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Okabe, Kota; Liu, Y.*; Otani, Masashi*; Moriya, Katsuhiro; Shibata, Takanori*; Chimura, Motoki*; Hirano, Koichiro; Oguri, Hidetomo; Kinsho, Michikazu
JPS Conference Proceedings (Internet), 33, p.011011_1 - 011011_6, 2021/03
To realize more stable operation of the J-PARC accelerators, we have a re-design plan of an MEBT1 (Medium Energy Beam Transport). At the J-PARC Linac, the MEBT1 has transverse and longitudinal beam matching section for the DTLs. However there are some locally activated spots in DTL area at the current beam power level. To reduce beam loss during a beam acceleration at the DTLs is a most important task for a stable user operation. The first thing we should do is investigation a connection between beam quality in the MEBT1 and parameters of the upstream hardware. In this presentation, we will report a high intensity beam study results at the MEBT1.
beam with 3 MeV using the carbon materialKitamura, Ryo; Futatsukawa, Kenta*; Hayashi, Naoki; Hirano, Koichiro; Kosaka, Satoshi*; Miyao, Tomoaki*; Moriya, Katsuhiro; Nemoto, Yasuo*; Oguri, Hidetomo
Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.51 - 54, 2019/07
The longitudinal measurement and tuning at the beam transport after the RFQ are important to reduce the beam loss and the emittance growth in the J-PARC linac, when the high-intensity H beam of more than 60 mA is supplied. The new bunch shape monitor (BSM) using the carbon-nanotube (CNT) wire is necessary to measure the bunch shape of the high-intensity H beam with 3 MeV, because the CNT wire has a high-temperature tolerance and a small energy deposit. However, when the high voltage was applied to the CNT wire to extract the secondary electron derived, the discharge prevents the power supply from applying the voltage. Therefore, the discharge should be suppressed to measure the bunch shape with stability. Considering the characteristics of the CNT as the emitter, when the length of the CNT wire was short, the high voltage of -10 kV was applied to the CNT wire. The current status and future prospects of the BSM using the CNT wire are reported in this presentation.
Kitamura, Ryo; Hayashi, Naoki; Hirano, Koichiro; Kondo, Yasuhiro; Moriya, Katsuhiro; Oguri, Hidetomo; Futatsukawa, Kenta*; Miyao, Tomoaki*; Otani, Masashi*; Kosaka, Satoshi*; et al.
Proceedings of 10th International Particle Accelerator Conference (IPAC '19) (Internet), p.2543 - 2546, 2019/06
A bunch shape monitor (BSM) is one of the important instruments to measure the longitudinal phase space distribution. For example in the J-PARC linac, three BSMs using the tungsten wire are installed at the ACS section to measure the bunch shapes between the accelerating cavities. However, this conventional BSM is hard to measure the bunch shape of H beam with 3 MeV at the beam transport between the RFQ and DTL sections, because the wire is broken around the center region of the beam. The new BSM using the carbon-nano-tube (CNT) wire is being developed to be able to measure the bunch shape of the H beam with 3 MeV. The careful attention should be paid to apply the high voltage of 
10 kV to the CNT wire. The several measures are taken to suppress the discharge from the wire and operate the CNT-BSM. This presentation reports the current status of the development and future prospective for the CNT-BSM.
Shibata, Masahiro; Sawada, Atsushi; Tachi, Yukio; Makino, Hitoshi; Wakasugi, Keiichiro; Mitsui, Seiichiro; Kitamura, Akira; Yoshikawa, Hideki; Oda, Chie; Ishidera, Takamitsu; et al.
JAEA-Research 2014-030, 457 Pages, 2015/03
JAEA-Research-2014-030.pdf:199.23MB
JAEA and NUMO have conducted a collaborative research work which is designed to enhance the methodology of repository design and post-closure performance assessment in preliminary investigation stage. With regard to (1) study on rock suitability in terms of hydrology, based on some examples of developing method of hydro-geological structure model, acquired knowledge are arranged using the tree diagram, and model uncertainty and its influence on the evaluation items were discussed. With regard to (2) study on scenario development, the developed approach for "defining conditions" has been reevaluated and improved from practical viewpoints. In addition, the uncertainty evaluation for the effect of use of cementitious material, as well as glass dissolution model, was conducted with analytical evaluation. With regard to (3) study on setting radionuclide migration parameters, based on survey of precedent procedures, multiple-approach for distribution coefficient of rocks was established, and the adequacy of the approach was confirmed though its application to sedimentary rock and granitic rock. Besides, an approach for solubility setting was developed including the procedure of selection of solubility limiting solid phase. The adequacy of the approach was confirmed though its application to key radionuclides.
