T. Shinozuka

Production and decay properties of 264Hs and 265Hs

The decay properties of 264 Hs and 265 Hs produced in the 207,208 Pb( 58 Fe, x n ) ( x =1,2) reactions were studied using a gas-filled recoil ion separator at the linear accelerator facility of RIKEN. A total of six decay chains were assigned to 264 Hs. The cross sections of 264 Hs produced in the 208 Pb( 58 Fe,2 n ) and 207 Pb( 58 Fe, n ) reactions were measured to be 2.8 +6.5 -2.3 and 6.9 +4.4 -3.1 pb, respectively. The isotope 264 Hs decayed by α-particle emission (five events) and spontaneous fission (one event). The α-particle energy of 264 Hs was observed at 10.61 ±0.04 and 10.80 ±0.08 MeV.

Study of a thick target surface ionizer at INS

Abstract A surface-ionization ion source for the use of a thick target has been studied by an isotope separator on-line at INS using the 40Ca(p,2pn)38K reaction. The ionization efficiency and release time were measured for CaC2, CaO and CaF2 targets. The measured efficiency turned out to be about 20% both for tantalum and platinum surface ionizers. The release time was also deduced for each target at various values of temperature by measuring time distributions of the extracted radioactivity after bombarding the target for a short time.

Ion-optical design of the high-resolution mass separator for the Japanese Hadron Project

Abstract An ion-optical design of the JHP-ISOL is presented. This separator consists of a beam guidance system, a main magnetic separator stage and an electrostatic energy focusing stage. This separator is to be coupled with a heavy-ion linac for post-acceleration of mass separated ions up to 6.5 MeV/u. The design goal of the separator is to realize a mass resolving power of R M = 20000 (basal) at a transmission approaching 100% with the initial phase space of ± 0.2 mm × ± 20 mrad.

OPERA: an on-line system of optical pumping in solids for unstable nuclei

Abstract An on-line system of optical pumping in solids for the study of unstable nuclei was developed. The system is operated in connection with mass separators on line. The mass-separated unstable isotopes are implanted into a host crystal set at the focal position of the separator and then spin-polarized with laser optical pumping in the crystal. The crystal can be cooled down to 20–100 K with a cold finger attached to a liquid He bath. The achieved nuclear polarization/alignment is detected by observing the asymmetry/anisotropy of the emitted beta-/gamma-radiation with scintillation/Ge counters. Nuclear magnetic resonances are observed by detecting the destruction and/or enhancement of the asymmetry/anisotropy distribution with an applied rf magnetic field. The system has been applied to the study of unstable Tm and Si isotopes. Apparatus and performance of the on-line system are described together with some of the results obtained.

High-Spin States in 93Nb

The high-spin states of 93 Nb are studied by the 82 Se( 16 O, p4n) 93 Nb reaction at a beam energy of 100 MeV. The in-beam γ-ray spectroscopic techniques are used. The γt-, γγt-coincidence, γ-ray a...

An ion trap for nuclear laser spectroscopy at Tohoku ISOL

Abstract An on-line ion trap directly connected to the Tohoku ISOL has been constructed. The trap is aimed at the study of nuclear magnetic properties through precision measurements of ionic ground-state hyperfine structures of unstable nuclei. As a first step to a systematic study, the hyperfine splitting of the ground state of 87 Sr + ions was measured by laser microwave double-resonance spectroscopy.

A fast data acquisition system for in-beam nuclear spectroscopy

Abstract A GPIB-based fast data acquisition system is designed and constructed. It consists of host microcomputers, MTs, and two kinds of intelligent front-end devices, one of which is for data acquisition of singles PHA mode and the other for data acquisition of multiparameter list mode. They are connected to each other through GPIB (IEEE-488) standard interface buses. The list data are transferred not only to the MTs but also simultaneously to the host computer for on-line real-time analysis if needed. If additional capabilities of real-time analysis are required, other computers, such as a Micro-VAX, can be connected to the interface bus; this important feature of the present system is realized by the multiple-listener function of the IEEE-488 interface bus.