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Your search keyword '"van der Werf, Dirk P."' showing total 9 results
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9 results on '"van der Werf, Dirk P."'

1. Towards Antihydrogen Trapping and Spectroscopy at ALPHA

Author

Butler, Eoin, Andresen, Gorm. B., Ashkezari, Mohammad. D., Baquero-Ruiz, Marcelo, Bertsche, William, Bowe, Paul D., Bray, Crystal C., Cesar, Claudio L., Chapman, Steven, Charlton, Michael, Fajans, Joel, Friesen, Tim, Fujiwara, Makoto C., Gill, David R., Hangst, Jeffrey S., Hardy, Walter N., Hayano, Ruyugo S., Hayden, Michael E., Humphries, Andrew J., Hydomako, Richard, Jonsell, Svante, Kurchaninov, Leonid, Lambo, Ricardo, Madsen, Niels, Menary, Scott, Nolan, Paul, Olchanski, Konstantin, Olin, Art, Povilus, Alexander, Pusa, Petteri, Robicheaux, Francis, Sarid, Eli, Silveira, Daniel M., So, Chukman, Storey, James W., Thompson, Robert I., van der Werf, Dirk P., Wilding, Dean, Wurtele, Jonathan S., and Yamazaki, Yasunori

Subjects
Physics - Atomic Physics, High Energy Physics - Experiment, Physics - Plasma Physics
Abstract

Spectroscopy of antihydrogen has the potential to yield high-precision tests of the CPT theorem and shed light on the matter-antimatter imbalance in the Universe. The ALPHA antihydrogen trap at CERN's Antiproton Decelerator aims to prepare a sample of antihydrogen atoms confined in an octupole-based Ioffe trap and to measure the frequency of several atomic transitions. We describe our techniques to directly measure the antiproton temperature and a new technique to cool them to below 10 K. We also show how our unique position-sensitive annihilation detector provides us with a highly sensitive method of identifying antiproton annihilations and effectively rejecting the cosmic-ray background., Comment: 10 pages, 5 figures

Published
2011
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2. Search For Trapped Antihydrogen

Author

Andresen, Gorm B., Ashkezari, Mohammad D., Baquero-Ruiz, Marcelo, Bertsche, William, Bowe, Paul D., Bray, Crystal C., Butler, Eoin, Cesar, Claudio L., Chapman, Steven, Charlton, Michael, Fajans, Joel, Friesen, Tim, Fujiwara, Makoto C., Gill, David R., Hangst, Jeffrey S., Hardy, Walter N., Hayano, Ryugo S., Hayden, Michael E., Humphries, Andrew J., Hydomako, Richard, Jonsell, Svante, Jørgensen, Lars V., Kurchaninov, Lenoid, Lambo, Ricardo, Madsen, Niels, Menary, Scott, Nolan, Paul, Olchanski, Konstantin, Olin, Art, Povilus, Alexander, Pusa, Petteri, Robicheaux, Francis, Sarid, Eli, Nasr, Sarah Seif El, Silveira, Daniel M., So, Chukman, Storey, James W., Thompson, Robert I., van der Werf, Dirk P., Wilding, Dean, Wurtele, Jonathan S., and Yamazaki, Yasunori

Subjects
Physics - Atomic Physics, High Energy Physics - Experiment
Abstract

We present the results of an experiment to search for trapped antihydrogen atoms with the ALPHA antihydrogen trap at the CERN Antiproton Decelerator. Sensitive diagnostics of the temperatures, sizes, and densities of the trapped antiproton and positron plasmas have been developed, which in turn permitted development of techniques to precisely and reproducibly control the initial experimental parameters. The use of a position-sensitive annihilation vertex detector, together with the capability of controllably quenching the superconducting magnetic minimum trap, enabled us to carry out a high-sensitivity and low-background search for trapped synthesised antihydrogen atoms. We aim to identify the annihilations of antihydrogen atoms held for at least 130 ms in the trap before being released over ~30 ms. After a three-week experimental run in 2009 involving mixing of 10^7 antiprotons with 1.3 10^9 positrons to produce 6 10^5 antihydrogen atoms, we have identified six antiproton annihilation events that are consistent with the release of trapped antihydrogen. The cosmic ray background, estimated to contribute 0.14 counts, is incompatible with this observation at a significance of 5.6 sigma. Extensive simulations predict that an alternative source of annihilations, the escape of mirror-trapped antiprotons, is highly unlikely, though this possibility has not yet been ruled out experimentally., Comment: 12 pages, 7 figures

Published
2010
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4. Progress towards microwave spectroscopy of trapped antihydrogen

