Yuasa, Takayuki*; Wada, Yuki*; Enoto, Teruaki*; Furuta, Yoshihiro; Tsuchiya, Harufumi; Hisadomi, Shohei*; Tsuji, Yuna*; Okuda, Kazufumi*; Matsumoto, Takahiro*; Nakazawa, Kazuhiro*; et al.
Progress of Theoretical and Experimental Physics (Internet), 2020(10), p.103H01_1 - 103H01_27, 2020/10
Kou, E.*; Tanida, Kiyoshi; Belle II Collaboration*; 537 of others*
Progress of Theoretical and Experimental Physics (Internet), 2020(2), p.029201_1 - 029201_6, 2020/02
Sonoda, Tetsu*; Katayama, Ichiro*; Wada, Michiharu*; Iimura, Hideki; Sonnenschein, V.*; Iimura, Shun*; Takamine, Aiko*; Rosenbusch, M.*; Kojima, Takao*; Ahn, D. S.*; et al.
Progress of Theoretical and Experimental Physics (Internet), 2019(11), p.113D02_1 - 113D02_12, 2019/11
An in-flight separator, BigRIPS, at RIBF in RIKEN provides each experiment with specific nuclides separated from many nuclides produced by projectile fragmentation or in-flight fission. In this process, nuclides other than separated ones are discarded on the slits in BigRIPS, although they include many nuclides interested from the view point of nuclear structure. In order to extract these nuclides for parasitic experiments, we are developing a method using laser ion-source (PALIS). A test experiment with Se beam from RIBF has been performed by using a gas cell set in BigRIPS. Unstable nuclides around Se were stopped in the gas cell in accordance with a calculation using LISE code. The stopping efficiency has been estimated to be about 30%. As a next step, we will establish the technique for extracting reaction products from the gas cell.
Ekawa, Hiroyuki; Ashikaga, Sakiko; Hasegawa, Shoichi; Hashimoto, Tadashi; Hayakawa, Shuhei; Hosomi, Kenji; Ichikawa, Yudai; Imai, Kenichi; Kimbara, Shinji*; Nanamura, Takuya; et al.
Progress of Theoretical and Experimental Physics (Internet), 2019(2), p.021D02_1 - 021D02_11, 2019/02
Theint, A. M. M.*; Ekawa, Hiroyuki; Yoshida, Junya; 7 of others*
Progress of Theoretical and Experimental Physics (Internet), 2019(2), p.021D01_1 - 021D01_10, 2019/02
Hagiwara, Kaito*; Yano, Takatomi*; Das, P. K.*; Lorenz, S.*; Ou, Iwa*; Sakuda, Makoto*; Kimura, Atsushi; Nakamura, Shoji; Iwamoto, Nobuyuki; Harada, Hideo; et al.
Progress of Theoretical and Experimental Physics (Internet), 2019(2), p.023D01_1 - 023D01_26, 2019/02
Progress of Theoretical and Experimental Physics (Internet), 2018(12), p.123G01_1 - 123G01_52, 2018/12
For an accurate calculation of the resistive-wall impedance of a resistive chamber, we must know the conductivity of a resistive material. The conductivity of the material at a given frequency can be evaluated by measuring the -matrix of a propagation mode in a waveguide. However, in most cases, only the absolute value of the -matrix is used for evaluation under the assumption that the conductivity is pure real, although both the -matrix and the conductivity are complex numbers in general. To evaluate complex conductivity from a measured complex -matrix, we derive new theoretical formulae of the -matrix for the TE and TM modes of a waveguide and for the quasi-TEM mode of a coaxial waveguide, where complex conductivity is assumed. In a reverse way, we can determine the conductivity of a material by using it as a fitting parameter in a comparison of a measured -matrix with those obtained using theoretical formulae. The three independent methods facilitate triple-checking of the accuracy of the measured conductivity.
Shimizu, Nobuhiro*; Tanida, Kiyoshi; Belle Collaboration*; 169 of others*
Progress of Theoretical and Experimental Physics (Internet), 2018(2), p.023C01_1 - 023C01_26, 2018/02
Shobuda, Yoshihiro; Chin, Y. H.*
Progress of Theoretical and Experimental Physics (Internet), 2017(12), p.123G01_1 - 123G01_22, 2017/12
no abstracts in English
Yamamoto, Masanobu; Nomura, Masahiro; Shimada, Taihei; Tamura, Fumihiko; Hara, Keigo*; Hasegawa, Katsushi*; Omori, Chihiro*; Sugiyama, Yasuyuki*; Yoshii, Masahito*
Progress of Theoretical and Experimental Physics (Internet), 2017(11), p.113G01_1 - 113G01_24, 2017/11
Two proton bunches circulates the accelerator ring in the J-PARC 3GeV synchrotoron (RCS). The accelerating voltage is also generated in twice of the revolution frequency. The major Fourier component of the wake voltage should become even harmonics. However, the odd harmonics grow and cause a large number of beam loss. The beam measurement suggests that the odd harmonic wake voltages promote oscillations of not only the bunch position but also the bunch shape. The oscillations continue because they amplify the odd harmonic beam components. A particle tracking simulation can reproduce these simultaneous oscillations. It is found that the odd harmonic wake voltages lead to severe rf bucket distortion that results in beam loss. As a result, introducing a beam loading compensation system for the minor harmonics can prevent the beam loss and it would contribute the stable accelerator operation with the reduction of the activation.
