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Journal Articles

Development of laser system for laser stripping injection

Harada, Hiroyuki; Saha, P. K.; Yoneda, Hitoki*; Michine, Yurina*; Fuchi, Aoi*; Sato, Atsushi*; Kinsho, Michikazu

JPS Conference Proceedings (Internet), 33, p.011026_1 - 011026_6, 2021/03

The charge-exchange multi-turn injection by using a carbon stripper foil is adopted in high-intensity proton ring accelerators worldwide. It is a beneficial method to compress the pulsed proton beam with high intensity but there are serious issues for high intensity. First issue is a short lifetime of the foil by deformation or breaking itself. Another issue is high radiation dose corresponding to the scattered particles on the foil. Therefore, a non-destructive stripping injection method is required for higher intensity proton beam. We newly propose a non-destructive method of H$$^{-}$$ stripping by using only laser. The new method is called "laser stripping injection". To establish our method, we are preparing for a POP (Proof-of-Principle) experiment of 400 MeV H- stripping to proton at J-PARC. In our presentation we will present the current status of laser system development for laser stripping injection at J-PARC.

Journal Articles

Studies of laser power reduction for the laser stripping of 400 MeV $$H^{-}$$ beam at J-PARC RCS

Saha, P. K.; Harada, Hiroyuki; Kinsho, Michikazu; Yoneda, Hitoki*; Michine, Yurina*; Fuchi, Aoi*; Sato, Atsushi*; Liu, Y.*

JPS Conference Proceedings (Internet), 33, p.011025_1 - 011025_7, 2021/03

Journal Articles

Status of laser development for laser stripping experiment at J-PARC

Harada, Hiroyuki; Saha, P. K.; Yoneda, Hitoki*; Michine, Yurina*; Fuchi, Aoi*; Sato, Atsushi*; Shibata, Takanori*; Kinsho, Michikazu

Proceedings of 17th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.441 - 445, 2020/09

The high-intensity proton accelerator adopts a charge exchange injection scheme, which injects with exchanging from negative Hydrogen ion to proton by using carbon foil. This scheme is destructive-type method by using the foil and can accumulate high intensity proton beam. However, the uncontrolled beam losses by scattering at the foil and the foil breaking by the beam collision are a key issue of high-intensity proton accelerator. In order to realize higher intensity, new injection scheme of non-destructive type is needed instead of the foil. We newly propose laser stripping injection scheme by using laser pulse. We plan proof of principle experiment at J-PARC and are developing the laser system. In my presentation, we introduce the overview of laser stripping injection scheme and report the status of laser development.

Journal Articles

Status of the proof-of-principle demonstration of 400 MeV H$$^{-}$$ laser stripping at J-PARC

Saha, P. K.; Harada, Hiroyuki; Yoneda, Hitoki*; Michine, Yurina*; Fuchi, Aoi*; Sato, Atsushi*; Shibata, Takanori*; Kinsho, Michikazu

Proceedings of 17th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.436 - 440, 2020/09

Journal Articles

Development of two-mirror multi-pass laser system to reduce laser power for laser stripping injection at J-PARC 3-GeV RCS

Saha, P. K.; Harada, Hiroyuki; Kinsho, Michikazu; Sato, Atsushi*; Yoneda, Hitoki*; Michine, Yurina*

Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.841 - 845, 2019/07

Journal Articles

Progress status of proof-of-principle demonstration of 400 MeV H$$^{-}$$ laser stripping at J-PARC 3-GeV RCS

Saha, P. K.; Harada, Hiroyuki; Kinsho, Michikazu; Miura, Akihiko; Yoshimoto, Masahiro; Okabe, Kota; Suganuma, Kazuaki; Yamane, Isao*; Irie, Yoshiro*; Liu, Y.*; et al.

Proceedings of 15th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.806 - 810, 2018/08

Journal Articles

Development of laser system for a proof-of-principle experiment of laser stripping injection

Harada, Hiroyuki; Saha, P. K.; Yoneda, Hitoki*; Michine, Yurina*; Inoue, Shunsuke*; Sato, Atsushi*; Suganuma, Kazuaki; Yamane, Isao*; Kinsho, Michikazu; Irie, Yoshiro*

Proceedings of 15th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.811 - 815, 2018/08

The high-intensity proton accelerator adopts a charge exchange injection scheme, which injects with exchanging from negative Hydrogen ion to proton by using carbon foil. This scheme can realize high intensity proton beam but the uncontrolled beam losses occur by scattering at the foil. Additionally, the beam collision at the foil may cause the break itself. Therefore, a new injection scheme for higher intensity is needed as an alternative to the foil. We newly propose and develop a laser stripping injection scheme. At the first step, we propose a proof-of-principle (POP) experiment of the scheme in J-PARC and develop a laser system. In this presentation, we will introduce the laser stripping injection scheme and describe an overview of a POP experiment. We will report a current status of the laser system.

