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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:12 Percentile:65.93(Physics, Nuclear)

Journal Articles

Development of a prototype GEM TPC with a gating grid for an H-dibaryon search experiment at J-PARC

Sako, Hiroyuki; Sugimura, Hitoshi; Ahn, J. K.*; Han, Y.*; Hasegawa, Shoichi; Hwang, S. H.*; Ichikawa, Yudai; Imai, Kenichi; Kiuchi, Ryuta*; Ozawa, Kyoichiro; et al.

Nuclear Instruments and Methods in Physics Research A, 763, p.65 - 81, 2014/11

 Times Cited Count:5 Percentile:38.2(Instruments & Instrumentation)

We developed a prototype TPC for an H-dibaryon search experiment at J-PARC. To investigate its performance, we conducted tests with Ar-CH$$_{4}$$ (90:10) and Ar-CF$$_{4}$$ (95:5), where the former is mainly used. The detection efficiency was measured to be 98% at the beam rate up to $$5times10^{5}$$ cps/cm$$^{2}$$, and 90% at the rate of $$3times10^{6}$$ cps/cm$$^{2}$$. Based on the measured horizontal resolution of 0.19-0.46 mm at the drift length of 5-20 cm, the position resolution of better than 0.3 mm is estimated in 1 T magnetic field. The ion backflow fraction was measured to be 5% and reduced up to 3% at the gain of $$1.6times10^{4}$$. The horizontal position distortion due to ion backflow in the gate operation was suppressed within $$pm 0.2$$ mm at the beam rates up to $$5times10^{5}$$ cps/cm$$^{2}$$. On the other hand, the distortion with the gate open was measured to be $$pm2$$ mm. The distortion in the final experiment is estimated to be $$0.3 pm 0.2$$ mm.

Journal Articles

Towards the heavy-ion program at J-PARC

Sako, Hiroyuki; Chujo, Tatsuya*; Gunji, Taku*; Harada, Hiroyuki; Imai, Kenichi; Kaneta, Masashi*; Kinsho, Michikazu; Liu, Y.*; Nagamiya, Shoji; Nishio, Katsuhisa; et al.

Nuclear Physics A, 931, p.1158 - 1162, 2014/11

 Times Cited Count:23 Percentile:80.47(Physics, Nuclear)

Recently, a heavy-ion program as a future J-PARC project has been discussed. The main goals of the program are to explore the QCD phase diagram at highbaryon density with heavy ions up to uranium at the beam energies of around 10A GeV. We are planning to focus on the electron and muon measurements and rare probe search such asmulti-strangeness and charmed hadrons with high beam rates at J-PARC. A heavy-ionacceleration scheme has been considered with a new heavy-ion linac and a new booster ring, with the existing 3-GeV Rapid-Cycling Synchrotron, and the 30-GeV Main Ring synchrotron. An overview of the heavy-ion program and accelerator design, as well as physics goals and conceptual design of the experiments are presented.

Journal Articles

Development of a GEM-TPC for H-dibaryon search experiment at J-PARC

Sako, Hiroyuki; Ahn, J. K.*; Baek, K. H.*; Bassalleck, B.*; Fujioka, H.*; Guo, L.*; Hasegawa, Shoichi; Hicks, K.*; Honda, R.*; Hwang, S. H.*; et al.

Journal of Instrumentation (Internet), 9(4), p.C04009_1 - C04009_10, 2014/04

 Times Cited Count:3 Percentile:16.14(Instruments & Instrumentation)

A TPC has been developed for J-PARC E42 experiment to search for H-dibaryon in ($$K^-$$, $$K^+$$) reaction. An event with 2 $$pi^-$$ and 2 protons decaying from H-dibaryon is searched for inside the TPC. The TPC has octagonal prism shape drift volume with about 50 cm diameter with 55 cm drift length filled with Ar-CH$$_{4}$$ (90:10) gas. At the end of the drift volume, 3-layer GEMs are equipped. In order to analyze momenta of produced particles, the TPC is applied with 1 T dipole magnetic field parallel to the drift electric field with a superconducting Helmholz magnet. In order to maximize the acceptance of H-dibaryon events, a diamond target is installed inside the TPC drift volume, in a cylindrical hole opened from the top to the middle of the drift volume. Since extremely high-rate $$K^-$$ beam is directly injected into the TPC drift volume to the target, a gating grid and GEMs are adopted to suppress positive-ion feedback.

