University of Cologne

Andreas Wendt

NUSTAR Annual Meeting

Darmstadt, 28.02.2013

• Isospin symmetry in the sd shell

• The Lund-York-Cologne-Calorimeter

• Analysis of the 33Ar Coulex-experiment

• Results and comparison to SM calculations

Isospin symmetry in the sd shell:

– Coulomb excitation of 33Ar –

and the new ‘Lund-York-Cologne-Calorimeter’

2221

ZNT

ZNtttT n

Isospin formalism

2/)( ZNTz

Proton und neutron: similar mass

and affected in similar way by nuclear interaction

D. D. Warner, M. A. Bentley und P. Van Isacker, Nature Phys. 2, 311 (2006).

tz(proton) = - ½

tz(neutron) = + ½

„nucleons“ in different states,

characterised by isospin t = ½.

1. Coulomb displacement energy

(shift of ground state)

2. Coulomb energy difference

between analogue exc. states

3. Isospin symmetry breaking (ISB)

effects of nucl. interaction

2+3 Mirror Energy Differences

Isospin symmetry

Mirror pair:

Nuclei with interchanged

proton and neutron numbers

e.g.

23

45

2222

45

23 TiV

M. A. Bentley et al., PRC 73, 024304 (2006)

Experimental data for sd shell nuclei

39Ca

37K

35Ar

33Cl

31S

29P

27Si

25Al

23Mg

21Na

19Ne

17F

38Ca

36K

34Ar

32Cl

30S

28P

26Si

24Al

22Mg

20Na

18Ne

37Ca

35K

33Ar

31Cl

27P

25Si

23Al

21Mg

19Na

36Ca

34K

32Ar

30Cl

28S

26P

24Si

22Al

20Mg

17O

39K

37Ar

35Cl

33S

31P

29Si

27Al

25Mg

23Na

21Ne

19F

18O

38Ar

36Cl

34S

32P

30Si

28Al

26Mg

24Na

22Ne

20F

19O

37Cl

35S

33P

31Si

29Al

27Mg

25Na

23Ne

21F

20O

36S

34P

32Si

30Al

28Mg

26Na

24Ne

22F

N

Z

23Si 22Si

21Al

25P

27S 26S

29Cl

31Ar 30Ar

35Ca 34Ca

33K

21O 22O 23O 24O 26O 27O 28O

23F 24F 25F 26F 27F 28F 29F

25Ne 26Ne 27Ne 28Ne 29Ne 30Ne

27Na 28Na 29Na 30Na 31Na

29Mg 30Mg 31Mg 32Mg

31Al 32Al 33Al

33Si 34Si

35P

29S

Energies / B(E2) known

Only energies known

No excited states known 16O

40Ca

38K

36Ar

34Cl

32S

30P

28Si

26Al

24Mg

22Na

20Ne

18F

Stable nuclei

N=Z nuclei

Excitation energies of Tz= -1 sd shell nuclei

16O

40Ca

38K

36Ar

34Cl

32S

30P

28Si

26Al

24Mg

22Na

20Ne

18F

39Ca

37K

35Ar

33Cl

31S

29P

27Si

25Al

23Mg

21Na

19Ne

17F

38Ca

36K

34Ar

32Cl

30S

28P

26Si

24Al

22Mg

20Na

18Ne

37Ca

35K

33Ar

31Cl

27P

25Si

23Al

21Mg

19Na

36Ca

34K

32Ar

30Cl

28S

26P

24Si

22Al

20Mg

17O

39K

37Ar

35Cl

33S

31P

29Si

27Al

25Mg

23Na

21Ne

19F

18O

38Ar

36Cl

34S

32P

30Si

28Al

26Mg

24Na

22Ne

20F

19O

37Cl

35S

33P

31Si

29Al

27Mg

25Na

23Ne

21F

20O

36S

34P

32Si

30Al

28Mg

26Na

24Ne

22F

N

Z

23Si 22Si

21Al

25P

27S 26S

29Cl

31Ar 30Ar

35Ca 34Ca

33K

21O 22O 23O 24O 26O 27O 28O

23F 24F 25F 26F 27F 28F 29F

25Ne 26Ne 27Ne 28Ne 29Ne 30Ne

27Na 28Na 29Na 30Na 31Na

29Mg 30Mg 31Mg 32Mg

31Al 32Al 33Al

33Si 34Si

35P

29S

Energies / B(E2) known

Only energies known

No excited states known

Known energies in

Tz = -1 nuclei

16O

