1999 was a very good year for ATRAP, despite the disappointment of not receiving antiprotons in numbers sufficient for particle trapping. Spokesperson Gerald Gabrielse pointed to five significant publications by collaboration members in Physical Review Letters and Physics Letters.1. Comparison of charge-to-mass ratio of the antiproton and proton to 9 parts in 10,000,000,000, nearly a million-fold improvement on measurements by other techniques. This was the final publication of the TRAP Collaboration which grew into ATRAP.ATRAP is very hopeful that CERN's new AD facility will get close to design performance during 2000 so that progress can be made towards the formation of cold antihydrogen.2. The first simultaneous confinement of the ingredients of cold antihydrogen was reported. Cold positrons and antiprotons were stored together in cryogenic vacuum for the first time and made to interact. This the closest approach to cold antihydrogen by far.
3. Trapped particles were cooled to 70 mK, the first time that charged particles have been stored below 4.2 K. The apparatus developed is a prototype of what will be used to cool trapped antiprotons and positrons to similar low temperatures.
4. The first coherent source of the Lyman alpha radiation, developed for antihydrogen experiments, was demonstrated. This source should allow sensitive optical detection of antihydrogen along with optical cooling of antihydrogen.
5. A greatly improved source of 4.2 K positrons was demonstrated. This unusual source derives positrons from the field ionization of Rydberg states of positronium. Only ATRAP has yet cooled positrons to 4.2 K and stored them in the cryogenic vacuum that is very desirable for experiments which avoid the rapid annihilation of antihydrogen.