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Journal Articles

Investigation of the $$Delta$$$$n$$ = 0 selection rule in Gamow-Teller transitions; The $$beta$$-decay of $$^{207}$$Hg

Berry, T. A.*; Podoly$'a$k, Zs.*; Carroll, R. J.*; Lic$u{a}$, R.*; Grawe, H.*; Timofeyuk, N. K.*; Alexander, T.*; Andreyev, A. N.; Ansari, S.*; Borge, M. J. G.*; et al.

Physics Letters B, 793, p.271 - 275, 2019/06

 Times Cited Count:5 Percentile:48.53(Astronomy & Astrophysics)

Journal Articles

Development of comprehensive techniques for coastal site characterisation; Integrated palaeohydrogeological approach for development of site evolution models

Amano, Kenji; Niizato, Tadafumi; Ota, Kunio; Lanyon, B.*; Alexander, W. R.*

Proceedings of 14th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2011) (CD-ROM), p.1477 - 1481, 2011/09

The assurance of the long-term stability of the geological environment is ${it sine qua non}$ for deep geological disposal. In Japan, since uplift/subsidence and climatic and sea-level changes would result in a significant change to hydraulic and hydrochemical conditions at coastal sites, it is of importance to establish comprehensive techniques for characterising the overall evolution of coastal sites over geological time. To this end, modelling techniques focussing on the coastal site evolution have been developed through the collaborative research programme at the Horonobe coastal study area. A palaeohydrogeological conceptual model has been developed based on all available information and eventually key geological properties and processes as well as a methodology for appropriately defining the initial and boundary conditions for long-term groundwater flow simulations have been clarified.

Journal Articles

Event structure and double helicity asymmetry in jet production from polarized $$p + p$$ collisions at $$sqrt{s}$$ = 200 GeV

Adare, 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:28 Percentile:72.42(Astronomy & Astrophysics)

We report on the event structure and double helicity asymmetry ($$A_{LL}$$) of jet production in longitudinally polarized $$p + p$$ collisions at $$sqrt{s}$$ = 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 $$A_{LL}$$ = -0.0014 $$pm$$ 0.0037 at the lowest $$P_T$$ bin and -0.0181 $$pm$$ 0.0282 at the highest $$P_T$$ bin. The measured $$A_{LL}$$ is compared with the predictions that assume various $$Delta G(x)$$ distributions.

JAEA Reports

Groundwater/porewater hydrochemistry at Horonobe URL; Data freeze II; Preliminary data quality evaluation for boreholes HDB-1 to 8

Kunimaru, Takanori; Ota, Kunio; Alexander, W. R.*; Yamamoto, Hajime*

JAEA-Research 2011-010, 52 Pages, 2011/06

JAEA-Research-2011-010.pdf:2.29MB

Work has been currently ongoing to establish an appropriate quality management system (QMS), which is applicable to all aspects of the site characterisation process, in the Horonobe Underground Research Laboratory project. A quality assurance (QA) audit of hydrochemical datasets for JAEA's deep boreholes HDB-1 to HDB-8 was carried out, along similar lines to that of the previous study for boreholes HDB-9 to HDB-11, by applying both the groundwater QA methodology employed in the recent site assessments in Sweden and a porewater QA regime proposed in this study. The results of the QA audit indicated that data were classified into low QA categories because mainly of a lack of relevant information, such as the records of groundwater sampling, which are necessary for more fully assessing the data quality. As such, a formalised field manual for hydrochemical sampling was developed. In addition, work to further improve the site characterisation QMS progressed.

Journal Articles

Identified charged hadron production in $$p + p$$ collisions at $$sqrt{s}$$ = 200 and 62.4 GeV

Adare, 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:176 Percentile:99.41(Physics, Nuclear)

Transverse momentum distributions and yields for $$pi^{pm}, K^{pm}, p$$, and $$bar{p}$$ in $$p + p$$ collisions at $$sqrt{s}$$ = 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 $$sqrt{s}$$ collisions. We also present the scaling properties such as $$m_T$$ and $$x_T$$ scaling and discuss the mechanism of the particle production in $$p + p$$ collisions. The measured spectra are compared to next-to-leading order perturbative QCD calculations.

