experiments with polarized beams at isolde dimiter l. balabanski, inrne

May 7th, 2010 R-ECFA meeting, Sofia 1

Experiments with polarized beams at ISOLDE

Dimiter L. Balabanski, INRNE

• the Bulgarian involvement at ISOLDE • alignment and polarization of exotic nuclei• collinear laser spectroscopy @ ISOLDE

• alignment of isomers in transfer reactions• tilted-foil polarization of exotic post-accelerated beams

• overlap with the ESFRI Spiral2 project• on the road to the EURISOL facility


The Bulgarian participation at ISOLDE

1. Bulgaria is not a member of ISOLDE! 2. The participation in the experiments is based on personal

contacts and is financed by individual research grants. 3. Bulgarians at ISOLDE

• early 1990s Prof. Krasimira Marinova – COLLAPS experiments in collaboration with Univ. Mainz

• early 2000s Prof. Balabanski – COLLAPS and REX-ISOLDE experiments in collaboration with Univ. Leuven

• 2005 – 2006 Dr. Georgi Georgiev – CERN fellow• since 2009 Dr. Deyan Yordanov – CERN fellow

4. FP6 EWON report (within EURONS) reporting on Bulgarian activities at ERI submitted to EC

5. in 2010 four experiments at ISOLDE with Bulgarian participation


Nuclear moment measurements

magnetic moment () quadrupole moment (Q)

single-particle configuration (configuration mixing)

collective properties(deformation, effective charges)

Spin-orientedbeams


Spin-oriented beams

some definitions

m-2 –1 0 +1 +2

spin-alignment

m-2 –1 0 +1 +2

spin-polarization


classical view quantum-mechanical view

Pop

ula

tion

I = 2

E

m =2m =1

m =0m =-1

m =-2

I=2 ensemble

Necessary to induce polarization of the beam prior the measurement

ISOL beamsISOLDE – CERN SPIRAL2


Part III: Halo nuclei

The Li chain

Why is 11Li so big?



The COLLAPS beam line at ISOLDE

know how: Univ. Mainz



Quadrupole moments of Li isotopes: 11Li vs 9Li(U. Leuven – U. Mainz experiment) 9Li 11Li

scan = RF – L,fix (kHz)

1992

LiNbO33 LiNbO3

ASYMMETRY (%)

2003

-.4

0

.4

.8

10 15 20

0 15 20 25(b) Li

-8.0

-7.0

-6.0

-5.0

-4.0

10 15 20 25

ZnZn

scan = RF – L,fix (kHz)

2004

0,050

0 ,052

0 ,054

0 ,056

0 ,058

0 ,060

0 ,062

0 ,064 9 Li

Asy

mm

etry

10 12 14 16 18 20 22

0 ,030

0 ,035

0 ,040

0 ,045

0 ,050

0 ,055

0 ,060

0 ,065

0 ,070

0 ,075

0 ,080 11 Li

Asy

mm

etr

y

scan

[kH z]

10 16 22

ASYMMETRY (%)

5.2

5.8

6.0

6.2

5.6

5.4

5.0

0,050

0 ,052

0 ,054

0 ,056

0 ,058

0 ,060

0 ,062

0 ,064 9 Li

Asy

mm

etry

10 12 14 16 18 20 22

0 ,030

0 ,035

0 ,040

0 ,045

0 ,050

0 ,055

0 ,060

0 ,065

0 ,070

0 ,075

0 ,080 11 Li

Asy

mm

etry

scan

[kH z] 10 16 22

ZnZn7.0

5.0

4.0

6.0

Q(11Li)Q(9Li) = 1.090(14)

Quadrupole Splitting

15,5

16

16,5

17

17,5

18

0 2 4 6 8 10Measurement nr.

(9

,11 L

i)9Li

11Li



Did we learn something from the Li chain ?

We think: YES

• A precision measurement of the electric quadrupole moments of 9,11Li reflects the charge distribution in these nuclei. The quadrupole moment of 11Li is found 9 ± 1% larger than that of 9Li.

• This small difference supports the interpretation of the two-neutron halo.

• The small but significant difference between both moments is a first direct proof that correlations between the halo and the core exist.

D. Borremans, D.L. Balabanski, K. Blaum, W. Geithner, S. Gheysen, P. Himpe, M. Kowalska, J. Lassen, P. Lievens, S. Mallion, R. Neugart, G. Neyens, N. Vermeulen, and D. Yordanov


Can we measure nuclear static moments with post-accelerated

ISOL beams ?


REX - ISOLDE @ CERN

REX - ISOLDE


Why transfer reactions ?

