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Journal Articles

Energy-dependent fragmentation cross sections of relativistic $$^{12}$$C

Ogawa, Tatsuhiko; Sato, Tatsuhiko; Hashimoto, Shintaro; Satoh, Daiki; Tsuda, Shuichi; Niita, Koji*

Physical Review C, 92(2), p.024614_1 - 024614_14, 2015/08

AA2015-0260.pdf:2.96MB

 Times Cited Count:35 Percentile:92.03(Physics, Nuclear)

For prediction of radiological impact of heavy ions in accelerator facilities, space missions and cancer therapy, nuclear reaction models play a fundamental role. As one of such models, JAERI Quantum molecular dynamics (JQMD) has been successfully used to describe production of residue and secondary particles in nucleus-nucleus collisions. However, it has been pinpointed that JQMD underestimates projectile-like fragments produced in peripheral collisions. Moreover, no cross section data systematically measured over a wide energy range are not available, which makes it difficult to benchmark the reaction models. In this study, we develop a method to measured fragmentation cross sections using a thick target and detecting fragments produced from incident ions fragmented in the target using telescope detectors. Thus we obtained fragmentation cross sections systematically over a wide energy range. We also revise the description of reaction mechanism and ground-state nuclear structure in JQMD to take into account for peripheral collisions accurately. So far, ground-state nuclei got excited and sometimes disintegrated owing to frame transform from the laboratory system to the center-of-mass system. Fragment production cross sections calculated by the revised JQMD (JQMD2.0) are in better agreement with the literature data.

Journal Articles

Beam instrumentation at the 1 MW Proton beam of J-PARC RCS

Yamamoto, Kazami; Hayashi, Naoki; Okabe, Kota; Harada, Hiroyuki; Saha, P. K.; Yoshimoto, Masahiro; Hatakeyama, Shuichiro; Hotchi, Hideaki; Hashimoto, Yoshinori*; Toyama, Takeshi*

Proceedings of 54th ICFA Advanced Beam Dynamics Workshop on High-Intensity, High Brightness and High Power Hadron Beams (HB 2014) (Internet), p.278 - 282, 2015/03

Rapid Cycling Synchrotron (RCS) of Japan Proton Accelerator Complex (J-PARC) is providing more than 300 kW of proton beam to Material and Life science Facility (MLF) and Main Ring (MR). Last summer shutdown, a new ion source was installed to increase output power to 1 MW. In order to achieve reliable operation of 1 MW, we need to reduce beam loss as well. Beam quality of such higher output power is also important for users. Therefore we developed new monitors that can measure the halo with higher accuracy. We present beam monitor systems for these purposes.

Journal Articles

Breakdown voltage in silicon carbide metal-oxide-semiconductor devices induced by ion beams

Oshima, Takeshi; Deki, Manato; Makino, Takahiro; Iwamoto, Naoya; Onoda, Shinobu; Hirao, Toshio*; Kojima, Kazutoshi*; Tomita, Takuro*; Matsuo, Shigeki*; Hashimoto, Shuichi*

AIP Conference Proceedings 1525, p.654 - 658, 2013/04

 Times Cited Count:0 Percentile:0.05

Metal-Oxide-Semiconductor (MOS) capacitors were fabricated on n-type 4H-SiC epitaxial layers, and the leakage current through the gate oxide during heavy ion irradiation was investigated in order to evaluate dielectric breakdown induced by heavy ions (Single Event Gate Rupture: SEGR). The gate oxide at thickness ranges between 60 and 80 nm was formed using pyrogenic oxidation at 1100 $$^{circ}$$C for 60 min. Circular electrodes with 180 $$mu$$ diameter were formed using Al evaporation and a lift-off technique. The leakage current observed through the gate oxide was monitored during 18 MeV oxygen (O) or nickel (Ni) ions. As a result, although no significant difference in the value of the electric field at the dielectric breakdown (around 8.2 MV/cm) was observed between non-irradiated and 18 MeV-O irradiated samples, the value decreased to be 7.3 MV/cm in the case of 18 MeV-Ni ion incidence. The Linier Energy Transfer (LET) for 18 MeV-O is 7 MeV cm$$^{2}$$/mg, and this value is smaller than that for 18 MeV-Ni (24 MeV cm$$^{2}$$/mg). Also, 18 MeV-Ni ions deposit energy in narrower regions than 18 MeV-O ions. Thus, it can be concluded that the high density of charge induced by 18 MeV-Ni ions triggers SEGR in SiC MOS capacitors.