Journal Articles

Photoperiod-insensitive mutants with shorter plant height identified in the M1 generation of rice irradiated with carbon ion beams

Azad, M. A. K.*; Mazumdar, M. N. N.*; Chaki, A. K.*; Ali, M.*; Hakim, M. L.*; Mamun, A. N. K.*; Hase, Yoshihiro; Nozawa, Shigeki; Tanaka, Atsushi; Koike, Aki*; et al.

SABRAO Journal of Breeding and Genetics, 45(2), p.179 - 186, 2013/06

no abstracts in English

Journal Articles

Event structure and double helicity asymmetry in jet production from polarized $$p + p$$ collisions at $$sqrt{s}$$ = 200 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Y.*; Al-Bataineh, H.*; Alexander, J.*; Aoki, K.*; Aphecetche, L.*; Armendariz, R.*; et al.

Physical Review D, 84(1), p.012006_1 - 012006_18, 2011/07

 Times Cited Count:28 Percentile:72.42(Astronomy & Astrophysics)

We report on the event structure and double helicity asymmetry ($$A_{LL}$$) of jet production in longitudinally polarized $$p + p$$ collisions at $$sqrt{s}$$ = 200 GeV. Photons and charged particles were measured by the PHENIX experiment. Event structure was compared with the results from PYTHIA event generator. The production rate of reconstructed jets is satisfactorily reproduced with the next-to-leading-order perturbative QCD calculation. We measured $$A_{LL}$$ = -0.0014 $$pm$$ 0.0037 at the lowest $$P_T$$ bin and -0.0181 $$pm$$ 0.0282 at the highest $$P_T$$ bin. The measured $$A_{LL}$$ is compared with the predictions that assume various $$Delta G(x)$$ distributions.

Journal Articles

Identified charged hadron production in $$p + p$$ collisions at $$sqrt{s}$$ = 200 and 62.4 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Armendariz, R.*; et al.

Physical Review C, 83(6), p.064903_1 - 064903_29, 2011/06

 Times Cited Count:176 Percentile:99.41(Physics, Nuclear)

Transverse momentum distributions and yields for $$pi^{pm}, K^{pm}, p$$, and $$bar{p}$$ in $$p + p$$ collisions at $$sqrt{s}$$ = 200 and 62.4 GeV at midrapidity are measured by the PHENIX experiment at the RHIC. We present the inverse slope parameter, mean transverse momentum, and yield per unit rapidity at each energy, and compare them to other measurements at different $$sqrt{s}$$ collisions. We also present the scaling properties such as $$m_T$$ and $$x_T$$ scaling and discuss the mechanism of the particle production in $$p + p$$ collisions. The measured spectra are compared to next-to-leading order perturbative QCD calculations.

Journal Articles

Azimuthal correlations of electrons from heavy-flavor decay with hadrons in $$p+p$$ and Au+Au collisions at $$sqrt{s_{NN}}$$ = 200 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Aramaki, Y.*; et al.

Physical Review C, 83(4), p.044912_1 - 044912_16, 2011/04

 Times Cited Count:7 Percentile:49.81(Physics, Nuclear)

Measurements of electrons from the decay of open-heavy-flavor mesons have shown that the yields are suppressed in Au+Au collisions compared to expectations from binary-scaled $$p+p$$ collisions. Here we extend these studies to two particle correlations where one particle is an electron from the decay of a heavy flavor meson and the other is a charged hadron from either the decay of the heavy meson or from jet fragmentation. These measurements provide more detailed information about the interaction between heavy quarks and the quark-gluon matter. We find the away-side-jet shape and yield to be modified in Au+Au collisions compared to $$p+p$$ collisions.

Journal Articles

Measurement of neutral mesons in $$p$$ + $$p$$ collisions at $$sqrt{s}$$ = 200 GeV and scaling properties of hadron production

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Y.*; Al-Bataineh, H.*; Alexander, J.*; Aoki, K.*; Aphecetche, L.*; Armendariz, R.*; et al.