98Mo 99Mo

100Tc

100Mo 101Mo

102Tc

63Cu 64Cu

65Zn

65Cu 66Cu

67ZnP P

• populate low-spin (single-particle) states• go a step further in the Nuclear Terra Exotica

Principle investigators: Georgi Georiev (Orsay) and DLB (Sofia)

Part IV: The future: Transfer reactions with RIBs


The 63m,65mNi experiment (I = 9/2+)

(d,p) reactions

Tandem at IPN-Orsay

• pulsed 6 MeV 1 nA D beam

• enriched 64Ni/62Ni (ferromagnetic)

targets

• known g(63mNi) = - 0.269(3)Muller et al. PR B40, 7633 (1989)

• HF field of Ni(Ni) = 6.90(5) TRiedi et al. PR B15, 5197 (1977)



63mNi 65mNi

gexp. = -0.296 (3)

G. Georgiev et al, J.Phys.(London) G31, S1439 (2005)

Ni exp.2004

Bg N

L

Larmor frequency

)}(2cos{4

3

),2(),(

),2(),()(

22

22

tBA

BA

tItI

tItItR L

HF field Ni(Ni) = 6.90(2) T

Experimental results

~ 15% alignment in transfer reactions at the Coulomb barrier (3 MeV/u)



Polarized beams at HIE-ISOLDE – from dreams to reality

G. Georgiev1, M. Hass2, A. Herlert3, D.L. Balabanski4, L. Hemmingsen5, K. Johnston3, M. Lindroos3, K. Riisager6, J. Van de Walle3, D. Voulot3, F. Wenander3, W.-D. Zeitz7

1. CSNSM, Orsay, France; 2. The Weizmann Institute, Rehovot, Israel; 3. ISOLDE, CERN, Geneva, Switzerland; 4. INRNE, BAS, Sofia, Bulgaria; 5. IGM, LIFE, University of Copenhagen, Denmark; 6. Department of Physics and

Astronomy, University of Aarhus, Denmark; 7. Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Germany

Polarized beams – WHY?

p

dd

pdd

dd

dd

Ay

Precise test of the nuclear models for exotic nuclei: • transfer reactions(analyzing power)• Coulomb excitation – spin/parity;multiplicity assignments etc.• nuclear moments – proton/neutron character, angular momentum j

21 j


Can one do it and how?

M. Hass et al., NPA 414, 316 (84)

Tilted Foils - the principles: • atomic polarization nuclear polarization• higher nuclear spins higher polarization (>10% achieved so far)• strong velocity dependence (poorly studied up to now)

•Can one post-accelerate the ions after polarizing them?done for stable beams - noble-gas like charge states + LINAC J. Bendahan et al., ZPA 331, 343 (88)


- unique opportunity

What do we need to achieve it?

-NMR setup from HMI Berlin transferred to ISOLDE

• gain of complete control on the TF polarization

• nuclear structure (moments, reactions …),

nuclear methods in the solid-state physics,

biophysics etc. …

3 MeV/u and 0.3 MeV/u


SPIRAL 2

SPIRAL2 is a new European facility to be built at GANIL laboratory in Caen, France. The project aims at delivering stable and rare isotope beams with intensities not yet available with present machines. SPIRAL2 will reinforce the European leadership in the field of nuclear physics based on exotic nuclei.

The scientific programme proposes the investigation of the most challenging nuclear and astrophysics questions aiming at deeper understanding of the nature of matter.


The SPIRAL 2 project


SPIRAL2 EFFORT

MoU between GANIL and INRNE, BAS

• participation in the Spiral2PP project (FP7 Infrastructures);

• production of prototypes for the superconducting LINAC;

• participation in the construction of the PARIS spectrometer;

• declared interest in the Spiral2 scientific programme.


EURISOL: The Main Challenges

• Design a 5MW; 1GeV proton driver with additional capability of 200 AMeV deuterons and A/Q=2 Heavy Ions; build and test prototypes of the cavities.

• Design a liquid Hg converter which will accept 5 MW of beam power.

• Design a UCx target which will make the most efficient use of the neutrons produced.

• Evaluate the safety constraints of the above set up.• Design an efficient multi-user beam distribution system.• Design a superconducting HI LINAC capable of accelerating 132Sn

up to 150 AMeV• Investigate technologies for the instrumentation of the future• Provide a conceptual study for a beta-beam neutrino facility.


EURISOL layout

experiments with polarized beams at isolde dimiter l. balabanski, inrne

Documents

ribsrecfa meeting

sofiarecfa meeting

definitionsrecfa meeting

yordanovrecfa meeting

mainzrecfa meeting

rexisolde experiments

sofiarex isolde

member of isolde