Journal Articles

Azimuthal correlations of electrons from heavy-flavor decay with hadrons in $$p+p$$ and Au+Au collisions at $$sqrt{s_{NN}}$$ = 200 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Aramaki, Y.*; et al.

Physical Review C, 83(4), p.044912_1 - 044912_16, 2011/04

 Times Cited Count:7 Percentile:49.81(Physics, Nuclear)

Measurements of electrons from the decay of open-heavy-flavor mesons have shown that the yields are suppressed in Au+Au collisions compared to expectations from binary-scaled $$p+p$$ collisions. Here we extend these studies to two particle correlations where one particle is an electron from the decay of a heavy flavor meson and the other is a charged hadron from either the decay of the heavy meson or from jet fragmentation. These measurements provide more detailed information about the interaction between heavy quarks and the quark-gluon matter. We find the away-side-jet shape and yield to be modified in Au+Au collisions compared to $$p+p$$ collisions.

Journal Articles

Measurement of neutral mesons in $$p$$ + $$p$$ collisions at $$sqrt{s}$$ = 200 GeV and scaling properties of hadron production

Adare, 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:169 Percentile:98.47(Astronomy & Astrophysics)

The PHENIX experiment at RHIC has measured the invariant differential cross section for production of $$K^0_s$$, $$omega$$, $$eta'$$ and $$phi$$ mesons in $$p + p$$ collisions at $$sqrt{s}$$ = 200 GeV. The spectral shapes of all hadron transverse momentum distributions are well described by a Tsallis distribution functional form with only two parameters, $$n$$ and $$T$$, determining the high $$p_T$$ and characterizing the low $$p_T$$ 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.

JAEA Reports

Groundwater/porewater hydrochemistry at Horonobe URL: Data Freeze I; Preliminary data quality evaluation for boreholes HDB-9, 10 and 11

Kunimaru, Takanori; Ota, Kunio; Alexander, W. R.*; Yamamoto, Hajime*

JAEA-Research 2010-035, 109 Pages, 2010/11

JAEA-Research-2010-035.pdf:2.53MB

A quality management system (QMS) will save on effort by reducing errors and the requirement to re-sample and re-analysis and eventually lead to ensuring the reliability of the investigation results. In the Horonobe Underground Research Laboratory project, work has been ongoing to develop an appropriate QMS which is applicable to surface-based investigations. A quality assurance (QA) audit of hydrochemical datasets for boreholes HDB-9 - 11 has been carried out by applying both the groundwater QA methodology employed in the recent site assessments in Sweden and the porewater QA regime newly proposed for assigning the QA categories. This QA audit exercise indicates that the HDB-9 - 11 hydrochemical data are classified into lower categories because mainly of contamination of waters by drilling fluids, poor time-series data coverage and oxidation of core materials and also clarifies areas where additional information/work would be required to the ongoing programme.

Journal Articles

Development of comprehensive techniques for coastal site characterisation, 1; Strategic overview

Ota, Kunio; Amano, Kenji; Niizato, Tadafumi; Alexander, W. R.*; Yamanaka, Yoshiaki*

Proceedings of 13th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2010) (CD-ROM), p.123 - 132, 2010/10

The assurance of the long-term stability of the geological environment is ${it sine qua non}$ for deep geological disposal. In Japan, since uplift/subsidence and climatic and sea-level changes would result in a significant change to hydraulic and hydrochemical conditions at coastal sites, it is of importance to establish comprehensive techniques for characterising the overall evolution of coastal sites over geological time. To this end, palaeohydrogeological study is ongoing in the coastal area around Horonobe in northern Hokkaido. A "Geosynthesis Data Flow Diagram" defining a methodology for characterising the palaeohydrogeological evolution of the site has been formulated and, based on the geosynthesis methodology, a basic strategy has been established for stepwise investigations from initial survey of existing information to the final borehole programme at any coastal site. This technique has now been tested and optimised with the progress of the investigations.

