Meson Factories

Meson factories are those accelerators designed to produce beams of protons in the energy range of 400 to 1000 MeV with intensities at least 1000 times greater than those presently available from FM cyclotrons. They have an important role in future research in nuclear structure physics, elementary particle physics, and bio-medical research. The criteria for selection of a meson factory are discussed. They include duty factor and the time structure of the beam, the possibility of varying the energy of the beam, the efficiency with which a large fraction of the beam can be brought to an experimental area, the possibility of the simultaneous use of high duty factor beams of differing energy, the amount of radioactivity induced in the accelerator, and general flexibility. Additional criteria are cost and the relative difficulty of the expected technological problems. Descriptions are given of the various types of accelerators which have been seriously suggested for this role. These include the sector-focusing cyclotron for the acceleration of positive ions, the sector-focusing cyclotron for the acceleration of negative hydrogen ions, and the sector-focusing ring cyclotron. The linear accelerator for the acceleration of protons has also been suggested as a meson factory, and the final description concerns the separated orbit cyclotron, combining some of the features of the linear accelerator and the sector focusing cyclotron. An attempt is made to use the criteria in a comparison of the promise of these various types of accelerators in the role of meson factory.