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Journal Articles

The Role of collision ionization of K-shell ions in nonequilibrium plasmas produced by the action of super strong, ultrashort PW-class laser pulses on micron-scale argon clusters with intensity up to 5 $$times$$ 10$$^{21}$$ W/cm$$^{2}$$

Skobelev, I. Yu.*; Ryazantsev, S. N.*; Kulikov, R. K.*; Sedov, M. V.*; Filippov, E. D.*; Pikuz, S. A.*; Asai, Takafumi*; Kanasaki, Masato*; Yamauchi, Tomoya*; Jinno, Satoshi; et al.

Photonics (Internet), 10(11), p.1250_1 - 1250_11, 2023/11

It is challenging to clearly distinguish the impacts of the optical field and collisional ionization in the evolution of the charge state of a plasma produced when matter interacts with high-intensity laser pulses. In this work, time-dependent calculations of plasma kinetics are used to show that it is possible only when low-density gaseous targets with sufficiently small clusters are used. In the case of Ar plasma, the upper limit of the cluster radius was estimated to be $$R_0 = 0.1 mu$$m.

Journal Articles

Present status of the JAEA-AMS-TONO (2021)

Matsubara, Akihiro*; Fujita, Natsuko; Miyake, Masayasu; Ishii, Masahiro*; Watanabe, Takahiro; Kokubu, Yoko; Nishio, Tomohiro*; Ogawa, Yumi; Jinno, Satoshi; Kimura, Kenji; et al.

JAEA-Conf 2022-002, p.55 - 62, 2023/03

We report the present status of the JAEA-AMS-TONO. Particularly, the destructions of varistors used in the beamline equipment will be presented. The cause of the destruction as well as implementation of the safety measures are mentioned.

Journal Articles

Present status of the JAEA-AMS-TONO (2022FY)

Fujita, Natsuko; Miyake, Masayasu; Matsubara, Akihiro*; Ishii, Masahiro*; Watanabe, Takahiro; Jinno, Satoshi; Nishio, Tomohiro*; Ogawa, Yumi; Yamamoto, Yusuke; Kimura, Kenji; et al.

Dai-23-Kai AMS Shimpojiumu Hokokushu, p.1 - 4, 2022/12

The JAEA-AMS-TONO facility at the Tono Geoscience Center, JAEA has three accelerator mass spectrometers. We report the present status of the JAEA-AMS-TONO.

Journal Articles

Development of an ion funnel reaction cell for suppression of isobaric interference in chrorin-36 dating

Jinno, Satoshi; Fujita, Natsuko; Tanuma, Hajime*

Dai-23-Kai AMS Shimpojiumu Hokokushu, p.89 - 92, 2022/12

The measurement of chlorine-36 ($$^{36}$$Cl) in AMS, which is important for the dating of saline groundwater, is more difficult than other nuclides due to the isobaric interference by sulfur-36 ($$^{36}$$S). In general, acceleration voltages of 6 MV or higher are required to separate $$^{36}$$Cl and $$^{36}$$S. Therefore, this study aims to develop an ion funnel reaction cell and incorporate it into the low energy side of JAEA-AMS-TONO-5MV to selectively suppress $$^{36}$$S.

Journal Articles

Project for development of a downsized AMS system based on the surface stripper technique

Fujita, Natsuko; Matsubara, Akihiro; Kimura, Kenji; Jinno, Satoshi; Kokubu, Yoko

Nuclear Instruments and Methods in Physics Research B, 532, p.13 - 18, 2022/12

 Times Cited Count:1 Percentile:35.78(Instruments & Instrumentation)

Over the last decade, significant technological advances were made to downsize the AMS systems. Japan Atomic Energy Agency has started a project for developing a prototype downsized AMS system (with the footprint of the system is 1.9 m $$times$$ 1.9 m) based on the surface stripper technique. Although the system configuration using an ion source, magnets, and detectors is similar to that in conventional systems, there is no tandem accelerator as well as a gas stripper. The ion acceleration is provided in the ion source (maximum ion energy 40 keV). For proof-of-principle experiments, we have planned two steps: (1) Observation of the specular reflection and the dissociation by using a compact electrostatic analyzer located just behind the stripper, and (2) Demonstration of $$^{14}$$C measurement, along with the experimental confirmation of the isobar suppression capability of the surface stripper.

