Charge exchange method of H beam by electron beam

Okabe, Kota

Proceedings of 17th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.446 - 448, 2020/09

https://www.pasj.jp/web_publish/pasj2020/proceedings/PDF/THPP/THPP04.pdf

One of the important research themes for further enhancement of the proton accelerator is the advancement of the charge exchange injection method. At present, the charge exchange injection method in the high-intensity proton accelerator facility currently in operation mainly uses the charge exchange foil. However, this method has a problem in that activation of the around the charge exchange injection point due to beam scattering by the foil and neutrons generated from the foil. In order to solve this problem, new charge exchange injection methods such as laser charge exchange method are being researched in accelerator facilities around the world. In this research, we focus on the charge exchange method using electron beams and proceed with the basic experiments. In this presentation, we will report the progress of the charge exchange efficiency measurement of negative hydrogen ion beam using electron beam.

Defect layer in SiO-SiC interface proved by a slow positron beam

Maekawa, Masaki; Kawasuso, Atsuo; Yoshikawa, Masahito; Miyashita, Atsumi; Suzuki, Ryoichi*; Odaira, Toshiyuki*

Physica B; Condensed Matter, 376-377, p.354 - 357, 2006/04

https://doi.org/10.1016/j.physb.2005.12.091

no abstracts in English

Effect of ion species on the production and thermal evolution of implantation induced defects in ZnO

Chen, Z. Q.; Maekawa, Masaki; Kawasuso, Atsuo; Sakai, Seiji; Naramoto, Hiroshi*

JAEA-Review 2005-001, TIARA Annual Report 2004, p.232 - 234, 2006/01

https://jopss.jaea.go.jp/pdfdata/JAEA-Review-2005-001-p0001-p0126.pdf

no abstracts in English

Cross-field flow of plasma produced by electron beam evaporation

Takayanagi, Tomohiro*; Ikehata, Takashi*; Mase, Hiroshi*; Oba, Hironori; Shibata, Takemasa

JAERI-Research 2005-024, 14 Pages, 2005/09

JAERI-Research-2005-024.pdf:1.71MB

A weakly ionized plasma contained in the gadolinium atomic beam produced by electron beam heating was passed led to a magnetic field of 01.5kG between iron cores. When the magnetic field was applied, the instability appeared in the ion saturation current. With increasing the magnetic field, the ions detected by the ion collectors decreased and no ions were detected at all. The magnetic field intensity at which the plasma does not flow and ions are not detected does not depend on plasma ion density. At this magnetic field, Larmor radius of ions are two times wider than plasma width. In addition, it is found that the plasma contained in the atomic beam can be removed by the magnetic field.

Interaction of nitrogen with vacancy defects in N-implanted ZnO studied using a slow positron beam

Chen, Z. Q.; Maekawa, Masaki; Kawasuso, Atsuo; Suzuki, Ryoichi*; Odaira, Toshiyuki*

Applied Physics Letters, 87(9), p.091910_1 - 091910_3, 2005/08

https://doi.org/10.1063/1.2037847

Zinc oxide crystals were implanted with N, O, and co-implanted with O/N ions. Positron annihilation measurements show the introduction of vacancy clusters upon implantation. In the N-implanted sample, these vacancy clusters are only partially annealed at 800C as compared to their full recovery in the O-implanted sample, suggesting a strong interaction between nitrogen and vacancy clusters. At 1000-1100C, nitrogen also forms stable complexes with thermally generated vacancies. To remove all the detectable vacancy defects, a high temperature annealing at 1250C is needed. Furthermore, Hall measurements of this sample show n-type conductivity though nitrogen is expected as acceptors. On the contrary, in the O/N co-implanted sample, most vacancy clusters disappear at 800C. Probably oxygen scavenges nitrogen to form N-O complexes and hence enhance the annealing of vacancy clusters. A highly compensated semi-insulating layer is formed in the co-implanted sample.

