Development of microbeam formation and single-ion hit technologies at the TIARA cyclotron

Yokota, Wataru; Sato, Takahiro; Kamiya, Tomihiro; Okumura, Susumu; Kurashima, Satoshi; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Yoshida, Kenichi; Funayama, Tomoo; Sakashita, Tetsuya; et al.

JAEA-Technology 2014-018, 103 Pages, 2014/09

JAEA-Technology-2014-018.pdf:123.66MB

The world's first microbeam focusing technology for heavy ions of hundreds MeV accelerated by a cyclotron has been developed at the TIARA facility in the Takasaki Advanced Radiation Research Institute of the Japan Atomic Energy Agency. The technology enables us to form a microbeam of less than 1 m in diameter and to shoot a specified point on a target by one ion (single-ion hit) with spatial accuracy of microbeam size. In the course of the development, a cyclotron technology to accelerate a small energy-spread beam of hundres MeV, which is necessary for focusing to 1 m, has been developed as well as a beam focusing apparatus, beam size measurement and so forth based on the several-MeV microbeam/single-ion hit system of the TIARA electrostatic accelerators. Applicability of the technologies was examined by actual use in irradiation experiment and the result were fed back to them. This paper reports the process and the results of the development over ten years.

Performance of a new signal processing system for a detector array

Kimura, Atsushi; Koizumi, Mitsuo; Toh, Yosuke; Oshima, Masumi; Mizumoto, Motoharu; Goto, Jun*; Arai, Yasuo*; Sagara, Masahiro*; Iri, Shinichi*; Kobayashi, Hirotsugu*; et al.

no journal, , 

To measure neutron cross-section data of minor actinides, we construct a Ge-spectrometer utilizing multiple -ray detection method. This spectrometer consists of 30 Ge crystals (40 detector outputs) and 128 BGO anti-Compton shields. Generally, a data acquisition system for such a big Ge spectrometer consists of many NIM modules; it requires large space and huge cost. To overcome these problems, we developed a new data acquisition system with digital signal processing techniques. We reported the conceptual design (and cost) in NSS 2004. In this NSS 2005, we report basic performance of this system (energy resolution, dead time and so on) and results of experiments with the Ge-spectrometer. We measured the energy resolution with a Eurisys clover detector, which is one component of the Ge-spectrometer. Obtained FWHMs (2.5 - 2.8 keV at 1.33 MeV) show good performances as normal MCA even with short shaping time and much higher channel density. The dead time of this system is only 3.2 micro sec per event.