Journal Articles

The Precise energy spectra measurement of laser-accelerated MeV/n-class high-Z ions and protons using CR-39 detectors

Kanasaki, Masato; Jinno, Satoshi*; Sakaki, Hironao; Kondo, Kiminori; Oda, Keiji*; Yamauchi, Tomoya*; Fukuda, Yuji

Plasma Physics and Controlled Fusion, 58(3), p.034013_1 - 034013_6, 2016/03

 Times Cited Count:21 Percentile:78.38(Physics, Fluids & Plasmas)

In order to understand the synergetic interplay between the Coulomb explosion of clusters and the background gas dynamics, we have conducted ion acceleration experiments using CO$$_2$$ clusters (250 nm in dia.) embedded in background H$$_2$$ gas with the J-KAREN laser (1 J, 40 fs, 10$$^{-10}$$ contrast) at JAEA-KPSI. By a careful analysis of etch pit positions on CR-39 and their structures including the etch pit growth behavior analysis with the multi-step etching technique, energy spectra for protons from the background gas and carbon/oxygen ions from the clusters are obtained separately. The maximum energies of protons and carbon/oxygen ions are determined as 1.6 MeV and 1.1 MeV/u, respectively. Based on the experimental results, the acceleration mechanism of the background gas ions induced by Coulomb explosion of clusters is discussed with the help from numerical simulations which employ a particle-in-cell (PIC) method including relaxation and ionization processes of plasma particles.

Journal Articles

Development of an apparatus for characterization of cluster-gas targets for laser-driven particle accelerations

Jinno, Satoshi; Fukuda, Yuji; Sakaki, Hironao; Yogo, Akifumi; Kanasaki, Masato; Kondo, Kiminori; Faenov, A. Y.; Skobelev, I. Yu.*; Pikuz, T.; Boldarev, A. S.*; et al.

Progress in Ultrafast Intense Laser Science XI; Springer Series in Chemical Physics, Vol.109, p.215 - 233, 2015/00

Clusters formed in supersonic gas expansion through a three-staged conical nozzle have been verified by measuring the angular distribution of the light scattered from cluster target. The size distirbutions of the clusters are calculated based on the Mie theory. The reliability of the size measurement is verified to be an experimental error of 10% using standard particles. The mean sizes of CO$$_2$$ clusters for the cases of CO$$_2$$/H$$_2$$ and CO$$_2$$/He mixed-gas targets are estimated to be 0.26 $$mu$$m and 0.22 $$mu$$m, respectively. For the CO$$_2$$/H$$_2$$, the cluster density is estimated to be 5.5 $$times 10^8$$ clusters/cm$$^2$$ by measuring the attenuation of the laser beam intensity. Furthermore, total gas density profiles are obtained via the Abel inversion from the phase shift of the light passing through the target using an interferometer. The variation of the cluster mass fraction along the radial direction of the target is almost constant, which is consistent with a Boldarev's model.

Journal Articles

Evaluation of dose level in a laser-driven ion accelerator using PHITS code

Sakaki, Hironao; Fukuda, Yuji; Nishiuchi, Mamiko; Jinno, Satoshi; Kanasaki, Masato; Yogo, Akifumi; Kondo, Kiminori; Saito, Fumihiro; Fukami, Tomoyo; Ueno, Masayuki; et al.

