M. Kurokawa

Coulomb Dissociation of B-8 and the Be-7(p, Gamma)b-8 Reaction At Low Energies

The cross section for Coulomb dissociation of [sup 8]B---the [sup 208]Pb([sup 8]B,[sup 7]Be [ital p])[sup 208]Pb reaction---was measured using a [sup 8]B radioactive beam of 46.5 MeV/nucleon energy, and the cross section for the [sup 7]Be([ital p],[gamma])[sup 8]B capture reaction was deduced at low energies; [ital E][sub c.m.]=0.6[minus]1.7 MeV. The extracted astrophysical [ital S][sub 17] factors were found to be consistent with the values measured by Vaughn [ital et] [ital al]. and Filippone [ital et] [ital al]. This result encourages further experimental studies extended to lower relative energies for a new determination of the [ital S][sub 17] value relevant to the [sup 8]B solar neutrino flux.

Radiation damage factor for ion-implanted silicon detectors irradiated with heavy ions

Ion-implanted silicon detectors were irradiated with 18-150 MeV /sup 16/O, 20 MeV /sup 40/Ar, and 53 MeV /sup 110/Xe. A linear increase of the leakage current was observed as a function of the particle fluence up to 2.2/spl times/10/sup 8/ cm/sup -2/. Extracted damage factors are proportional to the averaged nuclear stopping power over five orders of magnitude covering heavy ions studied in the present work and also protons of 25-800 MeV energies. >

Measurement of the 13N + 12,13C elastic scatterings

Abstract The 13 N + 12,13 C elastic scatterings have been measured at laboratory energies of 16.3, 20. and 29.5 MeV. It is shown that the 13 N + 12 C and 13 C + 12 C systems seem to comply with charge symmetry. A preliminary analysis of the 13 N + 13 C system reveals very interesting data which cannot be reproduced easily. First investigations are presented.

Development of an amplifier IC with wide dynamic range for Si detector in RIKEN SAMURAI spectrometer

A large acceptance and high magnetic rigidity spectrometer facility, SAMURAI is under construction at RlKEN. We plan to perform breakup reaction experiments that focus on the proton rich nuclei structure. The Si tracker needs to detect multiple nuclear fragments from the breakup reaction simultaneously. Atomic numbers of those fragments lie between 1 and 50. In the case of Sn breakup reaction, the energy deposition of fully stripped Z=50 fragment is 2500 times as large as that of Z=1 fragment. In order to realize such measurements, an amplifier with wide dynamic range of more than 2500 is required. Because it must operate under vacuum, it is necessary to minimize the amount of material. Therefore, we developed an amplifier IC which satisfies the requirements by implementing a square root gain response circuit.