40Ca

38K

36Ar

34Cl

32S

30P

28Si

26Al

24Mg

22Na

20Ne

18F

39Ca

37K

35Ar

33Cl

31S

29P

27Si

25Al

23Mg

21Na

19Ne

17F

38Ca

36K

34Ar

32Cl

30S

28P

26Si

24Al

22Mg

20Na

18Ne

37Ca

35K

33Ar

31Cl

27P

25Si

23Al

21Mg

19Na

36Ca

34K

32Ar

30Cl

28S

26P

24Si

22Al

20Mg

17O

39K

37Ar

35Cl

33S

31P

29Si

27Al

25Mg

23Na

21Ne

19F

18O

38Ar

36Cl

34S

32P

30Si

28Al

26Mg

24Na

22Ne

20F

19O

37Cl

35S

33P

31Si

29Al

27Mg

25Na

23Ne

21F

20O

36S

34P

32Si

30Al

28Mg

26Na

24Ne

22F

N

Z

23Si 22Si

21Al

25P

27S 26S

29Cl

31Ar 30Ar

35Ca 34Ca

33K

21O 22O 23O 24O 26O 27O 28O

23F 24F 25F 26F 27F 28F 29F

25Ne 26Ne 27Ne 28Ne 29Ne 30Ne

27Na 28Na 29Na 30Na 31Na

29Mg 30Mg 31Mg 32Mg

31Al 32Al 33Al

33Si 34Si

35P

29S

Excitation energies of Tz= -2 sd shell nuclei

Energies / B(E2) known

Only energies known

No excited states known

Known energies in

Tz = -2 nuclei

H. Schatz and K. Rehm

Nucl. Phys. A 777, 601 (2006)

24Si: H. Schatz et al., PRL 79, 203845 (1997)

28S, 32Ar: K. Yoneda et al., PRC 74, 021303 (2006)

36Ca: P. Doornenbal et al., PLB 647, 237 (2007)

20Mg: A. Gade et al., PRC 76, 024317 (2007)

MED for T=1,2 sd shell nuclei

USD*

‘Proton capture reaction rates in the rp-process’, H. Herndl et al., PRC 52, 1078 (1995)

A=24: H. Schatz et al., PRL 79, 3845 (1997)

A=28: K. Yoneda et al., PRC 74, 021303 (2006)

A=32: P. D. Cottle et al., PRL 88, 172502 (2002)

A=36: P. Doornenbal et al., PLB 647, 237 (2007)

Ad-hoc modifications:

Mass-dependent modifications

of SPE and TBME

Applicable for

T=3/2 mirror pairs?

B. A. Brown und B. H. Wildenthal,

Ann. Rev. Nucl. Part. Sci., 38, 29 (1988)

Y. Utsuno et al., PRC 60, 054315 (1999)

m USD1: USD* + exp. SPE

Violation of T-Symmetrie

H. Herndl et al., PRC 52, 1078 (1995)

USD*: USD + Coulomb WW

T-symmetric interaction

A=20: A. Gade et al., Phys. Rev. C 76, 024317 (2007)

16O

40Ca

38K

36Ar

34Cl

32S

30P

28Si

26Al

24Mg

22Na

20Ne

18F

39Ca

37K

35Ar

33Cl

31S

29P

27Si

25Al

23Mg

21Na

19Ne

17F

38Ca

36K

34Ar

32Cl

30S

28P

26Si

24Al

22Mg

20Na

18Ne

37Ca

35K

33Ar

31Cl

27P

23Al

21Mg

19Na

36Ca

34K

32Ar

30Cl

28S

26P

24Si

22Al

20Mg

17O

39K

37Ar

35Cl

33S

31P

29Si

27Al

25Mg

23Na

21Ne

19F

18O

38Ar

36Cl

34S

32P

30Si

28Al

26Mg

24Na

22Ne

20F

19O

37Cl

35S

33P

31Si

29Al

27Mg

25Na

23Ne

21F

20O

36S

34P

32Si

30Al

28Mg

26Na

24Ne

22F

N

Z

23Si 22Si

21Al

25P

27S 26S

29Cl

31Ar 30Ar

35Ca 34Ca

33K

21O 22O 23O 24O 26O 27O 28O

23F 24F 25F 26F 27F 28F 29F

25Ne 26Ne 27Ne 28Ne 29Ne 30Ne

27Na 28Na 29Na 30Na 31Na

29Mg 30Mg 31Mg 32Mg

31Al 32Al 33Al

33Si 34Si

35P

29S

25Si

Excitation energies of Tz= -3/2 sd shell nuclei

Energies / B(E2) known

Only energies known

No excited states known

Known energies in

Tz = -3/2 nuclei

Application on T=3/2 sd shell nuclei

R.R. Reynolds et al.

