Phenomena occurring in neutron deficient nuclei at N~50 M.Górska

RISING experimental data and many others RISING experimental data and many others

• location of the proton drip line • single particle energy evolution• spin-gap isomers:

gamma and beta decaying

valence and core excited states• 100Sn core excitation and shell gap measurement• enhanced collectivity in Sn isotopes• enhanced collectivity in Z>50 neutron deficient nuclei

Experimental conditions and techniques

Fusion symmetric reaction

EUROBALL, GASP + Ancillaries - in-beam - alpha decay MSEP at GSI - β decay - spin-gap isomers

Fragmentation - Coulex

- Transfer- Isomers

- β decay

Experiments with Stopped BeamsExperiments with Stopped Beams

production

selectionidentification

stopping

spectroscopy

~300MeV/uA,Z event-by-event ID

Time correlation >50ns - min

Rate < 1 ion/hour

• A,Z event-by-event ID

• Time correlation ns - min

• Rate < 1 ion/hour

• Alignment → g, Q moment

+

• prompt flash

• isomeric ratio

• ray sequence

• spin-parity assignment

- + -

RISING Active Stopper MeasurementsRISING Active Stopper Measurements

5 cm x 5 cm DSSSD (16 strips x 16 strips = 256 pixels) x 3 = 758 total pixels or x2 layers or x3 layers.

Active Stopper measurements: particles, internal conversion electrons, alphas.

T1/2 up to ~ minutes; associated with delayed -rays.

Passive Stopper: -ray from isomer cascades with T1/2 ~ 10 ns 1 ms.

Experiments with fast beamsExperiments with fast beams

production

selection

identification reaction

spectroscopy

identification

35m

Bρ - ∆E - Bρ

CATE

SI-CsI

<1GeV/u

100-700MeV/u

Scattering experiments : Coulomb excitation,

One-, two-neutron knock-out

Ge Cluster

beam

Target chamber

CATE

RISING RISING -array for fast beams-array for fast beams

Ge Miniball

Typically: 100MeV/u, ε=0.06, ∆E/E=0.02

Experimental conditions and techniques

Fusion symmetric reaction

EUROBALL, GASP + Ancillaries - in-beam

MSEP at GSI - β decay - spin-gap isomers

Fragmentation - Coulex

-Transfer- Isomers

- β decay

rp-processrp-processScenario: high temperature and density

(x-ray bursts in neutron stars)

Nuclei can be synthesized successively by binding more and more protons until proton dripline is reached.

Continuation to heavier nuclei after β+-decay.

β+ emitters with longer half lives are called waiting point nuclei

0 1 23 4

5 6

7 8

9 10

11 12 13

14

15 16

17 18 19 20

21 22

23 24

25 26 27 28

29 30

31 32

33 34 35 36

37 38 39 4041

42 43 44

45 46 47 48

49 5051 52

5354 55

56

57 58

59

H (1)H e (2)L i (3)

Be (4) B (5) C (6) N (7)

O (8) F (9)

N e (10)N a (11)

M g (12)A l (13)S i (14) P (15)

S (16)C l (17)

A r (18) K (19)

C a (20)Sc (21)

Ti (22) V (23)

C r (24)M n (25)

Fe (26)C o (27)

N i (28)C u (29)

Zn (30)G a (31)

G e (32)As (33)

Se (34)B r (35)K r (36)R b (37)

S r (38) Y (39)

Zr (40)N b (41)

M o (42)Tc (43)

R u (44)R h (45)Pd (46)Ag (47)

C d (48)In (49)

Sn (50)Sb (51)

Te (52) I (53)

Xe (54)

rp process

waiting points

N = ZH. Schatz et al. PRL 86, 2001

0 1 23 4

5 6

7 8

9 10

11 12 13

14

15 16

17 18 19 20

21 22

23 24

25 26 27 28

29 30

31 32

33 34 35 36

37 38 39 4041

42 43 44

45 46 47 48

49 5051 52

5354 55

56

57 58

59

H (1)H e (2)L i (3)

Be (4) B (5) C (6) N (7)

O (8) F (9)

N e (10)N a (11)

M g (12)A l (13)S i (14) P (15)

S (16)C l (17)

A r (18) K (19)

C a (20)Sc (21)

Ti (22) V (23)

C r (24)M n (25)

Fe (26)C o (27)

N i (28)C u (29)

Zn (30)G a (31)

G e (32)As (33)

Se (34)B r (35)K r (36)R b (37)

S r (38) Y (39)

Zr (40)N b (41)

M o (42)Tc (43)

R u (44)R h (45)Pd (46)Ag (47)

C d (48)In (49)

Sn (50)Sb (51)

Te (52) I (53)

Xe (54)

Where does the rp-process end?Where does the rp-process end?

