Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
collisions at 
= 200 GeVAdare, 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：29 Percentile：73.24(Astronomy & Astrophysics)We report on the event structure and double helicity asymmetry (
) of jet production in longitudinally polarized collisions at = 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 = -0.0014 
0.0037 at the lowest 
bin and -0.0181 0.0282 at the highest bin. The measured is compared with the predictions that assume various 
distributions.
collisions at = 200 and 62.4 GeVAdare, 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：184 Percentile：99.45(Physics, Nuclear)Transverse momentum distributions and yields for 
, and 
in collisions at = 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 collisions. We also present the scaling properties such as 
and 
scaling and discuss the mechanism of the particle production in collisions. The measured spectra are compared to next-to-leading order perturbative QCD calculations.
+ collisions at = 200 GeV and scaling properties of hadron productionAdare, 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：177 Percentile：98.48(Astronomy & Astrophysics)The PHENIX experiment at RHIC has measured the invariant differential cross section for production of 
, 
, 
and 
mesons in collisions at = 200 GeV. The spectral shapes of all hadron transverse momentum distributions are well described by a Tsallis distribution functional form with only two parameters, 
and 
, determining the high 
and characterizing the low 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.
Katayama, Yoshinori; Yagafarov, O.; Hattori, Takanori; Suzuya, Kentaro; Inamura, Yasuhiro; Chiba, Ayano*; Otomo, Toshiya*; Temleitner, L.*; Kohara, Shinji*
no journal, ,
The purpose of our project is structural analysis of liquid water and other structurally disordered materials under high pressure using a high-pressure neutron beamline which is under construction in J-PARC/MLF. In this presentation, we will review recent studies toward the neutron experiments, such as synchrotron radiation X-ray diffraction studies on liquid water under high-pressure and high-temperature conditions, and Reverse Monte Carlo modeling of permanently densified silica glass using both X-ray and neutron data.
Katayama, Yoshinori; Hattori, Takanori; Yagafarov, O.*; Saito, Hiroyuki; Sano, Asami; Suzuya, Kentaro; Chiba, Ayano*
no journal, ,
As the first high-pressure experiments on structurally disordered materials using a new high-pressure neutron diffractometer, PLANET, installed in J-PARC/MLF, measurements of silica glass were caried out. We compressed a sample in a ZrO
cube using a six-axis press and measured diffraction at pressures of 0.1 MPa, 2.3, 5.5, 7.5 and 9.9 GPa at room temperature. The size of the sample was 4.6 mm in diameter and 6.7 mm in height. The size of the incident beam was 2.5 mm in width and 4.5 mm in height. The pressure was estimated from the applied load. Vanadium sample and empty cell were also measured for the correction of the diffraction intensity. Clean diffraction patterns without diffraction lines from surrounding materials were obtained thanks to the radial collimator system. Measurements on heavy water at room temperature, 100
C and 200C at 0.8 GPa were also carried out. Significant temperature dependence of diffraction pattern was observed.
Katayama, Yoshinori; Yagafarov, O.*; Hattori, Takanori; Chiba, Ayano*; Sano, Asami; Saito, Hiroyuki; Suzuya, Kentaro; Otomo, Toshiya*
no journal, ,
As the first high-pressure experiments on structurally disordered materials using a newly-built high-pressure neutron diffractometer, PLANET, installed in J-PARC/MLF, measurements of silica glass, a typical oxide glass, were caried out. We compressed a sample in a ZrO cube using a six-axis press and measured diffraction at pressures of 0.1 MPa, 2.3, 5.5, 7.5 and 9.9 GPa at room temperature. Vanadium sample and empty cell were also measured for the correction of the diffraction intensity. Clean diffraction patterns without diffraction lines from surrounding materials were obtained thanks to the radial collimator system. Measurements on heavy water at room temperature, 100
C and 200C at 0.8 GPa were also carried out as the first high-pressure high-temperature liquid measurement using PLANET. Significant temperature dependence of diffraction pattern was observed.
