[en] KEK (High Energy Accelerator Research Organization) TRIAC (Tokai Radioactive Ion Accelerator Complex) was a radioactive isotope accelerator that can provide beams of uranium fission fragments with a maximum energy of 1.1 MeV/nucleon produced by protons of 30 MeV and 1 µA (30 W in beam power, actually deposited in the production target) from the JAEA Tandem Accelerator. The DIAC team has a plan to reassemble this device as a stable ion beam accelerator with a minimized change for the low energy beam line including the ion source and the target system. The new stable ion accelerator will be used not only for basic research but also for the application of heavy ion beams. Until recently, most of power supply, the cooling water supply and vacuum pump systems have been installed for a performance evaluation of the DIAC. The experimental results of the plasma generation in the ECR ion source are presented. We are planning to evaluate a radiation shielding analysis for an operation permit and perform the beam transport experiments from the ECR ion source to the IH linac by the end of next year

[en] DIAC (Daejeon Ion Accelerator Complex) system was developed, and operated at JAEA of Japan by KEK team with a name of TRIAC (Tokai Radioactive Ion Accelerator Complex) during 2004 to 2010. The TRIAC control system was based on LabView and had two independent control units for ion source and accelerator. To be an efficient system, it is necessary to have an integrated control capability. And the control software, which had implemented by using LabView at TRIAC, will be changed with EPICS in order to give an effective beam service to the users. In this presentation, the old TRIAC control system is described, and a new control system for DIAC is discussed. The control system of DIAC is based on TRIAC. But it is gradually improved performance using EPICS toolkits and changing some digital interface hardware of it. Details of the control system will be demonstrated during the conference

[en] A heavy ion beam facility, which is based on the transferred heavy ion accelerator TRIAC (Tokai Radioactive Isotope Accelerator Complex) from KEK of Japan, is being constructed at KAERI with a new name DIAC (Daejeon Ion Accelerator Complex). The assembly of the main beam line of the facility, which is composed of an ECR ion source, a RFQ and IH linear accelerators, has been finished, and the important characteristics of the accelerator has been measured successfully. Radiation shielding is necessary to start beam tuning and beam acceleration. Also three target rooms are being designed to use the heavy ion beam in the various R and Ds. The present status and future plan of the heavy ion beam facility will be discussed in this present. A heavy ion beam facility is being constructed at KAERI to open the opportunities to the internal researchers on materials, bio, nano and others topics. We will try the facility be open to other researchers with a stable beam in a nearest future

[en] The cosmic rays (both galactic and solar) play important role in the interplanetary and extraterrestrial space. At the same time they can affect the human activity. A modern and interesting topic is related to space weather studies. The space weather refers to the dynamic, variable conditions on the Sun, solar wind and Earth's magnetosphere that can diminish the performance and reliability of spacecraft and groundbased systems. Therefore study of cosmic rays, especially the variation of cosmic ray flux is very important

[en] Organic single crystal stilbene has the best spectrometry characteristics and light yield in comparison with plastics and liquids and has been widely used as neutron detectors or monitors due to their fast timing response and good pulse shape discrimination (PSD) properties in neutron/gamma mixed fields such as a particle accelerator, a generation IV nuclear reactor, a nuclear fusion reactor, and so on. However, single stilbene crystals are so difficult to obtain in large size that greater than 60-80 mm in diameter, and are also vulnerable to damage from thermal and mechanical shocks that its extensive use are limited. Recently, polycrystal composite stilbene based on grains of stilbene crystals have been developed in several Research Institute and it is manufactured in large size for neutron detection. We have investigated its characteristics, especially capability of neutron /gamma discrimination

[en] The Basic Atomic Energy Research Institute (BAERI) of Hanyang University in Korea constructed and operates a cosmic ray detection system. In this study, a muon detector composed of a plastic scintillator and a wavelength shifter was used to obtain data over a total of six experimental periods. Using the collected data, we analyzed the response dependence of the developed muon detector on the laboratory's environmental temperature. The detection results showed a correlation coefficient of over 0.7, as well as a negative proportional correlation in the experiments in which the thermostat did not operate. We performed a correction for the laboratory's environmental temperature and analyzed the correlation between the muon count rate and the atmospheric pressure. As a result, we obtained a barometric coefficient of -0.1191 ± 0.0054%/hPa. The analyzed data were compared with data from the eighteen NM64 type neutron monitors at our station. The correlation coefficient between the two detection systems was approximately 0.8046, confirming that the response changes were roughly identical to response of neutron monitors.

[en] 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 170degC. 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% ⁴He 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 ²²⁶Ra (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. (author)

[en] The NM64 neutron monitor is the most popular instrument that measures the number of high energy particles impacting the Earth from space. A simulation of the NM64 neutron monitor response function with the GEANT4 toolkit is conducted, and the result is processed to compare low- and high-energy hadronic models provided by this Monte Carlo code. Results shows that the thermal interaction for hydrogen in polyethlene for neutron energies less than 4 eV has a great influence. G4NeutronHP and G4LEND models are compared for low-energy neutrons in this study. At energies from 20 MeV to 10 GeV, the Bertini Cascade and the Binary Cascade models are used and evaluated as applicable physics lists. At energies above 10 GeV, the FTFP and the QGSP physics models are applied to calculate the response function, and the results are a few percents higher than the FLUKA results found in the literature.

[en] In order to study the cosmic rays at different altitude and latitude in Korea, Basic Atomic Energy Research Institute (BAERI) has been constructing the detection facility of charged and neutral particles at the atmosphere. The measured cosmic rays should be precisely interpreted for the cosmic ray distinction from the environmental radiations. The whole system consists of the neutron monitors, the charged particle detectors and signal process system. The prototype detector for the charged particle was fabricated and its detection efficiency, noise level, energy spectrum has been measured by using the cosmic rays. The descriptions of the scintillator, PMT, WLS, fabrication method and experimental setup are presented the following

[en] Cone-beam CT (CBCT) has been widely used for the purpose of image-guided radiation therapy. This image-guidance is an important development for precise treatment dose delivery and is being introduced for clinical applications such as adaptive radiation therapy. In this study, we propose new movable multiple slit system for reduction of scattering in CBCT. The multiple slits with equi-angled intervals prevent scatter radiations in a longitudinal direction, and this whole multiple slit system moves after one gantry rotation. The projection images were reconstructed using CBCT image reconstruction method. As a preliminary study, we performed the MCNP simulation to verify and effectiveness of this system