The antiproton annihilation detector system of the ATRAP experiment

The ATRAP (antihydrogen trap collaboration) at CERN (European organization for nuclear research) has developed a completely new, larger and more robust apparatus in the second experimental zone. The antiproton annihilation detector system consists of 10 layers of scintillating fibers, counts the antihydrogen atoms and determines the annihilation vertex of the atoms. This diagnostic element will allow to optimize the production of cold antihydrogen sufficiently to permit the optical observations and measurements. Using this new apparatus thousands of antihydrogen atoms have been produced within a combined Penning-Ioffe trap. These observed antihydrogen atoms resolve a debate about whether positrons and antiprotons can be brought together to form antihydrogen atoms within the divergent magnetic fields of a quadrupole Ioffe trap. Supported by the NSF (Grant No. 0306308) and AFOSR of the US, the BMBF, MPG and FZ-Juelich of Germany, and the NSERC, CRC, CFI (Grant No. 3756) and OIT of Canada