Journal Articles

Status of proof-of-principle demonstration of 400 MeV H- stripping to proton by using only lasers at J-PARC

Saha, P. K.; Harada, Hiroyuki; Kinsho, Michikazu; Miura, Akihiko; Yoshimoto, Masahiro; Irie, Yoshiro*; Yamane, Isao*; Yoneda, Hitoki*; Michine, Yurina*

Proceedings of 61st ICFA Advanced Beam Dynamics Workshop on High-Intensity and High-Brightness Hadron Beams (HB 2018) (Internet), p.422 - 427, 2018/07

Journal Articles

Zeeman splitting of laser-driven soft X-ray laser line by the enhancement of magnetic field in plasma

Kawachi, Tetsuya; Hasegawa, Noboru; Iwamae, Atsushi*; Yoneda, Hitoki*

Journal of Physics; Conference Series, 548(1), p.012038_1 - 012038_7, 2014/11

 Times Cited Count:0 Percentile:0.03

Polarization is a fundamental property of light, and the effective use provides us powerful tools for probing materials and for plasma diagnostics. In plasmas, alignment of emission shows the plasma anisotropy, and Zeeman splitting informs us the magnetic field strength. We took the plasma-based soft X-ray laser as an example and observed the Zeeman splitting under the external magnetic field. A grazing incidence spectrograph, HIREFS, with the resolution of 15000 was used to observe the X-ray laser line. A magnetic coil driven by an electrical pulsed power supply provided the external magnetic field of 10$$sim$$35 T along the direction of the plasma column, and the left-handed and right-handed circular polarization components were obtained separately. The experimental result indicated that the magnetic field was larger by a factor of 4 than that of the applied field, which implied that the magnetic field compression occurred in the dynamics of the intense laser-plasma interaction.

Journal Articles

High-precision measurement of the spectral width of the nickel-like molybdenum X-ray laser

Hasegawa, Noboru; Kawachi, Tetsuya; Sasaki, Akira; Yamatani, Hiroshi; Kishimoto, Maki; Ochi, Yoshihiro; Tanaka, Momoko; Nishikino, Masaharu; Kunieda, Yuichi; Nagashima, Keisuke; et al.

Journal of Physics; Conference Series, 163(1), p.012062_1 - 012062_4, 2009/06

 Times Cited Count:2 Percentile:68.23

The precise knowledge about the wavelength and the spectral width of the lasing line is important for the applications of X-ray lasers, and especially for the spectral width, it is good benchmark of the atomic code because it depends on the electron collisional excitation and de-excitation rate coefficient. Only a few measurements of the spectral width of the laser line have been reported, because the spectral width of the X-ray laser is so narrow that the required spectral resolution is quite high. In this study, we took the nickel-like molybdenum X-ray laser as an example, and measure the spectral width by use of the high resolution spectrometer in order to compare it with a theoretical one.

Journal Articles

High-resolution spectroscopy of the nickel-like molybdenum X-ray laser toward the generation of circularly polarized X-ray laser

Hasegawa, Noboru; Sasaki, Akira; Yamatani, Hiroshi; Kishimoto, Maki; Tanaka, Momoko; Ochi, Yoshihiro; Nishikino, Masaharu; Kunieda, Yuichi; Kawachi, Tetsuya; Yoneda, Hitoki*; et al.

Journal of the Optical Society of Korea, 13(1), p.60 - 64, 2009/03

 Times Cited Count:5 Percentile:31.16(Optics)

The precise knowledge about the spectral width of the X-ray laser line is important to generate the circularly polarized X-ray laser. There are three magnetic sub-levels at lower state of the collisional excitation X-ray laser transition of the nickel-like ion X-ray laser medium. The polarization of each transition is circular or linear. Therefore the circularly polarized X-ray laser could be extracted by the influence of the Zeeman effect if the X-ray laser medium was under the external magnetic field. The strength of the magnetic field required for the circularly polarized X-ray laser is determined by the spectral width of the X-ray laser. Only a few measurements of the spectral width of the laser line have been reported, because the spectral width of the X-ray laser is so narrow that the required spectral resolution is quite high. In this study, we took the nickel-like molybdenum X-ray laser as an example and succeeded the measurement of the spectral width of the X-ray laser.

