The Observation of a transient surface morphology in the femtosecond laser ablation process by using the soft X-ray laser probe

Hasegawa, Noboru; Nishikino, Masaharu; Tomita, Takuro*; Onishi, Naofumi*; Ito, Atsushi*; Eyama, Tsuyoshi*; Kakimoto, Naoya*; Izutsu, Rui*; Minami, Yasuo*; Baba, Motoyoshi*; et al.

X-Ray Lasers and Coherent X-Ray Sources; Development and Applications XI (Proceedings of SPIE, Vol.9589), p.95890A_1 - 95890A_8, 2015/09

https://doi.org/10.1117/12.2186744

We have improved a soft X-ray laser (SXRL) interferometer synchronized with a Ti:Sapphire laser pulse to observe the single-shot imaging of the nano-scaled structure dynamics of the laser induced materials. By the precise imaging optics and double time fiducial system having been installed, the lateral resolution on the sample surface and the precision of the temporal synchronization between the SXRL and Ti:Sapphire laser pulses were improved to be 700 nm and 2 ps, respectively. By using this system, the initial stage (before 200 ps) of the ablation process of the Pt surface pumped by 80 fs Ti:Sapphire laser pulse was observed by the comparison between the soft X-ray reflective image and interferogram. We have succeeded in the direct observation of the unique ablation process around the ablation threshold such as the rapid increase of the surface roughness and surface vibration.

Hydrodynamics driven by ultrashort laser pulse; Simulations and the optical pump - X-ray probe experiment

Inogamov, N. A.*; Zhakhovsky, V. V.*; Hasegawa, Noboru; Nishikino, Masaharu; Yamagiwa, Mitsuru; Ishino, Masahiko; Agranat, M. B.*; Ashitkov, S. I.*; Faenov, A. Y.*; Khokhlov, V. A.*; et al.

Applied Physics B, 119(3), p.413 - 419, 2015/06

https://doi.org/10.1007/s00340-015-6039-7

Time-resolved soft X-ray imaging of femtosecond laser ablation process in metals

Tomita, Takuro*; Nishikino, Masaharu; Hasegawa, Noboru; Minami, Yasuo*; Takei, Ryota*; Baba, Motoyoshi*; Eyama, Tsuyoshi*; Takayoshi, Shodai*; Kaihori, Takeshi*; Morita, Toshimasa; et al.

Journal of Laser Micro/Nanoengineering, 9(2), p.137 - 142, 2014/06

https://doi.org/10.2961/jlmn.2014.02.0011

Femtosecond laser ablation processes on platinum, gold, and tungsten were observed by the single shot pump and probe reflective imaging using a soft X-ray laser probe. To avoid the timing error due to the jitter, we adopted a posteriori correction technique by simultaneous measurement of timing between the pump and probe pulses for every single shot, using a soft X-ray streak camera. A clear difference was found in the temporal behavior of the dynamical response of the soft X-ray reflectivity depending on the irradiated laser fluence in these three materials. On the other hand, the narrow dark rings were found in Pt and W, while an additional bright ring was found outside the dark disk in Au. Our result gives the experimental data comparable with various numerical simulations.

Measurement of neutron- and photon-production cross sections from heavy-ion reactions on tissue equivalent elements

Uozumi, Yusuke*; Shigyo, Nobuhiro*; Kajimoto, Tsuyoshi*; Moriguchi, Daisuke*; Ueyama, Masahiko*; Yoshioka, Masakatsu*; Satoh, Daiki; Sanami, Toshiya*; Koba, Yusuke*; Takada, Masashi*; et al.

HIMAC-136, p.248 - 249, 2011/11

no abstracts in English

Measurement of neutron-production double-differential cross-sections on carbon bombarded with 290-MeV/nucleon carbon and oxygen ions

Satoh, Daiki; Moriguchi, Daisuke*; Kajimoto, Tsuyoshi*; Uehara, Haruhiko*; Shigyo, Nobuhiro*; Ueyama, Masahiko*; Yoshioka, Masakatsu*; Uozumi, Yusuke*; Sanami, Toshiya*; Koba, Yusuke*; et al.

Nuclear Instruments and Methods in Physics Research A, 644(1), p.59 - 67, 2011/07

https://doi.org/10.1016/j.nima.2011.04.054

Neutron-production double-differential cross sections on carbon-carbon and oxygen-carbon reactions with incident heavy-ion energy of 290 MeV/nucleon were measured by time-of-flight method using liquid organic scintillators. By use of a detection system specialized for low-energy neutrons, the cross sections were obtained in a wide energy region from several hundred MeV down to 0.6 MeV for the oxygen-ion incidences. The experimental data were compared with the calculation results using the Monte-Carlo simulation code, PHITS. The PHITS results gave an overall agreement with the measured data within a factor of two.

