Development of slowed down Development of slowed down beams at GSIbeams at GSI

P.BoutachkovGSI

Physics objectives Proposed solution Test experiments Future

Test setup for slowed down beams at FRS

INTAG 2008

Obtain 5 MeV/u to 10 MeV/u RIB to be used for secondary reaction studies at FRS / Super FRS

Project objective

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RIB with sufficient luminosity for slow down experiments at S-FRS

INTAG 2008

Development of slowed down beams around the world

High-spin states in 48Ca, using 5 MeV/u 46Ar beam slowed from 30 MeV/u to 5 MeV/u

E. Ideguchi, et al. EPJA 25, 429 (2005)

Fusion enhancement with neutron-rich RIB,32,38S+181Ta, slowed from 9 MeV/u to ~ 4 MeV/u

K.E. Zyromski, et al. PRC 55, R562 (1997)

INTAG 2008

Slowed down beams project and FRS

Tracking

Track the trajectory of each particle before slowing down

Track the trajectory of each particle after slowing down

Identify the energy of each particle before the secondary target

109pps

TA1 S2

107pps 3x106pps 106 pps

S4 Deg. TA2

64Ni 62CoD1 D2 D3 D45MeV/u700MeV/u

62Co250250

MeV/uMeV/u

INTAG 2008

Simple binary reactions performed with white beam

Degrader

~ 5 MeV/u

, X,Y

Fragments

Thin target

, dE, E, X,Y

~ 250 MeV/u

Energy straggling Angular straggling

TOF[ns]

E [M

eV

/u]

12Be

Contaminants from reactions into the degrader

Event-by-event tracking

INTAG 2008

9Be(3/2-,T=3/2)+np

n

E = 14.4 MeV9Li(T=3/2)+p

10Be(T=2)

9Be(T=1/2)+n

1.57MeV

Study IAS of 10Li in 10Be and 13Be in 13B

12B(0+,T=2)+np n

E= 12.8 MeV

12Be(T=2)+p

13B(T=5/2)

12Be(T=1)+n

10Li: D.R. Tilley et al. NPA 745 (2004) 15513Be: H. Simon et al. NPA 791 (2007) 267

and Ref. in the papersINTAG 2008

Eb(d) Ep(Eb(d))p-RIB p

Ep(Eb)

Yield

RIB+p

Radioactive Ion Beams(RIBs) and the Thick Target Technique

K. P. Artemov, et at., Sov. J. Nucl. Phys., 52 (1990).

MSU, Apr 2008

Eb - Eb

Eb + Eb

Eb=Er

Ep(Er)p

Ep(Er)p

Eb=Er

Ep(Eb)

Yield

Simple binary reactions performed with white beam

TOF[ns]E

[Me

V/u

]

12BeE/E =1%T=150 ps, for L=1 m

E(E

b)

YieldR

IB+

p

INTAG 2008 Thin/thick target

dE, E, X,Y

Degrader

Fragments

~ 250 MeV/u

D5

80% of the 62Co nuclei “survived” the slow down

Contaminants from reactions into the degrader

The contaminants from secondary reactions are of the order of 10-3 compared to the fragment of interest

INTAG 2008

Angle after slowing down [mrad]

Angular straggling

20 mrad at a distance of 1.5 m 3 cm

10 Mev/u

FWHM(10 MeV/u) ~ FWHM(5 MeV/u) ~ 20 mrad

Cou

nts

INTAG 2008

Estimated upper limit for the Doppler shift due to energy+angular straggling

Scintillator, 100 micron dE/ E= 0.02

Diamond, 40 micron, no energy loss information dE/ E= 0.05

Si, 40 micron, 100ps time resolution, energy loss added backdE/ E= 0.017 (1% energy resolution)

Secondary Electron Detectors, 150 ps time resolutiondE/ E= 0.0075

E=10 MeV/u L=1.5 m

INTAG 2008

Test experiment at FRS

Objectives: Investigate the concept with a simple

setup Compare simulations to experimental

results

INTAG 2008

vacuum62Co 250 MeV/u

Al Degrader

2.7m flight in vacuum

SC42(100micron)

