The silver-activated zinc sulfide, ZnS(Ag), sensor to detect alpha-particles is normally fabricated by means of heat-melting or epoxy mixing spread. However, the fabrication process is very complicated so that it creates high costs and requires special high-tech equipment to manufacture the detector. For this reason, we have developed a new fabrication method which has the advantages of process simplicity and also high efficiency. The alpha particle response of the detector manufactured by the new spreading method was evaluated at varied thicknesses of ZnS(Ag) and the detection efficiency was better than for other methods like liquid brush method with an Am-241 alpha radiation source. Compared to conventional ZnS(Ag) detectors, the new detector shows a good detection efficiency, and its simple and low cost design makes it an economical and commercial alternative to more expensive alpha survey instruments.

Tenreiro, C (Tenreiro, Claudio). Univ Talca, Talca, Chile.The Korea Rare Isotope Accelerator, currently referred to as KoRIA, is briefly presented. The KoRIA facility is aimed to enable cutting-edge sciences in a wide range of fields. It consists of a 70 kW isotope separator on-line (ISOL) facility driven by a 70 MeV, 1 mA proton cyclotron and a 400 kW in-flight fragmentation (IFF) facility. The ISOL facility uses a superconducting (SC) linac for post-acceleration of rare isotopes up to about 18 MeV/u, while the SC linac of IFF facility is capable of accelerating uranium beams up to 200 MeV/u, 8 p mu A and proton beams up to 600 MeV, 660 mu A. Overall features of the KoRIA facility are presented with a focus on the accelerator design

The key feature of the Isotope Separation On-Line (ISOL) facility is its ability to provide highintensity and high-quality beams of neutron-rich isotopes with masses in the range of 80 − 160 by means of a 70-MeV proton beam directly impinging on uranium-carbide thin-disc targets to perform forefront research in nuclear structure, nuclear astrophysics, reaction dynamics and interdisciplinary fields like medical, biological and material sciences. The technical design of the 10-kW and the 35-kW direct fission targets with in-target fission rates of up to 10 14 fissions/s has been finished, and for the development of the ISOL fission-target chemistry an initial effort has been made to produce porous lanthanum-carbide (LaCx) discs as a benchmark for the final production of porous UCx discs. For the production of various beams, three classes of ion sources are under development at RISP (Rare Isotope Science Project), the surface ion source, the plasma ion source (FEBIAD), the laser ion source, and the engineering design of the FEBIAD is in progress for prototype fabrication. The engineering design of the ISOL target/ion source front-end system is also in progress, and a prototype will be used for an off-line test facility in front of the pre-separator. The technical designs of other basic elements at the ISOL facility, such as the RF-cooler, the high-resolution mass separator, and the A/q separator, have been finished, and the results, along with the future plans, are introduced.

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Abstract. We are developing Isotope Separation On-Line (ISOL) target system, which consists of 1.3 mm-thick uranium-carbide multi-disks and cylindrical tantalum heater, to be installed in new facility for Rare Isotope Science Project in Korea. The intense neutron-rich nuclei are produced via the fission process using the uranium carbide targets with a 70 MeV proton beam. The fission rate was estimated to be ∼1.5 × 10 13 /sec for 10 kW proton beam. The target system has been designed to be operated at a temperature of ∼2000 • C so as to improve the release efficiency.Production and delivery of high purity intense of Rare Isotope Beam (RIB) have been a major concern for fundamental research fields such as astro− and nuclear−physics as well as applied research field such as material and bio-medical science. Rare Isotope Science Project (RISP) of Korea has proposed to construct Isotope Separation On-Line (ISOL) facility in order to provide the intense rare isotopes. The ISOL target enables us not only to produce the nuclei with the medium mass neutronrich region but also to obtain their high production rates. A uniform 70 MeV proton beam with a maximum current of 500 µA, which is delivered from a cyclotron driver, will impinge on an uranium carbide target. The neutron-rich isotopes are produced via proton-induced fission. A singly charged (1+) RIB is produced and extracted from the target and the ion source, respectively, then the beam emittance is reduced by a RF-cooler to be 3 πmm mrad before injecting to the high resolution mass separator (HRMS). The isotopes selected by the HRMS are delivered to an electron beam ion source (EBIS) or an electron cyclotron resonance (ECR) type charge breeder so as to breed the charge from the 1 + charge state to a n + charge state for efficient and economical post-acceleration. An A/q separator is installed at the downstream of the charge breeder to purify the ion beam contaminated during charge breeding. Here, we report on the results of the ISOL target design for 10 kW proton beam.The main issues concerning the design of the ISOL target can be divided into three categories; intarget fission rate, release time, and temperature of the target. Firstly, a total effective thickness of the target should be as thick as possible in order to maximize the in-target fission rate. This requires a large size of the target. Secondly, release time should be as short as possible so as to minimize the losses by the decay of isotopes. A small size of the target helps to reduce the release time by decreasing the flight length of the isotopes. However, it should be noted here that the small size can lead to melt down of the target due to the reduced radiant cooling. Lastly, the temperature of the target should be as high as possible to increase the thermal velocity of the isotopes, which leads to the reduction of the release time. Therefore, the correlations between the three points mentioned above should be investigated so as to find the optimum condition for the ISOL target. a

High-pressure Xe (HPXe) ionization chamber is considered as an ideal detector for the Radiation Monitoring System (RMS) in nuclear power plants, since detector response has been shown to be uniform over large temperature ranges up to 170 C. By using the MCNPX simulation code, the energy spectra were calculated with respect to the thickness of the outer shell and the dependence on the incident direction of the radiation sources in the nuclear power plant. A cylindrical HPXe ionization chamber, which was configured with a shielding mesh to improve its energy resolution, was designed and fabricated. With the gas purification and injection system, Xe and 7% 4 He was purified and injected into the chamber and the performances of the chamber were evaluated. The leakage and saturation currents of the chamber were measured with an electrometer, respectively. Linearity against dose rates was also measured with 226 Ra (0.906 mCi) radiation source and the 0.994 of root-mean-square value was estimated. In a future work, energy spectra with the fabricated HPXe ionization chamber will be measured and compared with the simulated energy spectra.