First report of geo- and thermochronological results from the Cordillera Central, Luzon, Philippines

Nakajima, Toru; Sueoka, Shigeru; Nagata, Mitsuhiro; Kohn, B. P.*; Ramos, N. T.*; Tsutsumi, Hiroyuki*; Tagami, Takahiro*

Earth, Planets and Space (Internet), 75(1), p.176_1 - 176_11, 2023/12

https://doi.org/10.1186/s40623-023-01927-z

Geo- and thermochronological methods were applied to dioritic rocks from the Cordillera Central, Luzon, Philippines, to understand their emplacement and exhumation history in the island arc mountains. Zircon U-Pb ages range from 32.54 0.70 to 6.11 0.15 (2SE) Ma, indicating that dioritic magmas intruded the middle and upper crust intermittently during Tertiary magmatism. Zircon fission-track (ZFT) pooled ages range from 35.63 2.17 to 6.91 0.36 (2SE) Ma, and are generally comparable with the U-Pb ages at each locality. These results suggest that the diorites cooled rapidly below 250-350 degree, (i.e. through the partial annealing zone of the ZFT system), following their intrusion. On the other hand, the zircon and apatite (U-Th-Sm)/He (ZHe and AHe) weighted mean ages, ranging from 11.71 0.36 to 8.82 0.26 and 9.21 0.52 to 0.98 0.088 (2SE) Ma respectively, indicate a decrease in cooling rates at a lower temperature range, especially through the partial retention zone of the AHe system. This observation suggests that the ZFT ages reflect initial cooling of the dioritic magma, whereas the AHe ages reflect the cooling history associated with regional exhumation following the initial cooling phase. Spatial distribution of the AHe ages suggest that rapid exhumation of the Cordillera Central during the Quaternary resulted from the block-like uplift of the entire mountain range.

Mesospheric ionization during substorm growth phase

Murase, Kiyoka*; Kataoka, Ryuho*; Nishiyama, Takanori*; Nishimura, Koji*; Hashimoto, Taishi*; Tanaka, Yoshimasa*; Kadokura, Akira*; Tomikawa, Yoshihiro*; Tsutsumi, Masaki*; Ogawa, Yasunobu*; et al.

Journal of Space Weather and Space Climate (Internet), 12, p.18_1 - 18_16, 2022/06

https://doi.org/10.1051/swsc/2022012

We identified two energetic electron precipitation (EEP) events during the growth phase of moderate substorms and estimated the mesospheric ionization rate for an EEP event for which the most comprehensive dataset from ground-based and space-born instruments was available. The mesospheric ionization signature reached below 70 km altitude and continued for ~15 min until the substorm onset, as observed by the PANSY radar and imaging riometer at Syowa Station in the Antarctic region. We also used energetic electron flux observed by the Arase and POES 15 satellites as the input for the air-shower simulation code PHITS to quantitatively estimate the mesospheric ionization rate. Combining the cutting-edge observations and simulations, we shed new light on the space weather impact of the EEP events during geomagnetically quiet times, which is important to understand the possible link between the space environment and climate.

Transient ionization of the mesosphere during auroral breakup; Arase satellite and ground-based conjugate observations at Syowa Station

Kataoka, Ryuho*; Nishiyama, Takanori*; Tanaka, Yoshimasa*; Kadokura, Akira*; Uchida, Herbert Akihito*; Ebihara, Yusuke*; Ejiri, Mitsumu*; Tomikawa, Yoshihiro*; Tsutsumi, Masaki*; Sato, Kaoru*; et al.

Earth, Planets and Space (Internet), 71(1), p.9_1 - 9_10, 2019/12

https://doi.org/10.1186/s40623-019-0989-7

Transient ionization of the mesosphere was detected at around 65 km altitude during the isolated auroral expansion occurred at 2221-2226 UT on June 30, 2017. A general-purpose Monte Carlo particle transport code PHITS suggested that significant ionization is possible in the middle atmosphere due to auroral X-rays from the auroral electrons of 10 keV.

New precise measurements of muonium hyperfine structure at J-PARC MUSE

Strasser, P.*; Abe, Mitsushi*; Aoki, Masaharu*; Choi, S.*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Katsuhiko*; et al.

EPJ Web of Conferences, 198, p.00003_1 - 00003_8, 2019/01

https://doi.org/10.1051/epjconf/201919800003

A 3 MeV linac for development of accelerator components at J-PARC

Kondo, Yasuhiro; Asano, Hiroyuki*; Chishiro, Etsuji; Hirano, Koichiro; Ishiyama, Tatsuya; Ito, Takashi; Kawane, Yusuke; Kikuzawa, Nobuhiro; Meigo, Shinichiro; Miura, Akihiko; et al.

Proceedings of 28th International Linear Accelerator Conference (LINAC 2016) (Internet), p.298 - 300, 2017/05

https://doi.org/10.18429/JACoW-LINAC2016-MOPLR071

We have constructed a linac for development of various accelerator components at J-PARC. The ion source is same as the J-PARC linac's, and the RFQ is a used one in the J-PARC linac. The beam energy is 3 MeV and nominal beam current is 30 mA. The accelerator has been already commissioned, and the first development program, laser-charge-exchange experiment for the transmutation experimental facility, has been started. In this paper, present status of this 3-MeV linac is presented.

