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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:17 Percentile:26.34(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

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:21 Percentile:26.74(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

The Spectra of the multicharged argon hollow ions; Observation, modeling and using for diagnostics of the early stage of the heating of clusters by a supper high contrast femtosecond laser pulses

Pikuz, T.; Faenov, A.*; Skobelev, I.*; Fortov, V. E.*; Boldarev, A.*; Gasilov, V.*; Chen, L. M.*; Zhang, L.*; Yan, W.*; Yuan, D.*; et al.

AIP Conference Proceedings 1465, p.181 - 201, 2012/07

 Times Cited Count:0 Percentile:100

Journal Articles

Ion acceleration in subcritical density plasma via interaction of intense laser pulse with cluster-gas target

Fukuda, Yuji; Faenov, A.*; Tampo, Motonobu; Pikuz, T.*; Nakamura, Tatsufumi; Kando, Masaki; Hayashi, Yukio; Yogo, Akifumi; Sakaki, Hironao; Kameshima, Takashi*; et al.

Progress in Ultrafast Intense Laser Science VII, p.225 - 240, 2011/05

We present substantial enhancement of the accelerated ion energies up to 10-20 MeV per nucleon by utilizing the unique properties of the cluster-gas target irradiated with 40-fs laser pulses of only 150 mJ energy, corresponding to approximately tenfold increase in the ion energies compared to previous experiments using thin foil targets. A particle-in-cell simulation infers that the high energy ions are generated at the rear side of the target due to the formation of a strong dipole vortex structure in sub-critical density plasmas. The demonstrated method can be important in the development of efficient laser ion accelerators for hadron therapy and other applications.

Journal Articles

Energy increase in multi-MeV ion acceleration in the interaction of a short pulse laser with a cluster-gas target

Fukuda, Yuji; Faenov, A. Y.; Tampo, Motonobu; Pikuz, T. A.*; Nakamura, Tatsufumi; Kando, Masaki; Hayashi, Yukio; Yogo, Akifumi; Sakaki, Hironao; Kameshima, Takashi*; et al.

Physical Review Letters, 103(16), p.165002_1 - 165002_4, 2009/10

 Times Cited Count:137 Percentile:3.1(Physics, Multidisciplinary)

A new approach for accelerating ions, based on the use of a cluster-gas target and a compact ultrashort pulse laser, is presented. It is shown that ions with energy 10-20 MeV per nucleon having a small divergence (full angle) of 3.4$$^{circ}$$ are generated, corresponding to an approximately tenfold increase in the ion energies compared to previous experiments using solid targets. It is inferred from a particle-in-cell code simulation that the high energy ions are generated at the rear side of the target due to the formation of a strong dipole vortex structure in near-critical density plasmas.

Journal Articles

Submicron ionography of nanostructures using a femtosecond- laser-driven-cluster-based source

Faenov, A. Y.; Pikuz, T. A.*; Fukuda, Yuji; Kando, Masaki; Kotaki, Hideyuki; Homma, Takayuki; Kawase, Keigo; Kameshima, Takashi*; Pirozhkov, A. S.; Yogo, Akifumi; et al.

Applied Physics Letters, 95(10), p.101107_1 - 101107_3, 2009/09

 Times Cited Count:25 Percentile:28.12(Physics, Applied)

Journal Articles

X-ray spectroscopic diagnostics of ultrashort laser-cluster interaction at the stage of the nonadiabatic scattering of clusters

Faenov, A. Y.; Magunov, A. I.*; Pikuz, T. A.*; Skobelev, I. Y.*; Giulietti, D.*; Betti, S.*; Galimberti, M.*; Gamucci, A.*; Giulietti, A.*; Gizzi, L. A.*; et al.

JETP Letters, 86(3), p.178 - 183, 2007/08

 Times Cited Count:5 Percentile:60.51(Physics, Multidisciplinary)

Journal Articles

Gas-cluster targets for femtosecond laser interaction; Modeling and optimization

Boldarev, A. S.*; Gasilov, V. A.*; Faenov, A. Y.*; Fukuda, Yuji; Yamakawa, Koichi

Review of Scientific Instruments, 77(8), p.083112_1 - 083112_10, 2006/08

 Times Cited Count:67 Percentile:6.73(Instruments & Instrumentation)

A novel mathematical model for the investigations of a cluster formation process in a gas jet is presented, which enables us to obtain the detailed description of the spatial and temporal distributions of all cluster target parameters. In this model, a cluster target is considered as a two-phase medium, consisting of the continuous gas phase and the discrete condensed phase (clusters). The detailed nozzle geometry is also taken into account in this model. In order to confirm the advantage of the present model over a conventional model, a considerable amount of numerical computations has been carried out, and the results are compared with the data obtained from the Hagena's theory. Based on the developed modeling, a three-staged nozzle, which cannot be modeled using the conventional model, is designed for the purpose of producing sufficient amount of micron-sized clusters. Generation of unprecedented amount of keV X rays from the laser-cluster interaction experiments with this nozzle and their accurate intensity dependences onvarious experimental parameters support the adequateness of the nozzle design.

