Osawa, Takahito; Nagasawa, Shunsaku*; Ninomiya, Kazuhiko*; Takahashi, Tadayuki*; Nakamura, Tomoki*; Wada, Taiga*; Taniguchi, Akihiro*; Umegaki, Izumi*; Kubo, Kenya*; Terada, Kentaro*; et al.
ACS Earth and Space Chemistry (Internet), 7(4), p.699 - 711, 2023/04
The concentrations of carbon and other major elements in asteroid samples provide very important information on the birth of life on the Earth and the solar-system evolution. Elemental analysis using muonic X-rays is one of the best analytical methods to determine the elemental composition of solid materials, and notably, is the only method to determine the concentration of light elements in bulk samples in a non-destructive manner. We developed a new analysis system using muonic X-rays to measure the concentrations of carbon and other major elements in precious and expectedly tiny samples recovered from the asteroid Ryugu by spacecraft Hayabusa2. Here we report the development process of the system in 4 stages and their system configurations, The analysis system is composed of a stainless-steel analysis chamber, an acrylic glove box for manipulating asteroid samples in a clean environment, and Ge semiconductor detectors arranged to surround the analysis chamber. The performance of the analysis system, including the background level, which is crucial for the measurement, was greatly improved from the first stage to the later ones. Our feasibility study showed that the latest model of our muonic X-ray analysis system is capable of determining the carbon concentration in Hayabusa2's sample model with an uncertainty of less than 10 percent in a 6-day measurement.
Chiu, I.-H. ; Terada, Kentaro*; Osawa, Takahito; Park, C.*; Takeshita, Soshi*; Miyake, Yasuhiro*; Ninomiya, Kazuhiko*
Journal of Physics; Conference Series, 2462, p.012004_1 - 012004_6, 2023/03
In the last decade, non-destructive elemental analysis using negative muon beams advanced significantly. This method can be used to determine the elemental composition of bulk materials without causing damage. In this study, we performed a negative muon irradiation experiment for a Northwest Africa 482 lunar meteorite (NWA482), which was installed in a stainless steel analysis chamber. The analysis chamber was filled with helium gas to suppress the background signals caused by air-scattering muons. The muonic X-rays from Al, Fe, Ca, Mg, Si, and O in the samples were detected using six high-purity germanium semiconductor detectors arranged around the analysis chamber. To correct the X-ray self-absorption effect of the samples, a Monte-Carlo simulation using Geant4 toolkit was used. Based on the quantitative analysis for muonic X-ray measurement with the correction application from the simulation, we successfully investigated the analytical sensitivity of each element in meteorites based on the NWA482 data.
Tang, P.*; Kita, Kazuyuki*; Igarashi, Yasuhito*; Satou, Yukihiko; Hatanaka, Kotaro*; Adachi, Koji*; Kinase, Takeshi*; Ninomiya, Kazuhiko*; Shinohara, Atsushi*
Progress in Earth and Planetary Science (Internet), 9(1), p.17_1 - 17_15, 2022/03
Okumura, Takuma*; Azuma, Toshiyuki*; Bennet, D. A.*; Caradonna, P.*; Chiu, I.-H.*; Doriese, W. B.*; Durkin, M. S.*; Fowler, J. W.*; Gard, J. D.*; Hashimoto, Tadashi; et al.
IEEE Transactions on Applied Superconductivity, 31(5), p.2101704_1 - 2101704_4, 2021/08
A superconducting transition-edge sensor (TES) microcalorimeter is an ideal X-ray detector for experiments at accelerator facilities because of good energy resolution and high efficiency. To study the performance of the TES detector with a high-intensity pulsed charged-particle beam, we measured X-ray spectra with a pulsed muon beam at the Japan Proton Accelerator Research Complex (J-PARC) in Japan. We found substantial temporal shifts of the X-ray energy correlated with the arrival time of the pulsed muon beam, which was reasonably explained by pulse pileup due to the incidence of energetic particles from the initial pulsed beam.
Okumura, Takuma*; Azuma, Toshiyuki*; Bennet, D. A.*; Caradonna, P.*; Chiu, I. H.*; Doriese, W. B.*; Durkin, M. S.*; Fowler, J. W.*; Gard, J. D.*; Hashimoto, Tadashi; et al.
