Characterisation and installation of the Mevex replacement Marx

Used for flash radiography of explosive experiments, the current suite of 800 kV Mevex machines [1] are approaching the end of their operational life due to subcomponent obsolescence in their Marx generators. A replacement Marx generator has been designed [2] in order to ensure continued operations and improve assembly design for mechanical assembly and maintenance. This paper describes the design and operation of a prototype resistive test load for the replacement Marx. Circuit codes are used to determine the optimal resistive values that electrically stress the Marx to 115% of the stress that it would experience when charging its ultimate capacitive load. This is then used to predict a reliability of one failure in 10,000 of the design. Evaluations to ensure no electrical breakdown of the test load and its sufficient thermal capacity to deal with the Marx energy were made and the results presented.