GRETINAATLAS 1 st AGATAGRETINA Collaboration Meeting Shaofei Zhu

GRETINA@ATLAS 1 st AGATA-GRETINA Collaboration Meeting Shaofei Zhu Physics Division, Argonne National Laboratory

Physics Opportunities at ATLAS • Coulomb Excitation (Stable/CARIBU, CHICO 2) • Deep Inelastic Reactions and Transfer/Multi-nucleon transfer reactions to study Neutron-Rich Nuclei (Stable/CARIBU, CHICO 2/Phoswich Wall) • Proton-Drip Line Nuclei (Stable, FMA) At ATLAS – GRETINA with 7 quads and GAMMASPHERE are complimentary devices 1 st AGATA-GRETINA Collaboration Meeting December 5, 2016 2

Installation of GRETINA at ATLAS q GRETINA support; ü MSU mechanical supporting structure; ü Existing LN 2 system; ü Existing Oxygen deficiency alarm and LN 2 exhaust; q DAQ system; ü ü Additional power to room G 126; Networks from AREA IV (10 GB) and data room (1 GB) to G 126; Auxiliary detectors electronics and DAQ systems; Rearranged data room for GRETINA on-line data monitoring workstations; q Electronics; ü Rearranging Gammasphere Shack; ü No loss of capabilities of running Gammasphere/FMA; q Detector Maintenance; ü Existing detector annealing and testing stations; ü Existing portable crane; 2016 Low Energy Community Meeting 08/12/2016 3

Installation of GRETINA at ATLAS GRETINA Stand Alone 1 st AGATA-GRETINA Collaboration Meeting GRETINA+CHICOII December 5, 2016 4

Benchmarking Gretina Detectors in the Array Concerns: Clean Ground 7 peaks symmetric; 16 peaks show left tail; 1 drifting peak (2 -Me. V full scale) bad cable Sum peak at 1332 ke. V: FWHM = 2. 58 ke. V (Gaussian) FWHM = 2. 40 ke. V (Gaussian+left tail) Full Scale = 2 Me. V 1 st AGATA-GRETINA Collaboration Meeting Full Scale = 5 Me. V December 5, 2016 5

Benchmarking Gretina Detectors in the Array Tail develops with number of fold: 1 fold is symmetric. No neutron damage. 1 st AGATA-GRETINA Collaboration Meeting December 5, 2016 6

Gretina Detection Efficiency 1 st AGATA-GRETINA Collaboration Meeting December 5, 2016 7

Interfacing with Other Detectors Ø Ø Receive timestamp from Master Trigger via SERDES Latch timestamps when remote detector triggers Provide gating logic as necessary with other NIM or ECL signals Add MγRIAD to remote detector readout so that events have matching timestamps for event building Ø Send remote detector trigger signals to GRETINA Master Trigger for coincidence. 1 st AGATA-GRETINA Collaboration Meeting December 5, 2016 8

CHICO-II and GRETINA q Angular coverage: ü 12 o ≤ θ ≤ 85 o, 95 o ≤ θ ≤ 168 o; 280 o in φ q Angular resolution: – Δθ = 1. 6 o, Δφ = 2. 5 o q Solid angle: ü ~69% of 4π q Energy-loss output: ü Improved time, mass and Z resolution q Time resolution: ü Δt ≤ 500 ps q Mass resolution for kinematic coincidence: ü Δm/m ≤ 5% q Q-value resolution: ü ≤ 20 Me. V q Gammasphere γ-ray Doppler broadening: ü 1. 0%* q GRETINA γ-ray Doppler broadening: ü 0. 5%* * Average recoil speed around 10% of c; Ignores contribution due to intrinsic resolution etc. 1 st AGATA-GRETINA Collaboration Meeting December 5, 2016 9

Time between CHICO-II and GRETINA 1 st AGATA-GRETINA Collaboration Meeting December 5, 2016 10

Dt Eg (ke. V) v 623 Me. V 136 Xe on 0. 581 mg/cm 2 194 Pt v Particle single rate up to 500 k/s for the scattering angle between 20 o and 85 o Eg (ke. V) Gretina/Gammasphere Coupled to CHICOII Comparison Angle 1 st AGATA-GRETINA Collaboration Meeting Tg (10 ns) December 5, 2016 11

Gretina/Gammasphere Coupled to CHICOII Comparison Same Beam Energy, Same Target b average = 7. 4% FWHM: q GS: 16. 4 ke. V q GT Untracked: 10. 4 ke. V q GT Tracked (0. 8): 9. 7 ke. V q GT Tracked (1. 0): 9. 7 ke. V Gammasphere Gretina Untracked Gretina Tracked (FOM<=0. 8) Gretina Tracked (FOM<=1. 0) Peak Area Relative to GT Untracked: q GS: 1. 0 q GT Tracked (0. 8): 1. 26 q GT Tracked (1. 0): 1. 31 1 st AGATA-GRETINA Collaboration Meeting December 5, 2016 12