10 MeV/u

Si(300 m)

14 MeV/u SC41

62CoE

Si [

0.5

MeV

/ch

]

TOF(SC41-SC42) [1/40 ns/ch]

in: 5x5 cm2

TOF gate +/- 200 ps E=620 +/- 9 MeVN(62Co into the gate)/N(62Co before the degrader) ~ 10-2

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INTAG 2008

Experiment:E(FWHM) ~ 86 MeVBeam size before and after slow-downX(after)/X(before) = 2.0+/-0.3

Simulation:E(FWHM) ~ 17 MeVX(after)/X(before) = 1.7

64Ni, E(Si) gated on TOF for 10 MeV/uC

oun

ts

ESi [0.5 MeV/ch]EURORIB 2008

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Discrepancy in E(FWHM)

64Ni 14 MeV/u

SC42(100 m)

64Ni E1 = 10.1 MeV/u,E1(FWHM) = 4 MeV

64Ni 14 MeV/u

SC42(80 m)

64Ni E2 = 10.95 MeV/u,E2(FWHM) = 3.8 MeV

(E2-E1) x 64 = 51 MeV

INTAG 2008

MCP

4 x 6 cm, 1.5 m Mylar foilT(FWHM) ~ 140 psX(FWHM) ~ 3 mmXfr(FWHM) ~ 1.5 mm~ 85 %fr~ 100%

Electronics:Phillips 715 CFD: walk +/- 75 psCAEN V1290A TDC, Resolution 25 ps

X(FWHM) ~ 1 mmINTAG 2008

Si fast timing

Estimated time resolution T(FWHM) ~ 100 ps

DSSD: 40 m 5x5 cm2 16x16 strips

Coulomb scattering of 48Ca beam, 12.6 MeV/u at 20o

INTAG 2008

Coulomb excitation 64Ni, 62Co Sep-Oct 2008.

Tracking

Track the trajectory of each particle before slowing down

109pps

TA1 S2

107pps 3x106pps 106 pps

S4 Deg. TA2

64Ni 62CoD1 D2 D3 D45MeV/u700MeV/u

62Co250250

MeV/uMeV/u

INTAG 2008

TPC efficiency & resolutionTPC efficiency & resolution

spatial resolution: x-direction: ~ 0.1 mm y-direction: ~ 0.05 mm

Tested up to 300kHz with Xe beam(500MeV/u) efficiency > 98% up to ~104 Hz

C. Nociforo, A. Prochazka (GSI)

drift space = active volume (20cm x 6,8,10 cm)gas: P10 at atm. pressure

delay line read-out2 x-position measurements4 y-position measurements

Used for high-resolution momentum measurements (~ 1.5 ·10-4) in knockout reactions at the FRS

INTAG 2008

Coulomb excitation 64Ni, 62Co Sep-Oct 2008.

INTAG 2008

Col

limat

or

MCP2

5 MeV/u

E - E

Au- Target

MCP1

- detector

- detector

E

Conclusions

Slowed down beam experiment can be performed at FRS / S-FRS

The simulations are consistent with the data from the test experiment with 62Co

Fast pre-amplifiers for Si DSSD and MCP detector were built for the future slowed down setup

INTAG 2008

CollaborationCollaboration

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P.Boutachkov1, M.Górska1, J.Gerl1, H.Geissel1, I.Kojouharov1, W.Koenig1, C.Nociforo1, W.Prokopowicz1, H.Schaffner1, H.Weick1, N.Kondratiev2, J.Jolie3, F.Naqvi3, J.J.Valiente4, A.Gadea4, M.Alvarez5, I.Muha5 and the HISPEC/DESPEC collaboration

1.GSI, 2.JINR Dubna, 3. Köln , 4. LNL Italy, 5. Sevilla

INTAG 2008INTAGINTAG EXIDEXID