Physical Review Letters, 127(5), p.053001_1 - 053001_7, 2021/07
We observed electronic X rays emitted from muonic iron atoms using a superconducting transition-edge-type sensor microcalorimeter. The energy resolution of 5.2 eV in FWHM allowed us to observe the asymmetric broad profile of the electronic characteristic and X rays together with the hypersatellite X rays around 6 keV. This signature reflects the time-dependent screening of the nuclear charge by the negative muon and the -shell electrons, accompanied by electron side-feeding. Assisted by a simulation, this data clearly reveals the electronic - and -shell hole production and their temporal evolution during the muon cascade process.
Martin, P. G.*; Jones, C. P.*; Bartlett, S.*; Ignatyev, K.*; Megson-Smith, D.*; Satou, Yukihiko; Cipiccia, S.*; Batey, D. J.*; Rau, C.*; Sueki, Keisuke*; et al.
Scientific Reports (Internet), 10, p.22056_1 - 22056_17, 2020/12
Igarashi, Junya*; Zhang, Z. J.*; Ninomiya, Kazuhiko*; Shinohara, Atsushi*; Satou, Yukihiko; Minowa, Haruka*; Yoshikawa, Hideki
KEK Proceedings 2019-2, p.54 - 59, 2019/11
no abstracts in English
Igarashi, Junya*; Zheng, J.*; Zhang, Z.*; Ninomiya, Kazuhiko*; Satou, Yukihiko; Fukuda, Miho*; Ni, Y.*; Aono, Tatsuo*; Shinohara, Atsushi*
Scientific Reports (Internet), 9(1), p.11807_1 - 11807_10, 2019/08
Radioactive particles were released into the environment during the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident. Many studies have been conducted to elucidate the chemical composition of released radioactive particles in order to understand their formation process. However, whether radioactive particles contain nuclear fuel radionuclides remains to be investigated. Here, we report the first determination of Pu isotopes in radioactive particles. To determine the Pu isotopes (Pu, Pu and Pu) in radioactive particles derived from the FDNPP accident which were free from the influence of global fallout, radiochemical analysis and inductively coupled plasma-mass spectrometry measurements were conducted. Radioactive particles derived from unit 1 and unit 2 or 3 were analyzed. For the radioactive particles derived from unit 1, activities of Pu and Pu were (1.70-7.06)10 Bq and (4.10-8.10)10 Bq, respectively and atom ratios of Pu/Pu and Pu/Pu were 0.330-0.415 and 0.162-0.178, respectively. These ratios were consistent with the simulation results from ORIGEN code and measurements from various environmental samples. In contrast, Pu was not detected in the radioactive particles derived from unit 2 or 3. The difference in Pu contents is clear evidence towards different formation processes of radioactive particles, and detailed formation processes can be investigated from Pu analysis.
Zhang, Z.*; Igarashi, Junya*; Satou, Yukihiko; Ninomiya, Kazuhiko*; Sueki, Keisuke*; Shinohara, Atsushi*
Environmental Science & Technology, 53(10), p.5868 - 5876, 2019/05
The Fukushima Daiichi Nuclear Power Plant (FDNPP) accident released abundant radioactive particles into the surrounding environment. Herein, we analyzed the activity of Sr in these particles to estimate the contribution of this radionuclide to the overall radiation exposure and shed light on the processes that occurred during the accident. Seven radioactive particles were isolated from the dust and soil samples collected from areas surrounding the FDNPP, and the minimum/maximum Cs activities were determined as 224/4,100 Bq. Based on the size, specific activity, and Cs/Cs activity ratios, we concluded that six of the seven radioactive particles were released from the Unit 1 reactor, while one particle was released from the Unit 3 reactor by a hydrogen explosion. Strontium-90 was detected in all radioactive particles, and the minimal/maximal Sr activities were determined as 0.046/1.4 Bq. Cs/Sr activity ratios above 1000 were observed for all seven particles, that is, compared to Cs, Sr had negligible contribution to the overall radiation exposure. The Cs/Sr activity ratios of the radioactive particles were similar to those of terrestrial environmental samples and were higher for particles released from the Unit 1 reactor than for samples collected from the Unit 1 reactor building, which indicates possibility of additional Sr -rich contamination after release of the particles.