Oral presentation

Generation of polarization control of plasma X-ray laser by strong magnetic field

Hasegawa, Noboru; Kawachi, Tetsuya; Sasaki, Akira; Kishimoto, Maki; Tanaka, Momoko; Ochi, Yoshihiro; Nishikino, Masaharu; Kunieda, Yuichi; Iwamae, Atsushi*; Yoneda, Hitoki*

no journal, , 

We tried to generate the circularly polarized X-ray laser by use of the high power pulse magnet system. There are three magnetic sub-levels at lower state of the collisional excitation X-ray laser transition. For example, nickel-like X-ray laser transition (4d (m = 0) - 4p (m = -1, 0, +1)), the polarization from each transitions are right-handed circular ($$Delta$$m = -1), left-handed circular ($$Delta$$m = +1), and linear ($$Delta$$m = 0) along to the quantization axis. If the quantization axis were decided by the magnetic field from the outside of the X-ray laser medium, the circularly polarized X-ray laser can be extracted. In this study, we tried to generate the circularly polarized X-ray laser by using the nickel-like molybdenum X-ray laser medium (18.9 nm) with 20 Tesla magnetic field generated by the pulse power magnet system.

Oral presentation

Polarization control of plasma X-ray laser by pulse magnetic field

Hasegawa, Noboru; Kawachi, Tetsuya; Sasaki, Akira; Kishimoto, Maki; Ochi, Yoshihiro; Nishikino, Masaharu; Yoneda, Hitoki*

no journal, , 

We proposed and demonstrated the polarization control method of an X-ray laser using the magnetic field for the first time. The line of nickel-like molybdenum X-ray laser was separated using a high-resolution spectrometer with strong magnetic field. The result of this experiments implied the left and right handed circularly polarized X-ray laser were generated at the same time. It is very applicable for a circular dichroism measurement.

Oral presentation

A Proof-Of-Principle (POP) experiment for laser stripping injection

Harada, Hiroyuki; Saha, P. K.; Yoneda, Hitoki*; Michine, Yurina*; Fuchi, Aoi*; Sato, Atsushi*; Kinsho, Michikazu

no journal, , 

The high-intensity proton accelerator adopts a charge exchange injection scheme, which injects with exchanging from negative Hydrogen ion to proton by using carbon foil. This scheme can realize high intensity proton beam but the uncontrolled beam losses are caused by scattering between beams and the foil. Additionally, the collision may occur the foil beak. Therefore, a new injection scheme for higher intensity is needed as an alternative to the foil. In the J-PARC, we newly propose a laser stripping injection scheme by using a laser and develop the laser system for a test. In my presentation, we introduce an overview of laser stripping injection and report the status of the development.

Oral presentation

Status of a proof-of-principle experiment for realizing laser stripping injection at high-intensity proton accelerator

Harada, Hiroyuki; Saha, P. K.; Yoneda, Hitoki*; Michine, Yurina*; Fuchi, Aoi*; Sato, Atsushi*; Shibata, Takanori*; Kinsho, Michikazu

no journal, , 

The high-intensity proton accelerator adopts a charge exchange injection scheme, which injects with exchanging from negative Hydrogen ion to proton by using carbon foil. This scheme is destructive-type method by using the foil and can accumulate high intensity proton beam. However, the uncontrolled beam losses by scattering at the foil and the foil breaking by the beam collision are a key issue of high-intensity proton accelerator in the world. In the J-PARC, we newly propose a laser stripping injection scheme of nondestructive-type method as an alternative to the foil and are under development for a proof-of-principle experiment of the method. In my presentation, we introduce an overview of laser stripping injection. Additionally, we report the status of the development and the schedule of the experiment.

Oral presentation

Development of high repetitive laser pulse system for charge exchange process of hydrogen beam in J-PARC

Fuchi, Aoi*; Yoneda, Hitoki*; Michine, Yurina*; Harada, Hiroyuki; Saha, P. K.; Sato, Atsushi*; Shibata, Takanori*; Kinsho, Michikazu

no journal, , 

In the J-PARC as high-intensity proton accelerator, beam injection into a synchrotron uses for charge exchange process from hydrogen to proton. For higher intensity beam, we study laser development and POP experiment for charge exchange by using laser. In our method, we consider doppler shift and multi process of electron stripping. Therefore, we are developing high power laser and the 5th harmonics. In order to reduce laser power, we must increase the utilization rate of laser. So, we develop multi-pass cavity and beam shaper. In our presentation, we will report about a status of high-repetition laser and optics devices under developing.

