Progress in the development of intense electron beam diodes for deep penetration radiographic applications

An overview of progress made in the development of intense electron beam diode for deep penetration radiographic applications is given. The Atomic Weapons Establishment (A WE) has a requirement to develop intense (1000 R at 1 m), fast duration (50 ns) Bremsstrahlung X-ray sources from small areas (<;2 mm diameter uniformly filled disc equivalent) at high peak energies (>; 10 MeV). In order to deliver such sources in a cost-effective manner an extensive collaborative research programme is being conducted at A WE, Sandia National Laboratories (SNL) and the Naval Research Laboratory (NRL). This programme is utilizing pulsed power drivers in several laboratories and improved diagnostic techniques coupled with extensive PIC and Monte Carlo simulations. Three diode technologies are being investigated. These are the paraxial diode, the pinch diode and immersed Bz diodes. Highlights in the field since BEAMS 2002 are given. These include: improved modeling of paraxial diode physics and fully ionized paraxial cell concepts, 2 Macm^-2 current densities at X-ray conversion targets in 4.25 MV self-magnetic pinch diode experiments and engineering of cryogenic Bz diode concepts.