Sugiyama, Jun*; Umegaki, Izumi*; Nozaki, Hiroshi*; Higemoto, Wataru; Hamada, Koji*; Takeshita, Soshi*; Koda, Akihiro*; Shimomura, Koichiro*; Ninomiya, Kazuhiko*; Kubo, Kenya*
Physical Review Letters, 121(8), p.087202_1 - 087202_5, 2018/08
Ninomiya, Kazuhiko*; Satou, Yukihiko; 53 of others*
KEK Proceedings 2017-6, p.31 - 34, 2017/11
no abstracts in English
Terada, Kentaro*; Sato, Akira*; Ninomiya, Kazuhiko*; Kawashima, Yoshitaka*; Shimomura, Koichiro*; Yoshida, Go*; Kawai, Yosuke*; Osawa, Takahito; Tachibana, Shogo*
Scientific Reports (Internet), 7(1), p.15478_1 - 15478_6, 2017/11
Electron- or X-ray-induced characteristic X-ray analysis has been widely used to determine chemical compositions of materials in vast research fields. In recent years, analysis of characteristic X-rays from muonic atoms, in which a muon is captured, has attracted attention because both a muon beam and a muon-induced characteristic X-ray have high transmission abilities. Here we report the first non-destructive elemental analysis of a carbonaceous chondrite using one of the world-leading intense direct current muon beam source (MuSIC; MUon Science Innovative Channel). We successfully detected characteristic muonic X-rays of Mg, Si, Fe, O, S and C from Jbilet Winselwan CM chondrite, of which carbon content is about 2 wt percent, and the obtained elemental abundance pattern was consistent with that of CM chondrites.
Ito, Takashi; Higemoto, Wataru; Ninomiya, Kazuhiko*; Kubo, Kenya*; Kawamura, Naritoshi*; Shimomura, Koichiro*
JPS Conference Proceedings (Internet), 8, p.036014_1 - 036014_5, 2015/09
Osawa, Takahito; Ninomiya, Kazuhiko*; Yoshida, Go*; Inagaki, Makoto*; Kubo, Kenya*; Kawamura, Naritoshi*; Miyake, Yasuhiro*
JPS Conference Proceedings (Internet), 8, p.025003_1 - 025003_6, 2015/09
We report a new elemental analysis system that uses an intense negative-muon beam at J-PARC Materials and Life Science Experimental Facility, Muon Science Establishment. This paper presents the preliminary results of measurements for meteorites and standard material. The main system components are a water-cooled electromagnet, an Al flight tube, an Al sample chamber, a lead shielding body, and a Ge detector. Optimum currents for the electromagnet were determined by recording beam profiles with a CCD camera; the muon beam was shaped by collimators. The background and signal-to-noise ratio was significantly better than that obtained in a previous study, and all significant elements in the meteorite and standard samples were detected. Thus, this system can be used for muonic X-ray analysis of extraterrestrial materials.
Tampo, Motonobu*; Hamada, Koji*; Kawamura, Naritoshi*; Inagaki, Makoto*; Ito, Takashi; Kojima, Kenji*; Kubo, Kenya*; Ninomiya, Kazuhiko*; Strasser, P.*; Yoshida, Go*; et al.
JPS Conference Proceedings (Internet), 8, p.036016_1 - 036016_6, 2015/09
Ninomiya, Kazuhiko*; Kubo, Kenya*; Nagatomo, Takashi*; Higemoto, Wataru; Ito, Takashi; Kawamura, Naritoshi*; Strasser, P.*; Shimomura, Koichiro*; Miyake, Yasuhiro*; Suzuki, Takao*; et al.
Analytical Chemistry, 87(9), p.4597 - 4600, 2015/05
Yashima, Hiroshi*; Sekimoto, Shun*; Ninomiya, Kazuhiko*; Kasamatsu, Yoshitaka*; Shima, Tatsushi*; Takahashi, Naruto*; Shinohara, Atsushi*; Matsumura, Hiroshi*; Satoh, Daiki; Iwamoto, Yosuke; et al.
