Precision timing and interlock systems for FEL heating experiments on MTX

Abstract

A new precision timing system has been installed on the Microwave Tokamak Experiment (MTX). The purpose of the system is to synchronize the tokamak's plasma discharge with a 140 GHz, 2 GW microwave pulse generated by a free-electron laser (FEL). The installation involved modifying the existing sequencer system and adding digital delay generators, three in-house-designed CAMAC modules, and other components. The system controls placement of the 30 ns FEL pulse during the MTX plasma discharge and provides decision triggers for the microwave plasma diagnostics. These triggers are distributed over 100 Mb/s fiber-optic links. The MTX interlock system has been expanded to provide personnel safety during FEL experiments, to protect the FEL and related equipment, and to control the path of the FEL beam starting from the FEL's output, through the beam transport system, and into the tokamak. How the existing MTX timing and interlock systems were upgraded to accommodate these new FEL experiments is described. >