Gretina/Gammasphere Coupled to CHICOII Comparison b average = 4. 6% Gammasphere Gretina Untracked Gretina Tracked (FOM<=0. 8) Gretina Tracked (FOM<=1. 0) 1 st AGATA-GRETINA Collaboration Meeting December 5, 2016 13

Experiment Setup for CARIBU Coulomb Excitation γ-ray spectroscopy Particles • angles • time of flight PPACs GRETINA Monitoring beam Intensities Impurities Accelerated CARIBU beam from ATLAS HPGe detector at beam dump 1. 0 mg/cm 2 208 Pb target CHICO 2 Rate determined from number of counts for transitions in daughter nucleus taking into account efficiency and branching ratios Counts g-ray spectrum from b decay Eg (channels) 1 st AGATA-GRETINA Collaboration Meeting December 5, 2016 14

Experimental results for 146 Ba 1 st AGATA-GRETINA Collaboration Meeting Shaofei Zhu December 5, 2016 15

Deep-inelastic reactions: Gretina + CHICOII q g-ray and isotope correlations FWHM: 6. 32 ke. V at 885 ke. V (0. 71%) ü reaction partners ü Δm/m ≤ 5% ü Q-value resolution: ≤ 20 Me. V q Sensitive to fast transitions ü proper Doppler corrections q Angular distributions 1 st AGATA-GRETINA Collaboration Meeting December 5, 2016 16

GRETINA + Phoswich Wall Experiments No. Pixels: 256 (4 PMT’s) Thin fast-plastic + Cs. I(Tl) Angle range: 9º ≤ θ ≤ 72º Preferred position: downstream 1 st AGATA-GRETINA Collaboration Meeting Shaofei Zhu 138 Ba+13 C Experiment: Coupling w/ Gretina and 9 La. Br 3(Ce)’s December 5, 2016 17

138 Ba + 13 C, Elab = 550 Me. V (ATLAS) “Online” analysis • Particle gates on so-called A-C maps (similar to ΔE-E gating) • 139 Ba + 12 C products (one-neutron transfer) • 142 Ce + 9 Be products (incomplete fusion) * 524 * 579 100 counts * Eγ (ke. V) 1 st AGATA-GRETINA Collaboration Meeting particle gate #1 red = 139 Ba 642 455 627 1000 counts * * particle gate #2 green = 142 Ce * contamination (144 Nd) December 5, 2016 18

18 PAC-approved experiments 130 days of beam time ü Shape coexistence in the neutron-rich germanium isotopes 72 Ge and 76 Ge ü Octupole Strength in Neutron-Rich Nuclei near A~140: Multi-step Coulomb Excitation of 142, 144, 146 Ba with Reaccelerated CARIBU Beams ü Shape coexistence in 100 Zr studied by lowenergy Coulomb excitation ü Sub-shell closure, proton-neutron symmetry and shape coexistence in 98 Zr ü Precision determination of electromagnetic matrix elements in triaxial 110 Ru ü Shape Evolution and Coexistence in the Mo. Ru Region ü Coulomb Excitation of neutron-rich odd-odd nucleus 98 m. Y 1 st AGATA-GRETINA Collaboration Meeting q Comparison of the performance of the GRETINA and GAMMASPHERE; q GRETINA Test: High-Energy Gamma. Ray Performance; q Commissioning experiment to study the polarization sensitivity of GRETINA; ü Fast-timing lifetime measurements in the 13 C(138 Ba, 12 Cg)139 Ba and 13 C(140 Ce, 12 Cg)141 Ce reactions ü Multi-Particle-Hole States in neutron rich 34 P ü Understanding the Low-Energy Enhancement of the Photon. Strength Function in Nuclei December 5, 2016 19

ANL Project Personnel M. Albers, J. Anderson, A. Ayangeakaa, M. P. Carpenter, H. David, C. Hoffman, R. Janssens, B. Kay, A. Korichi, T. Lauritsen, T. Levand, D. Potterveld, J. Rohrer, G. Savard, D. Seweryniak, B. Zanbransky, SZ LBNL: C. M. Campbell, H. Crawford, M. Cromaz, P. Fallon, I-Y. Lee, A. O. Macciavelli, A. Wiens NSCL: D. Weisshaar ORNL: J. M. Allmond, D. Radford Unv. Rochester and LLBL(CHICO 2): C. Y. Wu, D. Cline, B. M. Bucher, A. Hayes, R. Fox, D. Swan Wash. U. (Phoswich Wall): W. Reviol, D. G. Sarantites, J. Elson, J. Kinnison 1 st AGATA-GRETINA Collaboration Meeting December 5, 2016 20