Yoshihiko Tanimura

A Monte Carlo Program for Estimating Characteristics of Neutron Calibration Fields Using a Pelletron Accelerator

A Monte Carlo code system, MCNP-ANT, has been developed to simulate the transport of charged particles (<4MeV) and the neutron production in an accelerator neutron target as well as the neutron transport. The code system consists of a newly developed Monte Carlo code for charged particle transport and neutron production, and an existing neutron transport code, MCNP-4B. The available reactions in the code system are 2H(d,n)3He, 3H(d,n)4He, 3H(p,n)3He, 7Li(p,n)7Be and 45Sc(p,n)45Ti as main neutron sources. The calculated neutron spectra by MCNP-ANT were compared with the experimental ones in typical monoenergetic neutron fields.

Beam profile measurement with CR-39 track detector for low-energy ions

A CR-39 track detector was successfully used to measure the outline of thin low-energy ion beams. After the etching, the surface of the detector was examined with an observation system composed of a Normarski microscope, a CCD camera and a digital image processing computer. Beam images obtained with the system were in good agreement on the outline of the beam formed with a beam aperture. Also, the resolving power in the beam outline measurement was roughly explained from the consideration of the ion range and the etch-pit growth in the chemical etching for the CR-39 detector.

Effects of DD and DT neutron irradiation on some Si devices for fusion diagnostics

Abstract In order to examine the difference in the irradiation effects on Si devices between DT and DD neutrons, CCD image sensors, memory ICs and a Si detector were irradiated with neutrons from a deuteron accelerator. The transient effects (i.e. neutron-induced background noises) and permanent effects (i.e. neutron damage) on them were in situ measured during irradiation. Regarding the transient effects, brightening spot noises, soft-error upsets and induced-charge noises were measured for the CCDs, memory ICs and Si detector, respectively. As for the permanent effect, the number of damaged cells of the CCDs and the leakage current of the Si detector increased with neutron fluence. Also we developed a Monte-Carlo code with the TRIM code to evaluate the correlation of DT and DD neutron effects on Si devices. The calculated correlation factor of DT and DD neutron damage for Si devices agreed approximately with the correlation factor obtained from the irradiation experiments on the CCDs and Si detector.

Development of a Compact Single Ion Microprobe

A compact single ion microprobe has been developed for the examination of the microscopic characteristics of sensors, particle detectors and other devices used for fusion diagnostic systems. The microprobe has been constructed by use of commercially available standard components and can be easily recomposed according to beam requirements for various irradiation experiments. The beam size and position were successfully measured by use of a beam sensor with a quadrant-type electrode. Furthermore, the automatic beam control and adjustment were accomplished by a feedback system in obedience to a computer program based on a modified SIMPLEX iterative method. Some experiments for the examination of the performance of the microprobe were done by use of several elaborate beam detectors and indicated that a beam of a single ion (one ion in one pulse), Ins in pulse width and 2.5/im in diameter could be successfully produced by the present microprobe.