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101 results on '"Andresen, G. B."'

1. Impact of climatic, technical and economic uncertainties on the optimal design of a coupled fossil-free electricity, heating and cooling system in Europe

Author

Zhu, K., Victoria, M., Andresen, G. B., and Greiner, M.

Subjects
Physics - Physics and Society, Electrical Engineering and Systems Science - Systems and Control
Abstract

To limit the global temperature increase to 1.5 degrees Celsius, fossil-free energy systems will be required eventually. To understand how such systems can be designed, the current state-of-the-art is to apply techno-economical optimisation modelling with high spatial and temporal resolution. This approach relies on a number of climatic, technical and economic predictions that reach multiple decades into the future. In this paper, we investigate how the design of a fossil-free energy system for Europe is affected by changes in these assumptions. In particular, the synergy among renewable generators, power-to-heat converters, storage units, synthetic gas and transmission manage to deliver an affordable net-zero emissions system. We find that levelised cost of energy decreases due to heat savings, but not for global temperature increases. In both cases, heat pumps become less favourable as surplus electricity is more abundant for heating. Demand-side management through buildings' thermal inertia could shape the heating demand, yet has modest impact on the system configuration. Cost reductions of heat pumps impact resistive heaters substantially, but not the opposite. Cheaper power-to-gas could lower the need for thermal energy storage., Comment: The submitted version, with 16 pages, 17 figures and 1 table

Published
2019
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2. Impact of climate change on the cost-optimal mix of decentralised heat pump and gas boiler technologies in Europe

Author

Kozarcanin, S., Hanna, R., Staffell, I., Gross, R., and Andresen, G. B.

Subjects
Electrical Engineering and Systems Science - Systems and Control, Physics - Physics and Society
Abstract

Residential demands for space heating and hot water account for 31% of the total European energy demand. Space heating is highly dependent on ambient conditions and susceptible to climate change. We adopt a techno-economic standpoint and assess the impact of climate change on decentralised heating demand and the cost-optimal mix of heat pump and gas boiler technologies. Temperature data with high spatial resolution from nine climate models implementing three Representative Concentration Pathways from IPCC are used to estimate climate induced changes in the European demand side for heating. The demand side is modelled by the proxy of heating-degree days. The supply side is modelled by using a screening curve approach to the economics of heat generation. We find that space heating demand decreases by about 16%, 24% and 42% in low, intermediate and extreme global warming scenarios. When considering historic weather data, we find a heterogeneous mix of technologies are cost-optimal, depending on the heating load factor (number of full-load hours per year). Increasing ambient temperatures toward the end-century improve the economic performance of heat pumps in all concentration pathways. Cost optimal technologies broadly correspond to heat markets and policies in Europe, with some exceptions

Published
2019

3. Impact of CO2 prices on the design of a highly decarbonised coupled electricity and heating system in Europe

Author

Zhu, K., Victoria, M., Brown, T., Andresen, G. B., and Greiner, M.

Subjects
Physics - Physics and Society
Abstract

Ambitious targets for renewable energy and CO2 taxation both represent political instruments for decarbonisation of the energy system. We model a high number of coupled electricity and heating systems, where the primary sources of CO2 neutral energy are from variable renewable energy sources (VRES), i.e., wind and solar generators. The model includes hourly dispatch of all technologies for a full year for every country in Europe. In each model run, the amount of renewable energy and the level of CO2 tax are fixed exogenously, while the cost-optimal composition of energy generation, conversion, transmission and storage technologies and the corresponding CO2 emissions are calculated. We show that even for high penetrations of VRES, a significant CO2 tax of more than 100 euro/tCO2 is required to limit the combined CO2 emissions from the sectors to less than 5% of 1990 levels, because curtailment of VRES, combustion of fossil fuels and inefficient conversion technologies are economically favoured despite the presence of abundant VRES. A sufficiently high CO2 tax results in the more efficient use of VRES by means of heat pumps and hot water storage, in particular. We conclude that a renewable energy target on its own is not sufficient; in addition, a CO2 tax is required to decarbonise the electricity and heating sectors and incentivise the least cost combination of flexible and efficient energy conversion and storage., Comment: 20 pages and 9 figures in total

Published
2018
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4. Antihydrogen and mirror-trapped antiproton discrimination: Discriminating between antihydrogen and mirror-trapped antiprotons in a minimum-B trap

Author

Amole, C., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Butler, E., Cesar, C. L., Chapman, S., Charlton, M., Deller, A., Eriksson, S., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Gutierrez, A., Hangst, J. S., Hardy, W. N., Hayden, M. E., Humphries, A. J., Hydomako, R., Kurchaninov, L., Jonsell, S., Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., van der Werf, D. P., and Wurtele, J. S.

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

Recently, antihydrogen atoms were trapped at CERN in a magnetic minimum (minimum-B) trap formed by superconducting octupole and mirror magnet coils. The trapped antiatoms were detected by rapidly turning off these magnets, thereby eliminating the magnetic minimum and releasing any antiatoms contained in the trap. Once released, these antiatoms quickly hit the trap wall, whereupon the positrons and antiprotons in the antiatoms annihilated. The antiproton annihilations produce easily detected signals; we used these signals to prove that we trapped antihydrogen. However, our technique could be confounded by mirror-trapped antiprotons, which would produce seemingly-identical annihilation signals upon hitting the trap wall. In this paper, we discuss possible sources of mirror-trapped antiprotons and show that antihydrogen and antiprotons can be readily distinguished, often with the aid of applied electric fields, by analyzing the annihilation locations and times. We further discuss the general properties of antiproton and antihydrogen trajectories in this magnetic geometry, and reconstruct the antihydrogen energy distribution from the measured annihilation time history., Comment: 17 figures

Published
2012
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5. Confinement of antihydrogen for 1000 seconds

Author

ALPHA Collaboration, Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Butler, E., Cesar, C. L., Deller, A., Eriksson, S., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Gutierrez, A., Hangst, J. S., Hardy, W. N., Hayano, R. S., Hayden, M. E., Humphries, A. J., Hydomako, R., Jonsell, S., Kemp, S., Kurchaninov, L., Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Pusa, P., Rasmussen, C. Ø., Robicheaux, F., Sarid, E., Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wurtele, J. S., and Yamazaki, Y.

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

Atoms made of a particle and an antiparticle are unstable, usually surviving less than a microsecond. Antihydrogen, made entirely of antiparticles, is believed to be stable, and it is this longevity that holds the promise of precision studies of matter-antimatter symmetry. We have recently demonstrated trapping of antihydrogen atoms by releasing them after a confinement time of 172 ms. A critical question for future studies is: how long can anti-atoms be trapped? Here we report the observation of anti-atom confinement for 1000 s, extending our earlier results by nearly four orders of magnitude. Our calculations indicate that most of the trapped anti-atoms reach the ground state. Further, we report the first measurement of the energy distribution of trapped antihydrogen which, coupled with detailed comparisons with simulations, provides a key tool for the systematic investigation of trapping dynamics. These advances open up a range of experimental possibilities, including precision studies of CPT symmetry and cooling to temperatures where gravitational effects could become apparent., Comment: 30 pages, 4 figures

Published
2011
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6. Centrifugal separation and equilibration dynamics in an electron-antiproton plasma

Author

Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Butler, E., Cesar, C. L., Chapman, S., Charlton, M., Deller, A., Eriksson, S., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Gutierrez, A., Hangst, J. S., Hardy, W. N., Hayden, M. E., Humphries, A. J., Hydomako, R., Jonsell, S., Madsen, N., Menary, S., Nolan, P., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wurtele, J. S., and Yamazaki, Y.