Oral presentation

Status of laser stripping experiment in high-intensity proton accelerator

Harada, Hiroyuki; Saha, P. K.; Yoneda, Hitoki*; Michine, Yurina*; Fuchi, Aoi*; Shibata, Takanori*; Kinsho, Michikazu

no journal, , 

The high-intensity proton accelerator adopts a charge exchange injection scheme, which injects with exchanging from negative Hydrogen ion to proton by using carbon foil. This scheme is destructive-type method by using the foil and can accumulate high intensity proton beam. However, the uncontrolled beam losses by scattering at the foil and the foil breaking by the beam collision are a key issue of high-intensity proton accelerator in the world. In the J-PARC, we newly propose a laser stripping injection scheme of nondestructive-type method as an alternative to the foil and are under development for a proof-of-principle experiment of the method. In my presentation, we introduce an overview of laser stripping injection. Additionally, we report the status of the development and the results of the first experiment (day-1).

Oral presentation

Development of laser system for charge exchange negative hydrogen ion beam in high-intensity proton accelerator

Fuchi, Aoi*; Yoneda, Hitoki*; Michine, Yurina*; Harada, Hiroyuki; Saha, P. K.; Shibata, Takanori*; Kinsho, Michikazu

no journal, , 

In high-intensity proton accelerator, accelerated H- beams in linac are injected with charge exchange in the ring by using carbon foil. This scheme is destructive-type method by using the foil and can accumulate high intensity proton beam. However, the uncontrolled beam losses by scattering at the foil and the foil breaking by the beam collision are a key issue of high-intensity proton accelerator in the world. In the J-PARC, we newly propose a laser stripping injection scheme of nondestructive-type method as an alternative to the foil and are under development for a proof-of-principle experiment of the method. We developed laser system and optical cavity and started the first trial of the experiment. As this experimental result, we realized the charge exchange of 0.57% for final goal one of 99%. In our presentation, developed laser system and optics will be explained and we will report first results of the experiment.

Oral presentation

Development and calibration of Doppler shifted Balmer lines photometry system for 400 MeV $$H^0$$ atoms generated by laser $$H^-$$ stripping

Shibata, Takanori*; Harada, Hiroyuki; Saha, P. K.; Yoneda, Hitoki*; Michine, Yurina*; Fuchi, Aoi*; Kinsho, Michikazu

no journal, , 

In order to further increase the intensity of the proton beam at J-PARC, we are planning a laser charge conversion test to convert the proton beam to protons nondestructively instead of the current carbon film. In the laser charge conversion process, we are considering a scenario in which neutral hydrogen $$H^0$$ is passed through excited $$H^0*$$. For this experiment, it is necessary to understand the energy levels of $$H^0$$ and its excitation efficiency. In this study, we are developing a spectroscopic measurement system to spectroscopically detect the light emitted from the excited $$H^0$$. In this presentation, we will report on the development of the spectroscopic measurement system, which is important for laser charge conversion.

Oral presentation

Laser stripping experiment in J-PARC

Harada, Hiroyuki; Saha, P. K.; Yoshimoto, Masahiro; Kinsho, Michikazu; Yoneda, Hitoki*; Michine, Yurina*; Fuchi, Aoi*; Shibata, Takanori*

no journal, , 

In high-intensity proton accelerator, H$$^{-}$$ beams are injected with charge exchange into the ring by using a carbon foil. This scheme is destructive-type method and can accumulate high intensity proton beam. However, the uncontrolled beam losses by foil scattering and the foil breaking are a key issue in the world. In the J-PARC, we newly propose a laser stripping injection scheme of nondestructive-type method as an alternative to the foil and are under development for a proof-of-principle experiment of the method. We developed laser system and optical cavity and performed the second trial of the experiment. We were successfully matched laser pulse to ion beam one in time-space dimension. As this experimental result, we realized the charge exchange ratio of 16.8%, which is 30 times higher than first result of 0.57%. We present the experimental results with introducing the scheme.

Oral presentation

J-PARC charge exchange experiment with picosecond pulse train laser system

Fuchi, Aoi*; Harada, Hiroyuki; Yoneda, Hitoki*; Michine, Yurina*; Saha, P. K.; Yoshimoto, Masahiro; Kinsho, Michikazu; Shibata, Takanori*

no journal, , 

At the J-PARC, a non-destructive method of "laser charge exchange injection" has been proposed and is under development to replace the carbon foil. In addition, the development of a non-destructive beam profile monitor is also important to stabilize the beam operation. In this study, we developed a laser source and a multi-pass cavity for this purpose, and performed the second experiment. In the development of the laser source, the timing of each of the five laser amplifiers was staggered, and we succeeded in producing a laser with a flat pulse structure. In the development of the multi-pass cavity, we succeeded in focusing 16 pulses of laser simultaneously to the irradiation point. As a result, a charge exchange efficiency of 16.8%, 30 times higher than the previous efficiency of 0.57%, was achieved. In this presentation, we report the results of the laser source development and the multi-pass cavity development.

21 (Records 1-20 displayed on this page)