Koarashi, Jun; Moriya, Koichi*; Atarashi-Andoh, Mariko; Matsunaga, Takeshi; Fujita, Hiroki; Nagaoka, Mika
Scientific Reports (Internet), 2, p.1005_1 - 1005_5, 2012/12
Times Cited Count：40 Percentile：70.43(Multidisciplinary Sciences)The fate of 
Cs derived from the Fukushima nuclear accident fallout and associated radiological hazards are largely dependent on its mobility in the surface soils of forest ecosystems. Thus, we quantified microbial and adsorptive retentions of Cs in forest surface (0-3 cm) soils. The K
SO
extraction process liberated 2.1%-12.8% of the total Cs from the soils. Two soils with a higher content of clay- and silt-sized particles, organic carbon content, and cation exchange capacity showed higher Cs extractability. Microbial biomass was observed in all of the soils. However, the Cs extractability did not increase after destruction of the microbial biomass by chloroform fumigation, providing no evidence for microbial retention of the Fukushima-fallout Cs. The results indicate that uptake of Cs by soil microorganisms is less important for retention of potentially mobile Cs in the forest surface soils compared to ion-exchange adsorption on non-specific sites provided by abiotic components.
Kono, Takahiko; Ogino, Haruyuki*; Yoshitomi, Hiroshi; Fujiwara, Keiko*; Moriya, Koichi*
FBNews, (410), p.7 - 12, 2011/02
no abstracts in English
derived from soil organic matter decomposition over the incubation timeMoriya, Koichi*; Moriizumi, Jun*; Yamazawa, Hiromi*; Koarashi, Jun; Atarashi-Andoh, Mariko
KURRI-KR-153, p.53 - 59, 2010/03
To understand the decomposition mechanism in the soil, we researched the relationship between compositions of SOM and CO derived from SOM decomposition (SOMD-CO) by using 
C and 
C. With the soil incubation, we measured CO production rates of soil and carbon isotopic ratios in SOMD-CO. The CO production rates decreased rapidly at the beginning of incubation, and then decreased slowly. On the other hand, 
C
before incubation was larger than C
. After 40-70 days of incubation, C became smaller than C, and then C after 120-170 days approached C. We consider these results as follows. SOM is composed of three components, rapidly decomposable SOM that has large C, slowly decomposable SOM that has small C and passive SOM that has the same value as C. With the progress of soil decomposition, the dominant component in SOMD-CO changed. Therefore, C changed too.
derived from SOM decompositionMoriya, Koichi; Moriizumi, Jun*; Yamazawa, Hiromi*; Iida, Takao*; Koarashi, Jun; Atarashi-Andoh, Mariko
no journal, ,
Stable carbon isotopic ratios in soil organic matter (SOM) and CO derived from SOM decomposition were measured for two forests with different vegetation. The results showed the followings in both forests: (1) older SOM in deeper soil layer had higher C isotopic ratios (C), (2) CO derived from SOM decomposition showed higher C than the original SOM. These results probably suggest that the stable carbon isotopic ratios change with its decomposition, due to the isotopic discrimination and the variation of the SOM compositions that have different isotopic ratios.
produced through SOM decompositionsMoriya, Koichi*; Moriizumi, Jun*; Yamazawa, Hiromi*; Koarashi, Jun; Atarashi-Andoh, Mariko
no journal, ,
no abstracts in English
Koarashi, Jun; Atarashi-Andoh, Mariko; Ishizuka, Shigehiro*; Kadono, Atsunobu*; Moriya, Koichi*; Nakanishi, Takahiro
no journal, ,
Accelerated release of carbon (C) previously stored in soils is considered one of the most important positive feedbacks from terrestrial ecosystems to the atmosphere in a future warmer world. We used 14C analysis following chemical fractionation to quantify the sizes and turnover times of C pools of Japanese forest soils. The C-based approach revealed higher variations of the family of MRTs soil by soil. The size of C pools that cycle slowly on timescales of 100-1000 years strongly correlated with the content of pyrophosphate-extractable Al. In contrast, faster-cycling C pools that turn over within decades showed a negative correlation with mean annual temperature at the sites. Our results suggest that C dynamics in the isolated SOC pools may be regulated by different mechanisms: temperature control on decadal cycling C versus mineralogy control on slower-cycling C, and clearly demonstrate that the forest soils will respond very differently to climate change over the next century.