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

Charges in cold, multiple-species, non-neutral plasmas separate radially by mass, forming centrifugally-separated states. Here, we report the first detailed measurements of such states in an electron-antiproton plasma, and the first observations of the separation dynamics in any centrifugally-separated system. While the observed equilibrium states are expected and in agreement with theory, the equilibration time is approximately constant over a wide range of parameters, a surprising and as yet unexplained result. Electron-antiproton plasmas play a crucial role in antihydrogen trapping experiments.

Published
2011
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7. Alpha Antihydrogen Experiment

Author

ALPHA Collaboration, Fujiwara, M. C., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bray, C. C., Butler, E., Cesar, C. L., Chapman, S., Charlton, M., Fajans, J., Friesen, T., Gill, D. R., Hangst, J. S., Hardy, W. N., Hayano, R. S., Hayden, M. E., Humphries, A. J., Hydomako, R., Jonsell, S., Kurchaninov, L., Lambo, R., Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wilding, D., Wurtele, J. S., and Yamazaki, Y.

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

ALPHA is an experiment at CERN, whose ultimate goal is to perform a precise test of CPT symmetry with trapped antihydrogen atoms. After reviewing the motivations, we discuss our recent progress toward the initial goal of stable trapping of antihydrogen, with some emphasis on particle detection techniques., Comment: Invited talk presented at the Fifth Meeting on CPT and Lorentz Symmetry, Bloomington, Indiana, June 28-July 2, 2010

Published
2011

8. Evaporative Cooling of Antiprotons to Cryogenic Temperatures

Author

ALPHA Collaboration, 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., Hayano, R. S., Hayden, M. E., Humphries, A., Hydomako, R., Jonsell, S., Kurchaninov, L., Lambo, R., Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wilding, D., Wurtele, J. S., and Yamazaki, Y.

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

We report the application of evaporative cooling to clouds of trapped antiprotons, resulting in plasmas with measured temperature as low as 9~K. We have modeled the evaporation process for charged particles using appropriate rate equations. Good agreement between experiment and theory is observed, permitting prediction of cooling efficiency in future experiments. The technique opens up new possibilities for cooling of trapped ions and is of particular interest in antiproton physics, where a precise \emph{CPT} test on trapped antihydrogen is a long-standing goal., Comment: 5 pages, 4 figures

Published
2010
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9. Antihydrogen formation dynamics in a multipolar neutral anti-atom trap

Author

Andresen, G. B., Bertsche, W., Bowe, P. D., Bray, C., Butler, E., Cesar, C. L., Chapman, S., Charlton, M., Fajans, J., Fujiwara, M. C., Gill, D. R., Hangst, J. S., Hardy, W. N., Hayano, R. S., Hayden, M. E., Humphries, A. J., Hydomako, R., Jørgensen, L. V., Kerrigan, S. J., Kurchaninov, L., Lambo, R., Madsen, N., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Nasr, S. Seif El, Silveira, D. M., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wurtele, J. S., and Yamazaki, Y.

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

Antihydrogen production in a neutral atom trap formed by an octupole-based magnetic field minimum is demonstrated using field-ionization of weakly bound anti-atoms. Using our unique annihilation imaging detector, we correlate antihydrogen detection by imaging and by field-ionization for the first time. We further establish how field-ionization causes radial redistribution of the antiprotons during antihydrogen formation and use this effect for the first simultaneous measurements of strongly and weakly bound antihydrogen atoms. Distinguishing between these provides critical information needed in the process of optimizing for trappable antihydrogen. These observations are of crucial importance to the ultimate goal of performing CPT tests involving antihydrogen, which likely depends upon trapping the anti-atom.

Published
2010
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10. Production of antihydrogen at reduced magnetic field for anti-atom trapping

Author

Andresen, G B, Bertsche, W, Boston, A, Bowe, P D, Cesar, C L, Chapman, S, Charlton, M, Chartier, M, Deutsch, A, Fajans, J, Fujiwara, M C, Funakoshi, R, Gill, D R, Gomberoff, K, Hangst, J S, Hayano, R S, Hydomako, R, Jenkins, M J, Jorgensen, L V, Kurchaninov, L, Madsen, N, Nolan, P, Olchanski, K, Olin, A, Page, R D, Povilus, A, Robicheaux, F, Sarid, E, Silveira, D M, Storey, J W, Thompson, R I, van derWerf, D P, Wurtele, J S, and Yamazaki, Y

Subjects
Nuclear Experiment
Abstract

We have demonstrated production of antihydrogen in a 1$,$T solenoidal magnetic field. This field strength is significantly smaller than that used in the first generation experiments ATHENA (3$,$T) and ATRAP (5$,$T). The motivation for using a smaller magnetic field is to facilitate trapping of antihydrogen atoms in a neutral atom trap surrounding the production region. We report the results of measurements with the ALPHA (Antihydrogen Laser PHysics Apparatus) device, which can capture and cool antiprotons at 3$,$T, and then mix the antiprotons with positrons at 1$,$T. We infer antihydrogen production from the time structure of antiproton annihilations during mixing, using mixing with heated positrons as the null experiment, as demonstrated in ATHENA. Implications for antihydrogen trapping are discussed.

Published
2008
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11. A novel antiproton radial diagnostic based on octupole induced ballistic loss

Author

Andresen, G. B., Bertsche, W., Bowe, P. D., Bray, C. C., Butler, E., Cesar, C. L., Chapman, S., Charlton, M., Fajans, J., Fujiwara, M. C., Funakoshi, R., Gill, D. R., Hangst, J. S., Hardy, W. N., Hayano, R. S., Hayden, M. E., Humphries, A. J., Hydomako, R., Jenkins, M. J., Jorgensen, L. V., Kurchaninov, L., Lambo, R., Madsen, N., Nolan, P., Olchanski, K., Olin, A., Page, R. D., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Nasr, S. Seif El, Silveira, D. M., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wurtele, J. S., and Yamazaki, Y.

Subjects
Physics - Atomic Physics, Nuclear Experiment
Abstract

We report results from a novel diagnostic that probes the outer radial profile of trapped antiproton clouds. The diagnostic allows us to determine the profile by monitoring the time-history of antiproton losses that occur as an octupole field in the antiproton confinement region is increased. We show several examples of how this diagnostic helps us to understand the radial dynamics of antiprotons in normal and nested Penning-Malmberg traps. Better understanding of these dynamics may aid current attempts to trap antihydrogen atoms.

Published
2008
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12. Compression of Antiproton Clouds for Antihydrogen Trapping

Author

Andresen, G. B., Bertsche, W., Bowe, P. D., Bray, C. C., Butler, E., Cesar, C. L., Chapman, S., Charlton, M., Fajans, J., Fujiwara, M. C., Funakoshi, R., Gill, D. R., Hangst, J. S., Hardy, W. N., Hayano, R. S., Hayden, M. E., Hydomako, R., Jenkins, M. J., Jorgensen, L. V., Kurchaninov, L., Lambo, R., Madsen, N., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Nasr, S. Seif El, Silveira, D. M., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wurtele, J. S., and Yamazaki, Y.

Subjects
Nuclear Experiment
Abstract

Control of the radial profile of trapped antiproton clouds is critical to trapping antihydrogen. We report the first detailed measurements of the radial manipulation of antiproton clouds, including areal density compressions by factors as large as ten, by manipulating spatially overlapped electron plasmas. We show detailed measurements of the near-axis antiproton radial profile and its relation to that of the electron plasma.

Published
2008
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13. Particle Physics Aspects of Antihydrogen Studies with ALPHA at CERN

Author

ALPHA Collaboration, Fujiwara, M. C., Andresen, G. B., Bertsche, W., Bowe, P. D., Bray, C. C., Butler, E., Cesar, C. L., Chapman, S., Charlton, M., Fajans, J., Funakoshi, R., Gill, D. R., Hangst, J. S., Hardy, W. N., Hayano, R. S., Hayden, M. E., Humphries, A. J., Hydomako, R., Jenkins, M. J., Jorgensen, L. V., Kurchaninov, L., Lai, W., Lambo, R., Madsen, N., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Nasr, S. Seif El, Silveira, D. M., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wasilenko, L., Wurtele, J. S., and Yamazaki, Y.

