With a combination of magnets, we can hold antihydrogen in our apparatus without touching it
The central region of the electrode stack is where the ‘magic’ happens. These electrodes comprise the mixing trap: it is here that the antiprotons and positrons finally meet. The plasmas are transferred into this region and are held in potential wells until the antiprotons are merged with the positron plasma into the antiproton plasma. The mixing trap electrodes are surrounded by the octupole magnet and the mirror coils. These mixing electrodes are especially thin, so that antihydrogen atoms formed in the trap can get as close as possible to the octupole magnet without annihilating on the electrode surface. Once the magnets are energized, the Penning trap is superimposed with the magnetic minimum atom trap and neutral antihydrogen can be successfully trapped.
b. A plot of the on axis electric potential in the mixing trap region.
Figure from: Andresen et al., "Trapped Antihydrogen" Nature, 2010.
What's more?
- For more about Antimatter in general, have a look at the CERN Antimatter page
- Good descriptions of 'How ALPHA works' in detail can be found in the publication section on our website
- Particularly appropriate for students and non-physicists are Cold Antihydrogen: a new frontier in fundamental physics, Antihydrogen for precision tests in physics and Antihydrogen in a bottle
- For experts, a general overview of many of the important aspects can be found in Search for Trapped Antihydrogen