Journal Articles

LET dependence of gate oxide breakdown of SiC-MOS capacitors due to single heavy ion irradiation

Deki, Manato; Makino, Takahiro; Tomita, Takuro*; Hashimoto, Shuichi*; Kojima, Kazutoshi*; Oshima, Takeshi

Proceedings of 10th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-10) (Internet), p.78 - 81, 2012/12

Metal-Oxide-Semiconductor (MOS) capacitors fabricated on Silicon Carbide (SiC) under applied biases were irradiated with heavy ions. The relationship between critical electric field (E$$_{rm CR}$$) and Linear Energy Transfer (LET) was investigated. As a results of 9 MeV-Ni, 18 MeV-Ni, Kr-322 MeV and 454 MeV-Xeirradiation (the values of LET are 14.6, 23.8, 42.2 and 73.2 MeV cm$$^{2}$$/mg, respectively), reciprocal value of E$$_{rm CR}$$ increases with increasing LET. The similar relationship was also reported Si MOS capacitors. However, the increase in SiC MOS capacitors is smaller than that in Si ones because the generation energy of one electron-hole pair for SiC is larger than that for Si.

Journal Articles

Electrical conduction properties of SiC modified by femtosecond laser

Ito, Takuto*; Deki, Manato; Tomita, Takuro*; Matsuo, Shigeki*; Hashimoto, Shuichi*; Kitada, Takahiro*; Isu, Toshiro*; Onoda, Shinobu; Oshima, Takeshi

Proceedings of 12th International Symposium on Laser Precision Microfabrication (LPM 2011) (Internet), 5 Pages, 2011/06

Journal Articles

Enhancement of local electrical conductivities in SiC by femtosecond laser modification

Deki, Manato; Ito, Takuto*; Yamamoto, Minoru*; Tomita, Takuro*; Matsuo, Shigeki*; Hashimoto, Shuichi*; Kitada, Takahiro*; Isu, Toshiro*; Onoda, Shinobu; Oshima, Takeshi

Applied Physics Letters, 98(13), p.133104_1 - 133104_3, 2011/03

 Times Cited Count:13 Percentile:49.3(Physics, Applied)

Journal Articles

Laser modification aiming at the enhancement of local electrical conductivities in SiC

Deki, Manato; Ito, Takuto*; Tomita, Takuro*; Matsuo, Shigeki*; Hashimoto, Shuichi*; Kitada, Takahiro*; Isu, Toshiro*; Onoda, Shinobu; Oshima, Takeshi

Proceedings of 9th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-9), p.218 - 221, 2010/10

Journal Articles

The Data acquisition system of beam position monitors in J-PARC main ring

Hatakeyama, Shuichiro; Hayashi, Naoki; Arakawa, Dai*; Hashimoto, Yoshinori*; Hiramatsu, Shigenori*; Odagiri, Junichi*; Sato, Kenichiro*; Tejima, Masaki*; Tobiyama, Makoto*; Toyama, Takeshi*; et al.

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.2698 - 2700, 2010/05

The Data Acquisition System of Beam Position Monitors (BPMs) in J-PARC Main Ring are consist of 186 Linux-based Data Processing Circuits (BPMCs) and 12 EPICS IOCs. They are important tool to see the COD and turn-by-turn beam positions. This report describes the process of the data reconstruction which include how the various calibration constants are applied.

Journal Articles

Beam injection tuning of the J-PARC main ring

Wei, G.; Koseki, Tadashi*; Igarashi, Susumu*; Tomizawa, Masahito*; Takano, Jumpei*; Ishii, Koji*; Shirakata, Masashi*; Fan, K.*; Hatakeyama, Shuichiro; Uota, Masahiko*; et al.