Journal Articles

Generation of X-rays and energetic ions from superintense laser irradiation of micron-sized Ar clusters

Fukuda, Yuji; Akahane, Yutaka; Aoyama, Makoto; Inoue, Norihiro*; Ueda, Hideki; Kishimoto, Yasuaki; Yamakawa, Koichi; Faenov, A. Y.*; Magunov, A. I.*; Pikuz, T. A.*; et al.

Laser and Particle Beams, 22(3), p.215 - 220, 2004/07

High resolution K-shell spectra of a plasma created by superintense laser irradiation of micron-sized Ar clusters have been measured with an intensity above 10$$^{19}$$ W/cm$$^2$$ and a pulse duration of 30 fs. The total photon flux of 2$$times$$10$$^8$$ photons/pulse was achieved for He$$_{alpha1}$$ resonant line of Ar ($$lambda$$=3.9491 AA , 3.14 keV). In parallel with X-ray measurements, energy distributions of emitted ions have been measured. The multiply-charged ions with kinetic energies up to 800 keV were observed. It is found that hot electrons produced by high contrast laser pulses allow the isochoric heating of clusters and shift the ion balance towards the higher charge states, which enhances both the X-ray line yield of the He-like argon ion and the ion kinetic energy.

Journal Articles

X-ray radiation of clusters irradiated by ultrafast, high-intensity laser pulses

Fukuda, Yuji; Akahane, Yutaka; Aoyama, Makoto; Inoue, Norihiro*; Ueda, Hideki; Kishimoto, Yasuaki; Yamakawa, Koichi; Faenov, A. Y.*; Magunov, A. I.*; Pikuz, T. A.*; et al.

Laser-Generated & Other Lab. X-Ray & EUV Sources (Proceedings of SPIE Vol.5196), p.234 - 243, 2004/00

High resolution X-ray emission spectra of plasma created by laser irradiation of rare-gas (Ar, Kr, Xe) clusters have been measured at laser intensities over 10$$^{19}$$ W/cm$$^2$$ and 30-fs pulse duration. To make these measurements possible, in addition to the effort to decrease a prepulse intensity using Pockels cell switches, micron-size clusters were produced using a specially designed conical nozzle. The Boltzmann equation and a detailed collisional radiative model are solved simultaneously as a function of time to model the time integrated X-ray spectra of the transient plasma. The results are quantitatively in good agreement with the experimentally observed X-ray emission spectra of Ar clusters.

Journal Articles

X-ray study of microdroplet plasma formation under the action of superintense laser radiation

Fukuda, Yuji; Yamakawa, Koichi; Akahane, Yutaka; Aoyama, Makoto; Inoue, Norihiro*; Ueda, Hideki; Abdallah, J. Jr.*; Csanak, G.*; Faenov, A. Y.*; Magunov, A. I.*; et al.

JETP Letters, 78(3), p.115 - 118, 2003/08

 Times Cited Count:28 Percentile:22.09(Physics, Multidisciplinary)

We have measured the X-ray emission spectra of a plasma generated by laser radiation with an intensity above 10$$^{19}$$ W/cm$$^2$$ and a pulse duration of 30 fs acting uon an argon jet target with a large aboundance of micron-sized clusters. The time variation of the X-ray yeild from various multiplicities, calculated within the framework of a nonstationary kinetic model, shows a good qualitative agreement with the experimental time-integrated spectrum.

Oral presentation

Novel path towards compact laser ion accelerators for hadron therapy; Tenfold energy increase in laser-driven multi-MeV ion generation using a cluster-gas target

Fukuda, Yuji; Faenov, A. Y.; Tampo, Motonobu; Pikuz, T.*; Nakamura, Tatsufumi; Kando, Masaki; Hayashi, Yukio; Yogo, Akifumi; Sakaki, Hironao; Kawase, Keigo; et al.

no journal, , 

We demonstrate generation of 10-20 MeV/u ions with a compact 4 TW laser using a gas target mixed with submicron clusters, corresponding to tenfold increase in the ion energies compared to previous experiments with solid targets. It is inferred that the high energy ions are generated due to formation of a strong dipole vortex structure. The demonstrated method has a potential to construct compact and high repetition rate ion sources for hadron therapy and other applications.

Oral presentation

Energy increase in laser-driven multi-MeV ion generation using a cluster-gas target

Fukuda, Yuji; Faenov, A. Y.; Tampo, Motonobu; Pikuz, T. A.*; Nakamura, Tatsufumi; Kando, Masaki; Hayashi, Yukio; Homma, Takayuki; Kawase, Keigo; Yogo, Akifumi; et al.

no journal, , 

We demonstrate generation of 10-20 MeV/u ions with a compact 4 TW laser using a gas target mixed with submicron clusters, corresponding to tenfold increase in the ion energies compared to previous experiments with solid targets. It is inferred that the high energy ions are generated due to formation of a strong dipole vortex structure.

