector array of CsI(Tl) scint., used in large γ-ray spectrometers for light charged-particles

The octal Part. Discr. Card in VXI standard

particles

ProtonsDeuterons

γ Rays (CsI)

γ Rays (PIN-diode)

Example spectrum of a CsI crystal

Efficiency: [% of 4

geometrical: 90

det. protons: 70

det. alphas: 50

Prague 2007

EXOGAM experiments using DIAMANT @ GANIL

Exp-# Physics Motivation; Stable-RadioactiveBeam/Target Detectors(Spokesperson) EXOGAM +--------------------------------------------------------------------------------------------------------------------------------E404S/E404aS Identification of γ-rays in nuclei around the drip-line nucleus Identification of γ-rays in nuclei around the drip-line nucleus 130130Sm :Sm : DIAMAMT &

(P.Nolan)(P.Nolan) probing the maximally deformed light rare-earth regionprobing the maximally deformed light rare-earth region DIAMANT76Kr(60MeV)/1.1mg/cm2 58Ni; +VAMOS

--------------------------------------------------------------------------------------------------------------------------------E498S High Spin States in the Tz=-3/2 Nucleus 37Ca – Mirror Symmetry DIAMANT(S.Williams) at the Largest Values of Isospin; 18Ne(60MeV)/1mg/cm2 24Mg; +N-Wall

E482 Mirror Energy Differences in the A=58, T=1 mass triplet and Charge DIAMANT(A.Gadea) Symmetry Breaking terms in the nuclear effective interaction above +N-Wall

56Ni; 36Ar(85MeV)/0.5 mg/cm2 24Mg target on 90Zr backing, 4pnA

E505 Electromagnetic decay properties of the Tz=±1/2, A=67 and 71 DIAMANT(G.deAngelis) mirror pairs: A test for isospin mixing and for pn pairing; +N-Wall

E514 Single-particle energies and proton-shell gap in 100Sn DIAMANT(M.Palacz) extracted from high-spin states in 103Sn; +N-Wall

58Ni(240 MeV) 8 mg/cm2 54Fe target, 1.7 pnA

E451 Search for T=0 pairing and a new coupling scheme in 92Pd and 88Ru DIAMANT(B.Cederwall) 36Ar(111 MeV) 6 mg/cm2 58Ni target, 5 pnA (Submitted to PRC) +N-Wall

Prague 2007

Future plans with LSF-s in Europe

•We plan to continue high-spin studies at LSF-s in Europe with special emphasis on: SPIRAL 2, EXOGAM (Ganil) GASP, CLARA, AGATA (Legnaro) •Diamant needs to be upgraded to fit to the new arrays

•It is very much suitable for studying proton drip line nuclei because of its high granularity

•Every groups are welcome to performe experiments with it!

Prague 2007