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.3915 - 3917, 2010/05

Journal Articles

Performance of the main ring BPM during the beam commissioning at J-PARC

Toyama, Takeshi*; Arakawa, Dai*; Hiramatsu, Shigenori*; Igarashi, Susumu*; Lee, S.*; Matsumoto, Hiroshi*; Odagiri, Junichi*; Tejima, Masaki*; Tobiyama, Makoto*; Hashimoto, Yoshinori*; et al.

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.981 - 983, 2010/05

Experiences of operating BPM's during beam commissioning at the J-PARC MR are reported. The subjects are: (1) bug report, statistics and especially the effect of a beam duct step, (2) position resolution estimation ($$<$$30 micrometers with 1 sec averaging), (3) beam based alignment.

Journal Articles

Electronic properties of femtosecond laser induced modified spots on single crystal silicon carbide

Tomita, Takuro*; Iwami, Masahiro*; Yamamoto, Minoru*; Deki, Manato*; Matsuo, Shigeki*; Hashimoto, Shuichi*; Nakagawa, Yoshinori*; Kitada, Takahiro*; Isu, Toshiro*; Saito, Shingo*; et al.

Materials Science Forum, 645-648, p.239 - 242, 2010/04

no abstracts in English

Journal Articles

Crossover from coherent quasiparticles to incoherent hole carriers in underdoped cuprates

Hashimoto, Makoto*; Yoshida, Teppei*; Tanaka, Kiyohisa*; Fujimori, Atsushi*; Okusawa, Makoto*; Wakimoto, Shuichi; Yamada, Kazuyoshi*; Kakeshita, Teruhisa*; Eisaki, Hiroshi*; Uchida, Shinichi*

Physical Review B, 79(14), p.140502_1 - 140502_4, 2009/04

 Times Cited Count:14 Percentile:52.41(Materials Science, Multidisciplinary)

Journal Articles

Relationship between the superconducting gap and the pseudogap; Temperature-dependent photoemission study of La$$_{2-x}$$Sr$$_{x}$$CuO$$_{4}$$ and La$$_{2}$$CuO$$_{4.10}$$

Hashimoto, Makoto*; Tanaka, Kiyohisa*; Yoshida, Teppei*; Fujimori, Atsushi*; Okusawa, Makoto*; Wakimoto, Shuichi; Yamada, Kazuyoshi*; Kakeshita, Teruhisa*; Eisaki, Hiroshi*; Uchida, Shinichi*

Physica C, 460-462(2), p.884 - 885, 2007/09

 Times Cited Count:3 Percentile:17.92(Physics, Applied)

In the high-${it T$_{rm c}$}$ research, relationship between the pseudogap and the superconducting gap has been an important issue. We have performed a detailed temperature-dependent angle-integrated photoemission study of lightly-doped to heavily-overdoped La$$_{2-x}$$Sr$$_{x}$$CuO$$_{4}$$ and oxygen-doped La$$_{2}$$CuO$$_{4.10}$$. We found that, while the magnitude of the pseudogap increased with decreasing doping, that of the superconducting gap did not increase. This behavior can be explained if the superconducting gap opens only on the Fermi arc around the node (0,0)-($$pi$$,$$pi$$) whereas the pseudogap opens primarily around ($$pi$$,0).

Journal Articles

Distinct doping dependences of the pseudogap and superconducting gap of La$$_{2-x}$$Sr$$_{x}$$CuO$$_{4}$$ cuprate superconductors

Hashimoto, Makoto*; Yoshida, Teppei*; Tanaka, Kiyohisa*; Fujimori, Atsushi*; Okusawa, Makoto*; Wakimoto, Shuichi; Yamada, Kazuyoshi*; Kakeshita, Teruhisa*; Eisaki, Hiroshi*; Uchida, Shinichi*

Physical Review B, 75(14), p.140503_1 - 140503_4, 2007/04

 Times Cited Count:66 Percentile:88.66(Materials Science, Multidisciplinary)

We have performed a temperature-dependent angle-integrated photoemission study of La$$_{2-x}$$Sr$$_{x}$$CuO$$_{4}$$ covering from lightly doped to heavily overdoped regions and oxygen -doped La$$_{2}$$CuO$$_{4.10}$$. The superconducting gap energy $$Delta_{sc}$$ was found to remain small for decreasing hole concentration while the pseudogap energy $$Delta^{*}$$ and temperature $$T^{*}$$ increase. The different behaviors of the superconducting gap and the pseudogap can be explained if the superconducting gap opens only on the Fermi arc around the nodal (0,0)-$$(pi,pi)$$ direction while the pseudogap opens around $$sim (pi,0)$$. The results suggest that the pseudogap and the superconducting gap have different microscopic origins.

