Observation of preformed plasma generated from a thin-foil target for laser-driven proton acceleration

Sagisaka, Akito; Pirozhkov, A. S.; Nishiuchi, Mamiko; Ogura, Koichi; Sakaki, Hironao; Yogo, Akifumi; Mori, Michiaki; Kiriyama, Hiromitsu; Okada, Hajime; Kanazawa, Shuhei; et al.

Reza Kenkyu, 42(2), p.160 - 162, 2014/02

High-intensity laser and thin-foil interactions produce high-energy particles, hard X-ray, high-order harmonics, and terahertz radiation. A proton beam driven by a high-intensity laser has received attention as a compact ion source for medical and other applications. We have measured the proton yield from thin-foil targets irradiated with a high-intensity Ti:sapphire laser (J-KAREN) at JAEA. The longitudinal extent of the preformed plasma protruding from the front surface of the target is reduced by decreasing the duration of the amplified spontaneous emission (ASE) before the main pulse. The maximum proton energy in the target normal direction increases when the size of the preformed plasma is controlled.

Temporal contrast enhancement of petawatt-class laser pulses

Kiriyama, Hiromitsu; Shimomura, Takuya; Sasao, Hajime; Nakai, Yoshiki*; Tanoue, Manabu; Kondo, Shuji; Kanazawa, Shuhei; Pirozhkov, A. S.; Mori, Michiaki; Fukuda, Yuji; et al.

Optics Letters, 37(16), p.3363 - 3365, 2012/08

https://doi.org/10.1364/OL.37.003363

We demonstrate the temporal contrast enhancement in a petawatt-class Ti:sapphire chirped-pulse amplification (CPA) laser system. An extra saturable absorber, introduced downstream a low gain optical parametric chirped-pulse amplification (OPCPA) preamplifier, has improved the temporal contrast in the system to 1.410 on the sub-nanosecond time scale at 70 TW power level. We have achieved 28 J of uncompressed broadband output energy with this system, indicating the potential for reaching peak powers near 600 TW.

Complementary characterization of radioactivity produced by repetitive laser-driven proton beam using shot-to-shot proton spectral measurement and direct activation measurement

Ogura, Koichi; Shizuma, Toshiyuki; Hayakawa, Takehito; Yogo, Akifumi; Nishiuchi, Mamiko; Orimo, Satoshi; Sagisaka, Akito; Pirozhkov, A. S.; Mori, Michiaki; Kiriyama, Hiromitsu; et al.

Japanese Journal of Applied Physics, 51(4), p.048003_1 - 048003_2, 2012/04

https://doi.org/10.1143/JJAP.51.048003

A proton beam driven by a repetitive high-intensity-laser is utilized to induce a Li(p,n)Be nuclear reaction. The total activity of Be are evaluated by two different methods. The activity obtained measuring the decay -rays after 1912 shots at 1 Hz is 1.70.2 Bq. This is in good agreement with 1.60.3 Bq evaluated from the proton energy distribution measured using a time-of-flight detector and the nuclear reaction cross-sections. We conclude that the production of activity can be monitored in real time using the time-of-flight-detector placed inside a diverging proton beam coupled with a high-speed signal processing system.

Effect of the laser contrast ratio within picosecond timescales on generating a high-quality electron beam by laser-plasma interaction

Kotaki, Hideyuki; Kando, Masaki; Daito, Izuru; Kameshima, Takashi*; Kawase, Keigo*; Chen, L. M.*; Fukuda, Yuji; Koga, J. K.; Kiriyama, Hiromitsu; Kondo, Shuji; et al.

Japanese Journal of Applied Physics, 50(6), p.066401_1 - 066401_3, 2011/06

https://doi.org/10.1143/JJAP.50.066401

Laser-driven proton generation with a thin-foil target

Sagisaka, Akito; Pirozhkov, A. S.; Mori, Michiaki; Yogo, Akifumi; Ogura, Koichi; Orimo, Satoshi; Nishiuchi, Mamiko; Ma, J.*; Kiriyama, Hiromitsu; Kanazawa, Shuhei; et al.

NIFS-PROC-85, p.30 - 33, 2011/02

http://www.nifs.ac.jp/report/nifs-proc85.html

The experiment of proton generation is performed for developing the laser-driven ion source. We observe proton signals in the laser-plasma interaction by using a thin-foil target. To get higher energy protons the size of the preformed plasma is reduced by changing the laser contrast level. In the high-contrast laser pulse case the maximum energy of the protons generated at rear side of the target increases.

Model experiment of cosmic ray acceleration due to an incoherent wakefield induced by an intense laser pulse

Kuramitsu, Yasuhiro*; Nakanii, Nobuhiko*; Kondo, Kiminori; Sakawa, Yoichi*; Mori, Yoshitaka*; Miura, Eisuke*; Tsuji, Kazuki*; Kimura, Kazuya*; Fukumochi, Shuji*; Kashihara, Mamoru*; et al.

