First Nuclear Reaction Experiment withStored Radioactive 56Ni Beam andInternal Hydrogen and Helium Targets

FAIR

Peter Egelhof
GSI Darmstadt, Germanyfor the EXL Collaboration

2nd Conference on Advances in Radioactive Isotope ScienceARIS2014

Tokyo, Japan
June 2 – 6, 2014

First Nuclear Reaction Experiment withStored Radioactive 56Ni Beam andInternal Hydrogen and Helium Targets

I.

Introduction

II.

The EXL* Project – an Overview

III. Feasibility Studies and First Experiments with RIB`sat the ESR Storage Ring
IV. Future Perspectives
V.

Conclusions_______* EXL: Exotic Nuclei Studied in Light-Ion Induced Reactions at the NESR Storage Ring

I. Introduction: Direct Reactions with Radioactive Beams in
Inverse Kinematics
1H - target

classical method of nuclear spectroscopy:
 light ion induced direct reactions: (p,p), (p,p'), (d,p), ...
 to investigate exotic nuclei: inverse kinematics
 important information at low momentum transfer!
of particular interest: radial shape of nuclei: skin, halo structures
 doubly magic nuclei: 56Ni, 132Ni
 giant resonances: nuclear compressibility

future perspectives at FAIR:
 profit from intensity upgrade (up to 104 !!) explore new regions of the chart of nuclides
and new phenomena use new and powerful methods:
EXL: direct reactions at internal storage ring target high luminosity even for very low
momentum transfer measurements
First Experiments at the ESR

beam of exotic
nuclei AX

1H (AX, 1H) AXprotondetector

Nuclear Physics with Radioactive Beams at FAIR: NUSTAR:
NUclear STructure, Astrophysics and Reactions
I High intensity primary beams from SIS 100 (e.g. 1012 238U / sec at 1 GeV/u)
II Superconducting
large acceptance
Fragmentseparator
Optimized forefficient transportof fission products

SIS-100

III Three experimental areas

Experiments with Stored Exotic Nuclei

Collector Ring
Bunch rotation
Fast stochastic cooling

RIB(740 MeV/nucleon)

NESR
Electron coolingContinuous accumulation
Internal gas jet targets

RESR
Deceleration (1T/s) to 100 - 400 MeV/nucleon

II. The EXL Project: EXotic Nuclei Studied in Light-Ion
Induced Reactions at the NESR Storage Ring

Electroncooler

RIB‘s from theSuper-FRS

EXL

Detection systems for:
 Target recoils and gammas (p,α,n,γ) Forward ejectiles (p,n)
 Beam-like heavy ions

Design goals:
 Universality: applicable to a wide class of reactions
 High energy resolution and high angular resolution
 Large solid angle acceptance Specially dedicated for low q measurementswith high luminosity (> 1029 cm-2 s-1)

Light-Ion Induced Direct Reactions
at Low Momentum Transfer
 elastic scattering (p,p), (,), …
nuclear matter distribution  (r), skins, halo structures inelastic scattering (p,p’), (,’), …
deformation parameters, B(E2) values, transition densities, giant resonances
 transfer reactions (p,d), (p,t), (p, 3He), (d,p), …
single particle structure, spectroscopic factors, spectroscopy beyond the driplines,
neutron pair correlations, neutron (proton) capture cross sections
 charge exchange reactions (p,n), (3He,t), (d, 2He), …
Gamow-Teller strength knock-out reactions (p,2p), (p,pn), (p,p 4He)…
ground state configurations, nucleon momentum distributions
for almost all cases:

Speciality of EXL:

region of low momentum transfer
measurements at very low momentum transfer
contains most important information
 complementary to R3B !!!

Experiments to be Performed at Very Low Momentum Transfer –Some Selected Examples
 Investigation of Nuclear Matter Distributions:
 halo, skin structure probe in-medium interactions at extreme isospin (almost pure neutron matter) in combination with electron scattering ( ELISe project @ FAIR ):separate neutron/proton content of nuclear matter (deduce neutron skins )method: elastic proton scattering  at low q: high sensitivity to nuclear peripheryExperiments to be Performed at Very Low Momentum Transfer –Some Selected Examples
 Investigation of Nuclear Matter Distributions:
 halo, skin structure probe in-medium interactions at extreme isospin (almost pure neutron matter) in combination with electron scattering ( ELISe project @ FAIR ):separate neutron/proton content of nuclear matter (deduce neutron skins )method: elastic proton scattering  at low q: high sensitivity to nuclear periphery Investigation of the Giant Monopole Resonance:
 gives access to nuclear compressibility  key parameters of the EOS
 new collective modes (breathing mode of neutron skin)method: inelastic  scattering at low q

Experiments to be Performed at Very Low Momentum Transfer –Some Selected Examples
 Investigation of Nuclear Matter Distributions:
 halo, skin structure probe in-medium interactions at extreme isospin (almost pure neutron matter) in combination with electron scattering ( ELISe project @ FAIR ):separate neutron/proton content of nuclear matter (deduce neutron skins )method: elastic proton scattering  at low q: high sensitivity to nuclear periphery Investigation of the Giant Monopole Resonance:
 gives access to nuclear compressibility  key parameters of the EOS
 new collective modes (breathing mode of neutron skin)method: inelastic  scattering at low q

