Numerical generation of radiographer´s equations for rod-pinch electron beam diodes

Summary form only given, as follows. High-power rod-pinch electron beam diodes are presently being developed as high-brightness flash X-ray sources. A small diameter(<1 mm) high-atomic-number anode extends through a thin cathode. Electrons emitted from the annular cathode strike the anode generating a bremsstrahlung spectrum. Typically, incident electrons have ranges in excess of the anode thickness and multiple interactions of a primary electron with the anode must be accounted for. Accurate modeling of this spectrum requires detailed modeling of the incident and scattered electrons and the bremsstrahlung spectrum that they produce. The particle-in-cell code LSP has been modified to include the electron scattering and energy-loss algorithms from the ITS Monte Carlo codes. These algorithms have been used to study the role of back-scattered electrons on mono- and bipolar space charge flows. The production of photons in the high-atomic-number anode is also tracked. The positions and momenta of these photons are stored for later processing in the, ITS codes to determine the dose in a thin far-field absorber. The LSP/ITS modeling is used to calculate a "radiographer\´s equation" (dose scaling as a function of diode current and voltage) for particular rod-pinch geometries and anode materials. Comparisons between these equations and SABRE rod-pinch diode data for measured dose in CaF/sub 2/ at 1-m are presented.