glass using J-PARC high-pressure neutron diffractometer PLANETHattori, Takanori; Yagafarov, O.*; Katayama, Yoshinori; Sano, Asami; Saito, Hiroyuki; Chiba, Ayano*; Inamura, Yasuhiro; Suzuya, Kentaro; Otomo, Toshiya*
no journal, ,
SiO glass consists of SiO
tetrahedra. This glass is easily densified by applying pressure, due to its relatively sparse network ring formed by the linkage of tetrahedra. The density increase amounts to 20% by room temperature compression to 8 GPa. This increase is, however, released after decompression because of insufficient structural relaxation. On the other hand, the heating at high pressures promotes the structural relaxation, resulting in permanent densification of 20% at most. The mechanism of this densification has been investigated so far, but the microscopic origin is still to be revealed. So, we performed in-situ high-pressure neutron experiments at newly constructed high-pressure neutron beamline PLANET in J-PARC. We will discuss the origin of the reversibility in the densification.
Hattori, Takanori; Sano, Asami; Inamura, Yasuhiro; Funakoshi, Kenichi*; Abe, Jun*; Machida, Shinichi*; Okazaki, Nobuo*; Katayama, Yoshinori; Yagafarov, O.*; Chiba, Ayano*
no journal, ,
SiO glass consists of SiO tetrahedra. This glass is easily densified by applying pressure, due to its relatively sparse network ring formed by the linkage of tetrhaera. The density increase amounts to 20% by room temperature compression to 8 GPa. This increase is, however, released after decompression because of insufficient structural relaxation. On the other hand, the heating at high pressures promotes the structural relaxation, resulting in permanent densification of 20% at most. The mechanism of this densification has been investigated so far, but the microscopic origin is still to be revealed. So, we performed in-situ high-pressure neutron experiments at newly constructed high-pressure neutron beamline PLANET in J-PARC. We will discuss the origin of the reversibility in the densification.
Katayama, Yoshinori; Hattori, Takanori; Saito, Hiroyuki; Sano, Asami; Suzuya, Kentaro; Yagafarov, O.*; Chiba, Ayano*; Otomo, Toshiya*
no journal, ,
Liquid water at ambient conditions has an ice-like, characteristic structure due to the hydrogen bonds between molecules. To study pressure and temperature dependence of the structure of water, we have carried out in-situ high-temperature high-pressure measurements on liquid water using synchrotron radiation at the SPring-8 and molecular dynamics simulations. The results revealed transformation from the ice-like structure to a simple-liquid-like structure. To investigate change in hydrogen bonds, neutron is an important probe. We carried out neutron diffraction measurements on heavy water at room temperature, 100C and 200C at 0.8 GPa using newly-built high-pressure diffractometer, PLANET, at J-PARC/MLF. Significant temperature dependence of diffraction pattern was observed.
glass using high-pressure neutron diffractometer PLANET at J-PARCHattori, Takanori; Yagafarov, O.*; Katayama, Yoshinori; Sano, Asami; Saito, Hiroyuki; Chiba, Ayano*; Inamura, Yasuhiro; Suzuya, Kentaro; Otomo, Toshiya*
no journal, ,
SiO
glass consists of SiO
tetrahedra. This glass is easily densified by applying pressure, due to its relatively sparse network formed by the linkage of tetrahedra. The density increase amounts to 20% by room temperature compression to 8 GPa. This increase is, however, released after decompression because of insufficient structural relaxation. On the other hand, the heating at high pressures promotes the structural relaxation, resulting in permanent densification of 20% at most. The mechanism of this densification has been investigated so far, but the microscopic origin is still to be revealed. So, we performed in-situ high-pressure neutron experiments at newly constructed high-pressure neutron beamline PLANET in J-PARC. We will discuss the origin of the reversibility in the densification.
Hattori, Takanori; Yagafarov, O.*; Katayama, Yoshinori; Chiba, Ayano*; Sano, Asami; Inamura, Yasuhiro; Otomo, Toshiya*
no journal, ,
SiO glass is an amorphous solid consisting of SiO tetrahedra. Each tetrahedra are connected to each other, and forms the many-menbered ring. Thus, the glass has large void space and therefore marked densification is expected under pressure. Actually, the density increases by 20% on compression to 8 GPa, accompanying the change in the intermediate range order. The density goes back to the original one on room-temperature decompression, but the high-density state is maintained once the sample is heated under pressure by structural relaxation (permanent densification). So far, the mechanism has been investigated, but remains to be revealed. To reveal the mechanism, in situ high-pressure diffraction is indispensable. Such data were obtained up to 10 GPa at the high-pressure neutron diffactometer PLANET in the last year, therefore we developed the method to analyze the data this year. By developing the program, we succeeded in obtaining structure factor and confirmed its reliability by comparing with the previous results.
