The AGATA campaign at GSI Zsolt Podolyák University of Surrey
γ-ray spectroscopy at GSI AGATA 2012-2014
In-beam Spectroscopy production selection identification reaction spectroscopy identification γ detectors 3 calorimeter
Lund-York-Cologne CAlorimeter ΔZ/Z 1%; ΔA/A 1% RIB from FRS 16 ΔE-E modules 1 target DSSSD 3 plastic multi-pmt Time-of-Flight 1240 detector channels TARGET plastic plastic multi-pmt ToF: Δt < 30 ps FWHM! R. Hoischen et al., NIM A654, 354 (2011) DSSSD STOP plastic CsI secondary target START plastic TOF1 (x, y) DSSSD TOF TOF2 ( E, x, y) (E) P. Golubev et al., Nucl. Instr. Meth. A723, 55 (2013)
Experiments at relativistic energies XY LYCCA Θ α XY Target
AGATA (Advanced GAmma Tracking Array) 4π γ-array for Nuclear Physics Experiments at European accelerators providing radioactive and high-intensity stable beams Efficiency: 43% (M γ =1) 28%(M γ =30) (gain ~4) (gain ~1000) 180 large volume 36-fold segmented Ge crystals Operation of Ge detectors in position sensitive mode γ-ray tracking AGATA collaboration
Tracking
S. Akkoyun et al., Nucl. Instr. and Meth. Phys. Res. A 668, 26 (2012).
PreSPEC-AGATA Set-up = Early Implementation of HISPEC @ relativistic radioactive heavy-ions from the GSI Fragment Separator Up to 1GeV/A 238 U, 50% v/c! FRS-detector suite yields A and Z of incoming beam and provides x,y tracking HECTOR+ Large BaF 2 and LaBr 3 detectors for high-energy γ rays Advanced Gamma-ray Tracking Array (AGATA) up to 5 x 2+10 x 3 = 40 segmented HP Ge-crystals d ~ 20 cm ε Ph 17% E 0.4% Lund-York-Cologne CAlorimeter (LYCCA) A and Z particle-id after secondary target by means of - x,y tracking - ΔE-E (Si-CsI) - Time-of-flight (plastic)
The Set-up in Reality LYCCA AGATA Hector AGATA Tracking array 3x2+6x3 crystals R = 12 22 cm ε Ph = 5-9% E = 22 0.4 1.2% 10
AGATA demonstrator at GSI (Germany) ~20 crystals
AGATA detector layout Status 13-3-2014 6 triplets 3 doublets 22 crystals X 12
Letter of Intents
Approved 2012 Proposals S424: Korten/Gerl 4 days 09/2012 Performance commissioning (PreSPEC-AGATA- LYCCA) S429: Rudolph / Podolyák / Gerl 6 days 10/2012; 4 d 03/2014 Quadrantic evolution of collectivity around 208 Pb S430: Wieland / Górska 5 days 10/2012; 2d 03/2014 Pygmy dipole resonance in 64 Fe and the properties of neutron skin S426: Pietralla / Rainovski / Gerl 1 day 11/2012; 7d 03/2014 Relativistic M1-Coulomb excitation of 85 Br S433: Gadea / Górska 5 days, 10/2012 Coulomb excitation of the band-terminating 12 + yrast trap in 52 Fe S431: Boutachkov / Korten 3 days, 11/2012 Proton hole states in 132 Sn and N=82 shell structure S428: Pietri 3 days, 11/2012 Shape evolution in neutron-rich Zr S434: Recchia / Bentley 8 days, 04/2014 Transition rates and mirror energy differences in isobaric multiplets S427: Sahin / de Angelis 0 days Study of the Tz=-1 nucleus 70 Kr (isospin symmetry A=70)
S424: Korten/Gerl PreSPEC-AGATA Commissioning Coulomb excitation of 80 Kr Secondary fragmentation of 80 Kr 9x10 7 ions; 37 W.u. data: M.Reese (TU Darmstadt) for PreSPEC