Phys. Rev. C 81, 067303(2010)

Next step: Measurement of 29S excitation energies with two-step-fragmentation: 36Ar→30S→29S+γ

PreSpec proposal: Jan. 2009

Next step: Investigation of transition strengths

B(E2) values for sd shell nuclei

16O

40Ca

38K

36Ar

34Cl

32S

30P

28Si

26Al

24Mg

22Na

20Ne

18F

39Ca

37K

35Ar

33Cl

31S

29P

27Si

25Al

23Mg

21Na

19Ne

17F

38Ca

36K

34Ar

32Cl

30S

28P

26Si

24Al

22Mg

20Na

18Ne

36Ca

34K

32Ar

30Cl

28S

26P

24Si

22Al

20Mg

17O

39K

37Ar

35Cl

33S

31P

29Si

27Al

25Mg

23Na

21Ne

19F

18O

38Ar

36Cl

34S

32P

30Si

28Al

26Mg

24Na

22Ne

20F

19O

37Cl

35S

33P

31Si

29Al

27Mg

25Na

23Ne

21F

20O

36S

34P

32Si

30Al

28Mg

26Na

24Ne

22F

N

Z

23Si 22Si

21Al

25P

27S 26S

29Cl

31Ar 30Ar

35Ca 34Ca

33K

21O 22O 23O 24O 26O 27O 28O

23F 24F 25F 26F 27F 28F 29F

25Ne 26Ne 27Ne 28Ne 29Ne 30Ne

27Na 28Na 29Na 30Na 31Na

29Mg 30Mg 31Mg 32Mg

31Al 32Al 33Al

33Si 34Si

35P

37Ca

35K

33Ar

31Cl

27P

25Si

23Al

21Mg

19Na

29S

Energies / B(E2) known

Only energies known

No excited states known

Known B(E2) values in

Tz = -3/2 nuclei

Tz= -3/2

SM calculations for B(E2) values of T=1,2 nuclei

Good agreement of all interactions for n-rich nuclei

p-rich nuclei: limited agreement, exp. very difficult

→ Comparison with T=3/2 nuclei

T=1 T=2

Blue: p-rich, Tz = -1, -2

Red: n-rich, Tz = +1, +2

Predictions from kockout differ: R. R. Reynolds et al., PRC 81, 067303 (2010).

Good agreement for n-rich nuclei

No exp. data for Tz= -3/2 nuclei

23T

21

23;2EB

Blue: p-rich, Tz = - 3/2

Red: n-rich, Tz = + 3/2

→ PreSpec experiment: Coulomb excitation of 25Si, 29S, 33Ar

SM calculations for B(E2) values of T=3/2 nuclei

21

25;2EB

S377 - Coulomb excitation of 33Ar

SIS – 36Ar, 450 MeV/u, 2·1010 ppspill

UNILAC 36Ar, 15 MeV/u

9Be 4 g/cm2

197Au 386 mg/cm2

Fragment Separator (FRS) 33Ar, 150 MeV/u, 30k ppspill

FRS id

33Ar

Target: Au

LYCCA

Tracked

ions from

FRS

EUROBALL

Cluster Array

Tracked ions

by LYCCA

Detected γ-rays

HECTOR

BaF2 Array

LYCCA – detection principle

RIB from FRS

Secondary

target

Time – of – flight

(ΔE, x, y) (E) (x, y)

Diamond

Plastic

scintillator

Plastic

scintillator

DSSD CsI

scintillators

DSSD

Event-by-event identification by

• Position → Tracking

• ΔE + TKE → Charge Q=Z

• ToF + TKE → Mass A

Needed for

• Doppler correction

• Selection of reaction channel

• Determination of scattering angle

LYCCA – detectors

DSSD

CsI

LYCCA – detector module

• Highest solid angle coverage

• Modularity

Observables

33,36Ar (135-145 AMeV) on 386 mg/cm² Au

→ γ-ray spectrum dominated by background radiation

FRS detectors • βFRS

• θ FRS, φFRS

• A/Q

• Z

LYCCA • ∆Etar

• Ttar

• DSSDtar muliplicity

• ∆Ewall

• ECsI

• θ LYCCA, φLYCCA

• βLYCCA

EUROBALL • Eγ

• Cluster multiplicity

• Crystal multiplicity

• T γ

• θ γ, φ γ

Gates: FRS A/Q

LYCCA ∆E-E

LYCCA ∆E- ∆E

βFRS - βLYCCA

βLYCCA - ECsI

∆Etar - Ttar

T γ

Crystal-Multiplicity

Optimization: • DSSDtar multiplicity

• Particle gate optimization

• Time gate optimization

• Add back

• Background subtraction

36Ar %19/VV

2+→0+: 1970 keV

Singles + add back 12% Optimized γ-spectra

3/2+→1/2+ 36Ar 33Ar 2+→0+

5/2+→1/2+

Vol: 179.9 (18.3)

