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Shell evolution in the neutron rich N=20, N=28 and Z=28 regions from measurements of moments and spins. Gerda Neyens, IKS, K.U. Leuven, Belgium. Belgian Research Initiative on eXotic nuclei. Layout Introduction: * motivation * methods to measure moments - PowerPoint PPT Presentation
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1
Shell evolution in the neutron rich N=20, N=28 and Z=28 regions
from measurements of moments and spinsGerda Neyens, IKS, K.U. Leuven, Belgium
Belgian Research Initiative on eXotic nuclei
2
Layout
1. Introduction: * motivation* methods to measure moments
2. Recent experiments at ISOL and fragmentation facilities
3. Highlights from Island of inversion4. Highlights from the Cu chain, from N=28 to N=465. Highlights from the Ga chain, from N=26 to N=506. Highlights from the N=28 region below Ca: Cl isotopes
7. Conclusions
3
Nuclear moments near magic shells very sensitive to nuclear wave function !
Magnetic moment of odd-even, even-odd and odd-odd isotopes (m=g.I) near closed shells:
g-factor is determined by the orbital occupied by unpaired valence protons and/or neutrons- depends on spin and orbital g-factors for protons and neutrons (gs
p, glp, gs
n, gln)
- depends on orbital momentum l and spin j of orbit occupied by unpaired nucleons sign of g sensitive to the parity of the wave function !!
- g-factor is not depending on the number of unpaired nucleons in an orbit: g(jn) = g(j)
57Cu = 56Ni + p 57Cu = 40Ca + 9p+8n
Comparing experimental and calculated g-factors: - confirm the proposed wave function - in some cases: assign spin and/or parity - test the shell model interaction and used model space
4
Nuclear moments near magic shells very sensitive to nuclear wave function !
Quadrupole moments of odd-even, even-odd and odd-odd isotopes
Q-moment is determined by the spin j and the <r2> of the orbit occupied by unpaired valence protons - neutrons are not charged but induce core polarization through p-n interaction- more sensitive to collectivity in the wave function
57Cu = 56Ni + p 57Cu = 40Ca + 9p+8n
Comparing experimental and calculated Q-moments near closed shells: - probing the proton-neutron interaction- study the softness of a core as a function of N and/or Z- study effects of core polarization - study shape coexistence in nuclei- confirm the proposed wave function- test the shell model interaction
Methods to measure moments, radii, spin: lifetime dependence / production method dependence
Lifetime of the isomeric excited state / isotope ground state
1 ps 1 ns 1 ms 1 ms 1s
Laser spectroscopy methods
magnetic moment, quadrupole moment, charge radius, spin
b-NMR/NQR on polarized nucleiNuclear Magnetic/Quadrupole Resonance
g-factorquadrupole moment
g-TDPAD on aligned beamsg-factor
quadrupole moment
Transient field methodg-factor
Fragmentation
Fusion-evaporationISOL methods
IN-SOURCE LASER SPECTROSCOPY at ISOL-facilities:magnetic moment (with sign) and charge radii
Hot cavity Sourcewith UCx target
to ISOLDE detection set-ups
Proton beam
Pulsed Dye Lasers for two(three) -step
resonant laser ionization
Cu hyperfine structure (HFS):
2S1/2
2P1/2
F1
F2I=1
ionisation step
Measure magnetic moment and isotope shift (charge radii)
