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