Physics of Plasmas, 18(1), p.010701_1 - 010701_4, 2011/01

https://doi.org/10.1063/1.3528434

Substituting an intensive laser pulse for the large amplitude light waves, we performed a model experiment of the shock environments in a laboratory plasma. An intensive laser pulse was propagated in a plasma tube created by imploding a hollow polystyrene cylinder, as the large amplitude light waves propagated in the upstream plasma at an astrophysical shock. Nonthermal electrons were generated, and the energy distribution functions of the electrons have a power-law component with an index of 2.

Proton generation and terahertz radiation from a thin-foil target with a high-intensity laser

Sagisaka, Akito; Pirozhkov, A. S.; Mori, Michiaki; Yogo, Akifumi; Ogura, Koichi; Orimo, Satoshi; Nishiuchi, Mamiko; Ma, J.*; Kiriyama, Hiromitsu; Kanazawa, Shuhei; et al.

Reza Kenkyu, 38(9), p.702 - 705, 2010/09

https://ci.nii.ac.jp/naid/10026690906

High-intensity laser and thin-foil interactions produce high-energy particles, hard X-ray, high-order harmonics, and terahertz (THz) radiation. A proton beam driven by a high-intensity laser has received attention as a compact ion source for medical applications. In this study we have tested simultaneous generation of protons and THz radiation from a thin-foil target. We use a Ti:sapphire laser system (J-KAREN) at JAEA. A laser beam is focused by an off-axis parabolic mirror at the thin-foil target. We observed the high-energy proton in the rear side of the target and THz radiation in the reflected direction. Next, high energy protons are observed by reducing the size of preformed plasma.

Measured and simulated transport of 1.9 MeV laser-accelerated proton bunches through an integrated test beam line at 1 Hz

Nishiuchi, Mamiko; Sakaki, Hironao; Hori, Toshihiko; Bolton, P.; Ogura, Koichi; Sagisaka, Akito; Yogo, Akifumi; Mori, Michiaki; Orimo, Satoshi; Pirozhkov, A. S.; et al.

Physical Review Special Topics; Accelerators and Beams, 13(7), p.071304_1 - 071304_7, 2010/07

https://doi.org/10.1103/PhysRevSTAB.13.071304

A laser-driven repetition-rated 1.9 MeV proton beam line composed of permanent quadrupole magnets (PMQs), a radio frequency (rf) phase rotation cavity, and a tunable monochromator is developed to evaluate and to test the simulation of laser-accelerated proton beam transport through an integrated system for the first time. In addition, the proton spectral modulation and focusing behavior of the rf phase rotationcavity device is monitored with input from a PMQ triplet. In the 1.9 MeV region we observe very weakproton defocusing by the phase rotation cavity. The final transmitted bunch duration and transverse profile are well predicted by the PARMILA particle transport code. The transmitted proton beam duration of 6 ns corresponds to an energy spread near 5% for which the transport efficiency is simulated to be 10%. The predictive capability of PARMILA suggests that it can be useful in the design of future higher energy transport beam lines as part of an integrated laser-driven ion accelerator system.

High-contrast (10), high-intensity (500 TW) J-KAREN laser system

Kiriyama, Hiromitsu; Mori, Michiaki; Nakai, Yoshiki; Shimomura, Takuya; Sasao, Hajime; Tanaka, Momoko; Ochi, Yoshihiro; Tanoue, Manabu*; Okada, Hajime; Kondo, Shuji; et al.

JAEA-Conf 2010-002, p.18 - 21, 2010/06

https://doi.org/10.11484/jaea-conf-2010-002

We have developed a femtosecond high intensity laser system, which combines both Ti:sapphire chirped-pulse amplification (CPA) and optical parametric chirped-pulse amplification (OPCPA) techniques, that produces more than 30 J broadband output energy, indicating the potential for achieving peak powers in excess of 500 TW. With a cleaned high-energy seeded OPCPA preamplifier as a front-end in the system, for the final compressed pulse (without pumping the booster amplifier) we found that the temporal contrast in this system exceeds 10 on the sub-nanosecond timescale, and is near 10 on the nanosecond timescale before the main femtosecond pulse. Using diffractive optical elements for beam homogenization of 100-J level high-energy Nd:glass green pump laser in a Ti:sapphire final amplifier, we have successfully generated broadband high-energy output with near-perfect top-hat intensity distributions.

Laser-driven proton accelerator for medical application

Nishiuchi, Mamiko; Sakaki, Hironao; Hori, Toshihiko; Bolton, P.; Ogura, Koichi; Sagisaka, Akito; Yogo, Akifumi; Mori, Michiaki; Orimo, Satoshi; Pirozhkov, A. S.; et al.

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.88 - 90, 2010/05

http://accelconf.web.cern.ch/accelconf/IPAC10/papers/mopea013.pdf

The concept of a compact ion particle accelerator has become attractive in view of recent progress in laser-driven ion acceleration. We report here the recent progress in the laser-driven proton beam transport at the Photo Medical Research Center (PMRC) at JAEA, which is established to address the challenge of laser-driven ion accelerator development for ion beam cancer therapy.