S430: Wieland / Górska Fine Structure of the Pygmy Resonance in 64 Fe LISE ++ 64 Fe 68 Ni Properties of the PDR in 64 Fe and the neutron skin, following the line of the 2005 RISING experiment on 68 Ni RISING Arb. Units 50 40 30 20 64Fe dipole strength expected distribution RPA (SKI2) Wieland RMF (NL3) Arteaga 10 O.Wieland et al., PRL 102, 092502 (2009) 0 5 10 15 20 Energy [MeV]
Neutron Skins Pygmy Resonance Neutron stars? EOS Sn=7.4MeV Coulomb excitation of 62,64 Fe at 400 MeV/u E γ_doppler_corrected [KeV] E γ_doppler_corrected [KeV] Riccardo Avigo
S426: Pietralla / Rainovski / Gerl Identification of the πp 3/2 πp 1/2 spin-flip transition in 85 Br Approaching 78 Ni from above (N=50): Z=40 to Z=28 5/2-1745 3/2-1507 1745 1507 1/2-89 Y 0 1/2-845 845 5/2-403 403 3/2-0 87 Rb 1/2-345 3/2-1191 1191 5/2-345 0 (1/2 - ) - - (3/2,5/2 ) Is this a πp 1/2 SP-state? 669 363 306 (3/2 - ) (3/2 - ) 452 - - - (5/2,3/2 ) 306 0 (5/2 ) 351 83 As 81 Ga 803 351 0 (1/2 - ) (3/2 - ) (5/2 - ) 85 Br 79 Cu? (391) (0) Z=28 N=50 ESPE (kev) p 1/2 p 3/2 f 5/2 p 1/2 p 1/2 1191 845 89 Y NNDC p 1/2 669 87 Rb L. Käubler et al., PRC 65, 054315; C. Stahl et al., PRC 306 351 87, 037302 85 0 p Br NNDC; 3/2 0 p 3/2 0 0 0 83 As NNDC fand E, Sahin et al., f 5/2 5/2 AIP Conf. 39-403 - 345 Proc. 1072, 298 (2008), 1012, 139 (2008); 81 Ga D. Verney at al. PRC 76, 054312 (2007) - 1507-1745 1) E(πp 3/2 ) E(πf 5/2 ) constant 2) E(πp 1/2 ) evolves? p 1/2 p 3/2 p 3/2 p 3/2 f 5/2 f 5/2 f 5/2 39 37 35 33 31 29 Evolution of the proton SPE towards 78 Ni?? (391) (0) E Fermi Z
Evolution of the proton SPE towards 78 Ni How to prove that the 1/2 - state of 85 Br at 1191 kev is the πp 1/2 state? If it is, we can directly observe the spin-orbit splitting via a Spin-Flip M1-transition! 1p 1/2 5/2-1745 3/2-1507 0.47(5) µ N 2??? 0.68(10) µ N 2 1/2-1191 1p (l=1) 1p 3/2 Unique signature!!! B(M1;j < j > ) 1 µ N 2 1745 1507 1/2-89 Y 0 1/2-845 845 5/2-403 403 3/2-0 87 Rb 1191 5/2-345 345 3/2-0 85 Br
Experimental method σ E2 (B(E2)=1 W.u.) E2 σ M1 (B(M1)=1 µ N ²) M1 M1 Coulomb excitation M1 E2 multipole mixing ratio δ: By measuring at two energies
Experimental method (two targets) DC for upstream target DC for downstream target Beam 300 MeV/u C. Stahl
S428: Pietri Shape evolution in Zr-Mo nuclei Half-lives in Mo isotopes (ps) 100Mo 102Mo D. Ralet, 104Mo S. Pietri et 106Mo al. 108Mo
Lifetime to be extracted from lineshape D. Ralet, S. Pietri, J. Gerl et al.
π ν i13/2 i11/2 Collectivity around 208 Pb h9/2 g9/2 Z=82 N=126 s1/2 p1/2 d3/2 f5/2 1.9 1.4 1.4 Pb In box: E(4 + )/E(2 + ) ratio
S429: Rudolph / Podolyák / Gerl B(E2;0 + 2 + ) transition strengths in the vicinity of 208 Pb 2012: 208Pb beam; 2014: 238U beam 206
1068 206 Hg 410x10 6 ions 803 206 Pb calibration point 166x10 6 ions T. Alexander et al.
Isotopic composition of the beam ( 206 Hg) IR = ~21% ( 206 Hg) and ~27% ( 206 Pb) T. Alexander et al.
Conclusions and outlook PreSPEC/AGATA is forerunner of HISPEC all equipment works Physics experiments performed with AGATA in 2012 and 2014 Challenging data analysis AGATA is in GANIL Shutdown at GSI 2015-2016 Next: DESPEC stopped beam campaign in 2017
Thanks! PRESPEC-AGATA Collaboration 22 29