Development of the external cooling device to increase the Productivity of Neutron-Transmutation-Doped Silicon Semiconductor (NTD-Si) (Joint research)

Hirose, Akira; Wada, Shigeru; Sasajima, Fumio; Kusunoki, Tsuyoshi; Kameyama, Iwao*; Aizawa, Ryoji*; Kikuchi, Naoyuki*

JAEA-Technology 2006-059, 122 Pages, 2007/01

JAEA-Technology-2006-059.pdf:26.03MB

It is expected that the demand for NTD-Si increases rapidly because of recent productive increase of hybrid-cars. In order to meet the demand, we have investigated the expansion technology of the NTD-Si productivity using the JRR3. This report describes the production of equipment for the external cooling device while proposed as one of the result of the investigation for the JRR-3 uniformity irradiation equipment. After an ingot was irradiated once, it is turned over manually and irradiated again in order irradiate the ingot uniformly. With the conventional equipment, it was necessary to wait the radioactivity of ingot decrease less than the permissible level with holding the ingot in the irradiation equipment. It was effective to shorten the waiting period by using an external cooling device for production increase of NTD-Si. It is expected that the productivity of NTD-Si will be increased by using the external cooling device.

Characterization of non-magnetic Mn-Cr steel as a low induced activation material for vacuum vessels

Saito, Shigeru; Fukaya, Kiyoshi; Ishiyama, Shintaro; Eto, Motokuni; Sato, Ikuo*; Kusuhashi, Mikio*; Hatakeyama, Tsuyoshi*; Takahashi, Heishichiro*; Kikuchi, Mitsuru

Journal of Nuclear Materials, 283-287(Part1), p.593 - 596, 2000/12

https://doi.org/10.1016/S0022-3115(00)00088-X

no abstracts in English

R&D of low activated Fe-Mn-Cr high strength non-magnetic steel, 1; Screening test for constituent optimization and fundamental characterization test

Ishiyama, Shintaro; Fukaya, Kiyoshi; Eto, Motokuni; Kikuchi, Mitsuru; Sato, Ikuo*; Kusuhashi, Mikio*; Hatakeyama, Tsuyoshi*; Takahashi, Heishichiro*

Nihon Genshiryoku Gakkai-Shi, 42(2), p.116 - 123, 2000/02

https://doi.org/10.3327/jaesj.42.116

no abstracts in English

Study for neutron production cross sections by heavy ion interactions, 2; Evaluation of cross sections, and comparison with predictions of Monte Carlo codes

Satoh, Daiki; Moriguchi, Daisuke*; Nakamura, Yasuhiro*; Kajimoto, Tsuyoshi*; Ueyama, Masahiko*; Yoshioka, Masakatsu*; Koba, Yusuke*; Shigyo, Nobuhiro*; Uozumi, Yusuke*; Matsufuji, Naruhiro*; et al.

no journal, , 

Neutron production double differential cross sections have been measured at HIMAC in National Institute of Radiological Sciences. The cross sections were obtained in the energy region from a few MeV to several hundred MeV. In addition, we got the systematic cross section data by revising the detection efficiencies in the existing data. All the data were compared with the predictions of Monte Carlo simulation codes. While the codes show a good agreement in the backward angular region, they can not reproduce the peak structure observed in the forward angular region. This indicates that the nucleus-nucleus reaction model in the simulation codes must be revised.

Measurement of carbon ion incident neutron production double differential cross sections for carbon target

Shigyo, Nobuhiro*; Uozumi, Yusuke*; Kajimoto, Tsuyoshi*; Moriguchi, Daisuke*; Ueyama, Masahiko*; Yoshioka, Masakatsu*; Koba, Yusuke*; Nakamura, Yasuhiro*; Satoh, Daiki; Sanami, Toshiya*; et al.

no journal, , 

Radiation dose by neutrons produced by proton and heavy ion induced nuclear reactions around tumor is essential for dose assessment in proton and heavy ion radiotherapies. Double differential cross section (DDX) of neutron production is one of important physical quantities for dose estimation by radiation transport codes. Some experimental data of neutron production DDXs have been reported above 5 MeV of neutron energy for heavy ion incident reactions. Neutron production DDX for carbon ion incidence on carbon target was measured at the Heavy Ion Medical Accelerator in Chiba (HIMAC) including low neutron energy region for validation of radiation transport codes. Incident carbon energy was 290 MeV/u. NE213 liquid organic scintillators were deployed as neutron detectors and placed at 15, 30 45, 60, 75 and 90. Neutron energies were determined by the time-of-flight methods. Neutron detection efficiency was calculated by the SCINFUL-QMD code. The obtained minimum neutron energy was about 2.8 MeV. The experimental data of neutron production DDX was compared with that by one of radiation transport codes, PHITS.