Author

Ashkezari, Mohammad D., Andresen, Gorm B., Baquero-Ruiz, Marcelo, Bertsche, Wil, Bowe, Paul D., Butler, Eoin, Cesar, Claudio L., Chapman, Steve, Charlton, Michael, Deller, Adam, Eriksson, Stefan, Fajans, Joel, Friesen, Tim, Fujiwara, Makoto C., Gill, Dave R., Gutierrez, Andrea, Hangst, Jeffrey S., Hardy, Walter N., Hayano, Ryugo S., Hayden, Michael E., Humphries, Andrew J., Hydomako, Richard, Jonsell, Svante, Kurchaninov, Lenoid, Madsen, Niels, Menary, Scott, Nolan, Paul, Olchanski, Konstantin, Olin, Art, Povilus, Alex, Pusa, Petteri, Robicheaux, Francis, Sarid, Eli, Silveira, Daniel M., So, Chukman, Storey, James W., Thompson, Robert I., van der Werf, Dirk P., Wurtele, Jonathan S., Yamazaki, Yasunori, and ALPHA Collaboration

Published
2012
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5. Antihydrogen detection in ALPHA

Author

Hydomako, Richard, Andresen, Gorm Bruun, Ashkezari, Mohammad Dehghani, Baquero-Ruiz, Marcelo, Bertsche, William, Butler, Eoin, Bowe, Paul David, Cesar, Claudo Lenz, Chapman, Steve, Charlton, Michael, Fajans, Joel, Friesen, Tim, Fujiwara, Makoto C., Gill, David Russell, Hangst, Jeffrey Scott, Hardy, Walter Newbold, Hayano, Ryugo S., Hayden, Michael Edward, Humphries, Andrew James, Jonsell, Svante, Kurchaninov, Leonid, Madsen, Niels, Menary, Scott, Nolan, Paul, Olchanski, Konstantin, Olin, Arthur, Povilus, Alexander, Pusa, Petteri, Robicheaux, Francis, Sarid, Elazar, Silveira, Daniel Miranda, So, Chukman, Storey, James William, Thompson, Robert Ian, van der Werf, Dirk Peter, Wurtele, Jonathan Syrkin, Yamazaki, Yasunori, and ALPHA Collaboration

Published
2012
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6. Reviews

Author

Hennipman, P., Gilles, R. P., Plasmeijer, Henk W., van Nieuwkerk, M., Chichilnisky, G., Brakman, S., van Sinderen, J., Ellman, Michael, van Leeuwen, E. H., Bos, H. C., van Stiphout, A., Reijnders, L., and van der Werf, Dirk

Published
1989
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7. Book reviews

Author

Whitbread, Michael, Rabinov/itz, Alan, Lehmacher, Helmut, Cohen, Bruce, McMullen, Kathryn E., Quintanilla, Ernesto, Huttman, John, Oosterhven, Jan, Robin, Roland, Mason, Greg, Termote, Marc, Brosio, Giorgio, Kontuly, Thomas, Momsen, Janet Henshall, Trumbull, William N., Lacour, Claud, van der Werf, Dirk, Shin, Sukhan, Mera, Koichi, Husain, Ishrat, Atkinson, Glen W., Roper, Burkhardt, Grigg, Neil S., Beaman, Jay, Roulac, Stephen E., Penouil, Marc, Kim, T. John, Princic, R., Seidenfus, H. St., Doeksen, Gerald A., Spinetti, Patrizia, Yamauchi, Hiroshi, Taganyi, Zoltan, McGregor, John R., Pitfield, D. E., Studenmund, A. H., Paul, Alec H., Pederson, Eldor, Leung, Hok Lin, Ayer, Harry W., Dokmeci, Vedia, Meier, Peter M., Johnston, R. J., Chappelle, Daniel E., Robertson, C. J., and Missirian, Harry A.

Published
1984
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8. Reviews

Author

Hoogduin, L., Pruntel, Jan Rein, Zuidema, R. P., Wagener, H. A., van de Klundert, Th., Tims, Wouter, van der Werf, Dirk, Hartog, F., Plasmeijer, Henk, and Boot, Pieter

Published
1985
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9. Advances in Antihydrogen Physics

Author

Charlton, Mike and Van Der Werf, Dirk Peter

Abstract

The creation of cold antihydrogen atoms by the controlled combination of positrons and antiprotons has opened up a new window on fundamental physics. More recently, techniques have been developed that allow some antihydrogen atoms to be created at low enough kinetic energies that they can be held inside magnetic minimum neutral atom traps. With confinement times of many minutes possible, it has become feasible to perform experiments to probe the properties of the antiatom for the first time. We review the experimental progress in this area, outline some of the motivation for studying basic aspects of antimatter physics and provide an outlook of where we might expect this field to go in the coming years.

Published
2015
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