Present performance of the LEP pre-injector klystron modulators and the impact of a proposed upgrade

The authors review the actual working parameters of the LEP (Large Electron-Positron Collider) pre-injector (LPI) klystron modulators, and look at the equipment reliability from the early commissioning stages to the present production runs for the LEP. In order to improve the positron particle production rate in the LPI, to match improvements envisaged in the LEP program, several closely linked modifications are being studied and are discussed. Increasing the repetition frequency of the klystron modulators is one of the possible changes that could be made, and an improvement factor in the production rate of between 1.5 to 2.0 could be obtained. An analysis has been made of the modulator system in order to pin-point areas where equipment modifications would be required and to realize the improved performance without degrading the present reliability