New approach to resolve the amount of Quaternary uplift and associated denudation of the mountain ranges in the Japanese Islands

Sueoka, Shigeru; Tsutsumi, Hiroyuki*; Tagami, Takahiro*

Geoscience Frontiers, 7(2), p.197 - 210, 2016/03

https://doi.org/10.1016/j.gsf.2015.06.005

Thermochronology is a discipline to determine the timing/temperature of past thermal events based on radiometric ages, which is used to reconstruct denudation history of mountains and has been successfully applied to major orogens worldwide. It has been however difficult to apply the method to relatively young/low-relief mountains in Japan. Nonetheless, the recent development of low-temperature thermochronology has greatly expanded its applicability. In this review, we introduce (1) tectonic and geomorphic settings of the Japanese Islands and their mountains, (2) previous attempts to measure uplift/denudation of the mountains in Japan by using methods other than thermochronology, (3) problems of the thermochronologic applications to reveal denudation histories of the Japanese mountains and overview of some previous attempts, and (4) a case study of the Kiso Range and discussions about the current effectivity and applicability of low-temperature thermochronology on the Japanese mountains.

Non-destructive examination of jacket sections for ITER central solenoid conductors

Takahashi, Yoshikazu; Suwa, Tomone; Nabara, Yoshihiro; Ozeki, Hidemasa; Hemmi, Tsutomu; Nunoya, Yoshihiko; Isono, Takaaki; Matsui, Kunihiro; Kawano, Katsumi; Oshikiri, Masayuki; et al.

IEEE Transactions on Applied Superconductivity, 25(3), p.4200904_1 - 4200904_4, 2015/06

https://doi.org/10.1109/TASC.2014.2364632

The Japan Atomic Energy Agency (JAEA) is responsible for procuring all amounts of Central Solenoid (CS) Conductors for ITER, including CS jacket sections. The conductor is cable-in-conduit conductor (CICC) with a central spiral. A total of 576 NbSn strands and 288 copper strands are cabled around the central spiral. The maximum operating current is 40 kA at magnetic field of 13 T. CS jacket section is circular in square type tube made of JK2LB, which is high manganese stainless steel with boron added. Unit length of jacket sections is 7 m and 6,300 sections will be manufactured and inspected. Outer/inner dimension and weight are 51.3/35.3 mm and around 90 kg, respectively. Eddy Current Test (ECT) and Phased Array Ultrasonic Test (PAUT) were developed for non-destructive examination. The defects on inner and outer surfaces can be detected by ECT. The defects inside jacket section can be detected by PAUT. These technology and the inspected results are reported in this paper.

Field-orientation dependence of low-energy quasiparticle excitations in the heavy-electron superconductor UBe

Shimizu, Yusei*; Kittaka, Shunichiro*; Sakakibara, Toshiro*; Haga, Yoshinori; Yamamoto, Etsuji; Amitsuka, Hiroshi*; Tsutsumi, Yasumasa*; Machida, Kazushige*

Physical Review Letters, 114(14), p.147002_1 - 147002_6, 2015/04

https://doi.org/10.1103/PhysRevLett.114.147002

Uplift and denudation history of the Yoro-Suzuka-Nunobiki mountains based on apatite fission-track thermochronology

Sueoka, Shigeru; Tsutsumi, Hiroyuki*; Tagami, Takahiro*; Hasebe, Noriko*; Tamura, Akihiro*; Arai, Shoji*; Shibata, Kenji

Fisshion, Torakku Nyusureta, (27), p.17 - 19, 2014/12

http://www.ftrgj.org/FTNLs/FTNLparts/sueoka14.pdf

We are attempting to reveal uplift/denudation history of the Yoro-Suzuka-Nunobiki mountains, southwest Japan, by using apatite fission-track (AFT) thermochronology. We obtained AFT ages of 47-30 Ma. The ages are younger in the central and southern part of the Suzuka Range and get older to the north and south. Inverse thermal modeling based on the AFT ages and lengths indicates the difference among the ages reflect amount of denudation accommodate with the mountains uplifting in the past few million years. These results imply the process of the mountain uplifting of this area is more complicated than the developments of the basins propagating from south to north.

Status quo of the injector for the IFMIF/EVEDA prototype accelerator

Shinto, Katsuhiro; Ichikawa, Masahiro; Takahashi, Yasuyuki*; Kubo, Takashi*; Tsutsumi, Kazuyoshi; Kikuchi, Takayuki; Kasugai, Atsushi; Sugimoto, Masayoshi; Gobin, R.*; Girardot, P.*; et al.

Proceedings of 11th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1009 - 1012, 2014/10

http://www.pasj.jp/web_publish/pasj2014/proceedings/PDF/SUP0/SUP025.pdf

The prototype accelerator is being developed as an engineering validation for the International Fusion Materials Irradiation Facility (IFMIF) equipped with an accelerator-driven-type neutron source for developing fusion reactor materials. This prototype accelerator is a deuteron linear accelerator consisting of an injector, an RFQ, a superconducting linac and their auxiliaries. It aims to produce a CW D beam with the energy and current of 9 MeV/125 mA. The injector test was completed at CEA/Saclay in 2012 for producing a CW H beam and a CW D beam with the energy and current of 100 keV/140 mA. After the beam test at CEA/Saclay, the injector was transported to the International Fusion Energy Research Centre (IFERC) located in Rokkasho, Aomori, Japan. In the end of 2013, installation of the injector was started at IFERC for the injector beam test beginning from summer 2014 in order to obtain better beam qualities to be satisfied with the injection and acceleration of the following accelerators. In this paper, some results of the injector beam test performed at CEA/Saclay and the status quo of the installation of the injector at IFERC are presented.