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

We discuss aspects of antihydrogen studies, that relate to particle physics ideas and techniques, within the context of the ALPHA experiment at CERN's Antiproton Decelerator facility. We review the fundamental physics motivations for antihydrogen studies, and their potential physics reach. We argue that initial spectroscopy measurements, once antihydrogen is trapped, could provide competitive tests of CPT, possibly probing physics at the Planck Scale. We discuss some of the particle detection techniques used in ALPHA. Preliminary results from commissioning studies of a partial system of the ALPHA Si vertex detector are presented, the results of which highlight the power of annihilation vertex detection capability in antihydrogen studies., Comment: Invited talk at Pbar08 - Workshop on Cold Antimatter Plasmas and Application to Fundamental Physics, Okinawa, Japan, 2008. 14 pages, 8 figures

Published
2008
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14. Microwave-plasma interactions studied via mode diagnostics in ALPHA

Author

Friesen, T., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Butler, E., Cesar, C. L., Chapman, S., Charlton, M., Eriksson, S., Fajans, J., Fujiwara, M. C., Gill, D. R., Gutierrez, A., Hangst, J. S., Hardy, W. N., Hayano, R. S., Hayden, M. E., Humphries, A. J., Hydomako, R., Jonsell, S., Kurchaninov, L., Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wurtele, J. S., Yamazaki, Y., and ALPHA Collaboration

Published
2012
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15. Trapped antihydrogen

Author

Butler, E., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Cesar, C. L., Chapman, S., Charlton, M., Deller, A., Eriksson, S., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Gutierrez, A., Hangst, J. S., Hardy, W. N., Hayden, M. E., Humphries, A. J., Hydomako, R., Jenkins, M. J., Jonsell, S., Jørgensen, L. V., Kemp, S. L., Kurchaninov, L., Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Rasmussen, C. Ø., Robicheaux, F., Sarid, E., Seif el Nasr, S., Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wurtele, J. S., Yamazaki, Y., and ALPHA Collaboration

Published
2012
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16. Alternative method for reconstruction of antihydrogen annihilation vertices

Author

Amole, C., Ashkezari, M. D., Andresen, G. B., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Butler, E., Cesar, C. L., Chapman, S., Charlton, M., Deller, A., Eriksson, S., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Gutierrez, A., Hangst, J. S., Hardy, W. N., Hayano, R. S., Hayden, M. E., Humphries, A. J., Hydomako, R., Jonsell, S., Kurchaninov, L., Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wurtele, J. S., Yamazaki, Y., and ALPHA Collaboration

Published
2012
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17. Antihydrogen formation by autoresonant excitation of antiproton plasmas

Author

Bertsche, William Alan, Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bowe, P. D., Carpenter, P. T., Butler, E., Cesar, C. L., Chapman, S. F., Charlton, M., Eriksson, S., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Gutierrez, A., Hangst, J. S., Hardy, W. N., Hayano, R. S., Hayden, M. E., Humphries, A. J., Hurt, J. L., Hydomako, R., Jonsell, S., Kurchaninov, L., Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., Werf, D. P. van der, Wurtele, J. S., Yamazaki, Y., and ALPHA Collaboration

Published
2012
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18. Towards antihydrogen trapping and spectroscopy at ALPHA

Author

Butler, E., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Bray, C. C., Cesar, C. L., Chapman, S., Charlton, M., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Hangst, J. S., Hardy, W. N., Hayano, R. S., Hayden, M. E., Humphries, A. J., Hydomako, R., Jonsell, S., Kurchaninov, L., Lambo, R., Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wilding, D., Wurtele, J. S., Yamazaki, Y., and ALPHA Collaboration

Published
2011
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19. Trapped antihydrogen

Author

Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Butler, E., Cesar, C. L., Chapman, S., Charlton, M., Deller, A., Eriksson, S., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Gutierrez, A., Hangst, J. S., Hardy, W. N., Hayden, M. E., Humphries, A. J., Hydomako, R., Jenkins, M. J., Jonsell, S., Jørgensen, L. V., Kurchaninov, L., Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Nasr, S. Seif el, Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wurtele, J. S., and Yamazaki, Y.

Published
2010
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20. Fundamental properties of and transition to a fully renewable pan-European power system

Author

Andresen, G. B., Rasmussen, M. G., Rodriguez, R. A., Becker, S., and Greiner, M.

Abstract

We introduce a top-down stylized model to analyse the impact of a transition to a European power system based only on wind and solar power. Wind and solar power generation is calculated from high-resolution weather data and based on the country specific electricity demand alone, we introduce a model of the conventional power system that facilitates simple spatio-temporal modelling of its macroscopic behaviour without direct reference to the underlying technological, economical, and political development in the system. Using this model, we find that wind and solar power generation can replace conventional power generation and power capacity to a large degree if power transmission across the continent is made possible.

Published
2012
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21. ALPHA ANTIHYDROGEN EXPERIMENT

Author

ALPHA Collaboration, Fujiwara, M. C., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bray, C. C., Butler, E., Cesar, C. L., Chapman, S., Charlton, M., Fajans, J., Friesen, T., Gill, D. R., Hangst, J. S., Hardy, W. N., Hayano, R. S., Hayden, M. E., Humphries, A. J., Hydomako, R., Jonsell, S., Kurchaninov, L., Lambo, R., Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wilding, D., Wurtele, J. S., and Yamazaki, Y.

Subjects
Condensed Matter::Quantum Gases, Physics, Physics::General Physics, Atomic Physics (physics.atom-ph), FOS: Physical sciences, Alpha (ethology), Physics - Plasma Physics, High Energy Physics - Experiment, Physics - Atomic Physics, 3. Good health, Plasma Physics (physics.plasm-ph), Nuclear physics, High Energy Physics - Phenomenology, High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), Physics::Atomic and Molecular Clusters, Nuclear Physics - Experiment, Physics::Atomic Physics, Nuclear Experiment (nucl-ex), Antihydrogen, Nuclear Experiment
Abstract

ALPHA is an experiment at CERN, whose ultimate goal is to perform a precise test of CPT symmetry with trapped antihydrogen atoms. After reviewing the motivations, we discuss our recent progress toward the initial goal of stable trapping of antihydrogen, with some emphasis on particle detection techniques., Comment: Invited talk presented at the Fifth Meeting on CPT and Lorentz Symmetry, Bloomington, Indiana, June 28-July 2, 2010

Published
2010
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22. The ALPHA antihydrogen trapping apparatus

Author

Amole, C., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Butler, E., Capra, A., Carpenter, P. T., Cesar, C. L., Chapman, S., Charlton, M., Deller, A., Eriksson, S., Escallier, J., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Gutierrez, A., Hangst, J. S., Hardy, W. N., Hayano, R. S., Hayden, M. E., Humphries, A. J., Hurt, J. L., Hydomako, R., Isaac, C. A., Jenkins, M. J., Jonsell, Svante, Jörgensen, L. V., Kerrigan, S. J., Kurchaninov, L., Madsen, N., Morone, A., McKenna, J. T. K., Menary, S., Nolan, P., Olchanski, K., Olin, A., Parker, B., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Seddon, D., El Nasr, S. Seif, Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., Thornhill, J., Wells, D., van der Werf, D. P., Wurtele, J. S., Yamazaki, Y., Amole, C., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Butler, E., Capra, A., Carpenter, P. T., Cesar, C. L., Chapman, S., Charlton, M., Deller, A., Eriksson, S., Escallier, J., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Gutierrez, A., Hangst, J. S., Hardy, W. N., Hayano, R. S., Hayden, M. E., Humphries, A. J., Hurt, J. L., Hydomako, R., Isaac, C. A., Jenkins, M. J., Jonsell, Svante, Jörgensen, L. V., Kerrigan, S. J., Kurchaninov, L., Madsen, N., Morone, A., McKenna, J. T. K., Menary, S., Nolan, P., Olchanski, K., Olin, A., Parker, B., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Seddon, D., El Nasr, S. Seif, Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., Thornhill, J., Wells, D., van der Werf, D. P., Wurtele, J. S., and Yamazaki, Y.