Katayama, Yoshinori; Hattori, Takanori; Yagafarov, O.*; Saito, Hiroyuki; Sano, Asami; Suzuya, Kentaro; Chiba, Ayano*; Otomo, Toshiya*
no journal, ,
Liquid water at ambient conditions has an ice-like, characteristic structure due to the hydrogen bonds between molecules. To study pressure and temperature dependence of the structure of water, we have carried out in-situ high-temperature high-pressure measurements on liquid water by in-situ synchrtorn X-ray diffraction experiments at the SPring-8 and molecular dynamics simulations. The results revealed transformation from the ice-like structure to a simple-liquid-like structure. To investigate change in hydrogen bonds, neutron is an important probe. We carried out neturon diffraction measurements on heavy water at 100C and 200C at 2 GPa using high-pressure diffractometer, PLANET, at J-PARC/MLF. Significant temperature dependence of width of first peak in diffraction pattern, which is similar to that observed in the previous neutron diffraction experiments at 0.8 GPa.
Hattori, Takanori; Yagafarov, O.*; Katayama, Yoshinori; Chiba, Ayano*; Sano, Asami; Inamura, Yasuhiro; Otomo, Toshiya*; Matsuzaki, Yuki*; Shimojo, Fuyuki*
no journal, ,
PLANET is the beamline dedicated for the high-pressure experiments. The operation has been started at JFY 2013, and now many users are coming to use. In this talk, we introduce the current state of the PLANET and the example of the structure analysis of disordered materials. PLANET adopted the double staged compression system of the multi anvil 6-6, and enables the data collation at 10 GPa and 2000 K. To extend accessible PT range, we newly introduce another compression system of multi-anvil 6-8, and succeeded in generating 16 GPa and 1273 K. In addition, the PLANET is designed so that we can analyze the structure of liquid under pressure. In the analysis, the program for liquid analysis developed at BL21 NOVA is used. Here, we briefly introduce the reliability of the results and the pressure evolution of the silica glass.
Hattori, Takanori; Yagafarov, O.*; Katayama, Yoshinori; Chiba, Ayano*; Sano, Asami; Inamura, Yasuhiro; Otomo, Toshiya*; Matsuzaki, Yuki*; Shimojo, Fuyuki*
no journal, ,
PLANET is the beamline dedicated for the high-pressure experiments. The operation has been started at JFY 2013, and now many users are coming to use. In this talk, we introduce the current state of the PLANET and the example of the structure analysis of disordered materials. PLANET adopted the double staged compression system of the multi anvil 6-6, and enables the data collation at 10 GPa and 2000 K. To extend accessible PT range, we newly introduce another compression system of multi-anvil 6-8, and succeeded in generating 16 GPa and 1273 K. In addition, the PLANET is designed so that we can analyze the structure of liquid under pressure. In the analysis, the program for liquid analysis developed at BL21 NOVA is used. Here, we briefly introduce the reliability of the results and the pressure evolution of the silica glass.
Hattori, Takanori; Yagafarov, O.*; Katayama, Yoshinori; Chiba, Ayano*; Sano, Asami; Inamura, Yasuhiro; Otomo, Toshiya*; Matsuzaki, Yuki*; Shimojo, Fuyuki*
no journal, ,
We recently constructed the diffractometer dedicated to high-pressure purpose at pulsed neutron source J-PARC. This beamline has the huge 6-axis multi-anvil press, which is good at generating high-pressure and high-temperature condition simultaneously. By developing devices to eliminate scattering from materials around the sample, such as a sample container, a heater, we can obtain very clear pattern even under high-PT condition. This enables us to analyze the PT dependence of the structure of amorphous solids and liquids with high quality. I will explain the performance of the beamline and the PT modification of SiO glass.
