Driven Production of Cold Antihydrogen and the First Measured Distribution of Antihydrogen States

Gabrielse, Gerald; Bowden, N. S.; Oxley, Paul; Speck, A.; Storry, C. H.; Tan, Joseph N.; Wessels, M.; Grzonka, D.; Oelert, W.; Schepers, G.; Sefzick, T.; Walz, J.; Pittner, Heiko; Hänsch, Theodor W.; Hessels, E. A.

doi:10.1103/physrevlett.89.233401

Cited by 227 publications

(128 citation statements)

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“…An alternative indirect method, first used by the ATRAP collaboration, is to strip, or field-ionize, the antihydrogen atom of the positron using a strong electric field and trap the resulting bare antiproton (Gabrielse et al 2002). The number of antiprotons trapped in this way is therefore a measure of how many antihydrogen atoms were field-ionized.…”

Section: (C) Detectionmentioning

confidence: 99%

Cold antihydrogen: a new frontier in fundamental physics

Madsen

2010

Phil. Trans. R. Soc. A.

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The year 2002 heralded a breakthrough in antimatter research when the first low energy antihydrogen atoms were produced. Antimatter has inspired both science and fiction writers for many years, but detailed studies have until now eluded science. Antimatter is notoriously difficult to study as it does not readily occur in nature, even though our current understanding of the laws of physics have us expecting that it should make up half of the universe. The pursuit of cold antihydrogen is driven by a desire to solve this profound mystery. This paper will motivate the current effort to make cold antihydrogen, explain how antihydrogen is currently made, and how and why we are attempting to trap it. It will also discuss what kind of measurements are planned to gain new insights into the unexplained asymmetry between matter and antimatter in the universe.

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Section: (C) Detectionmentioning

confidence: 99%

Cold antihydrogen: a new frontier in fundamental physics

Madsen

2010

Phil. Trans. R. Soc. A.

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“…Precision laser and microwave spectroscopy will likely require ground-state anti-atoms, and hence estimation of the quantum state distribution of antihydrogen is of considerable importance [ 41,42,43,44 ]. In all previous work involving un-trapped atoms only highly excited states have been experimentally identified.…”

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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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“…Those sparkling achievements are respectively due to the ATRAP (Gabrielse et al [27]) collaboration and the ATHENA collaboration (Hangst et al [28]). Then, one can try to produce and confine thousands of antihydrogen atoms in a Pritchard-Ioffe trap, consisting of a vacuum cylinder within a quadrupole magnet, augmented with confining pinch coils at each.…”

Section: -Transporting Antiprotons To Spacementioning

confidence: 99%

Fusion reactions and matter–antimatter annihilation for space propulsion

Deutsch

Tahir

2006

Laser Part. Beams

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RÉSUMÉ : La fusion par confinement magnétique (FCM) et la fusion par confinement inertiel (FCI) sont comparées dans le contexte de missions à longue distance, à travers le système solaire. Ces deux approches montrent des capacités manoeuvrières bien supérieures, à celles de la propulsion cryogénique standard (PCS). Les contraintes de coût sont bien inférieures à celles exigées par la production d'énergie, au sol. Un problème crucial est celui du décollage (problématique des 300 premiers kms), étant donné les risques de pollution radioactive de la basse atmosphère. Il est recommandé d'assembler le vaisseau spatial à haute altitude ~ 700 kms, ou mieux, sur la lune. En ce qui concerne les impulsions spécifiques en sec, on s'attend à 500-3000 pour la fission, et jusqu'à 10 4 -10 5 pour la fusion deuterium + tritium.Enfin, on aborde la réaction de fusion la plus performante, l'annihilation pp avec I sp (sec) ~ 10 3 -10 6 et un rapport poussée/poids ~ 10 -3 -1. Production et coûts sont détaillés, autant que possible. Ces derniers pourraient être réduits de quatre ordres de grandeur, si la fusion contrôlée devenait économiquement viable.On discute plusieurs schémas de propulsion par annihilation matière-antimatière. On accorde une certaine attention à la propulsion par fusion inertielle et catalysée par annihilation de p , et en particulier, au projet ICAN-II, potentiellement en mesure d'atteindre Mars en 30 jours en utilisant une fusion catalysée par 140 ng de p avec une impulsion spécifique ~ 13500 sec.ABSTRACT: Magnetic confinement fusion (MCF) and inertial confinement fusion (ICF are critically contrasted in the context of far-distant travels throughout solar system.Both are shown to potentially display superior capabilities for vessel maneuvring at high speed, which are unmatched by standard cryogenic propulsion (SCP).Costs constraints seem less demanding than for ground-based power plants. Main issue is the highly problematic takeoff from earth, in view of safety hazards concomitant to ratioactive spills in case of emergency. So, it is recommended to assemble the given powered vessel at high earth altitude ~ 700 km, above upper atmosphere.

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Driven Production of Cold Antihydrogen and the First Measured Distribution of Antihydrogen States

Cited by 227 publications

References 21 publications

Cold antihydrogen: a new frontier in fundamental physics

Cold antihydrogen: a new frontier in fundamental physics

Confinement of antihydrogen for 1,000 seconds

Fusion reactions and matter–antimatter annihilation for space propulsion

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