Progress in Nuclear Science and Technology (Internet), 4, p.182 - 185, 2014/04

The concept of a compact ion particle accelerator has become attractive in view of recent progress in laser-driven ions acceleration. In the development of many applications of laser-accelerated ions, it is necessary for securing the radiation safety to calculate the dose evaluation. The dose was measured with the radio-photoluminescent (RPL) glass dosimeter on the test beamline of at laser-driven accelerator. The Monte Carlo code, PHITS (Particle and Heavy Ion Transport code system) simulation is shown to be reasonably predictive at the test beamline for measured with the RPL glass dosimeter. We compare of the measured dose level on the laser-driven accelerator with the result of PHITS code in this report.

Journal Articles

Insertable pulse cleaning module with a saturable absorber pair and a compensating amplifier for high-intensity ultrashort-pulse lasers

Yogo, Akifumi; Kondo, Kiminori; Mori, Michiaki; Kiriyama, Hiromitsu; Ogura, Koichi; Shimomura, Takuya; Inoue, Norihiro*; Fukuda, Yuji; Sakaki, Hironao; Jinno, Satoshi; et al.

Optics Express (Internet), 22(2), p.2060 - 2069, 2014/01

 Times Cited Count:10 Percentile:49.64(Optics)

Journal Articles

Mie scattering from submicron-sized CO$$_2$$ clusters formed in a supersonic expansion of a gas mixture

Jinno, Satoshi; Fukuda, Yuji; Sakaki, Hironao; Yogo, Akifumi; Kanasaki, Masato; Kondo, Kiminori; Faenov, A. Ya.*; Skobelev, I. Yu.*; Pikuz, T.; Boldarev, A. S.*; et al.

Optics Express (Internet), 21(18), p.20656 - 20674, 2013/09

 Times Cited Count:20 Percentile:72.12(Optics)

A detailed mathematical model is presented for a submicron-sized cluster formation in a binary gas mixture flowing through a three-staged conical nozzle. In order to experimentally confirm this model, the cluster sizes have been evaluated using the Mie scattering method, which is to measure the angular distribution of light scattered from targets. The mean sizes of CO$$_2$$ clusters produced in the gas mixtures of CO$$_2$$(30%)/H$$_2$$(70%) and CO$$_2$$(10%)/He(90%) are estimated to be 0.28$$pm$$ 0.03 $$mu$$m and 0.26$$pm$$0.04 $$mu$$m, respectively. In addition, total gas density profiles measured with an interferometer were found to be agreed with the numerical modeling within a factor of two. The dryness ($$=monomer/(monomer+cluster)$$ ratio) in the targets was found to support the numerical modeling. Thus, our mathematical model of cluster formation was proved to be reliable enough for the binary gas mixture by the experimental results.

Journal Articles

Generation of 50-MeV/u He ions in laser-driven ion acceleration with cluster-gas targets

Fukuda, Yuji; Sakaki, Hironao; Kanasaki, Masato; Yogo, Akifumi; Jinno, Satoshi; Tampo, Motonobu*; Faenov, A. Ya.*; Pikuz, T. A.*; Hayashi, Yukio; Kando, Masaki; et al.

Proceedings of SPIE, Vol.8779 (Internet), p.87790F_1 - 87790F_7, 2013/05

 Times Cited Count:0 Percentile:0.05

We demonstrate a new ion diagnosis method for high energy ions by utilizing a combination of a single CR-39 detector and plastic plates, which enables to detect high energy ions beyond the detection threshold limit of the CR-39. This detection method coupled with a magnetic spectrometer is applied to identify high energy ions of 50 MeV per nucleon in laser-driven ion acceleration experiments using cluster-gas targets.

Journal Articles

Characterization of submicron-sized CO$$_2$$ clusters formed with a supersonic expansion of a mixed-gas using a three-staged nozzle

Jinno, Satoshi; Fukuda, Yuji; Sakaki, Hironao; Yogo, Akifumi; Kanasaki, Masato; Kondo, Kiminori; Faenov, A. Ya.*; Skobelev, I. Yu.*; Pikuz, T.; Boldarev, A. S.*; et al.