JAEA Reports

Report of tests for radiation control executed in the JOYO MK-III performance tests

Hoshiba, Hideaki; Hashimoto, Makoto; Irokawa, H.; Usui, Toshihide; Sato, Hayato; Emori, Shuichi

JNC TN9410 2004-017, 170 Pages, 2004/08

JNC-TN9410-2004-017.pdf:18.93MB

While the JOYO MK-III Project, after the modification of primary coolant system started in oct.2000 and the integrated function tests, from Jun.2003, the performance test was executed for the purpose of verification of designed performance and confirmation of basic characteristics as an irradiation reactor. While the JOYO MK-III performance test, 28 tests were executed. Radiation control section took charge of 3 of them, "Dose Rate Distribution", "Radiation Control" and "Gaseous Waste Radioactive Concentration Measurement". The performance tests in charge of radiation control section was started on Jun.27, 2003, that is before the start-up of reactor, and were carried out when the thermal output of reactor was 40MWt, 70MWt, 105MWt and effective full power, 140MWt. The pre-operation tests in charge of radiation control section are "Test of dose rate measurement in operation and after shutdown". "Test of radioactive concentration measurement of air", and "Test of gaseous waste processing performance". The final test was "Test of dose rate measurement after shutdown", which was executed on Nov.27 2003. JOYO passed the inspection and the performance test was finished. The representative results in these performance tests are; 1.Every result is under the criterion 2.Dose rate and monitoring data are totally less than the data in MK-II operation. Though it confirmed that all the data are under the criterion, it is considered that these tests should be performed at proper intervals because the circumstances may change.

Journal Articles

Investigation on the Performance of Dosimeters for Individual Monitoring

Hashimoto, Tomoharu; Hashimoto, Makoto; Ishikawa, Masayasu; Emori, Shuichi

Hoken Butsuri, 39(3), 229- Pages, 2004/00

It was executed that the investigation on the performance of dosimeters for individual monitoring which compare present TLD with recently dosimeters, OSL, Glass dosimeter, EPD, SSTD. It also surveyed operating method of each dosimeter.

JAEA Reports

Result of the investigation for a performance about the new tipe dosimeter

Hashimoto, Tomoharu; Ishikawa, Masayasu; Emori, Shuichi

JNC TN9420 2003-001, 50 Pages, 2003/09

JNC-TN9420-2003-001.pdf:1.93MB

We investigate the new tipe dosimeter to prepare for renewal of the present TLD in the near future.As a result of investigation, if we pursue the rationalization and convenience in the operation of dosimeter more and more, then we will recommend the electric pocket dosimeter positively.

Oral presentation

Pulse pitch dependence of electric conduction by fs-laser-modification on 6H-SiC substrates

Deki, Manato*; Ito, Takuto*; Yamamoto, Minoru*; Tomita, Takuro*; Matsuo, Shigeki*; Hashimoto, Shuichi*; Kitada, Takahiro*; Isu, Toshiro*; Onoda, Shinobu; Oshima, Takeshi

no journal, , 

no abstracts in English

Oral presentation

Femtosecond laser modification aiming at the enhancement of local electric conductivities on SiC

Deki, Manato; Yamamoto, Minoru*; Ito, Takuto*; Tomita, Takuro*; Matsuo, Shigeki*; Hashimoto, Shuichi*; Kitada, Takahiro*; Isu, Toshiro*; Onoda, Shinobu; Oshima, Takeshi

no journal, , 

no abstracts in English

Oral presentation

Fluence dependence of local electrical conductivities in SiC irradiated with femtosecond laser

Deki, Manato; Ito, Takuto*; Tomita, Takuro*; Matsuo, Shigeki*; Hashimoto, Shuichi*; Kitada, Takahiro*; Isu, Toshiro*; Onoda, Shinobu; Oshima, Takeshi

no journal, , 

no abstracts in English

28 (Records 1-20 displayed on this page)