Physical Review D, 83(5), p.052004_1 - 052004_26, 2011/03

 Times Cited Count:169 Percentile:98.47(Astronomy & Astrophysics)

The PHENIX experiment at RHIC has measured the invariant differential cross section for production of $$K^0_s$$, $$omega$$, $$eta'$$ and $$phi$$ mesons in $$p + p$$ collisions at $$sqrt{s}$$ = 200 GeV. The spectral shapes of all hadron transverse momentum distributions are well described by a Tsallis distribution functional form with only two parameters, $$n$$ and $$T$$, determining the high $$p_T$$ and characterizing the low $$p_T$$ regions for the spectra, respectively. The integrated invariant cross sections calculated from the fitted distributions are found to be consistent with existing measurements and with statistical model predictions.

Journal Articles

Spins and parities of astrophysically important $$^{30}$$S states from $$^{28}$$Si($$^{3}$$He, $$n$$$$gamma$$)$$^{30}$$S

Setoodehnia, K.*; Chen, A. A.*; Komatsubara, Tetsuro*; Kubono, Shigeru*; Binh, D. N.*; Carpino, J. F.*; Chen, J.*; Hashimoto, Takashi*; Hayakawa, Takehito; Ishibashi, Yoko*; et al.

Physical Review C, 83(1), p.018803_1 - 018803_4, 2011/01

 Times Cited Count:12 Percentile:60.85(Physics, Nuclear)

The structure of proton-unbound $$^{30}$$S states strongly determines the thermonuclear $$^{29}$$P($$p$$, $$gamma$$)$$^{30}$$S reaction rate at temperatures characteristic of explosive hydrogen burning in classical novae and type I X-ray bursts. Specifically, the rate had been previously predicted to be dominated by two low-lying, unobserved, levels in the $$E$$$$_{x}$$=4.7-4.8 MeV region, with spin and parity assignments of 3$$^{+}$$ and 2$$^{+}$$. In recent experimental work, two candidate levels were observed with energies of 4.699 MeV and 4.814 MeV, but no experimental information on their spins and parities was obtained. We have performed an in-beam $$gamma$$-ray spectroscopy study of $$^{30}$$S with the $$^{28}$$Si($$^{3}$$He, $$n$$$$gamma$$)$$^{30}$$S reaction. The spin and parities were inferred from a comparison to the known decay schemes of the corresponding mirror states.

Journal Articles

FUJI, an initial sintering comparison test for pelletized-, sphere-pac- and vipac-fast breeder reactor mixed oxide fuel

Bart, G.*; Bakker, K.*; Hellwig, C.*; Kihara, Yoshiyuki; Ozawa, Takayuki; Wallin, H.*; Shigetome, Yoshiaki

Journal of Nuclear Science and Technology, 44(3), p.329 - 336, 2007/03

 Times Cited Count:4 Percentile:37.26(Nuclear Science & Technology)

Within the FUJI collaboration program among Japan Atomic Energy Agency (JAEA, former JNC), Paul Scherrer Institute (PSI, Switzerland) and Nuclear Research and Consultancy Group (NRG, the Netherlands) the production paths of plutonium and neptunium mixed oxide- (sphere-pac- and vipac-) particle fuels (20wt% Pu and 5wt% Np) are tested as well as the initial sintering and power-to-melt behavior under simulated FBR conditions. The various fuel forms were produced at PSI under the support of JNC, the irradiations were accomplished at High Flux Reactor (HFR) in Petten, the post irradiation examinations are being achieved mainly at NRG and the fuel modelling being performed at JNC and PSI. The present paper reviews mainly the project planning, fuel behaviour- pre-calculations and the fuel- and fuel segment- production. A short overview of the irradiation conditions and ceramographic post irradiation examination analyses is also given.