Hattori, Takanori; Yagafarov, O.*; Katayama, Yoshinori; Chiba, Ayano*; Sano, Asami; Inamura, Yasuhiro; Otomo, Toshiya*; Funakoshi, Kenichi*; Abe, Jun*; Machida, Shinichi*
no journal, ,
SiO glass consists of SiO tetrahedra which are mutually connected and forms the many-membered ring. Thus, the glass has large void in its structure, and therefore marked densification is expected under pressure. Actually, it is known that the density increases by 20% on compression to 8 GPa, accompanying the change in the intermediate range order. The density goes back to the original value by decompression, whereas the high-density state is recovered at ambient condition once the structure is relaxed by heating at high pressure. The mechanism has been investigated, but is still unknown. To reveal the mechanism, in situ high-pressure diffraction is indispensable. In this study, we collected data up to about 17 GPa by using 6-axis press below 10 GPa and Paris-Edinburgh press above 10 GPa. Thanks to incident slits and receiving collimator, no peaks from the materials surrounding sample were observed. In the talk, I will discuss differences between the densifications with and without structural relaxation.
glass at high-PT condition by in-situ neutron diffractionHattori, Takanori; Sano, Asami; Inamura, Yasuhiro; Yagafarov, O.*; Katayama, Yoshinori*; Chiba, Ayano*; Otomo, Toshiya*; Funakoshi, Kenichi*; Abe, Jun*; Machida, Shinichi*; et al.
no journal, ,
SiO glass consists of SiO
tetrahedra which are mutually connected and forms the many-membered ring. Thus, the glass has large void in its structure, and therefore marked densification is expected under pressure. Actually, it is known that the density increases by 20% on compression to 8 GPa, accompanying the change in the intermediate range order. The density goes back to the original value by decompression, whereas the high-density state is retained at ambient condition once the structure is relaxed by being heated at high pressures. In this study, the mechanism of the densification at room-temperature and high-temperature has been investigated by in-situ high-pressure neutron diffraction at high-pressure neutron beamline PLANET in J-PARC. Then, we have constructed 3-dimensional atomic arrangements by Reverse Monte Carlo simulation, coupling with previously reported X-ray data. In this talk, the mechanism of densification at room-temperature and high-temperature and their differences will be discussed based on the obtained atomic arrangements.
glass at high-PT condition by in-situ X-ray and neutron diffractionHattori, Takanori; Yagafarov, O.*; Katayama, Yoshinori*; Chiba, Ayano*; Sano, Asami; Inamura, Yasuhiro; Otomo, Toshiya*; Machida, Shinichi*; Abe, Jun*; Funakoshi, Kenichi*; et al.
no journal, ,
SiO glass consists of SiO tetrahedra which are mutually connected and forms the many-membered ring. Thus, the glass has large void in its structure, and therefore marked densification is expected under pressure. Actually, it is known that the density increases by 20% on compression to 8 GPa, accompanying the change in the intermediate range order. The density goes back to the original value by decompression, whereas the high-density state is retained at ambient condition once the structure is relaxed by being heated at high pressures. In this study, the mechanism of the densification at room-temperature and high-temperature has been investigated by in-situ high-pressure neutron diffraction at high-pressure neutron beamline PLANET in J-PARC. Then, we have constructed 3-dimensional atomic arrangements by Reverse Monte Carlo simulation, coupling with previously reported X-ray data. In this talk, the mechanism of densification at room-temperature and high-temperature and their differences will be discussed based on the obtained atomic arrangements.
glass at high-PT condition by in-situ X-ray and neutron diffractionHattori, Takanori; Sano, Asami; Inamura, Yasuhiro; Yagafarov, O.*; Katayama, Yoshinori*; Chiba, Ayano*; Otomo, Toshiya*
no journal, ,
SiO glass consists of SiO tetrahedra which are mutually connected and forms the many-membered ring. Thus, the glass has large void in its structure, and therefore marked densification is expected under pressure. Actually, it is known that the density increases by 20% on compression to 8 GPa, accompanying the change in the intermediate range order. The density goes back to the original value by decompression, whereas the high-density state is retained once the structure is relaxed by being heated at high pressures. In this study, the mechanism of the densification at room-temperature and high-temperature has been investigated by in-situ high-pressure neutron diffraction at high-pressure neutron beamline PLANET in J-PARC, coupling with previously reported X-ray data. We have constructed 3-dimensional atomic arrangements by Reverse Monte Carlo simulation. In this talk, the mechanism of densification at room-temperature and high-temperature and their differences will be discussed based on the obtained atomic arrangements.
