R. Qiao

A New Uniform Calibration Method for Double-Sided Silicon Strip Detectors

We proposed and implemented a new uniform calibration approach for double-sided silicon strip detector, named the self-calibration method (SCM). This method uses the strips on one side of the detector as references, to calibrate the strips on the other side, and vice versa. This calibration method has the inherent advantages that it can be run during the experiment corresponding exactly to the required particle type and energy range, and provides good statistics based on flexible selection of the event samples. Two strategies based on the same working principle but with deferent complexities, named simple SCM and overall SCM, were introduced and examined experimentally. The simple SCM requires less computation but a large number of events, while the overall SCM exhibits excellent performance even with a relatively small number of events.

Knockout reaction induced by 6He at 82.3 MeV/u

A knockout reaction experiment was carried out using a 6He beam at 82.3 MeV/u impinged on carbon and hydrogen targets. The recoil protons were detected in coincidence with the forward moving charged fragments and neutrons. It is demonstrated that through the correlation between the recoil protons and forward moving charged fragments, the core fragment knockout and valence nucleon knockout reaction mechanisms can be discriminated at energies around 100 MeV/u. The 5He ground-state resonance was reconstructed based on the selection of the valence nucleon knockout mechanism. The resonance parameters were obtained for both carbon and hydrogen targets, which are consistent with those previously reported in the literature. The importance of selecting appropriate reaction mechanisms is discussed based on reconstructions using events with larger transverse momentum transfer.

8He cluster structure studied by recoil proton tagged knockout reaction

Knockout reaction experiment for 8He at 82.3 MeV/u on Hydrogen target was carried out at the RIPS beam line in RIKEN. Recoil protons were detected in coincidence with the forward moving core fragments and neutrons. The quasi-free knockout mechanism is identified through the polar angle correlation and checked by various kinematics conditions. The absolute differential cross sections for 6He core cluster are obtained and compared with the simple Glauber model calculations. The extracted spectroscopic factor is close to unity and a shrinking of the cluster size is evidenced.

Recoiled Proton Tagged Knockout Reaction for 8He

Recently recoiled proton tagged knockout reaction experiments were carried‐out for 8He at 82 MeV/nucleon. The purpose of the experiment are: (1) Through the core knocked out technique, to study the correlation of the valence neutrons in the ground state of 8He. This should provide new experimental information to the neutron coupling and neutron matter, including the BCS pairing and BEC pairing. (2) Through the valence neutron knocked out technique, to study the resonant states 7He and the related single particle states. This will be complementary to the previous similar measurement but with better selection of the reaction mechanism.Some new recoiled proton telescopes and the forward neutron spectrometer was applied in the experiment. Performance of the detection system and very preliminary experimental results are shown here.