EMU, a new 10 MV electron beam machine at AWE

During the last year the 5.5 MV E minor machine at AWE has been upgraded to 10 MV operation. This has involved the complete replacement of the insulator stack and front end of the machine including a new high impedance magnetically insulated transmission line (MITL) and 2 MV prepulse switch. Also modifications have been made to the intermediate cylinder of the Blumlein and the self-breaking oil switch has been modified to increase its reliability and operating range. The E minor upgrade (EMU) machine is to be used for X-ray diode research, largely concentrating on the paraxial and immersed magnetic field diode. The first shots have now been fired on EMU. These have performed well up to 60 kV charge with the high impedance MITL helping to increase the output volts. Unfortunately problems have arisen once the charging voltage has been increased beyond 60kV with what looks like a capacitor failure. Initial immersed magnetic field diode shots have also been performed. It is planned that by next year that EMU will be moved into a larger facility to allow plasma diagnostics to be fielded around the front of the machine. The X-ray tube is also going to be modified to reduce the vacuum pressure to 5 /spl times/ 10/sup -6/ torr.