 Investigation of Gamow-Teller Transitions: weak interaction rates for N = Z waiting point nuclei in the rp-process electron capture rates in the presupernova evolution (core collaps)
method: (3He,t), (d,2He) charge exchange reactions at low q

Kinematical Conditions for Light-Ion Induced
Direct Reactions in Inverse Kinematics132

Sn(p, p)

E=740 MeV/u, E* = 0 MeV

18C(, )

E=400 MeV/u, E* = 0 MeV

18C(p, p')0CM = 20100

E=400 MeV/u, E* = 25 MeV

196

Pb(, ') E=400 MeV/u, E* = 15 MeV

196

3123Pb( He, t) E=400 MeV/u, E* = 0 MeV

Be( He, t) E=400 MeV/u, E* = 0 MeV

22C(p, d)• required targets: 1,2H, 3,4He

E=15 MeV/u, E* = 0 MeV

Erecoil (MeV)

132

Sn(d, p) E=15 MeV/u, E* = 0 MeV

1010

CM = 100

CM = 50

CM = 50

CM = 5EXL0

CM = 10.1(,‘)

204060

Points are: CM = 1, 5, 10 and 200(3He, t)

80

100120lab (deg)(p,p)

140160• required beam energies:
E  200 … 740 MeV/u(except for transfer reactions)• most important information inregion of low momentum transfer
 low recoil energies ofrecoil particles
 need thin targets for sufficientangular and energy resolution

Advantage of Storage Rings for
Direct Reactions in Inverse Kinematics

 low threshold and high resolution due to: beam cooling, thin target (1014-1015 cm-2)
 gain of luminosity due to: continuous beam accumulation and recirculation
 low background due to: pure, windowless 1,2H2, 3,4He, etc. targets
 experiments with isomeric beams

Experiments at very low momentum transfer can only be performed at EXL(except with active targets, but with substantial lower luminosity)

The EXL Recoil and Gamma Array

Si DSSD E, x, y
300 µm thick, spatial resolution
better than 500 µm in x and y,∆E = 30 keV (FWHM)
Thin Si DSSD
 tracking<100 µm thick, spatial resolution
better than 100 µm in x and y,∆E = 30 keV (FWHM)

Si(Li)
E
9 mm thick, large area
100 x 100 mm2,
∆E = 50 keV (FWHM)
CsI crystals
 E, High efficiency, high resolution, 20cm thickIII. Feasibility Studies andFirst Experiments with RIB`s at the ESR Storage Ring
specially designed scatteringchamber for the ESR:

reactions with 58Ni:
proof of principles and feasibility studies: UHV capability of detector setup
 background conditions in ESR environment
at the internal target
 low energy threshold beam and target performance

reactions with 56Ni:
56Ni: doubly magic nucleus!!

 (p,p) reactions: nuclear matter distribution (α,α`) reactions: giant resonances (GMR)
EOS parameters (nucl. compressibility) (3He,t) reactions: Gamow-Teller
matrix elements, important for astrophys.

Theorectical Predictions(p,p) on 56Ni
E = 400 MeV/u

4 days with L = 1025 cm-2 sec-1
recoil energies: 1 – 45 MeV(α,α`) on 56Ni
E = 200 MeV/u

14 days with L = 1025 cm-2 sec-1
recoil energies: 200 – 700 keV

needed: large solid angle detectors with low threshold and large dynamic range

Setup at the ESR Storage RingUHV Capability of the EXL Silicon Array:
Concept: using DSSD`s as high vacuum barrier• Differential pumping proposed to separate (N)ESR vacuum
from EXL instrumentation (cabling, FEE, other detectors)
Space for other DSSDs, Si(Li), FEE
and cabling

Inner shell of DSSDs on support frameforms (bakeable) vacuum barrier
B. Streicher et al., Nucl. Instr. Meth. A654 (2011) 604

Experimental ConceptExperimental Concept

Si(Li)
1st DSSD& Si(Li)s

DSSD

●

●

●

●targetDSSD: 128×64 strips,(6×6) cm², 285 µm thickapertureSi(Li): 8 pads, (8×4) cm²,6.5 mm thickactive vacuum barrier
moveable aperture toimprove angular resolution

2nd DSSDbeamExperimental Concept for the E105 Experiment

Experimental Setup at the ESR

Scattering Chamber mounted
at the Internal Target of the ESR

challenge:
UHV capable and bakeable
DSSD and Si(Li) detectors

Preparation of the Stored Radioactive 56Ni Beam

FRS: In-Flight Separator & High-Resolution Spectrometer
ALADINPRODUCTION TARGET

SIS
SIS

LAND

Secondary Beam Branches

FRS

ESR
EXL prototype setup
Direct Reactions with stored RIB`sINJECTIONFROM UNILAC

Preparation of the Stored Radioactive 56Ni Beam

FRS:

fragmentation of 600 MeV/u 58Ni beam

injection to ESR:

7 x 104 56 Ni per injection

stochastic cooling, bunching and stacking (60 injections):
4.8 x 106 56Ni in the ringluminosity:

H2 target: 2 x 1013 cm-2
 L = 2 x 1026 cm-2 sec-1(reduced by aperture)First Results with Radioactive Beam

25. 10. 2012:
First Nuclear Reaction
Experiment with Stored
Radioactive Beam!!!!

