Development of a gamma-ray tracking detector and its performance test

The gamma-ray tracking detector is a germanium detector realizing both high efficiency and Compton background suppression by reconstructing the scattering process of the incident gamma-rays from the positions and energy deposits of the gamma-rays at each interaction points in the detector. Its high position resolution is also beneficial for accurate Doppler correction. In the tracking detector, the interaction positions are determined three-dimensionally with high position resolution by analyzing the signal waveform from the segmented electrodes. We have measured waveforms for different interaction points of gamma-rays using a GRETINA Quad Detector. The experiment was performed using a gamma-ray beam from the GACKO beam line at the NewSUBARU electron storage ring facility. The three dimensional position of the interaction in points are selected first by collimating the incident gamma-rays and then by measuring the gamma-rays scatted at 90 degree in the detector by using a narrow slit. Obtained waveforms were compared with the simulated waveform.5th Joint Meeting of the APS Division of Nuclear Physics and the Physical Society of Japa

New insights into the resonance states of 5H and 5He

The 5H system was produced in the 3H(t, p) 5H reaction studied at small CM angles with a 58MeV tritium ion beam. High statistics data were used to reconstruct the energy and angular correlations between the 5H decay fragments. A broad structure in the 5H missing-mass spectrum showing up above 2.5MeV was identified as a mixture of the 3/2+ and 5/2+ states. The data also present an evidence that the 1/2+ ground state of 5H is located at about 2MeV. Then, the 5H and 5He systems were explored by means of transfer reactions occurring in the interactions of 132MeV 6He beam nuclei with deuterium. In the 2H( 6He, 3H) reaction a T = 3/2 isobaric analog state of 5H in 5He was observed at an excitation energy of 22.0±0.3MeV with a width of 2.5±0.3MeV. © Società Italiana di Fisica / Springer-Verlag 2005.SCOPUS: cp.jinfo:eu-repo/semantics/publishe

Correlation studies of the H5 spectrum

The nuclear system H5 was studied using the H3(t,p)H5 transfer reaction at a laboratory energy of 57.7 MeV and small center of mass angles. The energy and angular correlations among the H5 decay fragments were obtained by complete kinematical reconstruction. A broad structure in the H5 missing mass spectrum above 2.5 MeV with a typical width of several MeV was identified as a mixture of 3/2+ and 5/2+ states. Analysis of interference patterns observed in the measured angular correlations disclosed the 1/2+ ground state of H5 concealed in the smooth missing mass spectrum. The deduced values for the resonance energy and width are Eg.s. 1.8 MeV and Γg.s. 1.3 MeV. The estimated cross sections for population of the ground state and the doublet of excited states at θc.m.=5°-10° are 150±50 μb/sr and 4.6±2 mb/sr, respectively. © 2005 The American Physical Society.SCOPUS: ar.jinfo:eu-repo/semantics/publishe