48 Ca INTCP313 ML Bissell On behalf of COLLAPS Background Program initiated with IS484 Groundstate properties of Kisotopes from laser and β NMR spectroscopy ID: 508136
Download Presentation The PPT/PDF document "Spins, Moments and Charge Radii Beyond" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
Spins, Moments and Charge Radii Beyond 48CaINTC-P-313
M.L. Bissell - On behalf of COLLAPS Slide2
Background
Program initiated with IS-484 -
“
Ground-state properties
of
K-isotopes from laser and
β
-NMR
spectroscopy
”
Extended with
I-117 -
“Moments, Spins and Charge Radii Beyond
48
Ca.”
Substantial theoretical interest and recent developments encourage us to bring forward part of this programSlide3
New magic numbers N = 32, 34
Whilst β-decay spectroscopy, deep inelastic scattering and Coulomb-excitation experiments have all provided evidence for a sub-shell closure at
N
=32, no direct experimental evidence exists for such a closure at
N
=34.
Maierbeck
et al., Phys.
Lett. B 675, 22 (2009)-> 55Ti has a 1/2− ground state. GXPF1A predicts this , KB3G predicts 5/2 −
A.Gade
, T.
Glasmacher
, Progress in Particle and Nuclear Physics 60, 161–224 (2008)
54
Ca
is “the key nucleus for a search for the new magic number
N=34.”Slide4
Ca: An ideal testing ground for theory
Gaute
Hagen (Oak Ridge) :
“ I
think it would really great idea for a proposal to measure the neutron rich
calciums
. We can within coupled-cluster theory compute radii, masses, spectra and moments of
39,40,41,47,48,49,51,50,52,53,54,55,59,60,61
Ca.
So basically its only a few calciums we cannot compute at the moment. To have experiments measure radii and moments of the n-Ca would be of really huge interest for the theory community and provide tests for ab-initio approaches. ”Slide5
Ca: An ideal testing ground for theory
Existing charge radii of Ca are probably the most theoretically investigated of any isotopic chain:
I.Talami
,
Nucl
. Phys. A 423, 189 (1984
)
->
Linear
+ Parabolic + OESEach of these terms related to particular components of the interaction used. Slide6
Charge radii beyond 48Ca
Fe
-> Normal OES
Mn
-> Downturn at
N
=31 but could be just OES.
IS-508 will extend this beyond
N
=32 K -> Preliminary results indicate a downturn at N=32. Statistics to be improved. Slide7
Only old SC yields available on the database:49Ca 2.5x105 /
uC
Old design
UCx49Ca 1.4x10
7 /uC Ta (Should be equivalent to new UCx)51Ca 1.0x104 /uC Ta powder (last yield measurements for
51
K claimed we had approximately equal amount of K and Ca)
52
Ca 1.0x10
2
/uC T. Stora- Yield will be 1 order of
magnitude higher than this. (All yield measurements at the PSB have been in the 1x103 range.)+ Possible factor of 10 from RILIS
YieldsSlide8
Stage 1 – Optical detection
Optical detection efficiency for K improved from
1 : 300 k
to
1 in 20 k+ low background .
∫
η
(new)
dx
/ ∫η
(existing) dx ≈14For Cd we observed 1 in 6k -> 1 in 4k for CaSlide9
What is possible?
Strong ionic
J
=1/2 to
J=3/2 393.4 nm transition.4 shifts on 52Ca with 1k ions /μ
C
3 Such spectra required to reduce
systmatics
+ 5 shifts for
51Ca+ 1 shift for
49Ca+ 3 offline shifts directly prior to the run for stable measurements.Stage 1 total 18 online shifts + 3 offline.Slide10
Stage 2 – Radioactive detection
Radioactive
detection
of Optically pumped ions after state selective
Charge exchange (ROC)
The theoretical
possibilities:
1 ion/s of an even isotope over 5 shifts.
An additional
18 shifts
53,54
CaSlide11
Why is stage 2 stage 2?
ROC is not ideally suited to odd cases. We must introduce multiple pumping.
In the previous setup it was not possible to reliably focus both the ion and atom beam onto the detectors.
-> Shutdown will be an ideal time to develop this.Slide12
Summary of Request
Stage 1 – Investigation of
N
=32
18 shifts
with
UCx
and RILIS prior to shutdown
.
Stage
2 – Investigation of N=3418 shifts with UCx and RILIS after the shutdown .Slide13
Collaboration
M. L. Bissell,
1
K. Blaum,
2
I. Budincevic,
1
N.Frömmgen,
3
R.F. Garcia Ruiz,
1
Ch. Geppert,
3
M. Hammen,
3
M. Kowalska,
4
K. Kreim,
2
P. Lievens,
5
R. Neugart,
3
G. Neyens,
1
W. Nörtershäuser,
3
J. Papuga
1
, M.M. Rajabali
1
and D. T. Yordanov
4