Journal Articles

Natural analogues of cement; Overview of the unique systems in Jordan

Kamei, Gento; Alexander, W. R.*; Clark, I. D.*; Degnan, P.*; Elie, M.*; Khoury, H.*; Milodowski, A. E.*; Pitty, A. F.*; Salameh, E.*; Smellie, J. A. T.*

Proceedings of 13th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2010) (CD-ROM), p.141 - 147, 2010/10

Journal Articles

Development of a Quality Management System (QMS) for borehole investigations, 2; Evaluation of applicability of QMS methodology for the hydrochemical dataset

Kunimaru, Takanori; Ota, Kunio; Amano, Kenji; Alexander, W. R.*

Proceedings of 13th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2010) (CD-ROM), p.159 - 168, 2010/10

Journal Articles

Development of comprehensive techniques for coastal site characterisation, 3; Conceptualisation of long-term geosphere evolution

Niizato, Tadafumi; Amano, Kenji; Ota, Kunio; Kunimaru, Takanori; Lanyon, B.*; Alexander, W. R.*

Proceedings of 13th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2010) (CD-ROM), p.97 - 106, 2010/10

A critical issue for building confidence in the long-term safety of geological disposal is to demonstrate the stability of the geosphere, taking into account its likely future evolution. This study aims to establish comprehensive techniques for characterising the overall evolution of coastal sites through studying the palaeohydrogeological evolution in the coastal system around the Horonobe area, Hokkaido, northern Japan. Information on natural events and processes related to the palaeohydrogelogical evolution of the area have been integrated into the conceptual models that indicates the temporal and spatial sequences of the events and processes, such as climatic and sea-level changes, palaeogeography, and geomorphological and geological evolution in the area. The methodology will be applied to other analogous coastal areas on Japan to produce comprehensive techniques to support understanding the geosphere evolution of potential coastal sites for the repositories.

Journal Articles

Grimsel test site investigation phase IV; The Nagra-JAEA in situ study of safety relevant radionuclide retardation in fractured crystalline rock, 3; The RRP project final report

Alexander, W. R.*; Frieg, B.*; Ota, Kunio

Nagra NTB 00-07, 105 Pages, 2009/11

Nagra and JAEA worked together for nearly a decade on a Radionuclide Retardation Project (RRP) at Nagra's Grimsel Test Site in Switzerland with the main aim of enhancing the understanding of radionuclide transport/retardation in fractured rock. This report summarises the results of the final phase (1996-1998) of excavation project that is an integral part of RRP. It focuses on in situ characterisation of the shear zone structure and the behaviour of radionuclides that are relevant to repository post-closure safety, but are so strongly retarded by interaction with the shear zone rock that they are not expected to migrate through the dipole flow-field in experimentally reasonable time scales. The subsequent excavation of the experimental shear zone is detailed and the results of the laboratory analysis of the three-dimensional geological structure and of the distribution of injected radionuclides within the flow-field are presented.

Journal Articles

The 2008 public release of the international multi-tokamak confinement profile database

Roach, C. M.*; Walters, M.*; Budny, R. V.*; Imbeaux, F.*; Fredian, T. W.*; Greenwald, M.*; Stillerman, J. A.*; Alexander, D. A.*; Carlsson, J.*; Cary, J. R.*; et al.

Nuclear Fusion, 48(12), p.125001_1 - 125001_19, 2008/12

 Times Cited Count:35 Percentile:28.57(Physics, Fluids & Plasmas)

This paper documents the public release PR08 of the International Tokamak Physics Activity profile database, which should be of particular interest to the magnetic confinement fusion community. Data from a wide variety of interesting discharges from many of the world's leading tokamak experiments are now made available in PR08, which also includes predictive simulations of an initial set of operating scenarios for ITER. In this paper we describe the discharges that have been included and the tools that are available to the reader who is interested in accessing and working with the data.

