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Volume 40, Issue 11
Special Issue on Recent Progress and Future Prospect toward Applications in Laser Acceleration
Displaying 1-12 of 12 articles from this issue
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Special Issue on Recent Progress and Future Prospect toward Applications in Laser Acceleration
Special Issue
Laser Review
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Eisuke MIURA2012 Volume 40 Issue 11 Pages 810-
Published: 2012
Released on J-STAGE: August 26, 2020
JOURNAL FREE ACCESSDownload PDF (305K) -
Hideyuki KOTAKI2012 Volume 40 Issue 11 Pages 814-
Published: 2012
Released on J-STAGE: August 26, 2020
JOURNAL FREE ACCESSLaser wakefi eld acceleration, based on the effect of plasma waves excitation in the wake of an intense laser pulse, is now regarded as a basis for the next generation of charged particle accelerators. In order to generate a bunch with high quality and stability, required for applications, the electrons should be duly injected into the wakefi eld and this injection should be controllable. This paper reviews optical injection of electrons into the wakefi eld for a stable and a controllable electron beam generation. The wakefi eld is generated by a laser pulse. The second laser pulse collides with the fi rst pulse at 180 and at 135 degrees realizing optical injection of an electron bunch. The electron bunch has high stability and high reproducibility compared with single pulse electron generation.View full abstractDownload PDF (959K) -
Nobuhiko NAKANII, Shin-ichi MASUDA, Tomonao HOSOKAI2012 Volume 40 Issue 11 Pages 819-
Published: 2012
Released on J-STAGE: August 26, 2020
JOURNAL FREE ACCESSLaser wakefield accelerator is expected to be one of the novel accelerators for a new energy frontier and an ultrashort electron source for many attractive applications such as ultrafast electron microscopy. In recent studies, pointing stability of an electron beam emitted from laser wakefield acceleration has been extremely improved by applying an external magnetic field to preplasma. Emission direction of the electron beam can be controlled by the direction of the magnetic field. This stable and controllable electron beam can be a precise injector of staged laser wakefield acceleration and the energy spectrum of electron bunch can be modified by further acceleration and phase rotation in next wakefield. Also conventional beam optics is available for such stable electron beam. We are developing a reliable laser wakefield accelerator/electron source based on staged laser wakefield acceleration and new ultrashort electron bunch transport system with conventional beam optics towards practical use.View full abstractDownload PDF (3010K) -
Michiaki MORI2012 Volume 40 Issue 11 Pages 826-
Published: 2012
Released on J-STAGE: August 26, 2020
JOURNAL FREE ACCESSWe investigate the pointing stability and the divergence of a quasi-monoenergetic electron beam generated in a self-injected laser-plasma acceleration regime using high-Z gas-jet target. Gas-jet targets have been irradiated with focused 40 fs laser pulses at the 4-TW peak power. A pointing stability and a beam divergence of electron beam were improved using argon target. These values were about three times smaller than at the optimum condition using helium. This stabilization method is available for another gas material such as nitrogen. At nitrogen gas-jet target, the pointing stability is more improved to two times smaller than that in argon gas-jet target and the peak energy is increased to > 30 MeV. These results prove that this method not only stabilizes the e-beam but also allows controlling the electron energy.View full abstractDownload PDF (1781K) -
Mamiko NISHIUCHI2012 Volume 40 Issue 11 Pages 833-
Published: 2012
Released on J-STAGE: August 26, 2020
JOURNAL FREE ACCESSLaser-driven proton beam attracts many fields of potential applications because of its peculiar characteristics. However, in order to apply, for example, to the medical application, we need to increase the energy of the proton beam. We have been trying to increasing the energy of the laser-driven proton beam at JAEA. We established the beam transport line by using the beam optics of the conventional accelerator for the laser-driven～MeV proton beam and have made beam transport test.View full abstractDownload PDF (2188K) -
Akifumi YOGO2012 Volume 40 Issue 11 Pages 842-
Published: 2012
Released on J-STAGE: August 26, 2020
JOURNAL FREE ACCESSRecently, high-intensity laser ion acceleration has been suggested as a potential, cost-saving alternative technology to conventional accelerators for radiotherapy. In this review, investigations of the biological effects of the high bunch current and short bunch duration, that are typical of laser-acceleration, are reported. The radiobiological effects of high dose-rate irradiation with laser-driven proton beams are compared with those of beams derived from conventional ion accelerators.View full abstractDownload PDF (4253K) -
Eisuke MIURA2012 Volume 40 Issue 11 Pages 850-
Published: 2012
Released on J-STAGE: August 26, 2020
