Antiproton, positron, and electron imaging with a microchannel plate/phosphor detector

Refereed Publication
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. [...]
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Published in

Review of Scientific Instruments

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

Magnetic multipole induced zero-rotation frequency bounce-resonant loss in a Penning-Malmberg trap used for antihydrogen trapping

Refereed Publication
In many antihydrogen trapping schemes, antiprotons held in a short-well Penning–Malmberg trap are released into a longer well. This process necessarily causes the bounce-averaged rotation frequency \omegar of the antiprotons around the trap axis to pass through zero. [...]
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Published in

Physics of Plasmas

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

Compression of Antiproton Clouds for Antihydrogen Trapping

Refereed Publication
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. [...]
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Published in

Physical Review Letters

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

A Novel Antiproton Radial Diagnostic Based on Octupole Indused Ballistic Loss

Refereed Publication
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. [...]
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Published in

Physics of Plasmas

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

Antihydrogen For Precision Tests In Physics

Refereed Publication
The creation of atoms of antihydrogen under controlled conditions has opened up a new era in physics with antimatter. We describe the experimental realisation of low energy antihydrogen, via the mixing of carefully prepared clouds of positrons and antiprotons, and some of the progress that has been made in the last few years in characterising properties of the nascent anti-atoms. [...]
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Published in

Contemporary Physics

M. Charlton, S. Jonsell, L.V. Jørgensen, N. Madsen and D.P. van der Werf

Production of Antihydrogen at Reduced Magnetic Field for Anti-atom Trapping

Refereed Publication
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. [...]
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Published in

Journal of Physics B

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

Antimatter Plasmas in a Multipole Trap for Antihydrogen

Refereed Publication
We have demonstrated storage of plasmas of the charged constituents of the antihydrogen atom, antiprotons and positrons, in a Penning trap surrounded by a minimum-B magnetic trap designed for holding neutral antiatoms. The neutral trap comprises a superconducting octupole and two superconducting, solenoidal mirror coils. [...]
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Published in

Physical Review Letters

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

A Magnetic Trap for Antihydrogen Confinement

Refereed Publication
The goal of the ALPHA collaboration at CERN is to test CPT conservation by comparing the 1S–2S transitions of hydrogen and antihydrogen. To reach the ultimate accuracy of 1 part in 1018 , the (anti)atoms must be trapped. Using current technology, only magnetic minimum traps can confine (anti)hydrogen. [...]
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Published in

Nuclear Instruments and Methods in Physics Research A

W. Bertsche, A. Boston, P.D. Bowe, C.L. Cesar, S. Chapman, M. Charlton, M. Chartier, A. Deutsch, J. Fajans, M.C. Fujiwara, R. Funakoshi, K.Gomberoff, J.S. Hangst, R.S. Hayano, M. J. Jenkins, L. V. Jørgensen, P. Ko, N. Madsen, P. Nolan, R.D. Page, L.G.C. Posada, A. Povilus, E. Sarid, D. M. Silveira, D.P. van der Werf, Y. Yamazaki, B. Parker, J. Escallier, and A. Ghosh

Effects of extreme magnetic quadrupole fields on Penning Traps, and the consequences for antihydrogen trapping

Refereed Publication
Measurements on electrons confined in a Penning trap show that extreme quadrupole fields destroy particle confinement. Much of the particle loss comes from the hitherto unrecognized ballistic transport of particles directly into the wall. [...]
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Published in

Physical Review Letters

J. Fajans, W. Bertsche, K. Burke, S.F. Chapman and D.P van der Werf

Antihydrogen on tap

Refereed Publication
Plentiful quantities of antihydrogen, the bound state system of the antiparticles the positron and the antiproton, have recently been made under very controlled conditions in experiments at the European Laboratory of Particle Physics (CERN) near Geneva. [...]
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Published in

Physics Education

Mike Charlton

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