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Physics and Results from the AMANDA-II High Energy Neutrino Telescope
- Steven W. Barwick, the AMANDA Collaboration, J. Ahrens, X. Bai, S. W. Barwick, T. Becka, K.-H. Becker, E. Bernardini, D. Bertrand, F. Binon, A. Biron, S. Böser, O. Botner, O. Bouhali, T. Burgess, S. Carius, T. Castermans, D. Chirkin, J. Conrad, J. Cooley, D. F. Cowen, A. Davour, C. De Clercq, T. DeYoung, P. Desiati, J.-P. Dewulf, P. Doksus, P. Ekström, T. Feser, T. K. Gaisser, R. Ganupati, M. Gaug, H. Geenen, L. Gerhardt, A. Goldschmidt, A. Hallgren, F. Halzen, K. Hanson, R. Hardtke, T. Hauschildt, M. Hellwig, P. Herquet, G. C. Hill, P. O. Hulth, K. Hultqvist, S. Hundertmark, J. Jacobsen, A. Karle, L. Köpke, M. Kowalski, K. Kuehn, J. I. Lamoureux, H. Leich, M. Leuthold, P. Lindahl, J. Madsen, K. Mandli, P. Marciniewski, H. S. Matis, C. P. McParland, T. Messarius, Y. Minaeva, P. Miočinović, R. Morse, R. Nahnhauer, T. Neunhöffer, P. Niessen, D. R. Nygren, H. Ogelman, Ph. Olbrechts, C. Pérez de Los Heros, A. C. Pohl, P. B. Price, G. T. Przybylski, K. Rawlins, E. Resconi, W. Rhode, M. Ribordy, S. Richter, J. Rodríguez Martino, D. Ross, H.-G. Sander, K. Schinarakis, T. Schmidt, D. Schneider, R. Schwarz, A. Silvestri, M. Solarz, G. M. Spiczak, C. Spiering, D. Steele, P. Steffen, R. G. Stokstad, P. Sudhoff, K.-H. Sulanke, I. Taboada, L. Thollander, S. Tilav, W. Wagner, C. Walck, C. H. Wiebusch, C. Wiedemann, R. Wischnewski, H. Wissing, K. Woschnagg, G. Yodh, S. Young
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- Journal:
- Symposium - International Astronomical Union / Volume 214 / 2003
- Published online by Cambridge University Press:
- 26 May 2016, pp. 357-371
- Print publication:
- 2003
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This paper briefly describes the principle of operation and science goals of the AMANDA high energy neutrino telescope located at the South Pole, Antarctica. Results from an earlier phase of the telescope, called AMANDA-BIO, demonstrate both reliable operation and the broad astrophysical reach of this device, which includes searches for a variety of sources of ultrahigh energy neutrinos: generic point sources, Gamma-Ray Bursts and diffuse sources. The predicted sensitivity and angular resolution of the telescope were confirmed by studies of atmospheric muon and neutrino backgrounds. We also report on the status of the analysis from AMANDA-II, a larger version with far greater capabilities. At this stage of analysis, details of the ice properties and other systematic uncertainties of the AMANDA-II telescope are under study, but we have made progress toward critical science objectives. In particular, we present the first preliminary flux limits from AMANDA-II on the search for continuous emission from astrophysical point sources, and report on the search for correlated neutrino emission from Gamma Ray Bursts detected by BATSE before decommissioning in May 2000. During the next two years, we expect to exploit the full potential of AMANDA-II with the installation of a new data acquisition system that records full waveforms from the in-ice optical sensors.
Helium Pumping Strategies for D-T Fusion Devices
- A.R. Krauss, O. Auciello, J.N. Brooks, R. Mattas, R. McGrath, R. Nygren, D. L. Smith
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- Journal:
- MRS Bulletin / Volume 15 / Issue 7 / July 1990
- Published online by Cambridge University Press:
- 29 November 2013, pp. 47-49
- Print publication:
- July 1990
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In order for the new generation of long pulse D-T (deuterium-tritium) burning tokamaks to be successful, it is necessary to minimize the helium “ash” that accumulates during the thermonuclear burn. Since tritium is radioactive as well as relatively expensive, the tritium inventory stored at any given facility must also be minimized. It is therefore necessary either to preferentially remove the helium from the plasma, or to recycle all of the gas, extracting the deuterium and tritium for reuse as fuel. This latter approach requires incorporating a high pumping speed and correspondingly large pumping ducts into the fusion device design, as well as an external facility for separating helium from the D-T fuel. Since the He/H ratio in the plasma should not exceed ~5%, the pumping speed must be 20 times higher than required for a system which removes the helium only. The resulting complexity of the pumping system and the need to handle large quantities of tritium imposes a cost penalty of ~100M$ for a typical commercial fusion reactor design. It is therefore desirable to design a pumping system which removes helium only, leaving the D-T fuel in the fusion device. Recall, however, that existing pumping technologies generally provide better pumping of hydrogen, and many pump designs are totally ineffective at pumping helium.
Despite the low solubility of helium in many metals, permanent trapping of helium atoms occurs at defect sites, culminating ultimately in the formation of helium bubbles. Retention of trapped inert gas is determined by diffusional processes and is consequently temperature-dependent. Hydrogen has not only a much higher solubility, but also a much higher diffusion coefficient than helium in most metals. Consequently, it is to be expected that for some metals, there is a temperature range in which implanted hydrogen is released much more quickly than implanted helium. Brooks and Mattas proposed using this “self-pumping” effect as the basis for a pump which preferentially removes helium in the presence of hydrogen.