Abstract

The ALPHA collaboration, based at CERN, has recently succeeded in confining cold antihydrogen atoms in a magnetic minimum neutral atom trap and has performed the first study of a resonant transition of the anti-atoms. The ALPHA apparatus will be described herein, with emphasis on the structural aspects, diagnostic methods and techniques that have enabled antihydrogen trapping and experimentation to be achieved., AuthorCount:56

Published
2014
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23. Silicon vertex detector upgrade in the ALPHA experiment

Author

Amole, C., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Burrows, C., Butler, E., Capra, A., Cesar, C. L., Chapman, S., Charlton, M., Deller, A., Eriksson, S., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Gutierrez, A., Hangst, J. S., Hardy, W. N., Hayden, M. E., Humphries, A. J., Isaac, C. A., Jonsell, Svante, Kurchaninov, L., Little, A., Madsen, N., McKenna, J. T. K., Menary, S., Napoli, S. C., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Rasmussen, C. O., Robicheaux, F., Sacramento, R. L., Stracka, S., Sampson, J. A., Sarid, E., Seddon, D., Silveira, D. M., So, C., Thompson, R. I., Tharp, T., Thornhill, J., Tooley, M. P., van der Werf, D. P., Wells, D., Amole, C., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Burrows, C., Butler, E., Capra, A., Cesar, C. L., Chapman, S., Charlton, M., Deller, A., Eriksson, S., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Gutierrez, A., Hangst, J. S., Hardy, W. N., Hayden, M. E., Humphries, A. J., Isaac, C. A., Jonsell, Svante, Kurchaninov, L., Little, A., Madsen, N., McKenna, J. T. K., Menary, S., Napoli, S. C., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Rasmussen, C. O., Robicheaux, F., Sacramento, R. L., Stracka, S., Sampson, J. A., Sarid, E., Seddon, D., Silveira, D. M., So, C., Thompson, R. I., Tharp, T., Thornhill, J., Tooley, M. P., van der Werf, D. P., and Wells, D.

Abstract

The Silicon Vertex Detector (SVD) is the main diagnostic tool in the ALPHA-experiment. It provides precise spatial and timing information of antiproton (antihydrogen) annihilation events (vertices), and most importantly, the SVD is capable of directly identifying and analysing single annihilation events, thereby forming the basis of ALPHA's analysis. This paper describes the ALPHA SVD and its upgrade, installed in the ALPHA's new neutral atom trap., AuthorCount:50

Published
2013
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24. Antihydrogen annihilation reconstruction with the ALPHA silicon detector

Author

Andresen, G. B., Ashkezari, M. D., Bertsche, W., Bowe, P. D., Butler, E., Cesar, C. L., Chapman, S., Charlton, M., Deller, A., Eriksson, S., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Gutierrez, A., Hangst, J. S., Hardy, W. N., Hayden, M. E., Hayano, R. S., Humphries, A. J., Hydomako, R., Jonsell, Svante, Jorgensen, L. V., Kurchaninov, L., Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Sarid, E., el Nasr, S. Seif, Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., van der Werf, D. P., Yamazaki, Y., Andresen, G. B., Ashkezari, M. D., Bertsche, W., Bowe, P. D., Butler, E., Cesar, C. L., Chapman, S., Charlton, M., Deller, A., Eriksson, S., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Gutierrez, A., Hangst, J. S., Hardy, W. N., Hayden, M. E., Hayano, R. S., Humphries, A. J., Hydomako, R., Jonsell, Svante, Jorgensen, L. V., Kurchaninov, L., Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Sarid, E., el Nasr, S. Seif, Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., van der Werf, D. P., and Yamazaki, Y.

Abstract

The ALPHA experiment has succeeded in trapping antihydrogen, a major milestone on the road to spectroscopic comparisons of antihydrogen with hydrogen. An annihilation vertex detector, which determines the time and position of antiproton annihilations, has been central to this achievement. This detector, an array of double-sided silicon microstrip detector modules arranged in three concentric cylindrical tiers, is sensitive to the passage of charged particles resulting from antiproton annihilation. This article describes the method used to reconstruct the annihilation location and to distinguish the annihilation signal from the cosmic ray background. Recent experimental results using this detector are outlined., AuthorCount:39

Published
2012
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25. The ALPHA-detector : Module Production and Assembly

Author

Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Butler, E., Cesar, C. L., Chapman, S., Charlton, M., Deller, A., Eriksson, S., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Gutierrez, A., Hangst, J. S., Hardy, W. N., Hayden, M. E., Humphries, A. J., Hydomako, R., Jenkins, M. J., Jonsell, Svante, Jorgensen, L. V., Kurchaninov, L., Madsen, N., McKenna, J. T. K., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sampson, J., Sarid, E., Seddon, D., el Nasr, S. Seif, Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., Thornhill, J., Wells, D., van der Werf, D. P., Wurtele, J. S., Yamazaki, Y., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Butler, E., Cesar, C. L., Chapman, S., Charlton, M., Deller, A., Eriksson, S., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Gutierrez, A., Hangst, J. S., Hardy, W. N., Hayden, M. E., Humphries, A. J., Hydomako, R., Jenkins, M. J., Jonsell, Svante, Jorgensen, L. V., Kurchaninov, L., Madsen, N., McKenna, J. T. K., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sampson, J., Sarid, E., Seddon, D., el Nasr, S. Seif, Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., Thornhill, J., Wells, D., van der Werf, D. P., Wurtele, J. S., and Yamazaki, Y.

Abstract

ALPHA is one of the experiments situated at CERN's Antiproton Decelerator (AD). A Silicon Vertex Detector (SVD) is placed to surround the ALPHA atom trap. The main purpose of the SVD is to detect and locate antiproton annihilation events by means of the emitted charged pions. The SVD system is presented with special focus given to the design, fabrication and performance of the modules., AuthorCount:47

Published
2012
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26. Discriminating between antihydrogen and mirror-trapped antiprotons in a minimum-B trap

Author

Amole, C., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Butler, E., Cesar, C. L., Chapman, S., Charlton, M., Deller, A., Eriksson, S., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Gutierrez, A., Hangst, J. S., Hardy, W. N., Hayden, M. E., Humphries, A. J., Hydomako, R., Kurchaninov, L., Jonsell, Svante, Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wurtele, J. S., Amole, C., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Butler, E., Cesar, C. L., Chapman, S., Charlton, M., Deller, A., Eriksson, S., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Gutierrez, A., Hangst, J. S., Hardy, W. N., Hayden, M. E., Humphries, A. J., Hydomako, R., Kurchaninov, L., Jonsell, Svante, Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., van der Werf, D. P., and Wurtele, J. S.