JOURNAL FREE ACCESSIn laser acceleration, electrons are accelerated by an electric fi eld of a plasma wave driven by an intense laser pulse. The electron pulse duration is extremely short, on the order of 10 fs, because the plasma wavelength is of the order of 10 μm. Furthermore, a compact electron accelerator can be realized using a high accelerating field. Such unique characteristics of laser acceleration enable us to produce alloptical, compact, ultrashort X-ray sources, which have attracted much attention, because of their potential applications in investigating the ultrafast structural dynamics of materials through timeresolved X-ray diffraction and spectroscopy. One type of ultrashort X-ray sources is a laser Compton scattering (LCS) X-ray source, which is produced by scattering a femtosecond laser pulse off a highenergy electron beam. By focusing on LCS X-ray generation, we review the recent progress of the research on X-ray generation using a laser-accelerated electron beam.View full abstractDownload PDF (725K) -
Ryunosuke KURODA, Hiromi IKEURA, Masato YASUMOTO, Hiroyuki TOYOKAWA, K ...2012 Volume 40 Issue 11 Pages 858-
Published: 2012
Released on J-STAGE: August 26, 2020
JOURNAL FREE ACCESSA quasi-monochromatic X-ray source has been developed via laser Compton scattering (LCS) between a high power laser and a high charge electron beam on the basis of an S-band compact electron linac at AIST. The LCS X-ray source consists of the 42 MeV electron linac with a laser photocathode rf gun and a Ti:Sapphire chirped pulse amplifi cation (CPA) laser system. The LCS X-ray has been generated with arbitrary center energy of 10 – 40 keV with narrow bandwidth by changing electron energy and collision angle. The in-line phase-contrast (refraction contrast) imaging and the K-shell absorption edge imaging with biological specimens have been successfully demonstrated using the LCS X-ray for future medical applications. We describe details of the LCS X-ray source and these imaging results.View full abstractDownload PDF (620K)
Laser Original
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Yuji FUKUDA2012 Volume 40 Issue 11 Pages 863-
Published: 2012
Released on J-STAGE: August 26, 2020
JOURNAL FREE ACCESSWe have developed a new ion diagnosis method, namely “a backscattering technique,” for high energy ions by utilizing a combination of one CR-39 detector and plastic plates, which enables to detect high energy ions beyond the detection threshold limit of CR-39 detectors. This detection method coupled with a magnetic spectrometer is applied to identify high energy ions of 50 MeV per nucleon in laserdriven ion acceleration experiments using cluster-gas targets.View full abstractDownload PDF (3793K) -
Hironori TAKAHASHI, Masatoshi FUJIMOTO, Koji MATSUKADO, Yoichi KAWADA, ...2012 Volume 40 Issue 11 Pages 869-
Published: 2012
Released on J-STAGE: August 26, 2020
JOURNAL FREE ACCESSRadioactive water was obtained using a laser-driven deuteron beam. A Ti:sapphire tabletop laser was used to generate optical pulses with a peak power of 36 TW, a pulse duration of 30 fs, and a repetition frequency of 10 Hz. The pulses were focused on a tape target to accelerate deuterons via laser-plasma interaction. The deuterons were incident on nitrogen gas held in a gas chamber. Short-lived positron emitters of 15O were created via a nuclear reaction of 14N (d, n)15O in the chamber and were carried to a synthetic instrument. After laser irradiation for 180 s, we confi rmed activity of 1.2 ± 0.5 Bq in the form of water molecules included in the liquid. To obtain radioactive water, we developed two main experimental techniques: automatic adjustment of laser focusing in a vacuum environment; and image evaluation of the spatial distribution of a deuteron beam.View full abstractDownload PDF (659K) -
Yoshitaka MORI, Hajime KUWABARA, Katsuhiro ISHII, Ryohei HANAYAMA, Tos ...2012 Volume 40 Issue 11 Pages 877-
Published: 2012
Released on J-STAGE: August 26, 2020
JOURNAL FREE ACCESSWe proposed the stand-off inspection of unknown or hidden objects by a laser-produced X-ray that has a great potential for security applications or disaster relief. To demonstrate its principle, ultra-intense laser-produced sub-ps X-ray pulses detected backscattered signals from objects hidden in a container with the coincident technique. Coincident measurement with primary X-rays enabled differentiation inside an aluminum container among the following object materials: acrylic, copper, and lead blocks. The spectrum of these backscattered signals can distinguish the atomic number of the materials. To realize a collimated X-ray source to scan these objects, we proposed X-ray generation by inverse Compton scattering of laser-plasma accelerated electrons. We also presented the present status of this X-ray generation.View full abstractDownload PDF (2665K)
Regular Paper
Laser Original
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Akihiro KAMEYAMA, Eka MAULANA, Masahito KATTO, Atsushi YOKOTANI2012 Volume 40 Issue 11 Pages 883-
Published: 2012
Released on J-STAGE: August 26, 2020
JOURNAL FREE ACCESSWe demonstrated that a simple technique combining a 266-nm laser and a phase mask was quite effective at fabricating tilted fi ber Bragg gratings (TFBG) for refractive index sensor of liquids. Using fabricated TFBGs that have the tilted angles of 3.3, 6.7, 7.3, 8.0, and 9.9 °, we tried to measure the refractive index of liquids that have different indices. We have directed our attention to the fact that the wavelength of cladding mode becomes longer as the refractive index of sample liquids increases. Utilizing this wavelength shift, we proposed a new measurement method. As a result, we could successfully measure the refractive index of liquids within a range from 1.00 to 1.41 with a maximum resolution of 2.1 × 10－3. In addition, we have found that a writing length only 2 mm long is enough for measuring the refractive index of liquid.View full abstractDownload PDF (475K)
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