In-beam -ray spectroscopy with GRETINA
at NSCL
Alexandra Gade
NSCL and Michigan State University

FRIB construction

Outline
April 23, 2012 – truck from LBNL atNSCL loading dock

• In-beam -ray spectroscopy• GRETINA at NSCL
• Selected science examples–Nuclear structure physics (N=40)–Nuclear astrophysics (proton-rich)

48Ar
43Cl

• Summary and outlook
June 2013 – last science run(the 24th experiment)
A. Gade, 6/2/2014, Slide 2

In-beam -ray spectroscopy with fastbeams
-ray spectrometers
Driverprovides
stable“primarybeam”

Fragment
separator
selectsspecies ofinterest
A1900, FRS,BigRIPS,ALPHA/LISE

SeGA,CAESAR,Grape,DALI2,RISING, …
New generation: GRETINA and AGATA
v/c > 0.3-0.4

beamtarget

Nuclear structure

Single-particle
properties• Knockout• HI-induced pickup• Light-ion transfer

reactedbeam

Spectrographs
or detectors to
the ID reaction
residue ofinterest
S800, CATE/Aladin, zerodeg./TOF spectrometer, SPEG

Nuclear astrophysics

Collective phenomena

Level schemes

Weak interactions• Excited-state lifetime
measurements• Coulomb-excitation• Inelastic proton
scattering• Coincidence
spectroscopy• B(GT) values fromcharge-exchange
reactionsA. Gade, 6/2/2014, Slide 3

In-beam -ray spectroscopy at ARIS
Needed for all these measurements: Emission angle ofthe -ray to Doppler-reconstruct the transition energies
into the rest frame of the projectile

High detection efficiency
and high beam intensities
Increased luminosity,
determination of theinteraction point forimproved energy
resolution after Doppler
reconstruction

High energy resolution
after Doppler
reconstruction andopportunities at astable-beam facility
AGATA@LNL – D. Mengoni(Plenary 9)

SUNFLOWER – N. Aoi (Plenary 9)

MINOS – A. Obertelli (Plenary 8)

A. Gade, 6/2/2014, Slide 4

The different configurations of theGRETINA campaign“Standard configuration”:
4 detectors underforward angles and 3 at90 degree

Plunger lifetime measurements
TargetDegrader

Plunger campaign led byHiro Iwasaki

All detectors under 90 degree

All detectors in one
hemisphere and LH2target inA. Gade, 6/2/2014, Slide 5

GRETINA at NSCL: beams from Z=4 to Z=92 –A campaign of 24 experiments
Nuclear Shell Evolution• N=Z Mirror Spectroscopy • Structure in 221,223Rn • 50-52Ca neutron knock-out • Neutron-rich Ti 
• Structure evolution beyond N=28 in Ca
and Ar isotopes • Odd neutron-rich Ni 
• 34Si Bubble nucleus? • Neutron-rich Si 
• GRETINA commissioning • Neutron-rich N=40 nuclei • Normal and intruder configurations in
the Island of Inversion  CompletedNuclear Astrophysics• Excitation energies in 58Zn • Measurement with the (d,n)
transfer reaction • GT strength distributions in 45Scand 46Ti Collective Phenomena• Transition matrix elements in 70,72Ni • Quadrupole collectivity in light Sn 
• γ-γ spectroscopy in neutron-rich Mg 
• Neutron-rich C lifetime measurement • Collectivity at N=Z via RDM lifetimemeasurements • B(E2:2→0) in 12Be • 71-74Ni excited-state lifetimes • Inelastic excitations beyond 48Ca • Triple configuration coexistence in 44S • Search for isovector giant monopole
resonance A. Gade, 6/2/2014, Slide 6

GRETINA science in talks at ARIS 2014
72Kr - H. Iwasaki (Parallel 3B)

Upper fp shell - T. Henry (PS1-010)
58Zn - C. Langer (this talk)
45Ti,45Sc - R. Zegers (Plenary 3)

72Ni - K. Kolos (Parallel 4A)
68Ni - C. Chiara (PS1-014)

N=40 - K. Wimmer (Parallel 4A)
60Ti - A. Gade (this talk)48-52Ca - H. Crawford (PS1-008)

N=20 - O. Sorlin (Plenary 11)

Nuclear chart courtesy of Thomas Duguet

A. Gade, 6/2/2014, Slide 7

GRETINA surrounding the target positionof the S800 spectrograph
S800

48Ar

GRETINAGRETINA
electronics

A. Gade, 6/2/2014, Slide 8

Shell evolution around N=40 – nuclear
structure towards 60Ca
LNPS effective interaction• Effective shell model interaction withthe largest model space available
predict f5/2, d5/2, g9/2 degenerate –essentially no N=40 gap at all