Koarashi, Jun; Atarashi-Andoh, Mariko; Ishizuka, Shigehiro*; Kadono, Atsunobu*; Moriya, Koichi*; Nakanishi, Takahiro
no journal, ,
Soils are the largest carbon (C) reservoir in terrestrial ecosystems, and may act as both a source and sink of atmospheric CO in response to climate change. Identifying the sizes and turnover times of soil organic carbon (SOC) pools is a crucial step to predicting the fate of soil C. Here, we used a C-based approach to quantitatively understand how much and how long Japanese forest soils store C in their surface horizons. We collected soil samples from deciduous forests, separated the samples into SOC fractions, and then determined their C ratios to estimate mean residence times (MRTs). The MRTs ranged from years to millennia, which revealed a different distribution of MRTs between the soils. We found that the total amount of C correlated positively with the size of the SOC pools cycling on time scales of 
100 years, but poorly with the size of faster-cycling pools. The results suggest that the soils with higher C stocks do not necessarily have higher potential for CO emission.
C measurementsMoriya, Koichi*; Koarashi, Jun; Atarashi-Andoh, Mariko; Moriizumi, Jun*; Yamazawa, Hiromi*; Hirai, Keizo*
no journal, ,
Soil organic carbon (SOC) decomposition is an important component of the global carbon cycle, because SOC is the largest carbon reservoir in terrestrial ecosystems and a small change in the CO flux from SOC may lead to a large change in atmospheric CO concentration. For the accurate estimation of SOC decomposition, it is important to identify sizes and turnover times of SOC pools. We tried to estimate three SOC pools (active, slow and resistant) with different mean residence times (MRTs) by a combination of soil incubation and C analysis. The active SOC held 
1% of the total SOC with MRTs of 1-3 weeks. The slow SOC accounted for 20-50% of the total with MRTs of 1 to 17 years. The active and slow SOC contributed greatly to the total CO production, and the primary source shifted from the active to the slow one. Our result shows the importance of quantifying the dynamics of rapidly-cycling SOC pools to accurately predicting the response of soils to climate change.
respired from a beech forest floorAtarashi-Andoh, Mariko; Koarashi, Jun; Moriya, Koichi; Nakanishi, Takahiro; Ishizuka, Shigehiro*; Hirai, Keizo*
no journal, ,
no abstracts in English
Kono, Takahiko; Ogino, Haruyuki*; Fujiwara, Keiko*; Moriya, Koichi*; Fujimichi, Yuki*; Koike, Yuya*
no journal, ,
no abstracts in English
Moriya, Koichi; Koarashi, Jun; Atarashi-Andoh, Mariko; Moriizumi, Jun*; Yamazawa, Hiromi*; Ishizuka, Shigehiro*
no journal, ,
no abstracts in English
Moriya, Koichi; Koarashi, Jun; Atarashi-Andoh, Mariko; Moriizumi, Jun*; Yamazawa, Hiromi*; Ishizuka, Shigehiro*
no journal, ,
no abstracts in English
Moriya, Koichi; Koarashi, Jun; Atarashi-Andoh, Mariko; Moriizumi, Jun*; Yamazawa, Hiromi*; Hirai, Keizo*
no journal, ,
no abstracts in English
Koarashi, Jun; Atarashi-Andoh, Mariko; Ishizuka, Shigehiro*; Kadono, Atsunobu*; Moriya, Koichi*; Nakanishi, Takahiro
no journal, ,
no abstracts in English
Moriya, Koichi; Koarashi, Jun; Atarashi-Andoh, Mariko; Ishizuka, Shigehiro*; Moriizumi, Jun*; Yamazawa, Hiromi*
no journal, ,
no abstracts in English
Koarashi, Jun; Atarashi-Andoh, Mariko; Ishizuka, Shigehiro*; Kadono, Atsunobu*; Moriya, Koichi; Nakanishi, Takahiro
no journal, ,
no abstracts in English
