Rare ISotope INvestigation at GSI Status of the relativistic beam campaign Introduction Fast beam physics program Experimental methods Status and perspectives.

Rare ISotope INvestigation at GSI Status of the relativistic beam campaign

Introduction

Fast beam physics program

Experimental methods

Status and perspectives

P. Reiter for the RISING collaboration

Workshop: RISING with stopped beams

University of Surrey, March 29 – 30, 2004

RISING introduction

• RISING physics with stopped beams, March 29/30, 2004 Surrey

• GSI Program Advisory Committee January 26/27, 2004 Darmstadt 4 RISING proposals

• Commissioning & first experiments August-October 2003

• GSI Program Advisory Committee June 20/21, 2002 Darmstadt 12 RISING proposals

• Physics with RISING at GSI, March 22, 2002 Orsay • RISING physics with relativistic HI-beams, April 6, 2001 Darmstadt• RISING physics with stopped beams, March 9, 2001 Göttingen• RISING physics with slowed-down beams, April 2/3, 2001 Legnaro• Physics with EUROBALL detectors at GSI, November 23/24, 2000 Darmstadt

High resolution -spectroscopy at the FRS

RISING

• fragmentation and fission of primary beams

• projectile energy 400 – 750 MeV/u

• primary targets: Be or Pb

• Dipoles:

• Identification of fragmentation product (A,Z)

-spectroscopy at secondary target• Channel selection after target (A,Z)

• Tracking before/after secondary target

FRS

RISING approved experimentsNo. Nuclei of Interest

Primary Beam

Spokespersons Experiment Typeapproved

(days)

1 32,34Mg 48Ca P. Mayet2 step fragmentation

lifetime6

2 45Cr, 53Ni, 45Sc, 53Mn 58Ni M. Bentley 2 step fragmentation 7

3 68Ni 86Kr A. Bracco Coulex, E1 strength 7

4 36Ca, 66Fe 86KrH. Grawe,H. Hübel

P. ReiterCoulex, 2+

1 13

5 69Br 78Kr F. Becker 2 step fragmentation 7

6 88Kr, 90Sr, 86Se 238U J. Jolie Coulex, 2+2 10

7 104-112Sn 124XeC. Fahlander

M. GórskaCoulex , 2+

1 7

8 132Sn 238U G. de Angelis Knock-out 5

9 132Xe 136Xe A. Maj Coulex, Angular Distr. 3

10 134Te 136Xe K.-H. Speidel Coulex, g-factor 7

11 136Nd 144Sm T. Saito Coulex 7

12 185,186,187Pb 238UJ. Gerl, A. Andreyev

G.D. Dracoulis2 step fragmentation

lifetime8

Physics program

66Fe

53Ni

32,34Mg

104-112Sn

68Ni

134Te

132Sn

Shell structure of unstable magic- and double magic nuclei

Isospin symmetry at N=Z

50Fe

50Mn

50Cr

46V

46Cr

46Ti

53Co

49Fe

45Cr

53Fe

55Ni

55Co

45V

45Ti43Ti

43Sc

41Ca

41Sc

53Ni

45Sc

42Ti

42Sc

42Ca

f7/2-shell

T= 1/2

T= 1

T=3/2 no excited states

45Cr, 49Fe, 53Ni 69Br

?

Shapes and shape coexistence

2+

3+

185,186,187Pb136Nd

potential energy surface for 186Pb

-decay of the GDR in the Exotic Nucleus 68Ni

• Giant Dipole Resonance (GDR) : basic collective excitation modes

• effective NN interactions

• Evolution of GDR strength in exotic nuclei : • Fine structures • GDR strength at lower energy• astrophysical implications

RISING: relativistic Coulomb excitation (virtual photon scattering) -decay branch: tot ~ 10-3 - 10-2

Relativistic RPA, Vretenar et al.

68Ni 78Ni

58Ni48Ni

experimental methods

Established methods:

• Coulomb excitation - first 2+ states => B(E2) - giant dipole resonance (virtual photon absorption)

• Secondary fragmentation - excited states at higher

spins and excitation energy

RISING new developmentsCoulomb excitation - Low lying states B(E1), B(E2, 0+

gs -> 2+1,2,3)

- 2+ states + angular correlation- 2+ states + g-factor

-decay of the GDR in the Exotic Nucleus 68Ni Excited via Coulomb Excitation-decay of the GDR in the Exotic Nucleus 68Ni

reaction68Ni (400 MeV/A) + natPb (2 g/cm2)

BaF2 for the whole GDR strength function

Ge cluster for the Pygmy part

HECTOR

6 BaF2 detectors efficiency at high energies:

knock-out reactions

Spectroscopic factors: -ray intensity of excited states in the A-1 fragment.

No l-value of ejected nucleon, missing momentum distribution.

Recoil

momentum

-decay of

excited states

132Sn

Shape evolution in n-rich Mg nuclei

Primarybeam : 48Ca

Secondarybeam : 38Si

SIS FRS S4

Secondary fragmentation& lifetime measurement

targets:Au : 3 x 0.3 g/cm2

0.7 mm 2.1 mm

38Si 100 MeV/u

E

2

32Mg , 2

E2

1

32Mg , 1

E1

3

32Mg , 3

E3

RISING timetable 2003

22.4.- 16.5.2003 Cluster shipment

22.4.- 4.8.2003 annealing, assembly, testing and mounting

16.6.- 20.6.2003 assembly of support structure

14.7.- 5.8.2003 VXI-MBS tests (S4)

beam time• Commissioning I• Commissioning II• New Shell Structure at N>>Z • Isospin Symmetry, Coulomb Effects• Coulomb Excitation Near 100Sn

beam132Xe84Kr84Kr58Ni

124Xe

date

Aug 06 – Aug 11

Sep 12 – Sep 21

Sep 22 – Sep 28

Oct 11 - Oct 20

Oct 21 - Oct 27

short term outlook

2004Block 2/2004:    March 31 - May 21(Therapy:          March 31 - April 30)RISING: May 1 – 18 - E1 strength in 68Ni RISING & HECTOR - Shell structure in N>>Z nuclei

Block 3/2004:    July 14 - October 7(Therapy:          July 14  - August 13)

Block 4/2004:    Oct. 27 – Dec. 16(Therapy:          Oct. 27 – Nov. 26)RISING: Nov. 29 – Dec. 12 RISING & MINIBALL

2005 Winter: RISING & MINIBALL

Increased -efficiency: 4 - 10 %

SIS beam time is shared between:• HADES• FRS & ESR mass measurements• RISING

RISING & MINIBALL

Summary

RISING fast beam campaign

- started data taking on time in 2003

First experiments

- Coulomb excitation of stable 84Kr (commissioning)

- Coulomb excitation of fragments: 56Cr,108Sn,112Sn

- Spectroscopy after secondary fragmentation of 55Ni

see talks: N. Hashimoto, M. Gorska, A. Bürger, M. Bentley