56Ni (p,p)

E = 400 MeV/u

QLab = 72°

....

88°

First Results with Radioactive Beam
56Ni(p,p), E = 400 MeV/u

Response of Individual Detectors

2nd Si(Li)

1st Si(Li)

DSSD

beam
targetFirst Results with Radioactive Beam
56Ni(p,p), E = 400 MeV/u

Reconstructed Energy

2nd Si(Li)1st Si(Li)DSSD

beamtarget

First Results with Radioactive Beam
56Ni(p,p), E = 400 MeV/u

Benefit of the 1mm Aperture

2nd Si(Li)

1st Si(Li)DSSD

beamtarget

First Results with Radioactive Beam
56Ni(p,p`), E = 400 MeV/u

Identification of Inelastic Scattering

56Ni (p,p)

56Ni (p,p`)

1. excited state at 2.7 MeV

First Results with Radioactive Beam
56Ni(p,p), E = 400 MeV/u

Angular Distribution

First Results with Radioactive Beam
56Ni(p,p), E = 400 MeV/u

Angular Distribution (raw data!)

M. von Schmid et al., to be publishedInvestigation of the Giant Monopole Resonance in 58Ni

reaction: 58Ni on He target
energy:100 MeV/utarget:8 X 1012 /cm3

storedbeam

detectors: DSSDQLab = 27° - 38°

recoilscatteredbeam

Investigation of the Giant Monopole Resonance in 58Ni
58Ni(α,α`), E = 100 MeV/uchallenge: detect and identify very low energy recoils

Investigation of the Giant Monopole Resonance in 58Ni
58Ni(α,α`), E = 100 MeV/u, Θlab = 37 deg

Investigation of the Giant Monopole Resonance in 58Ni
58Ni(α,α`), E = 100 MeV/u, ΘISGMR

lab =37 deg

Investigation of the Giant Monopole Resonance in 58Ni
comparison with theoretical prediction:

datapreliminary

ISGMR

J. C. Zamora et al., to be publisheddata down toΘcm < 1 deg !

Future Perspectives
short term perspectives:
 (α,α`) on 56Ni  investigate ISGMR and ISGDR investigate the compressibility of nuclear matterFuture Perspectives
short term perspectives:
 (α,α`) on 56Ni  investigate ISGMR and ISGDR
needs upgrade of detector setupand readout (ASICS)

 (3He,t) on 56Ni  investigate Gamow – Teller strengthneeds upgrade of internal target transfer reactions at Cryring (GSI) and TSR@ISOLDE (CERN)

Future Perspectives
long term perspectives (EXL @ FAIR): for first phase of FAIR:
transfer line from SUPER-FRS / CR to the ESR

ESR

 very recently:
task force established

The E105 Collaboration

S. Bagachi1, S. Bönig2, M. Castlós3, I. Dillmann4, C. Dimopoulou4, P. Egelhof4, V. Eremin5,H. Geissel4, R. Gernhäuser6, M.N. Harakeh1, A.-L. Hartig2, S. Ilieva2, N. Kalantar-Nayestanaki1,O. Kiselev4, H. Kollmus4, C. Kozhuharov4, A. Krasznahorkay3, T. Kröll2, M. Kuilman1, S. Litvinov4,Yu.A. Litvinov4, M. Mahjour-Shafiei1, M. Mutterer4, D. Nagae8, M.A. Najafi1, C. Nociforo4,F. Nolden4, U. Popp4, C. Rigollet1, S. Roy1, C. Scheidenberger4, M. von Schmid2, M. Steck4,B. Streicher2,4, L. Stuhl3, M. Takechi4, M. Thürauf2, T. Uesaka9, H. Weick4, J.S. Winfield4,D. Winters4, P.J. Woods10, T. Yamaguchi11, K. Yue4,7, J.C. Zamora2, J. Zenihiro9
1 KVI, Groningen

7 Institute of Modern Physics, Lanzhou

2 Technische Universität Darmstadt

8 University of Tsukuba

3 ATOMKI, Debrecen

9 RIKEN Nishina Center

4 GSI, Darmstadt

10 The University of Edinburgh

5 Ioffe Physico-Technical Institute, St.Petersburg

11 Saitama University

6 Technische Universität München

V. Conclusions

 For the First Time (World Wide) a Nuclear Reaction Experiment withStored Radioactive Beams was successfully performed.
 A “Proof of Principle” of the Experimental Concept with UHV capable
Detectors and Infrastructure around the Internal Target was successful.
 A number of Important Physics Questions can be only addressed with
the EXL Technique which is up to date World Wide unique.

 EXL@ESR and EXL@FAIR has a large Potential for Nuclear Structure
and Nuclear Astrophysics.