Measurement

• total life time of waiting point nuclei• exact position of proton dripline

rp process

waiting points

N = Z

1 0 4S b 1 0 5S b 1 0 6 1 0 7S b

1 0 3S n 1 0 4S n 1 0 5S n 1 0 6S n

1 0 5Te 1 0 6Te 1 0 7Te 1 0 8Te

1 0 2In 1 0 3In 1 0 4In 1 0 5In

(,a )

S b

(p , )

The closed SnSbTe cycle

H. Schatz et al. PRL 86, 2001

In

Sn

Te

Sb

Cd

Ag

Pd

Rh

Ru

100Sn setting

T.Faestermann analysis: K.Eppinger, C.Hinke TU München

Probing the proton dripline

100Sn

what‘s new?what‘s new?

97In

93Ag

103Sb T1/2 < 50 ns !

99Sn?

95Cd

T 1/2 >

0.2

s

M. Górska et al., Proc. ENPE99, AIP CP495 (2000) 217M. Hjorth-Jensen et al., Phys. Rep. 261 (1995) 125 a

πν interaction tuned for the model space 88Sr, (p1/2,g9/2) (d5/2, g7/2, d3/2, s1/2, h11/2) gives the correct description of the evolution of SPEs

Tensor interaction monopole

νh11/2 – πg9/2, νg7/2 – πg9/2

T. Otsuka et al., PRL 95, 232502 (2005)

EXP: h11/2<30% spectroscopic strength

very old measurements

100Sn region

h11/2<30% spectroscopic strength

M. Górska et al., Proc. ENPE99, AIP CP495 (2000) 217M. Hjorth-Jensen et al., Phys. Rep. 261 (1995) 125 and priv. comm.

100Sn region

New !

h11/2›50% spectroscopic strength

56Ni and 100Sn analogy 1ћw apart: (nlj) → (n+1,l+1,j+1)

The Jan Blomqvist correspondence principle

If the orbits are the same the physics cannot be (much) different !

proton – neutronhole-hole interaction in p n g9/2

-n

core excitation in large-scale SMin p n g9/2-1 (d5/2 ,g7/2)1

Spin gap isomersbelow N = Z = 50

with RISING and

GSI - ISOL

100100Sn setting check : Sn setting check : 9898CdCd

0+

8+

6+

4+

2+

0

1395

208322812428

12+ 6635

147

198

688

1395

4207s.e.

d.e.

N. Braun, U. Cologne

Ch. Hinke, TUM

A. Blazhev et al., PRC 69, 064304 (2004)

M.G. et al., PRL 79 (1997) 2415

SM calculation

● gds LSSM t=1,5 (FN) in comparison to

● truncated to

1p1h in any orbit

in model spaces

●pgdg:

p3/2f5/2p1/2g9/2d5/2g7/2

●pgndg:

ν p3/2f5/2p1/2g9/2d5/2g7/2

with TBME from OXBASH package (SNA+GF) and SPE tuned to 100Sn

4157

preliminary !

100Sn core excitation in 98Cd

• LSSM smoothly converged at t=5 • 100Sn neutron shell gap N=50 inferred 6.46 (15) MeV• remaining E2,E4 deficiency is due to interaction and/or proton gap Z=50• effective E2 charge will not help !

Valence statesg9/2

-2

ph statesg9/2

-2g9/2-t (d5/2,g7/2)t

pairing

• Valence excitation energy increases with t• ph excitation energy decreases with t• Exception t=2 : pairing overbinds valence states

E2

E2

E4

Ordering of the SP Ordering of the SP states in states in 101101Sn? Sn? Argonne-Oak-Ridge polemicArgonne-Oak-Ridge polemic

58Ni + 45Sc -> 103In* -> 97Ag + 1a2nM. Palacz et al., preliminary resultsEUROBALL 2003

Core excitation in Core excitation in 9797AgAg

17/2-

No possibility for shell gap measurement?

Tf[s]

9696AgAg

R. Grzywacz et al. PRC 55 (1997) 1126

E[keV]

Co

un

ts

Tf<1 s

newknown

E[

keV

]

4000

Tc< 0.2 s

E[keV]

gate 470 keV

9696AgAg

Counts

Tc< 1 s; E>4MeV have Tf<1 s gate 4168 keV

E[keV]

Co

un

ts

96

470

668

0.27(14) s

1.58(3) s78(8) s

9696AgAg

SE

: 41

68 -

511

4168

4264

E[MeV]

GF: model space: (g9/2, p1/2) interaction: R.Gross and A.Frenkel,NPA 267(1976)85 → 13-, 15+ isomers

fpg: GF + 1p1h excitation from f5/2 and p3/2

Shell Model Calculations: H.Grawe

9647

Ag49

96Ag and 94Pd96Ag and 94Pd

T = 0

M. Górska et al., ZPA353,233(95)

M. La Commara et al., NPA708,167(02)

I. Mukha et al., PRC 70,044311(04)

C. Plettner et al., NPA733,20(04)

Need for LSSM

fpg: GF + 1p1h excitation from f5/2 and p3/2

fpndg: fpg + 1p1h excitation from vg9/2 to (g7/2 ,d5/2)

Shell Model Calculations: H.Grawe

9647

Ag49

CD decay including high CD decay including high spin!!spin!!

