Recent X-ray diode and magnetically insulated transmission line experiments performed on the 5.5MV Superswarf Machines at AWE Aldermaston

Summary form only given, as follows. The Superswarf Flash X-ray machines at Aldermaston have been running with a paraxial diode for a number of years. This is a passive method of focussing the electron beam to provide a small x-ray source. Within the last few years this has been enhanced to provide a smaller spot size with a slight loss in dose. The magnetically immersed diode is being investigated as an alternative method to focussing the electron beam. The external magnetic field, up to 25T, is produced by a solenoid which is driven by a 418 F, 22 kV capacitor bank. The best Bz shot to date has produced 82 R @ 1 m with a 4.2 mm spot. This compares to a standard paraxial diode 80 R @ 1 m with a 5.3 mm, spot and the enhanced vacuum cell paraxial diode 65 R @ I m with a 4.0 mm spot. The large flash x-ray machines at AWE have all been developed as single diode machines with the x-ray output along the axis of the machine. Two series of experiments were designed to look at the possibility of a single machine providing simultaneous multi axis radiographs of a single object. The First series of experiments was designed to look at the possibility of driving two diodes from a single MITL. This was used to confirm that turning the diode through a large angle to the MITL is possible. The second series of experiments used a novel configuration. This consisted of a single feed MITL splitting into two higher impedance MITLs each with its own diode. This arrangement was used to confirm that no significant current was lost at the MITL junction.