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Laser spectroscopy of gallium isotopes using ISCOOL

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Page 1: Laser spectroscopy of gallium isotopes using ISCOOLepsassets.manchester.ac.uk/medialand/physics/nuclear/bcisolde09.pdf · Laser spectroscopy at Collaps Protons Magnets ISCOOL 0 cm-1

Laser spectroscopy of gallium isotopes using ISCOOL

Page 2: Laser spectroscopy of gallium isotopes using ISCOOLepsassets.manchester.ac.uk/medialand/physics/nuclear/bcisolde09.pdf · Laser spectroscopy at Collaps Protons Magnets ISCOOL 0 cm-1

Optical measurementsin the region

N=50

Z=2829Cu31Ga

N=40

➔ spins, μ, Qs, δ< r 2 >

Page 3: Laser spectroscopy of gallium isotopes using ISCOOLepsassets.manchester.ac.uk/medialand/physics/nuclear/bcisolde09.pdf · Laser spectroscopy at Collaps Protons Magnets ISCOOL 0 cm-1

Physics motivation

Use laser spectroscopy to measure the gs spins...

Tensor force attractive between L+1/2 and L-1/2 (esp with ~radial wavefn)

28 28

40 401g9/2 1g9/2

2p1/21f5/2

1p3/2

1f7/2

2p1/21f5/2

2p3/2

1f7/2

Otsuka (PRL 95 232502):-

Does 5/2 replace 3/2 as gs in Ga? When?

Page 4: Laser spectroscopy of gallium isotopes using ISCOOLepsassets.manchester.ac.uk/medialand/physics/nuclear/bcisolde09.pdf · Laser spectroscopy at Collaps Protons Magnets ISCOOL 0 cm-1

Laser spectroscopy at CollapsProtons

Magnets

ISCOOL

0 cm-1826 cm-1

34782 cm-1

288 nm 295 nm

532 nm

RILISp-n converter

Page 5: Laser spectroscopy of gallium isotopes using ISCOOLepsassets.manchester.ac.uk/medialand/physics/nuclear/bcisolde09.pdf · Laser spectroscopy at Collaps Protons Magnets ISCOOL 0 cm-1

200ms PMT

ISCOOL for cooling & bunching

Photon background dominated by continuous

laser scatter

6μs gate

Page 6: Laser spectroscopy of gallium isotopes using ISCOOLepsassets.manchester.ac.uk/medialand/physics/nuclear/bcisolde09.pdf · Laser spectroscopy at Collaps Protons Magnets ISCOOL 0 cm-1

Example spectrum - 76Ga

Ungated

Gated (64μs - 70μs)

Time of flight(50ms accumulation)

Background suppression50ms / 6μs = ~104

Page 7: Laser spectroscopy of gallium isotopes using ISCOOLepsassets.manchester.ac.uk/medialand/physics/nuclear/bcisolde09.pdf · Laser spectroscopy at Collaps Protons Magnets ISCOOL 0 cm-1

417nm Ga I spectra826 cm-1 3d104s24p 2P3/2 ➔ 24789 cm-1 4s25s 2S1/2

3/2

3/2

3/23/2

3/2

(3/2)(3/2)

(5/2)

1

1

3(3)

2,3)

(3)(3)

1,2,3)

Page 8: Laser spectroscopy of gallium isotopes using ISCOOLepsassets.manchester.ac.uk/medialand/physics/nuclear/bcisolde09.pdf · Laser spectroscopy at Collaps Protons Magnets ISCOOL 0 cm-1

The strange case of 73Ga

All odd-A states previouslyassigned I=3/2

Au/Al ≠ 5.59(2)

π(p3/2)3 - hole state

Page 9: Laser spectroscopy of gallium isotopes using ISCOOLepsassets.manchester.ac.uk/medialand/physics/nuclear/bcisolde09.pdf · Laser spectroscopy at Collaps Protons Magnets ISCOOL 0 cm-1

403nm (2P1/2 ➔ 2S1/2) transition

F=1F=0J=1/2

F=1F=0J=1/2

F=2F=1J=1/2

F=2F=1J=1/2

I=3/2 I=1/2

➔ Must be spin 1/2

Page 10: Laser spectroscopy of gallium isotopes using ISCOOLepsassets.manchester.ac.uk/medialand/physics/nuclear/bcisolde09.pdf · Laser spectroscopy at Collaps Protons Magnets ISCOOL 0 cm-1

Intensity distribution (403nm)✔ Number of peaks

✔ Intensity distribution

✔ Au(2S1/2):Al(2P3/2) ratio

Page 11: Laser spectroscopy of gallium isotopes using ISCOOLepsassets.manchester.ac.uk/medialand/physics/nuclear/bcisolde09.pdf · Laser spectroscopy at Collaps Protons Magnets ISCOOL 0 cm-1

Gallium level systematicsNo low-lying

spin-1/2 state observed in 73Ga

Dip in 9/2 energyat this point

(onset of deformation)I. Stefanescu et al. PRC 79, 064302 (2009)

Page 12: Laser spectroscopy of gallium isotopes using ISCOOLepsassets.manchester.ac.uk/medialand/physics/nuclear/bcisolde09.pdf · Laser spectroscopy at Collaps Protons Magnets ISCOOL 0 cm-1

Shell model predictions

N. Yoshinaga,K. Higashiyama,and P. H. ReganPRC 78 044320 (2008)

Pairing + QQusing a valence space made up from nucleons occupying the g9/2, p1/2, p3/2 and f5/2 orbitals

Page 13: Laser spectroscopy of gallium isotopes using ISCOOLepsassets.manchester.ac.uk/medialand/physics/nuclear/bcisolde09.pdf · Laser spectroscopy at Collaps Protons Magnets ISCOOL 0 cm-1

Searching for the I=5/2...