Journal Articles

International progress in developing cases for long-term safety of repositories for transuranic and long-lived intermediate level wastes; Summary of the Third International Workshop

Mathieson, J.*; Hooper, A. J.*; Alexander, W. R.*; Shiotsuki, Masao; Kamei, Gento

Proceedings of International Waste Management Symposium 2006 (WM '06) (CD-ROM), 9 Pages, 2006/02

In January, 2005 an international workshop was held in Oxford, UK to discuss research progress in the disposability of transuranic (TRU) waste (also known as long-lived intermediate level waste. This was the third such workshop, with two previous ones being held in Switzerland in 1996 and Japan in 1999. Whilst TRU/ILW represents more complex wasteforms than high-level waste (HLW) or spent fuel (SF), it is recognised that it has not received the same amount of attention. This paper summarises the themes discussed at the workshop and the conclusions derived. Moreover, it provides a status report and future direction of work in relation to TRU and ILW wastes. The overall conclusion of the workshop was a recognition of the uncertainties surrounding the subject and outstanding issues where further work was required. However, there were no insurmountable obstacles to making safety cases for the disposal of TRU/ILW waste - safety assessment strategies were at a mature stage.

Journal Articles

A Natural analogue of a cementitious repository; A Brief overview of a study of unique sites in Jordan

Alexander, W. R.*; Kamei, Gento; Smellie, J. A. T.*

IAEA-CN-135/18, p.75 - 78, 2005/10

This paper presents a short overview of the studies on Jordan site, which are ideal natural analogues of the long-term evolution of cementitious repositories for radioactive waste.

Journal Articles

Review of international progress in transuranic and long-lived intermediate waste disposal

Hooper, A.*; Mathieson, J.*; Alexander, W. R.*; Shiotsuki, Masao

Proceedings of 10th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM '05) (CD-ROM), 6 Pages, 2005/09

This paper reviews the topics discussed at the 3rd international TRU workshop, presents the conclusions of the workshop and provides an update of the current status and the future direction of work in relation to TRU/ILW wastes.

JAEA Reports

Overview of the Maqarin Natural Analogue Project; Results from the Phase I to III

Kamei, Gento; Alexander, W. R.*; Smellie, J. A. T.*

JNC TN8400 2005-005, 43 Pages, 2005/03

JNC-TN8400-2005-005.pdf:10.86MB

The phenomena caused by hyperalkaline groundwater in the Maqarin area, in northern Jordan, have been investigating as natural analogue to understand long-term behavior and/or to validate performance assessment model for the cementitious radioactive waste repository. This report shows the outlines of these studies carried out as multi-national project since 1989.

Journal Articles

In situ radionuclide retardation in groundwater conducting systems; Overview of the research carried out at Nagra's Grimsel Test site, central Switzerland

Biggin, C.*; M$"o$ri, A.*; Alexander, W. R.*; Ota, Kunio; Frieg, B.*; Kickmaier, W.*; Mckinley, I. G.*

Environmental Radiochemical Analysis II, p.207 - 228, 2003/00

With increasing experience in the implementation of in-situ experiments, improved process understanding and more mature repository concepts, the experimental programmes at the Grimsel Test Site in Switzerland have gradually become more complex and more directly related to open questions defined by repository implementation organisations and regulatory bodies. To date, in situ radionuclide transport/retardation in fractured crystalline rocks have been studied, increasing in complexity from simple, non-sorbing to more chemically complex, strongly sorbing radionuclides. Currently, two ongoing in situ experiments at the GTS are investigating the in situ behaviour of radionuclides in the presence of clay colloids and the retardation of radionuclides under hyperalkaline conditions.

Journal Articles

Influence of the Mode of Matrix Porosity Determination on Matrix Diffusion Calculations; Laboratory Data Relevant to in Situ Conditions?

; Alexander, W. R.*; Frieg, B.*; Schild M*

Journal of Contaminant Hydrology, 61, p.131 - 145, 2002/00

 Times Cited Count:25 Percentile:51.16(Environmental Sciences)

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33 (Records 1-20 displayed on this page)