27-10-2012, 11:31 AM
Antiprotons and Cold Antihydrogen
ABSTRACT
The author’s ATRAP team has managed to simultaneously accumulate cold antiprotons and cold positrons. Cold
antihydrogen is produced when antiprotons are repeatedly driven into collisions with cold positrons within a nested Penning
trap. Efficient antihydrogen production takes place during many cycles of positron cooling of antiprotons. A first measurement
of a distribution of antihydrogen states is made using a preionizing electric field between separated production and detection
regions. Surviving antihydrogen is stripped in an ionization well that captures and stores the free antiproton for
background-free detection. A background-free observation of cold antihydrogen atoms was made using field ionization
followed by antiproton storage, a detection method that provided the first experimental information about antihydrogen atomic
states. More antihydrogen atoms can be field ionized in an hour than all the anti-matter atoms that have been previously
reported, and the production rate per incident high energy antiproton is higher than ever observed. The high rate and the high
Rydberg states suggest that the antihydrogen is formed via three-body recombination. This report presents bibliographic
citations for 10 publications and 36 lectures that were produced during 2004 under this contract. The author also was the
recipient of the George Ledlie Prize at Harvard University in 2004.
ABSTRACT
The author’s ATRAP team has managed to simultaneously accumulate cold antiprotons and cold positrons. Cold
antihydrogen is produced when antiprotons are repeatedly driven into collisions with cold positrons within a nested Penning
trap. Efficient antihydrogen production takes place during many cycles of positron cooling of antiprotons. A first measurement
of a distribution of antihydrogen states is made using a preionizing electric field between separated production and detection
regions. Surviving antihydrogen is stripped in an ionization well that captures and stores the free antiproton for
background-free detection. A background-free observation of cold antihydrogen atoms was made using field ionization
followed by antiproton storage, a detection method that provided the first experimental information about antihydrogen atomic
states. More antihydrogen atoms can be field ionized in an hour than all the anti-matter atoms that have been previously
reported, and the production rate per incident high energy antiproton is higher than ever observed. The high rate and the high
Rydberg states suggest that the antihydrogen is formed via three-body recombination. This report presents bibliographic
citations for 10 publications and 36 lectures that were produced during 2004 under this contract. The author also was the
recipient of the George Ledlie Prize at Harvard University in 2004.