PRELIMINARY!!!

66++ isomer in isomer in 102102SnSn

Lipoglavsek et al., PLB 1998

E(6-4) = 48keV

88keVB(E2)=3.6 W.u.

3 isomers after ToF=200nsdecaying within 25 ns ?

Search for 6Search for 6++ isomer in isomer in 100100SnSn

1

5

4

3

2

E/MeV

0 2015105 T/s

E/MeV

M1 conversion

M1

E2

Decay scheme

(shell model)

Decay scheme

M. Karny et al. EPJA 27, 129 (2006)

100,102Sn ß+/EC decay

I = 6+ isomerism

1472

1969+1969

10049In 51

10249In53

10050Sn50

10250Sn52GT

GT

T. Faesterman et al., to be published

T. Faesterman et al., to be published

T. Faesterman et al., to be published

T. Faesterman et al., to be published

T. Faesterman et al., to be published

B.A. Brown et al.

L. Batist et al., EPJA submitted

Relativistic Coulomb excitation of nuclei towards Relativistic Coulomb excitation of nuclei towards 100100SnSn

• 112,108Sn secondary beam with ~150MeV/u

• Au – Coulex target

A. Banu, PhD thesis, PR C72, 061305(R) (2005)A. Banu, PhD thesis, PR C72, 061305(R) (2005)

asymmetry: p-h excitation? N=64 subshell closure?

M. Hjorth-Jensen, ν(d5/2g7/2s1/2h11/2), eν = 1e

2003

Gap reduction vs. B(E2) increase !

Seniority fitSM e=1.0LSSM e=0.5

From N=Z 100Sn to N » Z 132Sn -- LSSM vs. SMTruncation level t : total number of ph excitations relative to valence configuration

B(E2;2+ → 0+) :SM: full neutron space (g7/2,d,s,h11/2), e=1.0 e ph missing !

LSSM: proton-neutron space(g,d,s), (g7/2,d,s,h11/2), t = 4 e=1.5 e, e=0.5 eph missing !Z=50 gap must be calculatedon the same footing !Z=50 shell gap :Extrapolation by quadratic fit• of precise data N ≥ 58 and• all data including 100Sn extrapolation

Sn chain: Enhanced Sn chain: Enhanced B(E2) systematics B(E2) systematics towards towards 100100SnSn

Shell Model: F. Nowacki et al., ν(d5/2g7/2s1/2h11/2), eν = 0.5e, π(g9/2g7/2d5/2d3/2s1/2), eπ = 1.5e

πν monopoles tuned toπESPEs and Z=50 shell gap

GSIRISING

P. Doornenbal et al., PRC(R) in print

A. Banu et al, PRC 72 061305(R) 2005

J. Cederkäll et al., PRL98, 172501(2007)

A. Ekström et al., PRL 101, 012502(2008)

C. Vaman et al., PRL 99, 162501(2007),

Enhanced collectivity Te-I-XeEnhanced collectivity Te-I-Xe B. Cederwall et al.B. Cederwall et al.

Importance of the isoscalar neutron-proton interactions Importance of the isoscalar neutron-proton interactions for the development of nuclear collectivityfor the development of nuclear collectivityB. HADINIA B. HADINIA et al.et al. PHYSICAL REVIEW C PHYSICAL REVIEW C 7272, 041303(R) (2005), 041303(R) (2005)

Same mechanism as in Sn isitopes?

Summary and conclusions ● Precision spectroscopy of exotic nuclei near 100Sn

→ tuning/extraction of effective NN interaction (mainly monopoles)

● "Pre"-mass shell gap determination by high-spin core excited isomers (98Cd-> gap in 100Sn)

•High spin isomeric (pure) core excited states may serve as SPE info?

•valence space corespondence principle for high spin states/isomers/beta decaying isomers (56Fe<->98Cd, ...) -> global interaction

•enchanced collectivity near closed shells

Collaboration:

A. Blazhev2, P. Boutachkov1, T. Brock3, N. Braun2, L. Caceres1, K. Eppinger4, T. Faestermann4, J. Gerl1, H. Grawe1, Ch. Hinke4, M. Hjorth-Jensen5

A. Jungclaus6, Z. Liu7, G. Martínez-Pinedo1, B.S. Nara Singh3, R. Krücken4,F. Nowacki8, S. Pietri1, M. Pfützner9, Zs. Podolyak10, P.H. Regan10,

D. Rudolph11, K. Sieja1, R. Wadsworth3, H.J. Wollersheim1 for the Rising collaboration

1GSI Darmstadt, Germany2IKP, University of Cologne, Germany

3Department of Physics, University of York, UK4Physics Department E12, TUM, Germany

5Oslo University, Norway6Universidad Aut´onoma de Madrid, Spain7University of Edinburgh, Edinburgh, UK

8 IPHC Strasbourg, France9IEP, University of Warsaw, Poland

10Department of Physics, University of Surrey, UK11Department of Physics, Lund University, Sweden