JAEA Reports

Final Report of the FUJI Project Concerning the Research and Development of Advanced Sphere-Pac Fuel among JNC, PSI and NRG

Morihira, Masayuki; Nakamura, Masahiro; Ozawa, Takayuki; Kihara, Yoshiyuki; Hellwig, C.*; Ingold, F.*; Bakker, K.*

JNC TY8400 2005-006, 320 Pages, 2005/08

JNC-TY8400-2005-006.pdf:18.0MB

The collaboration project concerning sphere-pac fuel (SPF) among JNC, PSI and NRG was performed from 1996 till 2005. Total sixteen fuel segments (eight pins) of three types of fuel were fabricated in PSI. Two SPF segments contained 5%Np in addition to 20%Pu-MOX. Other segments contained no Np. The fuel microsphere for SPF was fabricated by the internal gelation process. The trial to apply the internal gelation process to Np-MOX fabrication was successfully attained. The test pins were transported to Petten in the Netherlands in September 2003 and assembling of the sample holders was done. Three steady state irradiation tests and one power-to-melt test were performed in HFR. Two test pins (four segments) were irradiated every tests simultaneously. The former tests were performed mainly to obtain the restructuring data of SPF in the early beginning of irradiation. The later was done to evaluate PTM linear heat rate of SPF with the reference data for pellet fuel. The irradiation tests were performed in January to March 2004 and December 2004 to March 2005. Post irradiation examination was completed in August 2005. In this project the irradiation tests in HFR was doubtless main task but so many other works were also performed i.e. transfer of the technology concerning modeling and design of sphere-pac fuel from PSI to JNC, additional destructive PIE of IFA-550.11 fuel (a power ramp test of sphere-pac fuel segment irradiated in the Gösgen PWR), fabrication tests in PSI, etc. This report summarized the planning of the irradiation tests, fuel design, result of fabrication, irradiation, post irradiation examination and data analysis. SPF design codes, DIRAD-S, SIMPLE-S which was developed by implanting SPF models of PSI into the pellet design codes in JNC, were verified with the irradiation test data in this project to show good accuracy.

Journal Articles

Research committee on Ruthenium and Technetium Chemistry in PUREX System, Organized by the Atomic Energy Society of Japan

Matsumoto, Shiro*; Uchiyama, Gunzo; Ozawa, Masaki*; Kobayashi, Y.*; Shirato, K.*

Radiochemistry, 45(3), p.219 - 224, 2003/05

no abstracts in English

Journal Articles

An Ion channeling study on V$$_{2}$$D crystals

Yamaguchi, Sadae*; Takahiro, K.*; Fujino, Yutaka*; Naramoto, Hiroshi; Ozawa, Kunio*

Journal of Alloys and Compounds, 231, p.132 - 137, 1995/00

 Times Cited Count:4 Percentile:42.23(Chemistry, Physical)

no abstracts in English

Journal Articles

Spectal data for molybdenumions, Mo VI-Mo XLII

; ; Ozawa, K.; *; J.Suger*; *

Journal of Physical and Chemical Reference Data, 16(2), p.327 - 377, 1987/02

 Times Cited Count:24 Percentile:80.15(Chemistry, Multidisciplinary)

no abstracts in English

Journal Articles

Radiative electron capture in heavy ion and He collisions

Kawatsura, Kiyoshi; *; ; *; ; Ozawa, K.; ; *

Nuclear Instruments and Methods in Physics Research A, 262, p.33 - 36, 1987/00

 Times Cited Count:3 Percentile:51.93(Instruments & Instrumentation)

no abstracts in English

Journal Articles

Energy and lifetime measurements in highly ionized chlorine

Kawatsura, Kiyoshi; ; *; *; ; Ozawa, K.; ; *

Nuclear Instruments and Methods in Physics Research A, 262, p.150 - 155, 1987/00

 Times Cited Count:8 Percentile:69.78(Instruments & Instrumentation)

no abstracts in English

JAEA Reports

Data Compilation for Radiation Effects on Ceramic Insulators

*; Ozawa, K.; *; *

JAERI-M 86-127, 76 Pages, 1986/08

JAERI-M-86-127.pdf:1.48MB

no abstracts in English

JAEA Reports

Spectral Data for Highly Ionized Molybdenum,Mo VI-Mo XLII

; *; *; ; Ozawa, K.

JAERI-M 85-173, 116 Pages, 1985/10

JAERI-M-85-173.pdf:1.61MB

no abstracts in English

146 (Records 1-20 displayed on this page)