Harada, Hiroyuki; Saha, P. K.; Tamura, Fumihiko; Meigo, Shinichiro; Hotchi, Hideaki; Hayashi, Naoki; Kinsho, Michikazu; Hasegawa, Kazuo
Progress of Theoretical and Experimental Physics (Internet), 2017(9), p.093G01_1 - 093G01_16, 2017/09
The 3 GeV rapid cycling synchrotron (RCS) of the J-PARC is a high intensity proton accelerator of 1 MW. The accelerated proton beams in the RCS are extracted by eight pulsed kicker magnets and are delivered to a materials and life science experimental facility and main ring synchrotron. However, the fields of the magnets experience ringing that displaces the position of the extracted beam. This is a major issue from the viewpoint of target integrity and large beam loss. The ringing was directly measured as the displacement of the extracted beams by using a shorter pulsed beam and scanning the entire trigger timing of the kickers. We managed to cancel out the ringing by optimizing trigger timing and achieved the beam extraction with high accuracy. We developed automatic correction system of the timing and now have a higher stability. In this paper, we report our procedure and experimental results for ringing compensation.
Shobuda, Yoshihiro; Chin, Y. H.*; Saha, P. K.; Hotchi, Hideaki; Harada, Hiroyuki; Irie, Yoshiro*; Tamura, Fumihiko; Tani, Norio; Toyama, Takeshi*; Watanabe, Yasuhiro; et al.
Progress of Theoretical and Experimental Physics (Internet), 2017(1), p.013G01_1 - 013G01_39, 2017/01
The Rapid Cycling Synchrotron (RCS), whose beam energy ranges from 400 MeV to 3 GeV and which is located in the Japan Proton Accelerator Research Complex, is a kicker-impedance dominant machine, which violates the impedance budget from a classical viewpoint. Contrary to conventional understanding, we have succeeded to accelerate a 1-MW equivalent beam. The machine has some interesting features: for instance, the beam tends to be unstable for the smaller transverse beam size, the beam is stabilized by increasing the peak current . Space charge effects play an important role in the beam instability at the RCS. In this study, a new theory has been developed to calculate the beam growth rate with the head-tail and coupled-bunch modes () while taking space charge effects into account. The theory sufficiently explains the distinctive features of the beam instabilities at the RCS.
Sekihara, Takayasu; Oset, E.*; Ramos, A.*
Progress of Theoretical and Experimental Physics (Internet), 2016(12), p.123D03_1 - 123D03_27, 2016/12
Lee, J.*; Liu, H.*; Doornenbal, P.*; Kimura, Masaaki*; Minomo, Kosho*; Ogata, Kazuyuki*; Utsuno, Yutaka; Aoi, Nori*; Li, K.*; Matsushita, Masafumi*; et al.
Progress of Theoretical and Experimental Physics (Internet), 2016(8), p.083D01_1 - 083D01_7, 2016/08
no abstracts in English
Sada, Yuta*; Tanida, Kiyoshi; J-PARC E15 Collaboration*; 69 of others*
Progress of Theoretical and Experimental Physics (Internet), 2016(5), p.051D01_1 - 051D01_11, 2016/05
Maeda, Saori*; Oka, Makoto; Yokota, Akira*; Hiyama, Emiko*; Liu, Y.-R.*
Progress of Theoretical and Experimental Physics (Internet), 2016(2), p.023D02_1 - 023D02_29, 2016/02
A potential model for the interaction between a charmed baryon (, , and ) and the nucleon () is constructed. The model contains a long-range meson ( and ) exchange part and a short-distance quark exchange part. The quark cluster model is used to evaluate the short-range repulsion and a monopole type form factor is introduced to the long-range potential to reflect the extended structure of hadrons. We determine the cutoff parameters in the form factors by fitting the scattering data with the same approach and we obtain four sets of parameters (a)-(d). The most attractive potential (d) leads to bound c states with and once the channel couplings among and are taken into account. One can also investigate many-body problems with the model. Here, we construct an effective one-channel potential with the parameter set (d) and apply it to the 3-body system. The bound states with = 1/2 and 3/2 are predicted.
Hosomi, Kenji; Ma, Y.*; Ajimura, Shuhei*; Aoki, Kanae*; Dairaku, Seishi*; Fu, Y.*; Fujioka, Hiroyuki*; Futatsukawa, Kenta*; Imoto, Wataru*; Kakiguchi, Yutaka*; et al.
Progress of Theoretical and Experimental Physics (Internet), 2015(8), p.081D01_1 - 081D01_8, 2015/08
Level structure of the C hypernucleus was precisely determined by means of -ray spectroscopy. We identified four -ray transitions via the C reaction using a germanium detector array, Hyperball2. The spacing of the ground-state doublet was measured to be (stat) (syst)keV from the direct transition. Excitation energies of the and states were measured to be , keV and , keV, respectively. The obtained level energies provide definitive references for the reaction spectroscopy of hypernuclei.
Hashimoto, Tadashi*; Tanida, Kiyoshi; J-PARC E15 Collaboration*; 65 of others*
Progress of Theoretical and Experimental Physics (Internet), 2015(6), p.061D01_1 - 061D01_11, 2015/06
Ajimura, Shuhei*; Bezerra, T. J. C.*; Chauveau, E.*; Enomoto, T.*; Furuta, Hisataka*; Harada, Masahide; Hasegawa, Shoichi; Hiraiwa, T.*; Igarashi, Yoichi*; Iwai, Eito*; et al.
Progress of Theoretical and Experimental Physics (Internet), 2015(6), p.063C01_1 - 063C01_19, 2015/06
The J-PARC E56 experiment aims to search for sterile neutrinos at the J-PARC Materials and Life Science Experimental Facility (MLF). In order to examine the feasibility of the experiment, we measured the background rates of different detector candidate sites, which are located at the third floor of the MLF, using a detector consisting of plastic scintillators with a fiducial mass of 500 kg. The gammas and neutrons induced by the beam as well as the backgrounds from the cosmic rays were measured, and the results are described in this article.