of very exotic isotopes (rate > 1/s)
68Cu
possible to separate nuclear isomeric state (6-) from its ground state (1+) produce isomeric radioactive beams
I=6
E.g. at ISOLDE:
COLLINEAR LASER SPECTROSCOPY at ISOL-facilities:magnetic and quadrupole moments (with sign), radii, spin
Cu+ beam from ISOLDE
LASER beam
iondeflector
Cu hyperfine structure:
2S1/2
2P3/2
F1
F2
F’i
68Cu, Ip=1-
Pho
ton
coun
ts
Measure spin, magnetic moment quadrupole moment and isotope shift (charge radii)
of exotic isotopes (rate > 104/s)
E.g. at ISOLDE: COLLAPS
~Q,m
~ ,mI
Nuclear Magnetic/Quadrupole Resonance (b-NMR)at ISOL or fragmentation facility:
g-factor or Q-moment (no sign) of ground startes
b- detectors
Implantation crystal
B
NMR-magnet
Radioactive beam
hnL
Zeeman splitting of nuclear quantum levelsin static magnetic field B
I=2
m=2
m=1
m=0
m=-1
m=-2
If nrf = nL = g mN B/h population equalized
(P=0)
1. Implant the polarized radioactive beam in a crystal (unequal population of m-levels)
and apply static field B
RF-coil
2. Apply a radiofrequency field Brf, with frequency nrf
3. Measure the asymmetry of emitted b-particles as function of the applied frequency
34Al g factor
Time Differential Perturbed Angular Distribution (TDPAD)at fragmentation facility:
g-factor or Q-moment (no sign) of ms isomeric statesTDPAD-magnet
1. Implant the aligned radioactive beam in a crystal 2. Perturbation of spin-orientation due to static field B or
electric field gradient in the crystal
3. Measure the anisotropy of isomeric g-decay as a function of time since implantation:
use ion-g correlation method
BJ Zor
XLAB
g
det 1det 2
t=0t=0 t
Period of R(t) Larmor or quadrupole frequency
10
Recent experiments
The COLLAPS collaboration at CERN-ISOLDE Mainz – Heidelberg – Leuven – Manchester - …
- collinear laser spectroscopy on bunched beams: I, ,m Q measured61Cu - 75Cu (Z=29, from N=32 to N=46) odd-even and odd-odd67Ga - 81Ga (Z=31, from N=36 to N=50) odd-even and odd-odd
- b-NMR and laser spectroscopy on laser-polarized beams: I, g, m measured21Mg - 33Mg (Z=12, from N=9 to N=21) even-odd only
The b-NMR collaboration at LISE-GANIL Leuven – GANIL – Bruyères-le-Chatel – Tokyo …
- b-NMR spectroscopy on reaction-polarized beams: |g| and |Q| measured, I deduced31Al-34Al (Z=13, from N=18 to N=21) odd-even and odd-odd44Cl (Z=17, N=27)
Others: - in-source laser spectroscopy at LISOL@CRC Louvain-la-Neuve: 57Cu (m)- TDPAD on isomeric states at GANIL: 43mS (Z=16, N=27) (|g|)
11
fp-shell
sd-shell
pf
sd
20
20
8
f7/2p3/2
d3/2
d5/2
s1/2Si29
Si30
Si31
Si32
Si33
Si34
Si35
Si36
Si37
Al28
Al29
Al30
Al31
Al32
Al33
Al34
Al35
Al36
Mg27
Mg28
Mg29
Mg30
Mg31
Mg32
Mg33
Mg34
Mg35
Na26
Na27
Na28
Na29
Na30
Na31
Na32
Na33
Na34
Ne25
Ne26
Ne27
Ne28
Ne29
Ne30
Ne32
F24
F25
F26
F27
F29 22
201816
P35
S36
12
13
14
Experimental challenge: how large is this ‘region of inversion’ ?
Study transition region difficult to make theoretical predictions !
The “island of inversion”
11
empt
ying
pd 5/
2 approaching N=20
active neutron orbits around N=20
influence of particle-hole excitationsin the ground state wave functions ?
12
g-factors of Al isotopes ground states dominated by pd5/2-
1P. Himpe et al., Phys. Lett. B 643 (2006) 257–262
Conclusion for 33Al (N=20): small (<25-30 %) intruder admixture in the 33Al ground state.