Applied Physics Letters, 102(16), p.164103_1 - 164103_4, 2013/04

 Times Cited Count:25 Percentile:71.64(Physics, Applied)

The size of CO$$_2$$ clusters, produced in a supersonic expansion of a mixed-gas of CO$$_2$$/He or CO$$_2$$/H$$_2$$ through a three-staged conical nozzle designed based on the Boldarev's model, has been evaluated by measuring the angular distribution of light scattered from the clusters. The data are analyzed utilizing the Mie scattering theory, and the sizes of CO$$_2$$ clusters are estimated as 0.22 $$mu$$m and 0.25 $$mu$$m for the cases of CO$$_2$$/He and CO$$_2$$/H$$_2$$ gas mixtures, respectively. The results confirm that the Boldarev's model is reliable enough for the production of micron-sized clusters.

Journal Articles

Identification of high energy ions using backscattered particles in laser-driven ion acceleration with cluster-gas targets

Fukuda, Yuji; Sakaki, Hironao; Kanasaki, Masato; Yogo, Akifumi; Jinno, Satoshi; Tampo, Motonobu; Faenov, A. Ya.*; Pikuz, T.; Hayashi, Yukio; Kando, Masaki; et al.

Radiation Measurements, 50, p.92 - 96, 2013/03

 Times Cited Count:12 Percentile:67.64(Nuclear Science & Technology)

A new diagnosis method for high energy ions utilizing a single CR-39 detector mounted on plastic plates is demonstrated to identify the presence of the high energy component beyond the CR-39's detection threshold limit. On irradiation with a 25 MeV per nucleon He ion beam from conventional rf-accelerators, a large number of etch pits having elliptical opening shapes are observed on the rear surface. Detailed investigations reveal that these etch pits are created by heavy ions inelastically backscattered from the plastic plates. This ion detection method is applied to laser-driven ion acceleration experiments using cluster-gas targets, and acceleration of ions with energies up to 50 MeV per nucleon are identified.

Journal Articles

A High energy component of the intense laser-accelerated proton beams detected by stacked CR-39

Kanasaki, Masato; Hattori, Atsuto; Sakaki, Hironao; Fukuda, Yuji; Yogo, Akifumi; Jinno, Satoshi; Nishiuchi, Mamiko; Ogura, Koichi; Kondo, Kiminori; Oda, Keiji*; et al.

Radiation Measurements, 50, p.46 - 49, 2013/03

 Times Cited Count:15 Percentile:74.93(Nuclear Science & Technology)

A precise measurement has been made utilizing a stacked CR-39 detectors unit for laser accelerated high intensity protons. The proton beams are derived from a thin polyimide target exposed to an high intense Ti:sapphire laser 8 J energy and 40 fs duration. The sample sets, stacked radiochromic film and CR-39 detectors covered with 13 $$mu$$m aluminum filter, are irradiated under vacuum condition. By analyzing the etch pits on the last layer of CR-39 which recorded etchable tracks, the proton energy in high energy region is evaluate more precisely than in the past. The residual ranges for each particle in the last layer has been obtained from etch pit growth curves with multi-stepetching technique. The maximum energy of proton is 14.39$$pm$$0.05 MeV. This method allows us to measure the maximum energy of proton precisely, which is obtained up to the hundredth place in unit of MeV in the laser-driven particle acceleration experiment.

