An asymptotic approximation for EPMC in linear discriminant analysis based on two-step monotone missing samples

In this paper, we consider the expected probabilities of misclassification (EPMC) in the linear discriminant function (LDF) based on two-step monotone missing samples and derive an asymptotic approximation for the EPMC with an explicit form for the considered LDF. For this purpose, we also provide some results of the expectations for the inverted Wishart matrices in this paper. Finally, we conduct the Monte Carlo simulation for evaluating our result.Linear discriminant analysis Expected probability of misclassification Asymptotic approximation Monotone missing samples

Energy measurement of laser-accelerated protons by using a nuclear emulsion

The purpose of this study is measuring energy of laser-accelerated protons from the hydrogen cluster target by using a nuclear emulsion, and crosschecking the results of CR-39 detectors. The CR-39 detectors, which are the most sensitive solid state nuclear track detectors (SSNTD), have been used for long time to understand the both of spatial distributions and energy spectra of laser-accelerated ions. In such a situation, we have studied the applicability of a nuclear emulsion as the alternative ion detector for laser-accelerated ions. In the laser-driven ion acceleration experiments, not only ions, but also copious energetic electrons and X rays are simultaneously generated. Threfore, to suppress the background noise signals from the electrons and X rays, pH level of the developer and the development time of a nuclear emulsion are optimized. As a result, we have for the first time succeeded in identifying the signals from laser-accelerated protons up to 11.5 MeV and obtained an energy spectrum. The spectrum shows a good agreement with that obtained by CR-39.第2回QST国際シンポジウ

Application of a nuclear emulsion to laser-driven ion acceleration experiment using micron-sized hydrogen cluster target

A nuclear emulsion is one of photographic films, which can record the three-dimensional trajectories of charged particles. It has the special features of sub-micron spatial resolution and high sensitivity, so that it has been utilized for various research fields. In laser-driven ion acceleration, etched type track detectors such as CR-39 are used as the ion detector to understand the both of spatial distributions and energy spectra. Although the CR-39 detectors are the most reliable detector for laser-accelerated ions, other track detectors, which can crosscheck the results of CR-39 detectors, have not been applied for laser-driven ions acceleration experiments. In the present study, to evaluate the applicability of a nuclear emulsion for the measurements of laser-accelerated ions, we have applied a nuclear emulsion for the laser-driven ion acceleration experiment using micron-sized hydrogen clusters.第14回放射線モニタリングに係る国際ワークショッ

Development of the New Method to Measure Laser-accelerated Sub-GeV Protons Utilizing Multiple Coulomb Scattering in an Emulsion Cloud Chamber

Laser plasma proton acceleration, where it was recently reported that near-100-MeV proton acceleration was demonstrated, offers the potential to realize a compact and cost-effective accelerator in the future. Because it can generate an extreme electric field that is over six orders of magnitude higher than that of a conventional radio-frequency accelerator apparatus. To understand the underlying physics of the acceleration process and increase maximum proton energy, precise measurement of both the energy spectrum and the two-dimensional distribution is required. Against this background, we have developed a new measurement method for laser-accelerated sub-GeV-class protons using the nuclear emulsion. Based on the Multiple Coulomb Scattering (MCS) method in an Emulsion Cloud Chamber (ECC), which is a stack of nuclear emulsion films and scatterer plates, the incident energies were inversely evaluated by the scattering angle. The proof-of-principle experiment has been conducted with the Heavy-Ion Medical Accelerator in Chiba (HIMAC) to verify that the ECC is able to identify sub-GeV protons with the MCS method. Combined with a technique of machine learning, a new measurement method has been developed to obtain an energy spectrum of laser-accelerated sub-GeV protons by the ECC with the MCS method.ICMaSS202

Application of Nuclear Emulsions for the Identification of Laser-accelerated Multi-MeV Protons

By suppressing the background noise signals through the use of desensitized development conditions, for the first time, we have succeeded in identifying the tracks of multi-MeV laser-accelerated protons in nuclear emulsions. An additional benchmark experiment with a conventional accelerator apparatus confirmed that nuclear emulsions have the potential to measure 100-MeV-class laser-accelerated protons.ICMaSS201