Z=13: hole in pd5/2 orbital
Ip = 5/2+ expected for odd-Al isotopes wave function and spin confirmed by g-factor through comparison with calculated m=g.I in
sd-shell model (USD – 0p0h)sdf7/2p3/2 shell model space - SDPF-M (MCSM, mixed) - sdpf-interaction (2p2h)
(free-nucleon g-factors)
3,4
3,6
3,8
4
4,2
10 12 14 16 18 20 22 24N
m (mN) 0p-0h
exp
MCSM(50% intruder)
2p-2h
Ip=5/2+
Y. Utsuno et al., PRC 64, 011301R, 2001
b as
ymm
etry
B (gauss)
33Al(Si)
13
M. De Rydt et al., PLB 678, 344 (2009) Q(31Al)
very good agreement for 27,31Al with proton effective charge :
ep = 1.1 e neutron effective charge:
en = 0.5e
quadrupole moments of 31,33Al more sensitive to neutron excitations
exp
2p-2h
0p-0h
T. Nagatomo, et al., EPJA 42, 383–385 (2009) Q(33Al) … to be continued !
33Al has a mixed g.s. configuration: n(sd)-2(fp)2 contribution in wave function !
To determine amount of mixing: need more precise Q-moment value !
Experiment at GANIL, july 2010
Error bars smaller than dot size !
nQ(kHz)
31Al(Al203)
Calculations in sdp3/2f7/2-shell: * SDPF-M interaction (MCSM) Otsuka, Utsuno et al., private communication * sdpf-NR interaction (ANTOINE code) Nummela et al., PRC63 (2001)
14
33 sd-shell Q-momentssdpf-U effective interaction (Nowacki and Poves, PRC79, 014310 (2009))
M. Depuydt, M. De Rydt, G. Neyens, to be published
M. De Rydt et al., PLB 678, 344 (2009)
Fitted effective charges using static Q-moments
Compare Qexp of sd-shell isotopes (errors smaller than dot-size)with calculated values in sdp3/2f7/2-space using sdpf-NR effective interaction
epeff=1.3e
epeff=1.1e
c2=1.5
c2=3.4
sd-shell proton effective charge: ep = 1.12 e neutron effective charge: en= 0.45 e
odd-Z quadrupole moments
15
G. Neyens et al., PRL 94, 022501 (2005)D. Yordanov et al., PRL 99, 212501 (2007)
Measured spin 31Mg and 33MgFrom sign of g-factor parity
31Mg, Ip = 1/2+ n(sd)-3 (fp)2
33Mg, Ip = 3/2- n(sd)-2(fp)3
pure 2p-2h intruder ground states !
Al28
Al29
Al30
Al31
Al32
Al33
Al34
Al35
Al36
Mg27
Mg28
Mg29
Mg30
Mg31
Mg32
Mg33
Mg34
Mg35
20
nd3/2
+nf7/2
-
g-factor (+ sign) and spin of the 31,33Mg ground state
20
31Mg (N=19)
d3/2
20
33Mg (N=21)f7/2
Normal ground state configurations:
Ip=3/2+ Ip=7/2-
pf
sd
REAL ground state configurations:
20
31Mg (N=19)
d3/2
Ip=1/2+
n(s1/2-1)(d3/2
2)0(fp)20
[n(d3/2-1)p(sd)2+]1/2(fp)2
0
20
33Mg (N=21)
Ip=3/2-
n(d3/2-2)0(f7/2,s=3)3
3/2
n(d3/2-2)0(f2)0p3/2
16
Debate on the 33Mg ground state parity
Interpretation in Nilsson Model:31Mg ground state:build on ½+[200] g= -1.72 (exp=-1.7671)
33Mg ground state:and on 3/2-[321] g= -0.21 (exp= -0.4971) 3/2-[330] g= -0.51 (exp= -0.4971)
gexp(33Mg) = - 0.4971(4)g-0.51+0.56-0.21-1.98-1.72
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Parity of the 33Mg ground state: 3/2+ or 3/2- ?