Abstract

Recently, antihydrogen atoms were trapped at CERN in a magnetic minimum (minimum-B) trap formed by superconducting octupole and mirror magnet coils. The trapped antiatoms were detected by rapidly turning off these magnets, thereby eliminating the magnetic minimum and releasing any antiatoms contained in the trap. Once released, these antiatoms quickly hit the trap wall, whereupon the positrons and antiprotons in the antiatoms annihilate. The antiproton annihilations produce easily detected signals; we used these signals to prove that we trapped antihydrogen. However, our technique could be confounded by mirror-trapped antiprotons, which would produce seemingly identical annihilation signals upon hitting the trap wall. In this paper, we discuss possible sources of mirror-trapped antiprotons and show that antihydrogen and antiprotons can be readily distinguished, often with the aid of applied electric fields, by analyzing the annihilation locations and times. We further discuss the general properties of antiproton and antihydrogen trajectories in this magnetic geometry, and reconstruct the antihydrogen energy distribution from the measured annihilation time history., 38

Published
2012
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27. Search for trapped antihydrogen

Author

Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Bray, C. C., 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., Hayano, R. S., Hayden, M. E., Humphries, A. J., Hydomako, R., Jonsell, Svante, Jörgensen, L. V., Kurchaninov, L., Lambo, R., Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Seif El Nasr, S., Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wilding, D., Wurtele, J. S., Yamazaki, Y., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Bray, C. C., 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., Hayano, R. S., Hayden, M. E., Humphries, A. J., Hydomako, R., Jonsell, Svante, Jörgensen, L. V., Kurchaninov, L., Lambo, R., Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Seif El Nasr, S., Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wilding, D., Wurtele, J. S., and Yamazaki, Y.

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 107 antiprotons with 1.3ￜ109 positrons to produce 6ￜ105 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.

Published
2011
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28. Antiparticle sources for antihydrogen production and trapping

Author

Charlton, M, Andresen, G B, Ashkezari, M D, Baquero-Ruiz, M, Bertsche, W, Bowe, P D, Bray, C C, Butler, E, Cesar, C L, Chapman, S, Fajans, J, Friesen, T, Fujiwara, M C, Gill, D R, Hangst, J S, Hardy, W N, Hayano, R S, Hayden, M E, Humphries, A J, Hydomako, R, Jonsell, Svante, JÞrgensen, L V, Kerrigan, S J, Kurchaninov, L, Lambo, R, Madsen, N, Menary, S, Nolan, P, Olchanski, K, Povilus, A, Pusa, P, Robicheaux, F, Sarid, E, Nasr, S Seif El, Silveira, D M, So, C, Storey, J W, Thompson, R I, Werf, D P Van Der, Wilding, D, Wurtele, J S, Yamazaki, Y, Collaboration, Alpha, Charlton, M, Andresen, G B, Ashkezari, M D, Baquero-Ruiz, M, Bertsche, W, Bowe, P D, Bray, C C, Butler, E, Cesar, C L, Chapman, S, Fajans, J, Friesen, T, Fujiwara, M C, Gill, D R, Hangst, J S, Hardy, W N, Hayano, R S, Hayden, M E, Humphries, A J, Hydomako, R, Jonsell, Svante, JÞrgensen, L V, Kerrigan, S J, Kurchaninov, L, Lambo, R, Madsen, N, Menary, S, Nolan, P, Olchanski, K, Povilus, A, Pusa, P, Robicheaux, F, Sarid, E, Nasr, S Seif El, Silveira, D M, So, C, Storey, J W, Thompson, R I, Werf, D P Van Der, Wilding, D, Wurtele, J S, Yamazaki, Y, and Collaboration, Alpha

Abstract

Sources of positrons and antiprotons that are currently used for the formation of antihydrogen with low kinetic energies are reviewed, mostly in the context of the ALPHA collaboration and its predecessor ATHENA. The experiments were undertaken at the Antiproton Decelerator facility, which is located at CERN. Operations performed on the clouds of antiparticles to facilitate their mixing to produce antihydrogen are described. These include accumulation, cooling and manipulation. The formation of antihydrogen and some of the characteristics of the anti-atoms that are created are discussed. Prospects for trapping antihydrogen in a magnetic minimum trap, as envisaged by the ALPHA collaboration, are reviewed.

Published
2011
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29. Confinement of antihydrogen for 1,000 seconds

Author

Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Butler, E., Cesar, C. L., Charlton, M., Deller, A., Eriksson, S., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Gutierrez, A., Hangst, J. S., Hardy, W. N., Hayano, R. S., Hayden, M. E., Humphries, A. J., Hydomako, R., Jonsell, Svante, Kemp, S. L., Kurchaninov, L., Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Pusa, P., Rasmussen, C. O., Robicheaux, F., Sarid, E., Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wurtele, J. S., Yamazaki, Y., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Butler, E., Cesar, C. L., Charlton, M., Deller, A., Eriksson, S., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Gutierrez, A., Hangst, J. S., Hardy, W. N., Hayano, R. S., Hayden, M. E., Humphries, A. J., Hydomako, R., Jonsell, Svante, Kemp, S. L., Kurchaninov, L., Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Pusa, P., Rasmussen, C. O., Robicheaux, F., Sarid, E., Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wurtele, J. S., and Yamazaki, Y.

Abstract

Atoms made of a particle and an antiparticle are unstable, usually surviving less than a microsecond. Antihydrogen, made entirely of antiparticles, is believed to be stable, and it is this longevity that holds the promise of precision studies of matter-antimatter symmetry. We have recently demonstrated trapping of antihydrogen atoms by releasing them after a confinement time of 172 ms. A critical question for future studies is: how long can anti-atoms be trapped? Here, we report the observation of anti-atom confinement for 1,000 s, extending our earlier results by nearly four orders of magnitude. Our calculations indicate that most of the trapped anti-atoms reach the ground state. Further, we report the first measurement of the energy distribution of trapped antihydrogen, which, coupled with detailed comparisons with simulations, provides a key tool for the systematic investigation of trapping dynamics. These advances open up a range of experimental possibilities, including precision studies of charge-parity-time reversal symmetry and cooling to temperatures where gravitational effects could become apparent., authorCount :40

Published
2011
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30. Autoresonant Excitation of Antiproton Plasmas

Author

Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Butler, E., Carpenter, P. T., 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., Humphries, A. J., Hurt, J. L., Hydomako, R., Jonsell, Svante, Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wurtele, J. S., Yamazaki, Y., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Butler, E., Carpenter, P. T., 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., Humphries, A. J., Hurt, J. L., Hydomako, R., Jonsell, Svante, Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wurtele, J. S., and Yamazaki, Y.

Abstract

We demonstrate controllable excitation of the center-of-mass longitudinal motion of a thermal antiproton plasma using a swept-frequency autoresonant drive. When the plasma is cold, dense, and highly collective in nature, we observe that the entire system behaves as a single-particle nonlinear oscillator, as predicted by a recent theory. In contrast, only a fraction of the antiprotons in a warm plasma can be similarly excited. Antihydrogen was produced and trapped by using this technique to drive antiprotons into a positron plasma, thereby initiating atomic recombination, authorCount :37

Published
2011
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31. Search for trapped antihydrogen in ALPHA

Author

Madsen, N, Andresen, G B, Ashkezari, M D, Baquero-Ruiz, M, Bertsche, W, Bowe, P D, Bray, C C, 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 R, Humphries, A J, Hydomako, R, Jonsell, Svante, Jørgensen, L V, Kurchaninov, L, Lambo, R, Menary, S, Nolan, P, Olchanski, K, Olin, A, Povilus, A, Pusa, P, Robicheaux, F, Sarid, E, Seif El Nasr, S, Silveira, D M, So, C, Storey, J W, Thompson, R I, van der Werf, D P, Wurtele, J S, Yamazaki, Y, Madsen, N, Andresen, G B, Ashkezari, M D, Baquero-Ruiz, M, Bertsche, W, Bowe, P D, Bray, C C, 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 R, Humphries, A J, Hydomako, R, Jonsell, Svante, Jørgensen, L V, Kurchaninov, L, Lambo, R, Menary, S, Nolan, P, Olchanski, K, Olin, A, Povilus, A, Pusa, P, Robicheaux, F, Sarid, E, Seif El Nasr, S, Silveira, D M, So, C, Storey, J W, Thompson, R I, van der Werf, D P, Wurtele, J S, and Yamazaki, Y

Abstract

Antihydrogen spectroscopy promises precise tests of the symmetry of matter and antimatter, and can possibly offer new insights into the baryon asymmetry of the universe. Antihydrogen is, however, difficult to synthesize and is produced only in small quantities. The ALPHA collaboration is therefore pursuing a path towards trapping cold antihydrogen to permit the use of precision atomic physics tools to carry out comparisons of antihydrogen and hydrogen. ALPHA has addressed these challenges. Control of the plasma sizes has helped to lower the influence of the multipole field used in the neutral atom trap, and thus lowered the temperature of the created atoms. Finally, the first systematic attempt to identify trapped antihydrogen in our system is discussed. This discussion includes special techniques for fast release of the trapped anti-atoms, as well as a silicon vertex detector to identify antiproton annihilations. The silicon detector reduces the background of annihilations, including background from antiprotons that can be mirror trapped in the fields of the neutral atom trap. A description of how to differentiate between these events and those resulting from trapped antihydrogen atoms is also included.

