Electron dynamics in the bremsstrahlung reflex triode

Summary form only given, as follows. The reflex triode is a versatile bremsstrahlung source for Nuclear Weapons Effects simulation. The reflex triode employs a range-thin foil anode between two identical face-to-face hollow cathodes. Electrons undergo multiple reflexes through the anode foil converter as they lose their energy and are focused radially. The reflex triode can operate in the high total dose mode; the high dose rate mode; or the high fidelity mode, which maximizes the production of warm (5 keV < E < 50 keV) x-ray photons. When compared to bremsstrahlung production devices employing a range-thick anode converter, the use of a range-thin anode converter not only enhances the escape of warm x-rays, but also mitigates converter debris. Despite these advantages, key aspects of the physics of the operation of the reflex triode need to be better understood to optimize its radiation output. One of these unresolved aspects is the detailed motion of the electrons as they reflex through the anode foil. Modeling of the reflex triode operation with 2-1/2D PIC codes predicts an unexpectedly strong fluctuating electric field adjacent to the anode, having frequencies /spl sim//spl omega//sub pe/ and magnitudes roughly equal to the average electric field. This stochastic electric field causes the average number of reflexes to scale much less strongly that the inverse of the thickness of the anode foil. Results of analytic modeling and 2-1/2D particle-in-cell simulations will be presented which explore the dynamics of reflexing electrons and the accompanying fluctuating electric field in the reflex triode.