10 %

low: 74.9 (13.0)

17.3 %

hi: 127.6 (18.1)

14.2 %

• Optimized particle gates

• Optimized Ge-time gates

• Multiplicity conditions

• Add back

• Background subtraktion Reduction of relative error

by approx. 50 %

33Ar 33P

Comparison with mirror nuclei

Observed

Not observed

Singles + add back 12% Calculation of B(E2) values

• Efficiency calibration of the PreSpec setup with known transition in 36Ar: 2+→0+

• Correction for different γ-ray energies

• Correction for different ion velocity (Lorenz boost and scattering angle)

• Application of known 33Ar branching ratio

• Considering of feeding into 36Ar 2+ state

Nucleus 36Ar 33Ar

Transition 2+→0+ 3/2+→1/2+ 5/2+→1/2+

Lit. Exp. Lit. Exp. Lit. Exp.

Energy [keV] 1970.38(5) 1970(3) 1359(2) 1360(3) 1798(2) 1804(6)

B(E2) [W.U.] 8.5(8) --- --- 6.39(1.49) --- 5.80(1.62)

5/2+→ 1/2+ 3/2+→ 1/2+

SM calculations for B(E2) values of T=3/2 nuclei

• First experimental value in sd shell

• Comparison with SM calculation

Tz= - 3/2 nuclei with unpaired proton: only weakly bound

• Outlook:

Confirmation with further experiments

(S377-II and 21Mg)

Extension to pf shell (no exp. values)

Outlook – further Tz= -3/2 investigations

(5/2)+→(1/2)+

21Mg

25Si

29S

Complementary measurements

with stable beams:

• 22Mg (Tz=-1)

• 35Ar (Tz=-1/2)

• 33P (Tz=+3/2)

Summary

• A final PreSpec result

• Transition strengths in 33Ar measured

• Comparison with SM calculation

Further experiments recommended: 21Mg, 25Si, 29S

University of Cologne

Andreas Wendt

NUSTAR Annual Meeting

Darmstadt, 28.02.2013

Supported by the German BMBF (06KY9136 TP7+TP1) and by the "Helmholtz Graduate School for Hadron and Ion Research.

KÖLN

Andrey Blashev

Norbert Braun

Kerstin Geibel

Matthias Hackstein

Kevin Moschner

Peter Reiter

Burkhard Siebeck

Andreas Wendt

Jan Jolie

GSI

Frederic Ameil

Jürgen Gerl

Hubert Grawe

Tobias Habermann

Robert Hoischen

Stephane Pietri

Hans-Jürgen Wollersheim

Ivan Kojouharov

Niklas Kurz

Henning Schaffner

YORK

Mike Bentley

Dan Bloor

Nara Singh Bondili

Lianne Scruton

MILANO

Angela Bracco

Franco Camera

Fabio Crespi

Bénédicte Million

Anabel Morales

Oliver Wieland

LUND

Joakim Cederkall

Douglas DiJulio

Jnaneswari Gellanki

Pavel Golubev

Dirk Rudolph

MADRID

Andrea Jungclaus

Jan Taprogge

VALENCIA

Alejandro Algora

SURREY

Michael Bowry

Zsolt Podolyak

RIKEN

Pieter Doornenbal

KRAKAU

Jerzy Grebosz

Padova

Silvia Lenzi

Francesco Recchia

LYCCA

A. Wendt, J. Taprogge, N. Braun, C. Goergen,

G. Pascovici, P. Reiter, S. Thiel

University of Cologne

P. Golubev, R. Hoischen,

D. Rudolph

Lund University

M. A. Bentley, N. S. Bondili,

L. Scruton

University of York

F.Schirru, A.Lohstroh

University of Surrey

S377

PreSpec collaboration &

NUSTAR simulation group

TU Darmstadt

Plamen Boutachkov

Giulia Guastalla

Edana Merchan

Norbert Pietralla

Damian Ralet

Michael Reese