Oral presentation

Ion acceleration in the interaction of a short pulse laser with a cluster-gas target

Fukuda, Yuji; Faenov, A. Y.; Tampo, Motonobu; Pikuz, T. A.*; Nakamura, Tatsufumi; Kando, Masaki; Hayashi, Yukio; Homma, Takayuki; Kawase, Keigo; Kotaki, Hideyuki; et al.

no journal, , 

An approach for accelerating ions, with the use of a cluster-gas target and an ultrashort pulse laser of 150-mJ energy and 40-fs duration, is presented. Ions with energy 10-20 MeV per nucleon having a small divergence (full angle) of 3.4$$^{circ}$$ are generated in the forward direction, corresponding to approximately tenfold increase in the ion energies compared to previous experiments using solid targets. It is inferred from a particle-in-cell simulation that the high energy ions are generated at the rear side of the target due to the formation of a strong dipole vortex structure in subcritical density plasmas.

Oral presentation

Development of an apparatus for characterization of cluster-gas targets

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.

no journal, , 

In the laser drive ion acceleration using cluster-gas targets, the three-step conical nozzle specially designed based on the Boldarev's model is used to prepare the large-sized clusters. In the present work, the target diagnosis apparatus applying Mie scattering and interferometry has been developed to investigate the ion acceleration mechanism and search the optimal condition. The sub-micron sized CO$$_2$$ clusters were verified by measuring the angular distribution of the scattering light from the gas jet of the mixture gas of CO$$_2$$(30%) and H$$_2$$(70%). Moreover, the gas density was obtained by the interferometry.

Oral presentation

Identification of the micro-sized cluster by Mie scattering

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.

no journal, , 

We perform the laser driven ion acceleration using a gas jet target including large sized clusters which is formed by the special nozzle designed based on the Boldarev's model. The information of the cluster size and the gas jet profile is necessary for the investigation of the ion acceleration mechanism and the optimization of the acceleration condition. Therefore, we have developed a target diagnosis apparatus applying Mie scattering and interferometry. The sub-micron sized CO$$_2$$ clusters were verified by measuring the angular distribution of the scattering light from the gas jet of the mixture gas of CO$$_2$$ (30%) and H$$_2$$ (70%). Moreover, the gas density profile was obtained by using the interferometer.

Oral presentation

Characterization of sub-micron sized clusters in a supersonic gas jet using Mie scattering

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

no journal, , 

High-energy ion generation has been achieved by using cluster-gas targets in the laser driven ion acceleration. In this experiment, a three-step conical nozzle, designed based on the Boldarev's model, was used to prepare large sized clusters. However, a characterization of the targets formed by this nozzle was not sufficient to further investigate the ion acceleration mechanism and optimize the acceleration condition. For this reason, in present work, the target diagnosis apparatus applying Mie scattering and interferometry has been developed. CO$$_2$$ clusters are formed in the supersonic jet of the mixture gas of H$$_2$$ and CO$$_2$$ through the three-step conical nozzle. We have estimated the size distribution of CO$$_2$$ cluster by measuring the angular distribution of scattering light from the clusters for laser irradiation. The density profile was obtained from the phase shift of the laser light acquired by the interferometer. These results were compared with the Boldarev's model.

Oral presentation

Discussion of gas density dependence in the cluster size evaluation using Mie scattering

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.

no journal, , 

We have achieved high-energy ion generation in the laser driven ion acceleration using cluster-gas targets, which has been prepared by using the nozzle specially designed based on the Boldarev's model. However, a characterization of the cluster-gas targets is not sufficient to further investigate the ion acceleration mechanism and optimize the acceleration condition. In present work, the target diagnosis apparatus applying Mie scattering and interferometry has been developed. The sub-micron sized CO$$_2$$ clusters were verified by measuring the angular distribution of the scattering light from the mixed gas target of CO$$_2$$ (30%) and H$$_2$$ (70%). Moreover, the gas density profile was obtained by the interferometry. We will discuss the relation between gas density and a cluster size in the presentation.

Oral presentation

Ion acceleration by a cluster target; Target state dependence of an electron energy spectrum

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.

no journal, , 

no abstracts in English

Oral presentation

Characterization of cluster-gas targets and its application to laser-driven particle acceleration experiments

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

no journal, , 

We have achieved ion generations of several tens MeV in the laser driven ion acceleration using cluster-gas targets. The detailed knowledge of the initial target parameters is the key to understanding the acceleration mechanism. In present study, we have evaluated the sizes of CO$$_2$$ clusters, which formed in the supersonic expansion of CO$$_2$$/He and CO$$_2$$/H$$_2$$ mixed-gases, by measuring angular distributions of Mie scattered light from the clusters. The gas density profiles of the targets were also evaluated with an interferometry. Moreover, we have observed the energy spectra of generating electrons from the target irradiated by the J-KAREN laser in real time since the spectra can be a guide for searching the optimal condition of the ion acceleration. As a result, we found that the spectra vary significantly depending on the focal positions inside the target. We consider the correlation between the target initial condition and the electron energy spectra.

Oral presentation

Characterization of cluster targets by Mie scattering

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.

no journal, , 

no abstracts in English

21 (Records 1-20 displayed on this page)