Published
2011
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32. Antimatter transport processes

Author

Van Der Werf, D. P., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Bray, C. C., 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., Hayano, R. S., Hayden, M. E., Humphries, A. J., Hydomako, R., Jonsell, Svante, Jørgensen, L. V., Kurchaninov, L., Lambo, R., Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., Wurtele, J. S., Yamazaki, Y., Van Der Werf, D. P., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Bray, C. C., 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., Hayano, R. S., Hayden, M. E., Humphries, A. J., Hydomako, R., Jonsell, Svante, Jørgensen, L. V., Kurchaninov, L., Lambo, R., Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., Wurtele, J. S., and Yamazaki, Y.

Abstract

A comparison of the 1S-2S transitions of hydrogen and antihydrogen will yield a stringent test of CPT conservation. Necessarily, the antihydrogen atoms need to be trapped to perform high precision spectroscopy measurements. Therefore, an approximately 0.75 T deep neutral atom trap, equivalent to about 0.5 K for ground state (anti)hydrogen atoms, has been superimposed on a Penning-Malmberg trap in which the anti-atoms are formed. The antihydrogen atoms are produced following a number of steps. A bunch of antiprotons from the CERN Antiproton Decelerator is caught in a Penning-Malmberg trap and subsequently sympathetically cooled and then compressed using rotating wall electric fields. A positron plasma, formed in a separate accumulator, is transported to the main system and also compressed. Antihydrogen atoms are then formed by mixing the antiprotons and positrons. The velocity of the anti-atoms, and their binding energies, will strongly depend on the initial conditions of the constituent particles, for example their temperatures and densities, and on the details of the mixing process. In this paper the complete lifecycle of antihydrogen atoms will be presented, starting with the production of the constituent antiparticles and the description of the manipulations necessary to prepare them appropriately for antihydrogen formation. The latter will also be described, as will the possible fates of the anti-atoms.

Published
2010
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33. Evaporative Cooling of Antiprotons to Cryogenic Temperatures

Author

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., Hayano, R. S., Hayden, M. E., Humphries, A., Hydomako, R., Jonsell, Svante, Kurchaninov, L., Lambo, R., Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wilding, D., Wurtele, J. S., Yamazaki, Y., 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., Hayano, R. S., Hayden, M. E., Humphries, A., Hydomako, R., Jonsell, Svante, Kurchaninov, L., Lambo, R., Madsen, N., Menary, S., Nolan, P., Olchanski, K., Olin, A., Povilus, A., Pusa, P., Robicheaux, F., Sarid, E., Silveira, D. M., So, C., Storey, J. W., Thompson, R. I., van der Werf, D. P., Wilding, D., Wurtele, J. S., and Yamazaki, Y.

Abstract

We report the application of evaporative cooling to clouds of trapped antiprotons, resulting in plasmas with measured temperature as low as 9 K. We have modeled the evaporation process for charged particles using appropriate rate equations. Good agreement between experiment and theory is observed, permitting prediction of cooling efficiency in future experiments. The technique opens up new possibilities for cooling of trapped ions and is of particular interest in antiproton physics, where a precise CPT test on trapped antihydrogen is a long-standing goal.

Published
2010
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34. Evaporative cooling of antiprotons for the production of trappable antihydrogen

Author

Silveira, D. M., primary, Andresen, G. B., additional, Ashkezari, M. D., additional, Baquero-Ruiz, M., additional, Bertsche, W., additional, Bowe, P. D., additional, Butler, E., additional, Cesar, C. L., additional, Chapman, S., additional, Charlton, M., additional, Fajans, J., additional, Friesen, T., additional, Fujiwara, M. C., additional, Gill, D. R., additional, Hangst, J. S., additional, Hardy, W. N., additional, Hayden, M. E., additional, Hydomako, R., additional, Jonsell, S., additional, Kurchaninov, L., additional, Madsen, N., additional, Menary, S., additional, Nolan, P., additional, Olchanski, K., additional, Olin, A., additional, Povilus, A., additional, Pusa, P., additional, Robicheaux, F., additional, Sarid, E., additional, So, C., additional, Storey, J. W., additional, Thompson, R. I., additional, van der Werf, D. P., additional, and Wurtele, J. S., additional

Published
2013
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35. Discriminating between antihydrogen and mirror-trapped antiprotons in a minimum-B trap

Author

Amole, C, primary, Andresen, G B, additional, Ashkezari, M D, additional, Baquero-Ruiz, M, additional, Bertsche, W, additional, Butler, E, additional, Cesar, C L, additional, Chapman, S, additional, Charlton, M, additional, Deller, A, additional, Eriksson, S, additional, Fajans, J, additional, Friesen, T, additional, Fujiwara, M C, additional, Gill, D R, additional, Gutierrez, A, additional, Hangst, J S, additional, Hardy, W N, additional, Hayden, M E, additional, Humphries, A J, additional, Hydomako, R, additional, Kurchaninov, L, additional, Jonsell, S, additional, Madsen, N, additional, Menary, S, additional, Nolan, P, additional, Olchanski, K, additional, Olin, A, additional, Povilus, A, additional, Pusa, P, additional, Robicheaux, F, additional, Sarid, E, additional, Silveira, D M, additional, So, C, additional, Storey, J W, additional, Thompson, R I, additional, van der Werf, D P, additional, and Wurtele, J S, additional

Published
2012
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36. The ALPHA – detector: Module Production and Assembly

Author

Andresen, G B, primary, Ashkezari, M D, additional, Baquero-Ruiz, M, additional, Bertsche, W, additional, Bowe, P D, additional, Butler, E, additional, Cesar, C L, additional, Chapman, S, additional, Charlton, M, additional, Deller, A, additional, Eriksson, S, additional, Fajans, J, additional, Friesen, T, additional, Fujiwara, M C, additional, Gill, D R, additional, Gutierrez, A, additional, Hangst, J S, additional, Hardy, W N, additional, Hayden, M E, additional, Humphries, A J, additional, Hydomako, R, additional, Jenkins, M J, additional, Jonsell, S, additional, JØrgensen, L V, additional, Kurchaninov, L, additional, Madsen, N, additional, McKenna, J T K, additional, Menary, S, additional, Nolan, P, additional, Olchanski, K, additional, Olin, A, additional, Povilus, A, additional, Pusa, P, additional, Robicheaux, F, additional, Sampson, J, additional, Sarid, E, additional, Seddon, D, additional, Nasr, S Seif el, additional, Silveira, D M, additional, So, C, additional, Storey, J W, additional, Thompson, R I, additional, Thornhill, J, additional, Wells, D, additional, Werf, D P van der, additional, Wurtele, J S, additional, and Yamazaki, Y, additional

Published
2012
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37. Antiparticle plasmas for antihydrogen trapping

