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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