Radiation Protection Dosimetry, 161(1-4), p.139 - 143, 2014/10
The neutron activation cross sections up to GeV are important for the neutron dosimetry of the radiation field in high-energy and high-intensity accelerator facilities for a project of intense spallation neutron source. But the evaluation of neutron activation cross section data is not enough above 20 MeV because experimental data are still scarce. This study aimed to measure the neutron activation cross sections of Bi and Co by using a quasi-monoenergetic neutron field. In this symposium, we will present obtained experimental cross section data with the other experimental data (neutron-induced and proton-induced), the calculated data by PHITS code and the evaluated nuclear data.
Terada, Kentaro*; Ninomiya, Kazuhiko*; Osawa, Takahito; Tachibana, Shogo*; Miyake, Yasuhiro*; Kubo, Kenya*; Kawamura, Naritoshi*; Higemoto, Wataru; Tsuchiyama, Akira*; Ebihara, Mitsuru*; et al.
Scientific Reports (Internet), 4, p.5072_1 - 5072_6, 2014/05
After the discovery of X-ray by Rontgen, mankind got a new eye to see through things. This fluoroscopy, so-called X-ray radiography that gives the density distribution of the inside of an object, has been applied to the vast research field such as natural/material/medical sciences, industry and technology. The recent development on the intense pulsed muon source at J-PARC MUSE (rate of 106 cps for 60 MeV/c) enabled us to pioneer a new frontier of analytical sciences. Here we report on a non-destructive elemental analysis by using muon capture. Controlling muon's momentum from 32.5 to 57.5 MeV/c. we successfully demonstrated a depth-profile analysis of light elements from several mm-thick layered materials, and non-destructive bulk analyses of meteorites containing organics. Now it is a beginning to utilize a new eye, muon radiography.
Ito, Takashi; Higemoto, Wataru; Ninomiya, Kazuhiko; Sakai, Akito*; Nakatsuji, Satoru*
Journal of the Physical Society of Japan, 81(Suppl.B), p.SB050_1 - SB050_4, 2012/12
Recently, Al compounds (: rare earth, : transition metal) have attracted much attention due to interesting physical properties closely related to their caged-structure. Each ion is confined in a Frank-Kasper cage consisting of 16 Al atoms and the large coordination number leads to strong - hybridization. In addition, the Frank-Kasper cage allows various multipole degrees of freedom for the -electrons at low because of a highly symmetric crystalline-electric-field (CEF). Among the Al series, PrAl (: Ti, V) and SmAl (: Ti, V, Cr) exhibit both these features. The ground doublet systems PrAl (: Ti, V) show a phase transition at = 2.0K (Ti) and 0.6K (V). The order parameter is believed to be an electric quadrupole active in the subspace. A possibility of the quadrupole Kondo effect has been discussed based on characteristic -dependence in specific heat, resistivity, and magnetic susceptibility. The ground quartet systems SmAl (: Ti, V, Cr) also exhibit a phase transition at = 6.4K (Ti), 2.3K (V), and 1.8K (Cr). A nuclear specific heat study in SmTiAl suggests that the primary order parameter is a magnetic dipole in spite of field-insensitive nature of the phase boundary. A possible importance of a secondarily ordered octupole moment was discussed. We here present a microscopic study of PrTiAl and SmAl (: Ti, V, Cr) using muon spin relaxation. In PrTiAl, no additional local field was observed in the ordered phase. This strongly supports the quadrupole ordering scenario. On the other hand, an appearance of a coherent local field was observed below in SmAl. This is consistent with the primary magnetic dipole ordering. The frequency distribution suggests that the magnetic structure is possibly different between the SmAl compounds.
Higemoto, Wataru; Ito, Takashi; Ninomiya, Kazuhiko; Onimaru, Takahiro*; Matsumoto, Keisuke*; Takabatake, Toshiro*
Physical Review B, 85(23), p.235152_1 - 235152_4, 2012/06
We performed muon spin rotation and relaxation measurements (SR) in caged structural heavy fermion system PrIrZn to elucidate magnetic and superconducting properties. Temperature independent SR spectra were observed below 1K, indicating that the phase transition at 0.11K is non-magnetic origin, most probably pure quadrupole ordering. In the superconducting phase, no sign of unconventional superconductivity, like a broken time reversal symmetry superconductivity, is seen below =0.05K. Moreover, we have observed spontaneous muon spin precession in a zero field in the paramagnetic phase below 15K, suggesting a novel coupling between Pr nuclei and muon realize in PrIrZn.