Author

Charlton, M., primary, Andresen, G. B., additional, Ashkezari, M. D., additional, Baquero-Ruiz, M., additional, Bertsche, W., additional, Bowe, P. D., additional, Butler, E., additional, Carpenter, P. T., additional, Cesar, C. L., additional, Chapman, S., additional, Eriksson, S., additional, Fajans, J., additional, Friesen, T., additional, Fujiwara, M. C., additional, Gill, D. R., additional, Gutierrez, A., additional, Hangst, J. S., additional, Hardy, W. N., additional, Hayano, R. S., additional, Hayden, M. E., additional, Humphries, A. J., additional, Hurt, J. L., additional, Hydomako, R., additional, Jonsell, S., additional, Kurchaninov, L., additional, Madsen, N., additional, Menary, S., additional, Nolan, P., additional, Olchanski, K., additional, Olin, A., additional, Povilus, A., additional, Pusa, P., additional, Robicheaux, F., additional, Sarid, E., additional, Silveira, D. M., additional, So, C., additional, Storey, J. W., additional, Thompson, R. I., additional, van der Werf, D. P., additional, Wurtele, J. S., additional, and Yamazaki, Y., additional

Published
2012
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38. Search for trapped antihydrogen in ALPHAThis paper was presented at the International Conference on Precision Physics of Simple Atomic Systems, held at École de Physique, les Houches, France, 30 May – 4 June, 2010.

Author

Madsen, N., primary, Andresen, G. B., additional, Ashkezari, M. D., additional, Baquero-Ruiz, M., additional, Bertsche, W., additional, Bowe, P. D., additional, Bray, C., additional, Butler, E., additional, Cesar, C. L., additional, Chapman, S., additional, Charlton, M., additional, Fajans, J., additional, Friesen, T., additional, Fujiwara, M. C., additional, Gill, D. R., additional, Hangst, J. S., additional, Hardy, W. N., additional, Hayden, M. E., additional, Humphries, A. J., additional, Hydomako, R., additional, Jonsell, S., additional, Jørgensen, L. V., additional, Kurchaninov, L., additional, Lambo, R., additional, Menary, S., additional, Nolan, P., additional, Olchanski, K., additional, Olin, A., additional, Povilus, A., additional, Pusa, P., additional, Robicheaux, F., additional, Sarid, E., additional, El Nasr, S. Seif, additional, Silveira, D. M., additional, So, C., additional, Storey, J. W., additional, Thompson, R. I., additional, van der Werf, D. P., additional, Wurtele, J. S., additional, and Yamazaki, Y., additional

Published
2011
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39. Antimatter transport processes

Author

Van Der Werf, D P, primary, Andresen, G B, additional, Ashkezari, M D, additional, Baquero-Ruiz, M, additional, Bertsche, W, additional, Bowe, P D, additional, Bray, C C, additional, Butler, E, additional, Cesar, C L, additional, Chapman, S, additional, Charlton, M, additional, Fajans, J, additional, Friesen, T, additional, Fujiwara, M C, additional, Gill, D R, additional, Hangst, J S, additional, Hardy, W N, additional, Hayano, R S, additional, Hayden, M E, additional, Humphries, A J, additional, Hydomako, R, additional, Jonsell, S, additional, Jørgensen, L V, additional, Kurchaninov, L, additional, Lambo, R, additional, Madsen, N, additional, Menary, S, additional, Nolan, P, additional, Olchanski, K, additional, Olin, A, additional, Povilus, A, additional, Pusa, P, additional, Robicheaux, F, additional, Sarid, E, additional, Silveira, D M, additional, So, C, additional, Storey, J W, additional, Thompson, R I, additional, Wurtele, J S, additional, and Yamazaki, Y, additional

Published
2010
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40. Evaporative Cooling of Antiprotons to Cryogenic Temperatures

Author

Andresen, G. B., primary, Ashkezari, M. D., additional, Baquero-Ruiz, M., additional, Bertsche, W., additional, Bowe, P. D., additional, Butler, E., additional, Cesar, C. L., additional, Chapman, S., additional, Charlton, M., additional, Fajans, J., additional, Friesen, T., additional, Fujiwara, M. C., additional, Gill, D. R., additional, Hangst, J. S., additional, Hardy, W. N., additional, Hayano, R. S., additional, Hayden, M. E., additional, Humphries, A., additional, Hydomako, R., additional, Jonsell, S., additional, Kurchaninov, L., additional, Lambo, R., additional, Madsen, N., additional, Menary, S., additional, Nolan, P., additional, Olchanski, K., additional, Olin, A., additional, Povilus, A., additional, Pusa, P., additional, Robicheaux, F., additional, Sarid, E., additional, Silveira, D. M., additional, So, C., additional, Storey, J. W., additional, Thompson, R. I., additional, van der Werf, D. P., additional, Wilding, D., additional, Wurtele, J. S., additional, and Yamazaki, Y., additional

Published
2010
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41. Antihydrogen Physics at ALPHA/CERNThis paper was presented at the International Conference on Precision Physics of Simple Atomic Systems, held at University of Windsor, Windsor, Ontario, Canada on 21–26 July 2008.

Author

Cesar, C. L., primary, Andresen, G. B., additional, Bertsche, W., additional, Bowe, P. D., additional, Bray, C. C., additional, Butler, E., additional, Chapman, S., additional, Charlton, M., additional, Fajans, J., additional, Fujiwara, M. C., additional, Funakoshi, R., additional, Gill, D. R., additional, Hangst, J. S., additional, Hardy, W. N., additional, Hayano, R. S., additional, Hayden, M. E., additional, Humphries, A. J., additional, Hydomako, R., additional, Jenkins, M. J., additional, Jørgensen, L. V., additional, Kurchaninov, L., additional, Lambo, R., additional, Madsen, N., additional, Nolan, P., additional, Olchanski, K., additional, Olin, A., additional, Page, R. D., additional, Povilus, A., additional, Pusa, P., additional, Robicheaux, F., additional, Sarid, E., additional, El Nasr, S. Seif, additional, Silveira, D. M., additional, Storey, J. W., additional, Thompson, R. I., additional, van der Werf, D. P., additional, Wurtele, J. S., additional, and Yamazaki, Y., additional

Published
2009
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42. Compression of Antiproton Clouds for Antihydrogen Trapping

Author

Andresen, G. B., primary, Bertsche, W., additional, Bowe, P. D., additional, Bray, C. C., additional, Butler, E., additional, Cesar, C. L., additional, Chapman, S., additional, Charlton, M., additional, Fajans, J., additional, Fujiwara, M. C., additional, Funakoshi, R., additional, Gill, D. R., additional, Hangst, J. S., additional, Hardy, W. N., additional, Hayano, R. S., additional, Hayden, M. E., additional, Hydomako, R., additional, Jenkins, M. J., additional, Jørgensen, L. V., additional, Kurchaninov, L., additional, Lambo, R., additional, Madsen, N., additional, Nolan, P., additional, Olchanski, K., additional, Olin, A., additional, Povilus, A., additional, Pusa, P., additional, Robicheaux, F., additional, Sarid, E., additional, Seif El Nasr, S., additional, Silveira, D. M., additional, Storey, J. W., additional, Thompson, R. I., additional, van der Werf, D. P., additional, Wurtele, J. S., additional, and Yamazaki, Y., additional

Published
2008
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43. A novel antiproton radial diagnostic based on octupole induced ballistic loss

