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GRETINA. ATLAS. GAMMASPHERE. GRETINA at ATLAS. C.J. (Kim) Lister ATLAS Users Workshop 8-9 th October 2009. GRETINA at ATLAS. C.J. (Kim) Lister Richmond Workshop on optimizing GRETINA Science 14-15 th October 2007. “Home Run Experiments”.
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GRETINA ATLAS GAMMASPHERE GRETINA at ATLAS C.J. (Kim) Lister ATLAS Users Workshop 8-9th October 2009
GRETINA at ATLAS C.J. (Kim) Lister Richmond Workshop on optimizing GRETINA Science 14-15th October 2007
“Home Run Experiments” What are the GRETINA-and-ATLAS unique experiments that CANNOT be done with Gammasphere? Heavy Element Spectroscopy ~ 100Sn “In-Beam” Coulomb Excitation of CARIBU Beams Inelastic Transfer with CARIBU (& stable) beams
Our Nuclear Domain From: Yu. Ogenessian, DUBNA
“Home Run Experiments” What are the GRETINA-and-ATLAS unique experiments that CANNOT be done with Gammasphere? Heavy Element Spectroscopy ~ 100Sn “In-Beam” Coulomb Excitation of CARIBU Beams Inelastic Transfer with CARIBU (& stable) beams
100Sn Region “In-Beam” MUST have Mass Selection MUST have super-selective trigger. Advantages: Count rate, Compact geometry favors FMA trigger, Efficiency for high energy gamma rays, Excellent Doppler Correction. • Simulated single-g efficiency 10% at 1.0 MeV 5% at 4.0 MeV
“Home Run Experiments” What are the GRETINA-and-ATLAS unique experiments that CANNOT be done with Gammasphere? Heavy Element Spectroscopy ~ 100Sn “In-Beam” Coulomb Excitation of CARIBU Beams Inelastic Transfer with CARIBU (& stable) beams
Coulomb Excitation of CARIBU Neutron Rich beams Two very exciting paths: CHICO Conventional Multi-Step Coulomb Excitation OR Unconventional “goundstate excitations only” J E
How much beam do we need with Gammasphere? 14h at 6.109 pps! 1/25 107 pps for 2 weeks 1/250 106 pps for 2 weeks To identify excited 2+ state (beyond the 2+1) in vibrational nucleus (B(E2)~1Wu) with Gammasphere for 2 weeks beam time we need 105pps. For complete spectroscopy 106-107 pps will be needed! 1/2500 105 pps for 2 weeks
The Gretina Advantage This kind of experiment is a “singles” study. Rates will be low with CARIBU beams, so rate is not an issue.(Though probably needing an active beam detector) BUT Recoil velocity is well defined in direction, but large (~7%) Gammasphere does not Doppler correct well, as gamma angle is not well defined, so lines are many 10’s keV broad …. sharpening them back to ~5keV will be equivalent (in sensitivity) to 10 times more beam.
“Home Run Experiments” What are the GRETINA-and-ATLAS unique experiments that CANNOT be done with Gammasphere? Heavy Element Spectroscopy ~ 100Sn “In-Beam” Coulomb Excitation of CARIBU Beams Inelastic Transfer with CARIBU (& stable) beams
Fission products Deep-inelastic products Fission products Deep-inelastic products Multinucleon transfer with thick and thin targets.
Inelastic Transfer Is a dirty business….. Lots of exotic nuclei can be made by multi-neutron transfer....especially starting with CARIBU beam GRETINA counting at 50,000Hz is needed to improve on Gammasphere stable-beam transfer studies