G. Neyens et al., PRL 94, 022501 (2005)D. Yordanov et al., PRL 99, 212501 (2007)D. Yordanov et al., PRL 104, 129201 (2010)
normal ground state in 33Mg same g-factor (particle in f7/2) as 35Si
Ip=7/2-f7/2
sd
20
p3/228p3/2
1p1h intruder ground state in 33Mg same g-factor as 33Si
f7/2
s1/2
20
28
Ip=3/2+d3/2
g(35Si) = -0.47g(33Si) = +0.762p2h ground state in 33Mg similar g-factor as 35Si (3 particles in f7/2)
(f7/2)33/2
2 neutron holes in sd act as spectators (paired)gexp(33Mg) = -0.4971(4)
gsdpf(3/2+) = +0.78 (1w)gsdpf(3/2-) = -0.47 (2w)
Si33
Si34
Si35
Al32
Al33
Al34
Mg31
Mg32
Mg33
212019
P35
S36
Compare to g-factors of isotones with similar configuration:3/2+ : hole in d3/2 orbit (1h-2p configuration) 3/2-: particles in fp-shell (2h-3p configuration)
N=21 isotone: 35SiN=19 isotone: 33Si
=+p
=-p
18
Summary: “island of inversion” around 32Mg
Present status of the “Island of inversion”as deduced from static and dynamic moments measurements
P. Himpe et al., Phys. Lett. B. 658, 203 (2008)
All intruder g.s. configurationsare of the 2p-2h type !!
(two neutrons excited across N=20)
Utsuno et al., PRC70,0044307,2004
19
Evolution of the proton single particle states above Z=28
57Cu 59Cu 61Cu 63Cu 65Cu 67Cu 69Cu 71Cu 73Cu 75Cu3/2-
5/2-1/2-
1.5 ms200 ns
Evolution of the experimental 5/2- and 1/2- energies in Cu isotopes
pp3/2
pf5/2
pp1/2
S. Franchoo et al., PRC 64, 054308 (2001)Stefanescu et al., PRL 100, 112502 (2008)J.M. Daugas, Ph.D. Thesis, GANIL
Steep decrease of the 5/2- and 1/2- levels when ng9/2 is filledExperiment: g.s. spin assigned up to 73Cu (3/2-) from b-decay
N=28 N=40
N=40 N=50n1g9/2 n(p3/2,f5/2p1/2) 46 48
62Cu 63Cu 64Cu 65Cu 66Cu 67Cu 68Cu 70Cu 71Cu 72Cu 73Cu 74Cu 75Cu 76Cu69Cu
64Ni 65Ni 66Ni 67Ni 68Ni 69Ni 70Ni 71Ni 72Ni 73Ni 74Ni 75Ni 76Ni
64Zn 65Zn 66Zn 67Zn 69Zn 70Zn 71Zn 72Zn 73Zn 74Zn 75Zn68Zn
Z=28 77Ni 78Ni
77Cu 78Cu 79Cu
4466Ga 67Ga 68Ga 70Ga 71Ga 72Ga 73Ga 74Ga 75Ga 76Ga69Ga 4477Ga 78Ga 79Ga 80Ga 81Ga
61Cu
82Ga
20
Ground state spin of 71,73,75Cu
73Cu, I=3/2
75Cu, I=5/2
K.T. Flanagan et al., PRL 103, 142501 (2009)
g.s. spins measured with laser spectroscopy spins assigned to isomeric levels in 75Cu(based on measured lifetimes – Daugas, PhD Thesis)
JJ44b, Brown
Theory reproduces lowering of 5/2- correctly theory overestimates the 1/2- energy
by ~300 keV in 73Cu and 75Cu !!!
