Production and detection of cold antihydrogen atoms

Physik-Institut, Zürich University, CH-8057 Zürich, Switzerland
Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment (Impact Factor: 1.22). 02/2004; DOI: 10.1016/j.nima.2003.10.072


The production and observation of cold antihydrogen atoms have been recently reported by the ATHENA experiment at the CERN Antiproton Decelerator. The antiatoms were produced by mixing low-energy antiprotons and positrons in an electromagnetic trap. The antihydrogen detection is based on the observation of a characteristic signature in the annihilation of the neutral antiatoms on the trap walls by means of an imaging particle detector. An overview of the apparatus is given and the results obtained are discussed.

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    • "Instead, we rely on two other arguments: (1) As will be discussed in Section 7, the temporal-spatial characteristics of the candidate events are not compatible with mirror-trapped antiprotons. (2) By heating the positron plasma, we can shut off the production of antihydrogen [20]. When we do this, we observe essentially no trapped antihydrogen candidates (one candidate in 246 trials, as opposed to 38 candidates in 335 trials in [1]). "
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    • "A hollow electron column with axial mirrors has also been considered [7]. Penning–Malmberg traps have been recently used in experiments for the production of antihydrogen [8] [9] and are being considered, with mirror fields added, for future experiments to confine the anti-hydrogen itself [10] [11]. Recently, the effects of a multipole magnetic field intended to trap the anti-hydrogen radially in such a trap have been studied experimentally [12], theoretically [13], and with simulations [14]. "
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