75,77,79Ga are I = 3/281Ga is I = 5/2

Four 81Ga spectra:-

Page 14: Laser spectroscopy of gallium isotopes using ISCOOLepsassets.manchester.ac.uk/medialand/physics/nuclear/bcisolde09.pdf · Laser spectroscopy at Collaps Protons Magnets ISCOOL 0 cm-1

Odd-odd Ga isotopesIsomeric statediscovered in 80Ga

I=3

Can assign as I=2

No detectable splitting

Agrees with ABMR

Page 15: Laser spectroscopy of gallium isotopes using ISCOOLepsassets.manchester.ac.uk/medialand/physics/nuclear/bcisolde09.pdf · Laser spectroscopy at Collaps Protons Magnets ISCOOL 0 cm-1

Gallium nuclear moments

N=40 N=50 N=40 N=50

g-factors Qs

76 78

• g-factors of 75,77Ga similar to 67,69,71Ga➔ but different structure (Q < 0)

• Staggering of quadrupole moments 75,76,77,78Ga

Page 16: Laser spectroscopy of gallium isotopes using ISCOOLepsassets.manchester.ac.uk/medialand/physics/nuclear/bcisolde09.pdf · Laser spectroscopy at Collaps Protons Magnets ISCOOL 0 cm-1

Comparison with theory (Energy)JU

N45

inte

ract

ion

3/2 3/2 3/2 3/2 5/2 5/2

106

390

487

1107

199

<1

651

22

229

606

1895

279 351

5/21/2

7/2

5/2

7/2

1/25/2

1/2 5/21/2

3/2

1/2

7/2

7/2

1/2

3/2388

478

1168

61219

798

76181

152

251 350

430

1124

450

1263

1800

7/21593

5/2

3/2

1/2

1249

1111

882 5/21/2

3/2

7/21210

878

368

846

5/2

1/27/2

7/2

3/2339

653

768

10791082 1/2

7/2

7/2

5/2

3/2407

634

868

10751201 7/2

1/2

3/2

5/2

138

987

12101256

3/21024

5/21727

jj44b

inte

ract

ion

3/2 3/2 3/2 3/2 3/2 5/2

1/2

7/2

5/2336

412

822

1/25/2

7/2

1/25/2

7/2

5/21/2

7/2

3/2

1/27/2

5/2

1/2

7/2

91251

844

81244

803

216282

953

38

504

1026

239

12801458

Expe

rimen

t

71Ga 73Ga 75Ga 77Ga 79Ga 81Ga3/2 1/2 3/2 3/2 3/2 5/2

1/25/2

7/2

(7/2)

5/2 (5/2)(1/2)

(7/2)

(5/2)(1/2)

(7/2)

(5/2)

3/2

3/2

JUN45 - M. Honma

jj44b - B.A. BrownSpin inversion ✔

Low I=1/2 state in 73Ga ✔

Experimental1/2-, 3/2-, 5/2-, 7/2-

Page 17: Laser spectroscopy of gallium isotopes using ISCOOLepsassets.manchester.ac.uk/medialand/physics/nuclear/bcisolde09.pdf · Laser spectroscopy at Collaps Protons Magnets ISCOOL 0 cm-1

Theory - nuclear momentsMagnetic dipole Electric quadrupole

Fails for 79Ga in particular ....

Page 18: Laser spectroscopy of gallium isotopes using ISCOOLepsassets.manchester.ac.uk/medialand/physics/nuclear/bcisolde09.pdf · Laser spectroscopy at Collaps Protons Magnets ISCOOL 0 cm-1

Theory - nuclear momentsMagnetic dipole Electric quadrupole

“Second” 3/2 states..or the gs?

Page 19: Laser spectroscopy of gallium isotopes using ISCOOLepsassets.manchester.ac.uk/medialand/physics/nuclear/bcisolde09.pdf · Laser spectroscopy at Collaps Protons Magnets ISCOOL 0 cm-1

Isotope shift data

Need to calculate atomic factors...

Page 20: Laser spectroscopy of gallium isotopes using ISCOOLepsassets.manchester.ac.uk/medialand/physics/nuclear/bcisolde09.pdf · Laser spectroscopy at Collaps Protons Magnets ISCOOL 0 cm-1

Summary and outlook• Inversion seen between 79Ga and 81Ga• 73Ga is I = 1/2 (not I = 3/2)• Spins also confirmed for 76,77,78,79,80,81Ga

• Isomeric state discovered in 80Ga

• Theoretical predictions of moments

• Analysis of charge radii data

See talk by Pieter Vingerhoets (Cu) isotopes

Page 21: Laser spectroscopy of gallium isotopes using ISCOOLepsassets.manchester.ac.uk/medialand/physics/nuclear/bcisolde09.pdf · Laser spectroscopy at Collaps Protons Magnets ISCOOL 0 cm-1

Collaborating institutions

Manchester, UKKU Leuven, BelgiumBirmingham, UKISOLDE, CERNJyväskylä, FinlandOrsay, FranceHeidelberg, GermanyMainz, GermanyNew York, USA

Page 22: Laser spectroscopy of gallium isotopes using ISCOOLepsassets.manchester.ac.uk/medialand/physics/nuclear/bcisolde09.pdf · Laser spectroscopy at Collaps Protons Magnets ISCOOL 0 cm-1

Beta_2 values

67 +0.1669 +0.1371 +0.0875 -0.2576 +0.1777 -0.1878 +0.1779 +0.1281 -0.02