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Your search keyword '"Silveira, D. M."' showing total 4 results
Start Over Author "Silveira, D. M." Publisher american institute of physics
4 results on '"Silveira, D. M."'

1. Evaporative cooling of antiprotons for the production of trappable antihydrogen.

Author

Silveira, D. M., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Butler, E., Cesar, C. L., Chapman, S., Charlton, M., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Hangst, J. S., Hardy, W. N., Hayden, M. E., Hydomako, R., Jonsell, S., and Kurchaninov, L.

Subjects
*EVAPORATIVE cooling, *ANTIPROTONS, *ION traps, *ANTIHYDROGEN, *PARTICLES (Nuclear physics), *TEMPERATURE measurements, *DISTRIBUTION (Probability theory)
Abstract

We describe the implementation of evaporative cooling of charged particles in the ALPHA apparatus. Forced evaporation has been applied to cold samples of antiprotons held in Malmberg-Penning traps. Temperatures on the order of 10 K were obtained, while retaining a significant fraction of the initial number of particles. We have developed a model for the evaporation process based on simple rate equations and applied it succesfully to the experimental data. We have also observed radial re-distribution of the clouds following evaporation, explained by simple conservation laws. We discuss the relevance of this technique for the recent demonstration of magnetic trapping of antihydrogen. [ABSTRACT FROM AUTHOR]

Published
2013
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3. Autoresonant-spectrometric determination of the residual gas composition in the ALPHA experiment apparatus.

Author

Amole C, Ashkezari MD, Baquero-Ruiz M, Bertsche W, Butler E, Capra A, Cesar CL, Chapman S, Charlton M, Eriksson S, Fajans J, Friesen T, Fujiwara MC, Gill DR, Gutierrez A, Hangst JS, Hardy WN, Hayden ME, Isaac CA, Jonsell S, Kurchaninov L, Little A, Madsen N, McKenna JT, Menary S, Napoli SC, Nolan P, Olchanski K, Olin A, Povilus A, Pusa P, Rasmussen CØ, Robicheaux F, Sarid E, Silveira DM, Stracka S, So C, Thompson RI, Turner M, van der Werf DP, Wurtele JS, and Zhmoginov A

Abstract

Knowledge of the residual gas composition in the ALPHA experiment apparatus is important in our studies of antihydrogen and nonneutral plasmas. A technique based on autoresonant ion extraction from an electrostatic potential well has been developed that enables the study of the vacuum in our trap. Computer simulations allow an interpretation of our measurements and provide the residual gas composition under operating conditions typical of those used in experiments to produce, trap, and study antihydrogen. The methods developed may also be applicable in a range of atomic and molecular trap experiments where Penning-Malmberg traps are used and where access is limited.

Published
2013
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4. Antiproton, positron, and electron imaging with a microchannel plate/phosphor detector.

Author

Andresen GB, Bertsche W, Bowe PD, Bray CC, Butler E, Cesar CL, Chapman S, Charlton M, Fajans J, Fujiwara MC, Gill DR, Hangst JS, Hardy WN, Hayano RS, Hayden ME, Humphries AJ, Hydomako R, Jørgensen LV, Kerrigan SJ, Kurchaninov L, Lambo R, Madsen N, Nolan P, Olchanski K, Olin A, Povilus AP, Pusa P, Sarid E, Seif El Nasr S, Silveira DM, Storey JW, Thompson RI, van der Werf DP, and Yamazaki Y

Abstract

A microchannel plate (MCP)/phosphor screen assembly has been used to destructively measure the radial profile of cold, confined antiprotons, electrons, and positrons in the ALPHA experiment, with the goal of using these trapped particles for antihydrogen creation and confinement. The response of the MCP to low energy (10-200 eV, <1 eV spread) antiproton extractions is compared to that of electrons and positrons.

Published
2009
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