The 500 MeV Intense Positron Source of the Saclay Linac

Positron acceleration at the Saclay high duty cycle linac is made between 20 and 130 MeV at the Low Energy Station and between 150 and 500 MeV in the High Energy Room. Average intensities in the whole energy domain are the highest available among the various laboratories. Energy widths (FWHN) as low as 1 MeV are obtained for low energy beam (¿ 100 MeV) by special use of the first two sections (S7, S8) which rotates the phase space (¿E, ¿¿). Beams can be switched between Low Energy and High Energy Stations with a period of 1 second. Various factors of the e-/e+ conversion rate are including the magnetic and RF phase adjustments ; they are illustrated by analyzing the energy spectrum obtained with acceleration in the first section S7 only. Beam monitoring includes high sensitivity ferrite monitors, RF cavities, wire chambers and scintillation detectors. A removable converter assembly will be used for an easy maintenance in a highly activated field.