A fifty megawatt klystron for the Stanford Linear Collider
The proposed Stanford Linear Collider (SLC) has been designed to provide 50 on 50 GeV electron-positron collisions. The performance of the 240 klystrons driving the two-mile long linac must be upgraded to achieve at least 50 Megawatts of peak power output at a pulse width of 5 µsec and a pulse repetition frequency of 180 pulses per second. The operating frequency of the upgraded linac will continue to be 2856 MHz. A klystron amplifier meeting these new requirements has been designed to operate at 315 KV, µk = 2, with a computed efficiency of slightly greater than 50%. Initial tests indicate the achievement of the basic power objectives; however, observed parasitic instabilities make beam focusing, RF drive frequency and drive level extremely critical. High electric fields in the electron gun, output gap and output window are all potential problems. Steps taken in the design to overcome these problems are discussed and test results are presented.
Performance test of a 65-MW klystron unit relevant to the microwave source upgrade of the KEK 2.5-GeV linac
There is a plan to upgrade the Japan National Laboratory for High-Energy Physics (KEK) 2.5-GeV linear accelerator (linac) microwave source, which affects both the asymmetric B-factory two-ring collider project and the 3-GeV operation of the Photon Factory storage ring. The authors describe the upgrading of the microwave source as well as performance tests of a test station which was established in order to confirm the feasibility this upgrade. The required increase in the injection linac energy from the present 2.5 GeV to 4.25 GeV necessitates the replacement of the 30-MW klystrons with new 65-MW units. Since a total modification of the klystron modulator would be expensive, the output voltage and average power of the modulator have remained unchanged. An increase in the klystron beam voltage could only be obtained by increasing the pulse transformer step-up ratio from 1:12 to 1:15. A new test station using a 65-MW klystron was established to confirm stable operation of the modified unit. An output power of 58 MW with a 1- mu s duration was successfully generated in a preliminary test.<<ETX>>
Natural history and long‐term evolution in families with autosomal dominant cortical tremor, myoclonus, and epilepsy
Purpose:  To investigate for the first time the natural history and long‐term evolution of “familial cortical tremor, myoclonus, and epilepsy.”