Single-component plasma of photoelectrons ATRAP Collaboration

Abstract Ten-nanosecond pulses of photoelectrons liberated by intense UV laser pulses from a thin gold layer are captured into a single-component plasma that is ideally suited to cool antiprotons (p) for antihydrogen (H) production. Up to a billion electrons are accumulated using a series of laser pulses, more than are needed for efficientp cooling in the large traps now being used for loadingp forH production. The method is demonstrated within an enclosed vacuum space that is entirely at 4 K, and is thus compatible with the exceptional cryogenic vacuum that is desirable for the long-term storage of antihydrogen. The pitfalls of other electron accumulation methods are entirely avoided, including the particle heating and declining efficiency of field emission point loading, and the heat load and contamination of thermionic emission methods. © 2007 Elsevier B.V. All rights reserved. The quantum explanation of the surprising photoelectrons that light liberates from a metal surface was one of the early successes of a quantum view of the world Here we report the first use of short pulses of photoelectrons to quickly and robustly accumulate the large number of electrons needed to collisionally cool antiprotons (p)-a crucial step for slowH production [9-11]. CERN's unique Antiproton Decelerator facility (AD) delivers 5-MeVp. These are slowed to the keV energies at which they can be trapped-either i