Model space: 56Ni core +f5/2 p3/2 p1/2 g9/2
Effective interaction: Lisetsky and Brown based on A. F. Lisetskiy et al., Phys. Rev. C 70, 044314 (2004)
21
Energy levels of odd-Cu isotopes beyond N=40
57C u3/2 -
5/2 -10281106 1/2 -
59C u3/2 -
61C u3/2 -
63C u3/2 -
65C u3/2 -
67C u3/2 -
69C u3/2 -
71C u3/2 -
73C u 3/2 - 75C u5/2 -
57C u3/2 -
59C u3/2 -
61C u3/2 -
63C u3/2 -
65C u3/2 -
67C u3/2 -
69C u3/2 -
71C u3/2 -
73C u3/2 - 75C u
5/2 -
57C u3/2 -
59C u3/2 -
61C u3/2 -
63C u3/2 -
65C u3/2 -
67C u3/2 -
69C u3/2 -
71C u3/2 -
73C u3/2 - 75C u
5/2 -
1/2 -4915/2 -9147/2 -1399
1/2 -475
5/2 -9707/2 -1311
1/2 -6705/2 -9627/2 -1327
1/2 -7711/2 -1096
1/2 -454534 5/2 -
5/2 -11167/2 -1482 7/2 -1670
5/2 -11151170(1 /2-) 5/2 -1214
7/2 -981
(1/2 -)135166 5/2 -
(7/2 -)961
62 (3/2-)(1 /2 -)128
5/2 -11195/2 -1655
1/2 -1989
1/2 -422
7/2 -1457
1/2 -640
1387 7/2 -5/2 -1397
1/2 -824
7/2 -149416355/2 -
1/2 -931
1516 7/2 -5 /2 -1570
1213 1/2 -5/2 -1372
1699 7/2 -
1313 5/2 -1/2 -1470
7/2 -1153
5/2 -7941/2 -12857/2 -1562
5/2 -301
1/2 -10397/2 -1422
3/2 -136
1/2 -963
7/2 -1401
E xperim ent
J U N 45
5/2 -371
1/2 -1388
1/2 -4195/2 -681
7/2 -1530
1/2 -384
5/2 -841
7/2 -1512
1/2 -373
5/2 -9007/2 -1311
1/2 -6735/2 -909
7/2 -1551
5/2 -868977 1/2 -
7/2 -1647
5/2 -9161/2 -1177
7/2 -1965
5/2 -2531/2 -584
7/2 -1626
22 5/2 -1/2 -430
7/2 -1410
1/2 -145
1/2 -679
7/2 -1436
jj4b
Above N=40:• 5/2- level rather OK• ½- > 800 keV too high
3
N=40
Calculations:Model space
(56Ni core) + f5/2 p3/2 p1/2 g9/2
Effective Interactions: * JUN45, Honma et al.,
PRC80, 064323, 2009
22
Magnetic moments of odd-Cu isotopes from N=28 to N=46
T. Cocolios et al., PRL 103, 102501 (2009)
Calculations:
Model space (56Ni core) + f5/2 p3/2 p1/2 g9/2
Effective Interactions: (JUN45, Honma et al., PRC80, 064323, 2009) * jj44b, Brown, private communication
K.T. Flanagan et al., PRL 103, 142501 (2009)
Conclusions:(1) 69Cu magnetic moment very close to the
reduced single particle value
(2) used gs = 0.7 gsfree (56Ni core, no f7/2)
(3) Towards N=28: both p and n f7/2 core excitations needed to reproduce core softness (GXPF1 gives perfect agreement)!
(4) Beyond N=40: * 75Cu, 5/2 g-factor well reproduced (because nearly pure pf5/2 wave function) * 71,73Cu, 3/2 values largely overestimated need more mixing with (pf5/2 2+)3/2
23
single particle value Qsp(pp3/2) is reached at the borders of the model space (N=28, N=50)
jj44b interaction:56Ni core (N=Z=28)neutrons up to N=50
increase of Q-moments for 3/2 and 5/2 states towards mid-shell (normal behaviour between shells)
Q-moment of 69Cu very close to that of single particle value:N=40 behaves as a ‘magic’ gap reason: not ‘energy’ gap parity change pf (neg) to g9/2 (pos)
The model reproduces extremely well the Cu quadrupole moments around N=40. Deviation in 61Cu significant ? Signature of breakdown of magicity of 56Ni core ? 75Cu Q-moment in agreement with that for a 5/2- configuration !!
Quadrupole moments of odd-Cu isotopes from N=32 to N=46
24
Ground state spin of 72,74Cu, sign of m
72Cu, I=2
74Cu, I=2Ratio of A-factors should be constant,if the hyperfine structure is fitted with correct spin value(input in fit: I, Au, Ad, Bu, IS)
Ground state spin 72,74Cu is I=2, with more than 4 sigma confidence level
K.T. Flanagan et al., in preparation
5/2
I (72,74Cu) = 2
most intense line32S1/2
32P3/2
1/23/2
7/2
3/2
5/2
m < 0
25
Ground state parity and structure of 72Cu72Cu expected low-energy levels:
40
2p3/2
1f5/2
2p1/2
1g9/2
40
2p3/2
1f5/2
2p1/2
1g9/2
Z=29 N=43
(pp3/2 ng9/23) (3,4,5,6)-
(pf5/2 ng9/23) (2,…,7)-
proton excited to the f5/2 orbital
(pp3/2 np1/2-1g9/2
4) (1,2)+
neutron excitation across N=40
Ground state has spin I=2 But what is the parity ??
