1. Coincidence measurement of heavy ion and protons with SAMURAI
I would like to report the present status of the development for the coincidence measurement of HI and protons with SAMURAI
Y. Togano, K. Yoneda
RIKEN Nishina Center

2. Invariant mass spectroscopy of proton-rich nucleiAZ
(A+1)(Z+1)*
(A+1)(Z+1) p
Incident beam
AZ + p
In the proton breakup reaction the determination of the momentums of the reaction products is important for the reconstraction of the Invariant mass.
A+1Z+1
target
AZ and beam velocity
Determine momentum in coincidence
 Invariant Mass M
 Excitation Energy

3. HI-proton coincidence exps in early phase
Nuclear Astrophysics
rp-process, p-process
56Ni(p,g)57Cu, 64Ge(p,g)65As, 68Se(2p,g)70Kr,
100Sn(p,g)101Sb, …
2p decay
　17Ne, 20Mg, 22Si,…
Presentation tomorrow by Trache, Iwasa, and Togano

4. Large Acceptance Mode high resolution mode For the first experiment
PI, momentum of Heavy ion
PI, momentum of proton(s)
Larger geometrical acceptance with weaker magnetic field (~half 3T)
Beam go through the hole at the york  smaller geometrical acceptance

5. Setup using SAMURAI Heavy Ion Proton For the invariant mass
DC + plastic (+ IC)
Proton
2 DC + plastic
For the invariant mass
Opening angle of H.I. – p
Si detector before the magnet
Several mrad order
Strip Si detector
This is the experimental setup using the SAMURAI spectrometer. Magnet is rotated by 45 degrees. Heavy Ions are measured using these systems, with DC+ plastic or DC+ plastic+IC. Protons are measured using 2CRDCs + plastic achieving the momentum resolution of 1/600. For better resolution of the invariant mass of the scattered particle, we introduced the Si detectors infront of the magnet. This detectors improve the resolution of the opening angle between the breakup fragments, H.I. and proton. Several mrad resolution is desired to achieve good resolution, so we will use the Si detectors with fine strip pith.
Pb target

6. GLAST Si Single sided strip Si detector Size: 89.5 x 89.5 x 0.3 mm3
Number of strips: 384  128
Strip pitch: mm  mm
Full depletion voltage: 90~95 V

7. PCB design and bonding pattern for Si detector
Outer dimensions = 146 mm × 146 mm
Connectors made by KEL
(USL0040L) for ultrafine coaxial cable
0.4 mm pitch
Capacitors to suppress cross talk
through rear side < 1 / 10^4 = 0.01% Si
89.5 mm × 89.5mm C1 R1 3 5 1 6
stip1
Stip2
Stip3 :
stip384
stip383
enlarged view
Symmetric layout with upper side
Will be ready in May

8. Saturation suppressor
RIKEN Dual Gain C.S.P.
New ASIC type C.S.A.
Capacitive division: 1input  2outputs
High gain side circuit with saturation suppressor
Prototype have been tested
We develop the new ASIC type CSA, so called RIKEN Dual Gain C.S.P. (RIKEN DGCSP) This amp uses the capacitive division technique, so 1 input outputs two signals. One is high gain side for proton, low gain side for heavy ion. High gain side have the saturation avoiding circuit. The proto type have been fabricated, and we confirmed that ten thousand difference of the dE/dx can be measured using this circuit. This figure shows the input charge dependence of the output voltage of the DGCSP. Blue curve is for high gain side, red curve is low gain side. High gain side almost covers 0.1 MeV to 10 MeV, and low gain side covers 10 to 1000 MeV, so we measure times difference.
RIKEN DGCSP
Next presentation
Saturation suppressor
Inside of vacuum
HINP16C
Air
Chigh
S.A.
high gain -A
Clow -A
S.A.
low gain

9. Result: Dynamic range for dual channel CSAs
pulser
560 pF
SA-HG
ADC-H-H
CSA
SA-LG
ADC-H-L
Dynamic range ~ 10^4
10 times wider than that is obtained
for the single channel usage
CSA
56 pF
SA-LG
ADC-L-L
104
103
102
ADC-H-H
101
ADC-H-L
56 pc
ADC-L-L
5.8 fc
100
10-3
10-2
10-1
100
101
102
Definition of lower limit = 4s

10. Other option C.S.A. with sqrt compression 1input  1output
Size of C.S.A. is large
Ein [MeV]
Other option is the C.S.A with the sqrt compression. The response of the CSA is like this sqrt shape. CSA and sqrt compressor locate inside of the vacuum chamber. and HINP locates at the outside of chamber, and process the signals as a shaping amp. This circuit have poor resolution of the dE/dx, but number of output is less compared with the DGCSP.
Inside of vacuum
HINP16C
Sqrt
compression
Air
CSA -A
S.A.

11. Schedule & budget status
Assuming we have experiments from 2013
Bonding of GLAST Si to PCB board: ~May 2011
Dual Gain CSP: Mass production in 2011 or 2012
With Kakenhi ?
New preamp prepared later ?
2p setup sometime later ?
Electronics for DC must be modified

12. Summary
The detectors for the coincidence measurement of heavy ion and protons with SAMURAI is under development.
Fabrication of PCBs for Si detectors and the bonding will be finished by May 2011.
Development of new CSAs
Dual Gain C.S.P.: achieve dynamic range of ~104
CSA with sqrt compressor: proto type have been fabricated
First experiment  2013