Calculation of spatial distribution of dose rate for air under 300keV electron beam irradiation using a Monte Carlo code (EGS4-SPG code)

Hakoda, Teruyuki; Hanaya, Hiroaki; Kaneko, Hirohisa; Miyashita, Atsumi; Kojima, Takuji

Radioisotopes, 54(6), p.161 - 168, 2005/06

https://doi.org/10.3769/radioisotopes.54.161

no abstracts in English

Optical diagnostics

Kawano, Yasunori

Denki Gakkai Gijutsu Hokoku, Dai-1018-Go, p.25 - 29, 2005/05

Aims of "The Investigation Committee on Pulsed Power Generation and Application" are to investigate recent developments on generation and control of pulsed power, to clarify the technological issues, and to provide the future prospects of such research area. This paper is written as the "section 3.3 Optical Diagnostics" in the technical report of the committee. Here, "diagnostics of relativistic electron beam in a torus plasma by laser inverse Compton scattering" is reported. This method has been newly proposed by JAERI for active measurement of the energy distribution of runaway electrons in a tokamak plasma. The paper presents the basic properties of scattered photons estimated in the case of runaway electron beam observed in JT-60U (number of beam electrons=2e17 electrons, beam electron energy = 30 MeV). For instance, when we use the fundamental YAG laser with the energy of 10 J/pulse and pulse widths of 1 ns, maximum energy of scattered photons would be in the X-ray region, and the signal to noise ratio can be estimated as 3. It is also mentioned that the development of the pulse X-ray imaging spectroscopy is required for this diagnostics method.

Production and recovery of defects in phosphorus-implanted ZnO

Chen, Z. Q.; Kawasuso, Atsuo; Xu, Y.; Naramoto, Hiroshi; Yuan, X. L.*; Sekiguchi, Takashi*; Suzuki, Ryoichi*; Odaira, Toshiyuki*

Journal of Applied Physics, 97(1), p.013528_1 - 013528_6, 2005/01

https://doi.org/10.1063/1.1821636

Phosphorus ions were implanted into ZnO crystals with energies of 50-380 keV to a dose of 10-10 cm. Positron annihilation measurements show the introduction of vacancy clusters after implantation. These vacancy clusters evolve to microvoids after annealing at a temperature of 600C, and disappear gradually up to 1100C. Raman scattering measurements show the production of oxygen vacancies (V). They are annealed up to 700C accompanying the agglomeration of vacancy clusters. The light emissions of ZnO are suppressed due to the competing nonradiative recombination centers introduced by implantation. Recovery of the light emission occurs above 600C. The vacancy-type defects detected by positrons might be part of the nonradiative recombination centers. Hall measurement shows n-type conductivity for the P-implanted ZnO layer, which suggests that phosphorus is an amphoteric dopant.

Hydrogen bubble formation in H-implanted ZnO studied using a slow positron beam

Chen, Z. Q.; Maekawa, Masaki; Kawasuso, Atsuo; Yamamoto, Shunya; Yuan, X. L.*; Sekiguchi, Takashi*; Suzuki, Ryoichi*; Odaira, Toshiyuki*

JAERI-Review 2004-025, TIARA Annual Report 2003, p.193 - 195, 2004/11

https://jopss.jaea.go.jp/pdfdata/JAERI-Review-2004-025-p0117-p0247.pdf

20-80 keV hydrogen ions were implanted into ZnO single crystals up to a total dose of 4.410 cm. Positron annihilation measurements using a slow positron beam revealed introduction of vacancies after implantation, which are filled with hydrogen impurities. After annealing, these hydrogen filled vacancies grow into large hydrogen bubbles. At annealing temperature of 500-700C, these hydrogen impurities are released from the bubbles, and remain open microvoids. These microvoids are finally annealed out at about 1100C. The effects of hydrogen implantation on the light luminescence in ZnO will also be discussed.

Generation of high quality electron beam by laser-plasma interaction

Kotaki, Hideyuki; Masuda, Shinichi; Kando, Masaki; Kondo, Shuji; Kanazawa, Shuhei; Homma, Takayuki; Nakajima, Kazuhisa

Quantum Aspects of Beam Physics 2003, p.119 - 124, 2004/10

https://doi.org/10.1142/9789812702333_0013

no abstracts in English