Can we assign parity based on measuredmagnetic moment ?m = -1.3451(6) mN
Experiment
(3-)
(4-)
(1+)
0
137
219270
376
(2)
(6-) t1/2=1.76ms
J.C. Thomas et al., PRC74, 054309, 2006
??
Realistic interaction3-6-
4-
2+
2-
5-
1+
016
140
235
387418431
use Paar’s rule
26
Ground state parity and structure of 72Cu: Ip = 2- !!
Main negative parity configuration: (mpf5/2 ng9/23; 2-) mfree(2-) = -2.13 mN
memp (2-) = -1.94 mN
Main positive parity configuration: (mpp3/2 np1/2-1g9/2
4; 2+) mfree(2+) = +4.44 mN
memp (2+) = +1.44 mN
Conclusion: the measured SIGN of the moment, m = -1.3451(6) mN, is crucial to decide on the parity ! in absolute value it is in agreement with 2+ however, a negative sign is only compatible with a proton in f5/2 orbital
Use additivity rules for proton-neutron configurations:
Realistic interaction3-6-
4-
2+
2-
5-
1+
016
140
235
387418431
Experiment
(3-)
(4-)
(1+)
0
137
219270
376
(2-)
(6-) t1/2=1.76ms
27
Ground state spins in odd-Ga isotopes
N=40 N=50n1g9/2 n(p3/2,f5/2p1/2) 46 48
62Cu 63Cu 64Cu 65Cu 66Cu 67Cu 68Cu 70Cu 71Cu 72Cu 73Cu 74Cu 75Cu 76Cu69Cu
64Ni 65Ni 66Ni 67Ni 68Ni 69Ni 70Ni 71Ni 72Ni 73Ni 74Ni 75Ni 76Ni
64Zn 65Zn 66Zn 67Zn 69Zn 70Zn 71Zn 72Zn 73Zn 74Zn 75Zn68Zn
Z=28 77Ni 78Ni
77Cu 78Cu 79Cu
4466Ga 67Ga 68Ga 70Ga 71Ga 72Ga 73Ga 74Ga 75Ga 76Ga69Ga 4477Ga 78Ga 79Ga 80Ga 81Ga
61Cu
Normal ground state configuration of odd-Ga isotopes: (pp3/2)3 3/2-
This work: measured all g.s. spins from 67Ga up to 81Ga !!
Prior to our work: firmly assigned 3/2- value up to 75Ga tentatively assigned 3/2- for 77,79Ga
no assignment for 81Ga
Spin changes in 73Ga (I=1/2) and 81Ga (I=5/2) !!
Need the magnetic and quadrupole moment to understand this structure change !
82Ga
B. Cheal et al., submitted PRL
28
No low-lying spin-1/2 state observed in 73Ga before.
3/2- seen in 73Ga seen in (p,t) reaction study (Vergnes et al., PRC19, 1276, 1971)
½- g.s. must be near-degenerate with this 3/2- state (less than 1 keV according to Stefanescu)!!
