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Journal Articles

Comparison of heavy-ion transport simulations; Collision integral with pions and $$Delta$$ resonances in a box

Ono, Akira*; Xu, J.*; Colonna, M.*; Danielewicz, P.*; Ko, C. M.*; Tsang, M. B.*; Wang, Y,-J.*; Wolter, H.*; Zhang, Y.-X.*; Chen, L.-W.*; et al.

Physical Review C, 100(4), p.044617_1 - 044617_35, 2019/10

AA2019-0025.pdf:2.76MB

 Times Cited Count:29 Percentile:98.33(Physics, Nuclear)

International comparison of heavy-ion induced reaction models were discussed in the international conference "Transport2017" held in April 2017. Owing to their importance for safety assessment of heavy-ion accelerators and dosimetry of astronauts, various models to simulate heavy-ion induced reaction models are developed. This study is intended to clarify the difference among them to pinpoint their problems. In the comparison study, 320 protons and neutrons were packed in a 20-fm-large cube to calculate the number and energies of collisions during the time evolution. The author contributed to this study by running calculation using JQMD (JAERI Quantum Molecular Dynamics). This study showed that time step in the calculation is one of the biggest causes of the discrepancies. For example, the calculation by JQMD comprises 1-fm/c time steps, each of which is composed of transport, scattering and decay phases. Therefore a sequence of scattering, and decay followed by another scattering in 1 fm/c cannot be considered. Moreover, in JQMD particles are labeled by sequential numbers and scattering reactions are simulated by the order. Therefore scattering between low ID numbers, that between high ID numbers and that between the first (low ID) pair is overlooked in JQMD. Above indications obtained in this study must be kept in our mind for future JQMD upgrades.

Journal Articles

Comparison of heavy-ion transport simulations; Collision integral in a box

Zhang, Y.-X.*; Wang, Y,-J.*; Colonna, M.*; Danielewicz, P.*; Ono, Akira*; Tsang, M. B.*; Wolter, H.*; Xu, J.*; Chen, L.-W.*; Cozma, D.*; et al.

Physical Review C, 97(3), p.034625_1 - 034625_20, 2018/03

 Times Cited Count:63 Percentile:99.37(Physics, Nuclear)

International comparison of heavy-ion induced reaction models were discussed in the international conference "Transport2017" held in April 2017. Owing to their importance for safety assessment of heavy-ion accelerators and dosimetry of astronauts, various models to simulate heavy-ion induced reaction models are developed. This study is intended to clarify the difference among them to pinpoint their problems. In the comparison study, 320 protons and 320 neutrons were packed in a 20-fm-large cube to calculate the number of particle-particle collisions as well as the energies of collisions during the time evolution. In addition to the calculation, their algorithms were compared. The author contributed to this study by running calculation using JQMD (JAERI Quantum Molecular Dynamics). The results were compared with those calculated by the other 15 codes from over the world. Algorithm comparison showed that JQMD calculates collision probabilities from protons at first and collisions by neutrons are simulated later, which might be unreasonable. On the other hand, it was clarified that the calculation by JQMD agrees with those by the others. Despite the fact that some codes deviate from the average by a factor of 2, JQMD exhibited stable performance.

Journal Articles

Studies of high density baryon matter with high intensity heavy-ion beams at J-PARC

Sako, Hiroyuki; Harada, Hiroyuki; Sakaguchi, Takao*; Chujo, Tatsuya*; Esumi, Shinichi*; Gunji, Taku*; Hasegawa, Shoichi; Hwang, S.; Ichikawa, Yudai; Imai, Kenichi; et al.

Nuclear Physics A, 956, p.850 - 853, 2016/12

 Times Cited Count:11 Percentile:71(Physics, Nuclear)

Journal Articles

An Energy spread minimization system for microbeam generation in the JAERI AVF cyclotron

Fukuda, Mitsuhiro; Kurashima, Satoshi; Miyawaki, Nobumasa; Okumura, Susumu; Kamiya, Tomihiro; Oikawa, Masakazu*; Nakamura, Yoshiteru; Nara, Takayuki; Agematsu, Takashi; Ishibori, Ikuo; et al.

Nuclear Instruments and Methods in Physics Research B, 210, p.33 - 36, 2003/09

 Times Cited Count:4 Percentile:34.53(Instruments & Instrumentation)

A heavy ion microbeam with energy of hundreds MeV is a significantly useful probe for research in biotechnology. A single-ion hitting technique using a 260 MeV $$^{20}$$Ne$$^{7+}$$ microbeam is being developed at the JAERI AVF cyclotron facility for biofunction elucidation. Production of a microbeam with a spot size of one micro-meter in diameter requires reducing the energy spread of the beam to 0.02 % to minimize an effect of chromatic aberrations in focusing lenses. The typical energy spread of the cyclotron beam is around 0.1 % in an ordinary acceleration mode using a sinusoidal voltage waveform. The energy spread can be reduced by superimposing the fifth-harmonic voltage waveform on the fundamental one to generate a flattop waveform for uniform energy gain. We have designed an additional coaxial cavity to generate the fifth-harmonic voltage, coupled to the main resonator of one-fourth wavelength coaxial type. In a power test we successfully observed the fifth-harmonic voltage waveform by picking up an acceleration voltage signal.