Journal Articles

Development of a single-shot-imaging thin film for an online Thomson parabola spectrometer

Sakaki, Hironao; Kanasaki, Masato; Fukuda, Yuji; Nishiuchi, Mamiko; Hori, Toshihiko; Yogo, Akifumi; Jinno, Satoshi; Niita, Koji*

Review of Scientific Instruments, 84(1), p.013301_1 - 013301_7, 2013/01

 Times Cited Count:5 Percentile:35.1(Instruments & Instrumentation)

A single-shot-imaging thin scintillator film was developed for an online Thomson parabola (TP) spectrometer and the first analysis of laser accelerated ions, using the online TP spectrometer, was demonstrated at the JAEA-Kansai Advanced Relativistic Engineering Laser System (J-KAREN). An energy spectrum of 4.0 MeV protons is obtained using only this imaging film without the need of a microchannel plate that is typically utilized in online ion analyses. A general-purpose Monte Carlo particle and heavy ion-transport code system, which consists of various quantum dynamics models, was used for the prediction of the luminescent properties of the scintillator. The simulation can reasonably predict not only the ion trajectories detected by the spectrometer, but also luminescence properties.

Journal Articles

Analytical methods using a positron microprobe

Oka, Toshitaka; Jinno, Satoshi*; Fujinami, Masanori*

Analytical Sciences, 25(7), p.837 - 844, 2009/07

 Times Cited Count:13 Percentile:16.51(Chemistry, Analytical)

Positrons have been used for material analysis not only because of their novel characteristics, such as an ability to detect open-volume type defects in materials, but also because interactions with solids differ from those of electrons in such processes as scattering and diffraction. Monoenergetic positron beams and microbeams were developed in the 1980s, and positron experiments have made progress in material analyses. In this article we review the fundamental technique of microbeam fabrication, especially using a magnetically-guided positron beam, its extension to various analytical methods, and expectations for future research.

Oral presentation

Temperature dependence of free volume in polyethylene

Oka, Toshitaka; Jinno, Satoshi*; Fujiwara, Aya*; Fujinami, Masanori*

no journal, , 

Temperature dependence of free volume in polyethylene was investigated by positron annihilation lifetime spectroscopy. The relationship between the thermal expansion of free volume and the sample density was clearly shown.

Oral presentation

Development of positron probe microanalyzer using RI source and its applications

Fujinami, Masanori*; Jinno, Satoshi*; Oka, Toshitaka; Kawashima, Yuji*

no journal, , 

Oral presentation

Development of online Thomson parabola spectrometer for laser-driven ions

Sakaki, Hironao; Kanasaki, Masato; Fukuda, Yuji; Nishiuchi, Mamiko; Yogo, Akifumi; Jinno, Satoshi; Katagiri, Masaki*; Niita, Koji*

no journal, , 

A single-shot imaging thin scintillator film for online Thomson Parabola spectrometer (TP) has been developed, and the first diagnosis for laser-driven ion by the online TP is demonstrated at J-KAREN laser facility. The energy spectrum of $$sim$$4.0 MeV proton is obtained by only this imaging film without using Micro-Channel-Plate that is utilized on online ion diagnosis in general. The general-purpose Monte Carlo particle and heavy ion transport code systems (PHITS) consists various quantum dynamics models is used in the simulation of the scintillator's luminescent diagnostic. The simulation is reasonably predictive not only ion trajectories by the spectrometer but also the luminescence property.

Oral presentation

A Precise measurement of laser accelerated protons with CR-39 track detectors

Kanasaki, Masato; Fukuda, Yuji; Sakaki, Hironao; Yogo, Akifumi; Jinno, Satoshi; Nishiuchi, Mamiko; Ogura, Koichi; Kondo, Kiminori; Oda, Keiji*; Yamauchi, Tomoya*

no journal, , 

Recently, solid state nuclear track detectors such as CR-39 detectors have been extensively used in laser-driven ion acceleration experiments, because CR-39 can record the tracks of ion clearly even in the intense fields of photons and high energy electrons. By analyzing the etch pit growth behavior, we can obtain not only the radial intensity distribution of ion beam, but the energy and nuclear species for each ion precisely. This method allows us to measure the maximum energy of proton precisely, which is obtained up to the hundredth place in unit of MeV in the laser-driven particle acceleration experiment.

78 (Records 1-20 displayed on this page)