[en] Spatial heterogeneities of paramagnetic species were investigated in cylindrical samples of frozen sulfuric acid ices irradiated by γ-ray, using electron spin resonance imaging. The inverse of Abel's integral was used to derive radial density distributions from observed projection spectra. The symmetric radial density distributions of hydrogen, deuteron, and SO₄^- radical trapped in naked and aluminum foil covered samples were observed. Especially the spectral-spatial two-dimensional method allowed us to make the first measurement of the density of the SO₄^- radical which has never been observed because of its nonsimple ESR spectrum. The radical density measurement has made possible a discussion on the mechanism of the heterogeneity

[en] In order to improve the beam intensity, the beam development with the efficient measurement of ion beam emittance which should be matched to cyclotron acceptance is important. We aimed to obtain the emittance with the graph of the beam state by controlling and analyzing the Pepper Pot Emittance Measuring device (PPEM) with LabVIEW. As a result, it becomes possible to display the emittance with the graph of the beam state at 4 Hz and succeeded in speeding up. The emittance value are almost consistent with the existing emittance monitor. (author)

[en] The tuning of the ion source has a part that relies on human experience and intuition, and because the unknown parameters such as plasma, the reproducibility is low. Therefore, we apply machine learning, search for correlation between parameters and beams, and aim to improve the degree of reproducibility. In order to apply machine learning, it is necessary to know the conditions of beam in detail, and development of an emittance monitor, a beam profile monitor, and an environmental sensor as a diagnostic device is indispensable. In particular, the Emission Monitor is very important for making adjustments, and it is required to make a wide range of emittance measurements quickly. RCNP has developed Pepper-Pot Emittance Monitor (PPEM), and has achieved measurement at 4 Hz. This device is mainly intended for emittance measurement of 30π mm mrad or more, and needs to be improved to be able to measure low emittance beam in order to perform machine learning. Therefore, this time, we investigated the conditions of PPEM that can measure low emittance beam, and developed PPEM that can measure a wide range of measurement by replacing the pepper pot mask. (author)

[en] The techniques to heal fatigue damage by electric current have been studied. However, these mechanism was not investigated in detail. In this study, we observed dislocation motion by transmission electron microscope (TEM) before and after applying electric current in a sample cut out from fatigue specimen. The dislocation motion that depended on the current direction was confirmed from different plane orientations. (author)

[en] In recent years, accelerators have been implemented in the medical and industrial fields, but the difficulty of adjusting and controlling the accelerator itself and the ion source has become an issue. Since it is difficult to assign a dedicated operator to operate all accelerators, it is necessary for accelerators to be able to provide beams of a certain intensity and quality in a short period of time and to be extremely easy to operate, no matter when or who adjusts them, in order for them to be widely used in society. Therefore, we have developed a new tuning method using Bayesian optimization, a type of machine learning, aiming at the advancement and automation of ion source tuning. In this experiment, 14 parameters of the beam transport line were adjusted. As a result, we achieved in 20 minutes more than 90% of the beam intensity that took an experienced operator more than one hour to adjust, and achieved the same beam intensity as the operator in one hour, showing that it was practical enough. (author)

[en] The Upgrade work on the accelerator facility of Research Center for Nuclear Physics (RCNP) has been carried from 2019 in order revive the AVF cyclotron and improve the performance and functionality so that it can supply high-quality beams with higher intensity. During this upgrade, the control system consists with hard wired relays complex and SCADA with PLC and UDC is also updated and modified. At the same time, the EPICS system is introduced partially. Regarding the ion sources, almost all of equipment are controlled under the EPICS framework after the upgrade. Automatic beam tuning system can be construct with the EPICS and some machine learning frameworks, and higher intensity beam might be achieved with these systems. (author)

[en] In an ion source, various factors influence each other. Therefore, when operating the ion source, it is necessary to optimize and adjust various parameters such as the incident power of RF, the RF tuner, the flow rate of gas, and the electromagnet of the transportation line while observing the state of the beam. Since this adjustment is made by relying on the experience of the operator, the quantity, quality, and adjustment time of the beam are likely to vary depending on the operator. Therefore, this time, we have developed a control method that applies machine learning. This time, we specialized in maximizing the beam intensity, and succeeded in measuring a 0.4 mA ⁴He²⁺ beam on the Faraday cup, which is the same as the maximum value operated by human. (author)

[en] At RCNP, it is required to supply ion beam with high quality and high intensity, and we plan to introduce Duoplasmatron as a new ion source for proton and deuteron. It is expected that the quality of the accelerated beam can be improved by reducing the emittance of the beam from ion source. For the introduction, it is necessary to evaluate the influence of Duoplasmatron's operating parameters on the output beam and establish a method to extract the beam with low emittance. Also, in order to increase the intensity, it is necessary to reduce the beam loss during transportation, but the position of the magnet on the existing beam line can not be changed. Therefore, it is necessary to adjust the magnets and the drift distance from Duoplasmatron to the existing beam line and design for the efficient beam transport. This time, we will summarize the beam line design for beam transport without loss based on influence on output beam's envelope calculation using Graphic Transport which is matrix calculation software. (author)

[en] ESR imaging was applied to the measurement of radical depth profiles generated in organic solid dosimeters. Alanine/paraffin, alanine/polystyrene and sucrose/paraffin mixtures were irradiated with the electrons from the 4-MeV Linac. The theoretical energy-deposition distributions were calculated by using an algorithm derived by Tabata and Ito. Experimental radical depth profiles agree well with theoretical energy-deposition distribution. In spite of the existence of some problems, and the need to improve e.g. the occurrence of the artifact, the capability of depth-profile dosimetry using ESR imaging was shown. The radical-depth profiles in polypropylene-containing hindered amine light stabilizers, suggested the significance of depth-profile measurements in composite materials irradiated with high linear-energy-transfer radiations. (author)

[en] In this research, we propose a new simple method to fabricate hydrogen gas sensors by stacking multiwall carbon nanotube (MWCNT) sheets. MWCNT sheets offer a larger surface area and more CNT contact, which are key factors for gas sensing, because of their super-high alignment and end-to-end structure compared to traditional CNT film. Besides, MWCNT sheets can be directly drawn from spinnable CNT arrays on large scales. Therefore, this method is a potential answer for the mass production and commercialization of CNT-based sensors with high responsivity. By stacking layers of sheets in various arrangements, the microstructure and CNT interactions in the layers were changed and their influence on gas sensing investigated. It was observed that the sample with three layers of sheet and functionalized with 3 nm thick Pd showed the best gas sensing performance, with a response of 12.31% at 4% H₂ and response time below 200 s. (paper)