magnetic dipole moment of doubly closed-shell plus one nucleon nucleus of 49 sc

the 36th Meeting of the INTC, 2010.2.4, CERN

Magnetic dipole moment of doubly closed-shell plus one

nucleon nucleus of 49Sc.

T. Ohtsubo

Niigata University

CERN-INTC-2010-014; INTC-P-279


• The nuclear magnetic moment is a sensitive probe for the study of nuclear structure.

• The electromagnetic properties of nuclei that are doubly closed-shell plus or minus one nucleon are expected to be most approachable by theory, are most approachable to theory. Z,N = 2, 8, 20, 28, 50, 82, 126


42Ca 44Ca 46Ca

42Ti 44Ti 46Ti 48Ti 50Ti

39K 40K 41K 42K 43K 44K 45K 46K 47K 48K38K

39Ca 40Ca 48Ca41Ca 43Ca 45Ca 47Ca 49Ca

40Sc 41Sc 42Sc 43Sc 44Sc 45Sc 46Sc 47Sc 48Sc 49Sc 50Sc

41Ti 43Ti 45Ti 47Ti 49Ti 51Ti

: known Q : known

,Q moments around Z=20

20

20 28

2nd order configuration mixingMeson exchange currentIsobar currents


Shell model calculation

• Honma et al. used an effective GXPF1 interaction in their large-scale shell model calculation in the full pf shell.M. Honma et al., Phys. Rev. C69, 034335, (2004)

• Speidel et al. describes shell model calculations with four effective interactions, FPD6, KB3, VHG and FPY.K.-H. Speidel et al., Phys. Rev. C62, 031301(R), (2000).


40 42 44 46 48 50A

A=40

5.0

6.0

[N]

A=48

Schmidt value

Honma

Speidel

magnetic moment of odd A Sc isotopes

N=28 calc. Speidel

K.-H. Speidel et al., Phys. Rev. C62, 031301(R), (2000).


Experiment

• Nuclear orientation method (NICOLE)• Implanted nuclei are polarized by an

hyperfine field in Fe at very low temperature.

• Polarization is monitored by detecting -ray asymmetry.

• NMR is detected by change of -ray asymmetry


Decay scheme Experimental condition

4921Sc

4922Ti

7/2

7/299.94%

Q = 2006 keV

57.2 m0

0

• Frequency 140-170 MHz at Bext = 0.2 T• Temperature ~ 10mK• Relaxation time ~ 6 min

47ScFe data


-ray asymmetry

0.6

0.7

0.8

0.9

1

1.1

1.2

1.3

1.4

1 10 100 1000 1/T

W

Fraction factor = 1. Not consider backscattering. No background


ISOLDE/NICOLE


Setupsuperconducting magnet

Fe foil (cold finger)

counter

counter

49Ca(49K)

polarized field

49Sc


Recent results in NICOLE

V. V. Golovko et al., Phys. Rev. C72, 064316, 2005

N. J. Stone et al., Phys. Rev. C77, 014315,2008

71CuFe 69AsFe


Yields of Sc isotopes at ISOLDE

Nucleus yield at ISOLDE

(ions/C)

target material

47Sc 3.0E+7 Ti

2.5E+6 Ti48Sc 7.7E+6 Ta50Sc 3.6E+3 Ta


Production of 49Sc

• There is no data for the pure emitter 49Sc because of the presence of many activities at the A=49 position from multiply charged ion species from which any 49Sc component cannot be separated.

• Implant 49K or 39Ca with a Ti foil target plus CF4 leak plus plasma source, or a standard UCx target with surface ionizer.

• 49Sc ~ 5 x 105/C


Beam time estimation

Nucleus Prod. Target Time(Shifts)

49Ca , 49K

(49Sc)Ti/UCx 8

47Sc Ti 4

total 12

Cooling down/warm upWide range resonance searchLiq He/N2 charge

Main run fine structure external field dependence


CollaborationNiigata University T. Ohtsubo, S. Ohya

University of Oxford

University of Tennessee N.J. Stone, C.R. Bingham

University of Maryland J.R. Stone, W.B. Walters

CSNSM C, Gaulard, L. Risag ari

Institut Laue Langevin,

ISOLDE U. Köster

Toyama University K. Nishimura

KEK S. Muto

LPSC G. Simpson

University of Novi Sad M. Veskovic


end


0.2 T

0.4 T

0.6 T

frequency (MHz)144 146 148 150 152

47ScFe


J. Rikovska et al, Phys. Rev. Lett. 85, 1392, 2000


NMR-ON

H = -μ ・B= -gμ N I・B= -gμ N B0Iz

Em = <m| H | m>

= -gμ N B0m

B0

I = 5 case

energy

m = -5

m = +5

Magnetic Interaction

B = 0 B = 0

magnetic quantum number

μ

.

.

.

Population am ∝ e-Em/kT

low temperaturehigh field

Polarization(Orientation)

Boltzmann ditribution

Zeeman split


Ge detector

population population

γ -ray angular distribution

rf frequency

γ-r

ayde

tect

ion

hν =Δ E

transition

resonance

magnetic dipole moment of doubly closed-shell plus one nucleon nucleus of 49 sc

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