Author

Andresen, G. B., primary, Bertsche, W., additional, Bowe, P. D., additional, Bray, C. C., additional, Butler, E., additional, Cesar, C. L., additional, Chapman, S., additional, Charlton, M., additional, Fajans, J., additional, Fujiwara, M. C., additional, Funakoshi, R., additional, Gill, D. R., additional, Hangst, J. S., additional, Hardy, W. N., additional, Hayano, R. S., additional, Hayden, M. E., additional, Humphries, A. J., additional, Hydomako, R., additional, Jenkins, M. J., additional, Jørgensen, L. V., additional, Kurchaninov, L., additional, Lambo, R., additional, Madsen, N., additional, Nolan, P., additional, Olchanski, K., additional, Olin, A., additional, Page, R. D., additional, Povilus, A., additional, Pusa, P., additional, Robicheaux, F., additional, Sarid, E., additional, El Nasr, S. Seif, additional, Silveira, D. M., additional, Storey, J. W., additional, Thompson, R. I., additional, van der Werf, D. P., additional, Wurtele, J. S., additional, and Yamazaki, Y., additional

Published
2008
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44. Particle Physics Aspects of Antihydrogen Studies with ALPHA at CERN

Author

Fujiwara, M. C., primary, Andresen, G. B., additional, Bertsche, W., additional, Bowe, P. D., additional, Bray, C. C., additional, Butler, E., additional, Cesar, C. L., additional, Chapman, S., additional, Charlton, M., additional, Fajans, J., additional, Funakoshi, R., additional, Gill, D. R., additional, Hangst, J. S., additional, Hardy, W. N., additional, Hayano, R. S., additional, Hayden, M. E., additional, Humphries, A. J., additional, Hydomako, R., additional, Jenkins, M. J., additional, Jo̸rgensen, L. V., additional, Kurchaninov, L., additional, Lai, W., additional, Lambo, R., additional, Madsen, N., additional, Nolan, P., additional, Olchanski, K., additional, Olin, A., additional, Povilus, A., additional, Pusa, P., additional, Robicheaux, F., additional, Sarid, E., additional, El Nasr, S. Seif, additional, Silveira, D. M., additional, Storey, J. W., additional, Thompson, R. I., additional, van der Werf, D. P., additional, Wasilenko, L., additional, Wurtele, J. S., additional, Yamazaki, Y., additional, Kanai, Yasuyuki, additional, and Yamazaki, Yasunori, additional

Published
2008
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45. First Attempts at Antihydrogen Trapping in ALPHA

Author

Andresen, G. B., primary, Bertsche, W., additional, Bowe, P. D., additional, Bray, C. C., additional, Butler, E., additional, Cesar, C. L., additional, Chapman, S., additional, Charlton, M., additional, Fajans, J., additional, Fujiwara, M. C., additional, Funakoshi, R., additional, Gill, D. R., additional, Hangst, J. S., additional, Hardy, W. N., additional, Hayano, R. S., additional, Hayden, M. E., additional, Humphries, A. J., additional, Hydomako, R., additional, Jenkins, M. J., additional, Jo̸rgensen, L. V., additional, Kurchaninov, L., additional, Lambo, R., additional, Madsen, N., additional, Nolan, P., additional, Olchanski, K., additional, Olin, A., additional, Page, R. D., additional, Povilus, A., additional, Pusa, P., additional, Robicheaux, F., additional, Sarid, E., additional, El Nasr, S. Seif, additional, Silveira, D. M., additional, Storey, J. W., additional, Thompson, R. I., additional, van der Werf, D. P., additional, Wurtele, J. S., additional, Yamazaki, Y., additional, Kanai, Yasuyuki, additional, and Yamazaki, Yasunori, additional

Published
2008
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46. Antiproton compression and radial measurements

Author

Andresen, G. B., primary, Bertsche, W., additional, Bowe, P. D., additional, Bray, C. C., additional, Butler, E., additional, Cesar, C. L., additional, Chapman, S., additional, Charlton, M., additional, Fajans, J., additional, Fujiwara, M. C., additional, Funakoshi, R., additional, Gill, D. R., additional, Hangst, J. S., additional, Hardy, W. N., additional, Hayano, R. S., additional, Hayden, M. E., additional, Humphries, A. J., additional, Hydomako, R., additional, Jenkins, M. J., additional, Jo̸rgensen, L. V., additional, Kurchaninov, L., additional, Lambo, R., additional, Madsen, N., additional, Nolan, P., additional, Olchanski, K., additional, Olin, A., additional, Page, R. D., additional, Povilus, A., additional, Pusa, P., additional, Robicheaux, F., additional, Sarid, E., additional, El Nasr, S. Seif, additional, Silveira, D. M., additional, Storey, J. W., additional, Thompson, R. I., additional, van der Werf, D. P., additional, Wurtele, J. S., additional, Yamazaki, Y., additional, Kanai, Yasuyuki, additional, and Yamazaki, Yasunori, additional

Published
2008
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47. Production of antihydrogen at reduced magnetic field for anti-atom trapping

Author

Andresen, G B, primary, Bertsche, W, additional, Boston, A, additional, Bowe, P D, additional, Cesar, C L, additional, Chapman, S, additional, Charlton, M, additional, Chartier, M, additional, Deutsch, A, additional, Fajans, J, additional, Fujiwara, M C, additional, Funakoshi, R, additional, Gill, D R, additional, Gomberoff, K, additional, Hangst, J S, additional, Hayano, R S, additional, Hydomako, R, additional, Jenkins, M J, additional, Jørgensen, L V, additional, Kurchaninov, L, additional, Madsen, N, additional, Nolan, P, additional, Olchanski, K, additional, Olin, A, additional, Page, R D, additional, Povilus, A, additional, Robicheaux, F, additional, Sarid, E, additional, Silveira, D M, additional, Storey, J W, additional, Thompson, R I, additional, van der Werf, D P, additional, Wurtele, J S, additional, and Yamazaki, Y, additional

Published
2007
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48. 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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49. Antiparticle plasmas for antihydrogen trapping.

Author

Charlton, M., Andresen, G. B., Ashkezari, M. D., Baquero-Ruiz, M., Bertsche, W., Bowe, P. D., Butler, E., Carpenter, P. T., Cesar, C. L., Chapman, S., Eriksson, S., Fajans, J., Friesen, T., Fujiwara, M. C., Gill, D. R., Gutierrez, A., Hangst, J. S., Hardy, W. N., Hayano, R. S., and Hayden, M. E.

Subjects
*PLASMA gases, *ANTIHYDROGEN, *ANTIPROTONS, *EVAPORATIVE cooling, *NUCLEAR excitation, *CENTER of mass
Abstract

Over the last decades it has become routine to form beams of positrons and antiprotons and to use them to produce trapped samples of both species for a variety of purposes. Positrons can be captured efficiently, for instance using a buffer-gas system, and in such quantities to form dense, single component plasmas useful for antihydrogen formation. The latter is possible using developments of techniques for dynamically capturing and then cooling antiprotons ejected from the Antiproton Decelerator at CERN. The antiprotons can then be manipulated by cloud compression and evaporative cooling to form tailored plasmas. We will review recent advances that have allowed antihydrogen atoms to be confined for the first time in a shallow magnetic minimum neutral atom trap superimposed upon the region in which the antiparticles are held and mixed. A new mixing technique has been developed to help achieve this using autoresonant excitation of the centreofmass longitudinal motion of an antiproton cloud. This allows efficient antihydrogen formation without imparting excess energy to the antiprotons and helps enhance the probability of trapping the anti-atom. [ABSTRACT FROM AUTHOR]

Published
2012
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50. ALPHA ANTIHYDROGEN EXPERIMENT.

Author

FUJIWARA, M. C., ANDRESEN, G. B., ASHKEZARI, M. D., BAQUERO-RUIZ, M., BERTSCHE, W., BRAY, C. C., BUTLER, E., CESAR, C. L., CHAPMAN, S., CHARLTON, M., FAJANS, J., FRIESEN, T., GILL, D. R., HANGST, J. S., HARDY, W. N., HAYANO, R. S., HAYDEN, M. E., HUMPHRIES, A. J., HYDOMAKO, R., and JONSELL, S.

Subjects
ANTIHYDROGEN, SYMMETRY (Physics), PARTICLES, ANTIMATTER, QUANTUM theory
Published
2010

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