gretina at atlas
DESCRIPTION
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”. - PowerPoint PPT PresentationTRANSCRIPT
GRETINA at ATLAS
C.J. (Kim) Lister
ATLAS Users Workshop
8-9th October 2009GR
ETIN
A ATLAS
GAMMASPHERE
GRETINA at ATLAS
C.J. (Kim) Lister
Richmond Workshop on optimizing GRETINA Science
14-15th October 2007
3GRETINA Science Opportunities, U. of Richmond VA, 14-15th Oct 20007
“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 BeamsInelastic Transfer with CARIBU (& stable) beams
4GRETINA Science Opportunities, U. of Richmond VA, 14-15th Oct 20007
Our Nuclear Domain
From: Yu. Ogenessian, DUBNA
5GRETINA Science Opportunities, U. of Richmond VA, 14-15th Oct 20007
“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 BeamsInelastic Transfer with CARIBU (& stable) beams
6GRETINA Science Opportunities, U. of Richmond VA, 14-15th Oct 20007
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.
GRETINA
0.00
0.05
0.10
0.15
0.20
0 1 2 3 4 5E (MeV)
Effic
ienc
y
Peak
Trigger
Simulated single- efficiency 10% at 1.0 MeV 5%
at 4.0 MeV4 MeV, v/c=5%, sigx=1.5 mm
3.0
3.5
4.0
4.5
5.0
5.5
6.0
0 30 60 90 120 150 180
angle
FWH
M (k
eV)
7GRETINA Science Opportunities, U. of Richmond VA, 14-15th Oct 20007
“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 BeamsInelastic Transfer with CARIBU (& stable) beams
8GRETINA Science Opportunities, U. of Richmond VA, 14-15th Oct 20007
Coulomb Excitation of CARIBU Neutron Rich beams
Two very exciting paths:
CHICO
Conventional Multi-Step Coulomb Excitation
OR
Unconventional “goundstate excitations only”
E
J
9GRETINA Science Opportunities, U. of Richmond VA, 14-15th Oct 20007
10GRETINA Science Opportunities, U. of Richmond VA, 14-15th Oct 20007
How much beam do we need with Gammasphere?105
104
103
102
103
102
10
104
10
103
102
14h at 6.109 pps!1/25
1/250
1/2500
107 pps for 2 weeks
106 pps for 2 weeks
105 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!
11GRETINA Science Opportunities, U. of Richmond VA, 14-15th Oct 20007
The Gretina AdvantageThis 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.
12GRETINA Science Opportunities, U. of Richmond VA, 14-15th Oct 20007
“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 BeamsInelastic Transfer with CARIBU (& stable) beams
13GRETINA Science Opportunities, U. of Richmond VA, 14-15th Oct 20007
Multinucleon transfer with thick and thin targets.
Deep-inelastic products
Fission products
Deep-inelastic products
Fission products
14GRETINA Science Opportunities, U. of Richmond VA, 14-15th Oct 20007
Inelastic TransferIs 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
15GRETINA Science Opportunities, U. of Richmond VA, 14-15th Oct 20007
Gammasphere