Journal Articles

Flat-top acceleration system for the variable-energy multiparticle AVF cyclotron

Fukuda, Mitsuhiro; Kurashima, Satoshi; Okumura, Susumu; Miyawaki, Nobumasa; Agematsu, Takashi; Nakamura, Yoshiteru; Nara, Takayuki; Ishibori, Ikuo; Yoshida, Kenichi; Yokota, Wataru; et al.

Review of Scientific Instruments, 74(4), p.2293 - 2299, 2003/04

 Times Cited Count:14 Percentile:60.36(Instruments & Instrumentation)

A combination of the fundamental- and the fifth-harmonic voltages is ideally suited for flat-top acceleration in a variable-energy multi-particle cyclotron for energy-spread minimization. The flat-topping of the energy gain distribution using the fifth-harmonics has the advantages of minimizing an amplifier power, reducing power dissipation in a resonator and increasing the energy gain per turn. The flat-top acceleration system of the JAERI AVF cyclotron was designed to reduce the energy spread to 0.02 $$%$$, required for microbeam production. Tolerable fluctuations of acceleration voltages and the magnetic excitation were 2.0$$times$$10$$^{-4}$$ for the fundamental voltage, 1.0$$times$$10$$^{-3}$$ for the fifth-harmonic voltage, and 1.9$$times$$10$$^{-5}$$ for the magnetic field. In order to enhance compactness of the flat-topping cavity and to make a substantial saving of the amplifier power, optimum geometric parameters of the flat-topping cavity were determined by a cold model test and a calculation using the MAFIA code.

Journal Articles

Sideward peak of intermediate mass fragments in high energy proton induced reactions

Hirata, Yuichi*; Onishi, Akira*; Nara, Yasushi*; Kido, Toshihiko; Maruyama, Toshiki; Otsuka, Naohiko*; Niita, Koji*; Takada, Hiroshi; Chiba, Satoshi

Nuclear Physics A, 707(1-2), p.193 - 212, 2002/08

 Times Cited Count:10 Percentile:52.26(Physics, Nuclear)

no abstracts in English

Journal Articles

Design of the flat-top acceleration system for the JAERI AVF cyclotron

Kurashima, Satoshi; Fukuda, Mitsuhiro; Nakamura, Yoshiteru; Nara, Takayuki; Agematsu, Takashi; Ishibori, Ikuo; Tamura, Hiroyuki; Yokota, Wataru; Okumura, Susumu; Arakawa, Kazuo; et al.

AIP Conference Proceedings 600, p.303 - 305, 2001/00

A flat-top acceleration system for the JAERI AVF cyclotron has been designed. The fifth harmonic of the fundamental frequency is used to obtain uniform energy gain. To determine optimum parameters of the flat-top system, a cold model test was carried out and flat-top waveforms of the voltages were observed successfully in the whole range of the fundamental frequency. An rf power required for generating a flat-top dee voltage of 30 kV was estimated to be about 1 kW. The design of the flat-top cavity is being modified using the MAFIA code.

Journal Articles

Relativistic nuclear collisions at 10A GeV energies from p+Be to Au+Au with hadronic cascade model

Nara, Yasushi; Otsuka, Naohiko*; Onishi, Akira*; Niita, Koji*; Chiba, Satoshi

Physical Review C, 61(2), p.024901_1 - 024901_19, 2000/02

 Times Cited Count:255 Percentile:99.26(Physics, Nuclear)

no abstracts in English

JAEA Reports

Analysis of the proton-induced reactions at 150MeV $$sim$$ 24GeV by high energy nuclear reaction code JAM

Niita, Koji*; Nara, Yasushi; Takada, Hiroshi; Nakashima, Hiroshi; Chiba, Satoshi; Ikeda, Yujiro

JAERI-Tech 99-065, p.42 - 0, 1999/09

JAERI-Tech-99-065.pdf:1.83MB

no abstracts in English

JAEA Reports

Development of JQMD(Jaeri Quantum Molecular Dynamics) code

Niita, Koji*; Maruyama, Toshiki; Nara, Yasushi; Chiba, Satoshi; Iwamoto, Akira

JAERI-Data/Code 99-042, p.73 - 0, 1999/09

JAERI-Data-Code-99-042.pdf:2.18MB

no abstracts in English

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