No N=40 gap

pf shell for the protons
and the 0f5/2, 1p3/2,1p1/2, 0g9/2, and 1d5/2
orbits for the neutrons• The 12 CSkP Skyrme functionals by
B. A. Brown [PRL 111, 232502(2013)] give an N=40 shell gap
between 3-4 MeV and this wouldchange the particle-hole content of
the wave functions in this region• Experimental information is needed

S. Lenzi et al., PRC 82, 054301 (2010)

A. Gade, 6/2/2014, Slide 9

Shell evolution around N=40 in neutronrich Ti isotopes: 9Be(61V,60Ti+)X• The structure of neutron-rich Ti-Ni
isotopes is subject to shell evolution
largely driven by the monopole partsof the pn tensor force• Excited states are often one of thefirst benchmarks. Only one excitedstate was known in 58Ti, nothing in60Ti.
• Excited states in 58,60Ti werepopulated in nucleon removal
reactions and will provide firstbenchmarks towards N=40 in the Ti
isotopes

48Ar

43ClA. Gade et al., PRL 112, 112503 (2014)
A. Gade, 6/2/2014, Slide 10

Looks like a doublet, smells like adoublet …

48Ar
43Cl

60Ti

A. Gade, R. V. F. Janssens et al.,PRL 112, 112503 (2014)

A. Gade, 6/2/2014, Slide 11Probing the wave function with direct
reactions
Neutron fp shellneutron g9/2 d5/2 included

B. A. Brown

S.Lenzi, K. Sieja, F. Nowacki

48Ar

43Cl

Reaction theory: J. A. Tostevin
A. Gade, R. V. F. Janssens et al.,PRL 112, 112503 (2014)

A. Gade, 6/2/2014, Slide 12

rp process reaction flow through 56Ni:
Importance of excited states in 58Zn
Type I X-ray burst – the rp process

Nuclear reaction
flow powers Xray bursts
throughimportantwaiting point
56
Ni

What are themost important
reactions?
57

Cu(p,)58Zn
among TOP 20
reactions

24+
23+
22+

Variations of 57Cu(p,)58Zn
affect the eff. lifetime of 56Ni

Gamow window(E0 ~ 1.15 ± 0.73 MeV)

Reaction rate dominated by
2+ resonances

57Cu + p

21+
58Zn

0+

So far: no states
measured in 58Zn-> only from theory

C. Langer, F. Montes et al., PRL, accepted/10x10

A. Gade, 6/2/2014, Slide 13

Spectroscopy of neutron-deficient 58Zn ind(57Cu,58Zn+) at 75 MeV/u

C. Langer, F. Montes et al., PRL, accepted

A. Gade, 6/2/2014, Slide 14

Uncertainty of reaction rate reduced from4 orders of magnitude to factor of 10

C. Langer, F. Montes et al., PRL, accepted

A. Gade, 6/2/2014, Slide 15

Outlook – The future is bright• In-beam -ray spectroscopy is prospering around theworld with great opportunities afforded by advancedarrays, clever targets and powerful accelerators• GRETINA at NSCL was a great success and thesecond science campaign at ATLAS/ANL just started–First GRETINA@NSCL science results are out (seepublications and talks/posters during this week)• GRETINA will return to NSCL for a second fast beam
campaign in 2015 after the ANL campaign is completed(likely with more detectors!)

Partners in crime …
• 58Zn science slides contributed by Chris
Langer and Fernando Montes et al. (MSU)@Acknowledgement (for setting up and keeping GRETINA going at NSCL) :LBNL: I.Y. Lee, A.O. Macchiavelli, C.M. Campbell, H. Crawford, M. Cromaz, C. Lionberger,
A. Wiens
ORNL: D. Radford, J. M. Allmond
NSCL: D. Weisshaar, F. Recchia, T. Baugher, C. Langer, E. Lunderberg, A. Lemasson, S.
Noji, D. Smalley, K. Wimmer, and R. Fox (NSCL DAQ), and D. Bazin, S. Williams(S800), Hiro Iwasaki (Plunger)

GRETINA is funded by the US DOE - Office of Science. Operation of the array at
NSCL is supported by the NSF under PHY-1102511 (NSCL) and DOE underGrant DE-AC02-05CH11231 (LBNL)

A. Gade, 6/2/2014, Slide 18