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