Dip in 9/2+ energy at 73Ga (N=42)(intruder pg9/2 leading to onset of deformation around neutron mid-shell at N = 42)
I. Stefanescu et al. PRC 79, 064302 (2009)
Odd-Ga level systematics N=38
N=40N=42
N=44
N=46
29
g-factors of odd-Ga isotopes
N=40 N=50
g-factors
I=1/2
I=3/2 I=5/2
g.s. wave function dominated by unpaired pp3/2, in 67,69,71Ga and in 75,77Ga
g.s. dominated by odd pf5/2 configurations in 81Ga, having spin 5/2, but also in 79Ga having spin 3/2 79Ga: mixed p(p3/2
2f5/2) 2+ and p(f5/23, s=3)3/2
g.s very mixed in 73Ga: p(p3/23, s=3)1/2 with
pp1/2 and pf5/2 2+
the 73Ga g.s. g-factor gexp=0.418(4) is very close to gR ~ Z/A ~ 0.44)
B. Cheal et al., submitted to PRL
30
quadrupole moments of odd-Ga isotopes
N=40 N=50
QsShape changes
(1) around 73Ga
• Below N=42 (36,38,40): Q > 0main configuration: Q(p3/2
3) = Q(p3/2-1 )
(hole configuration has a positive Q-moment)
• Above N=42 (44,46) : Q < 0 main configuration: p3/2
+1 (f5/2p1/2)2
(particle configuration has a negative Q-moment)
(2) In 79Gapositive Q-moment and protons mostly in f5/2 from measured g-factor mixing between (pp3/2 (p f5/2)2 )3/2 (this does not give correct moments)
(f5/2)33/2 (gives correct moments leading term)
(3) In 81Gaslightly negative Q-moment (particle-like): 3 p in f5/2 coupling to 5/2 Q=0
B. Cheal et al., PRL submitted
31
Comparing magnetic moments to JUN45 and jj44b
JUN45
jj44b
Second 3/2- in calculations !!
Both interactions predict g.s. structure of 79Ga around 250-300 keV !
B. Cheal et al., submitted to PRL
32
Comparing quadrupole moments to JUN45 and jj4b
JUN45
jj4bSecond 3/2- in calculations !!
Conclusions: (1) jj44b has better overall agreement for the magnetic moments ! (2) in jj44b the quadrupole moment of 69Ga and 71Ga has wrong sign
too fast emptying of the p3/2 orbital ?
B. Cheal et al., submitted to PRL
ep=1.5een=0.5e
33
Comparing experimental levels to JUN45 and jj4b
Real ground state: m and Q reproduced !
Real ground state ???NO, magnetic moment not reproduced!
34
Reduction of the N=28 gap below 48Ca
N=20N=28
40Ca
35P
41Ca
39Ar
38Cl
37S
36P
39Cl
38S
37P
42K
41Ar
40Cl
39S
38P
43K
42Ar
41Cl
40S
39P
45Ca
44K
43Ar
42Cl
41S
40P
45K
44Ar
43Cl
42S
41P
47Ca
46K
45Ar
44Cl
43S
42P
47K
46Ar
45Cl
44S
43P
39Ca
38K
37Ar
36Cl
35S
34P
42Ca 43Ca 44Ca 46Ca 48Ca39K 40K 41K
40Ar38Ar
37Cl
36S
Z=20
nf7/2 np3/2
Evidence for N=28 gap reductionbelow 48Ca, in
- in Ar isotopes- in S isotopes
nf7/2
np3/2
N=27 isotonesExperimental 7/2- and 3/2-
From Gaudefroy et al., PRL 102 (2009): 7/2- isomer in 43S is dominated by nf7/2
(from g-factor) very good agreement with sdpf-U interaction suggested g.s. of 43S: a collective 3/2- state
dominated by np3/2
44Cl between 45Ar and 43S
35
Near-degeneracy of ps1/2 and pd3/2 near N=28
Hardly no experimental information available on 44Cl - knock-out reaction from 45Cl (PRC79, 2009) suggests 2- g.s. with significant
contribution from np3/2 in the wave function- no excited states known.
Normal 44Cl g.s. configuration = (pd3/2nf7/2-1) 2,3,4,5-
Mixed with (pd3/2np3/2) 0,1,2,3-
(ps1/2np3/2) 1,2- pushes 2- down in energy lowers the g-factor
pd3/2
ps1/2
Z=20
N=28N=22 N=24 N=26
44Cl is in between 43Cl and 45Cl
44Cl ground statepresumably dominated by πs1/2 configurations
nf7/243Cl and 45Cl have probably 1/2+ ground state (A. Gade, PRC 74(2006)034322)
36
g-factor and g.s. structure of 44Cl
b-NMR on 44Cl(NaCl)
|g|=0.27487(16)
b-as
ymm
etry
Calculation: sdpf-U interaction (Nowacki and Poves, PRC79 (2009))
protons in sd orbits neutrons in pf orbitsgs
eff=0.75gs
GOOD AGREEMENT :Ground state spin 2 confirmedVERY MIXED WAVE FUNCTION CONFIRMED
M. De Rydt et al., PRC 81, 034308 (2010)
Fragmentation of 48Ca beam, 2 mA select polarized beams at LISE-GANILfor b-Nuclear Magnetic Resonance
37
Conclusions
(1) Knowing magnetic moments and quadrupole moments in a series of isotopes or isotonesis extremely helpful to understand the structural changes in isotopes far from stability !
