Antimatter Plasmas in a Multipole Trap for Antihydrogen

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

doi:10.1103/physrevlett.98.023402

Cited by 80 publications

(43 citation statements)

References 24 publications

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“…The current generation of experiments [4,5] aims to trap H atoms as this is likely necessary for precision CPT and gravity tests. Neutral H atoms have a small permanent magnetic moment and can be trapped by a local, three-dimensional minimum of a magnetic field [6].…”

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confidence: 99%

Compression of Antiproton Clouds for Antihydrogen Trapping

Andresen¹,

Bertsche²,

Bowe³

et al. 2008

Phys. Rev. Lett.

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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.

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confidence: 99%

Compression of Antiproton Clouds for Antihydrogen Trapping

Andresen¹,

Bertsche²,

Bowe³

et al. 2008

Phys. Rev. Lett.

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“…The ALPHA antihydrogen trap [ 27,28 ] is comprised of the superposition of a Penning trap for antihydrogen production and a magnetic field configuration that has a three-dimensional minimum in magnitude (Fig. 1).…”

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confidence: 99%

Confinement of antihydrogen for 1,000 seconds

et al. 2011

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Reported trapping times of magnetically confined (matter) atoms range from <1 s in the first, room temperature, traps [ 18 ] to 10 to 30 minutes in cryogenic devices [ 19,20,21,22 ]. However, antimatter atoms can annihilate on background gases. Also, the loading of our trap (i.e., anti-atom production via merging of cold plasmas) is different from that of ordinary atom traps, and the loading dynamics could adversely affect the trapping and orbit dynamics. Mechanisms exist for temporary magnetic trapping of particles (e.g., in quasi-stable trapping orbits [ 23 ], or in excited internal states [ 24 ]); such particles could be short-lived with a trapping time of a few 100 ms. Thus, it is not a priori obvious what trapping time should be expected for antihydrogen. 5In this article, we report the first systematic investigations of the characteristics of trapped antihydrogen. These studies were made possible by significant advances in our trapping techniques subsequent to Ref. [ 17 ]. These developments, including incorporation of evaporative antiproton cooling[ 25 ] into our trapping operation, and optimisation of autoresonant mixing [ 26 ], resulted in up to a factor of five increase in the number of trapped atoms per attempt. A total sample of 309 trapped antihydrogen annihilation events was studied, a large increase from the previously published 38 events.Here we report trapping of antihydrogen for 1000 s, extending earlier results [ 17 ] by nearly four orders of magnitude. Further, we have exploited the temporal and spatial resolution of our detector system to perform a detailed analysis of the antihydrogen release process, from which we infer information on the trapped antihydrogen kinetic energy distribution.The ALPHA antihydrogen trap [ 27,28 ] is comprised of the superposition of a Penning trap for antihydrogen production and a magnetic field configuration that has a three-dimensional minimum in magnitude (Fig. 1). For ground-state antihydrogen, our trap well-depth is 0.54 K (in temperature units).The large discrepancy in the energy scales between the magnetic trap depth (~50 eV), and the characteristic energy scale of the trapped plasmas (a few eV) presents a formidable challenge to trapping neutral anti-atoms. antiprotons at ~100K, with radius 0.4 mm and density 7x10 7 cm -3 is prepared for mixing with positrons.Independently, the positron plasma, accumulated in a Surko-type buffer gas accumulator [ 33 ,34 ], is transferred to the mixing region, and is also radially compressed. The magnetic trap is then energized, 6 and the positron plasma is cooled further via evaporation, resulting in a plasma with a radius of 0.8 mm and containing 1x10 6 positrons at a density of 5x10 7 cm -3 and a temperature of ~40 K. The silicon vertex detector, surrounding the mixing trap in three layers (Fig. 1 a) ]. Knowledge of annihilation positions also provides sensitivity to the antihydrogen energy distribution, as we will show.In Table 1 and Fig. 2, we present the results for a series of measurements, wherein the confinemen...

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“…Some p clouds are completely imaged by this system, but others are far larger, and can extend all the way out to the walls of our trap at radius R w = 22.3 mm. Here, using the ALPHA collaboration trap [4], we describe a new diagnostic that probes the outer radial profile based on measurements of ballistic [16] losses induced by an octupole magnet. After a brief description of how we load particles into the trap, we describe the diagnostic.…”

Section: Introductionmentioning

confidence: 99%

“…The current generation of experiments [4,5] aims to trap H atoms as this is likely necessary for precision CPT and gravity tests. Neutral H atoms have a small permanent magnetic moment, and can be trapped in the magnetic minimum of a so-called Minimum-B trap [6].…”

Section: Introductionmentioning

confidence: 99%

A novel antiproton radial diagnostic based on octupole induced ballistic loss

et al. 2008

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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.

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Antimatter Plasmas in a Multipole Trap for Antihydrogen

Cited by 80 publications

References 24 publications

Compression of Antiproton Clouds for Antihydrogen Trapping

Compression of Antiproton Clouds for Antihydrogen Trapping

Confinement of antihydrogen for 1,000 seconds

A novel antiproton radial diagnostic based on octupole induced ballistic loss

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