(2) Measurements of the g.s. spin is needed in these exotic regions, because theories are not sufficiently well developed to make predictions !
(3) Measured g.s. spin values are crucial for further assigning spins of excited levels.
(4) Measuring the sign of the g-factor (magnetic moment) is crucial for interpretation of the mixed g.s. structures (less critical for isomeric states that are mostly of single particle nature)
38
33Al NQR
T. Nagatomo, H. Ueno et al., preliminary
M. De Rydt et al., PLB 678, 344 (2009)
34Al g factor
P. Himpe et al., Phys. Lett. B 643 (2006) 257–262
nQ(kHz)
31Al(Al203)
39
Energy levels of odd-Cu isotopes from N=28 to N=50
57C u3/2 -
5/2 -10281106 1/2 -
59C u3/2 -
61C u3/2 -
63C u3/2 -
65C u3/2 -
67C u3/2 -
69C u3/2 -
71C u3/2 -
73C u 3/2 - 75C u5/2 -
57C u3/2 -
59C u3/2 -
61C u3/2 -
63C u3/2 -
65C u3/2 -
67C u3/2 -
69C u3/2 -
71C u3/2 -
73C u3/2 - 75C u
5/2 -
57C u3/2 -
59C u3/2 -
61C u3/2 -
63C u3/2 -
65C u3/2 -
67C u3/2 -
69C u3/2 -
71C u3/2 -
73C u3/2 - 75C u
5/2 -
1/2 -4915/2 -9147/2 -1399
1/2 -475
5/2 -9707/2 -1311
1/2 -6705/2 -9627/2 -1327
1/2 -7711/2 -1096
1/2 -454534 5/2 -
5/2 -11167/2 -1482 7/2 -1670
5/2 -11151170(1 /2-) 5/2 -1214
7/2 -981
(1/2 -)135166 5/2 -
(7 /2 -)961
62 (3 /2-)(1/2 -)128
5/2 -11195/2 -1655
1/2 -1989
1/2 -422
7/2 -1457
1/2 -640
1387 7/2 -5/2 -1397
1/2 -824
7/2 -149416355/2 -
1/2 -931
1516 7/2 -5 /2 -1570
1213 1/2 -5/2 -1372
1699 7/2 -
1313 5/2 -1/2 -1470
7/2 -1153
5/2 -7941/2 -12857/2 -1562
5/2 -301
1/2 -10397/2 -1422
3/2 -136
1/2 -963
7/2 -1401
E xperim ent
J U N 45
5/2 -371
1/2 -1388
1/2 -4195/2 -681
7/2 -1530
1/2 -384
5/2 -841
7/2 -1512
1/2 -373
5/2 -9007/2 -1311
1/2 -6735/2 -909
7/2 -1551
5/2 -868977 1/2 -
7 /2 -1647
5/2 -9161/2 -1177
7/2 -1965
5/2 -2531/2 -584
7/2 -1626
22 5/2 -1/2 -430
7/2 -1410
1/2 -145
1/2 -679
7/2 -1436
jj4b
Below N=40:• 5/2- level ~500 keV high• ½- rather OK, not in 57Cu
Above N=40:• 5/2- level rather OK• ½- > 800 keV too high
Below N=40:• 5/2- level in 57Cu too low !• 5/2- level ~ 200 keV too low• ½- rather OK
Above N=40:• 5/2- level rather OK• ½- bit too high in 73,75Cu
3
N=40N=28
40
Energy levels Cu isotopes beyond N=42
(pp3/2ng9/2)3-6
(pf5/2ng9/2)2-7
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