Continuum X-Ray Generation from W Film on Cu Substrate

The dependence of the continuum X-ray generation from a W film on the primary energy (15 to 30 keV) and film thickness (0.1 to 0.7 µm) have been investigated by experiment and Monte Carlo (MC) simulation in order to develop a high-power rotor-type X-ray source of high efficiency. The continuum X-ray spectra obtained by MC simulation show excellent agreement with the experimental data, confirming the fact that the present MC simulation is applicable for a systematic study to optimize the construction of an X-ray source. The dependence of the continuum X-ray generation on the thickness of the W film has revealed that the continuum X-ray spectra from the W film of thickness ∼0.7 µm are almost similar to those of the bulk W in the investigated range of primary energies. This indicates that the thickness of the W film of ∼0.5 µm is sufficient for the rotor-type X-ray source, although a commercial-type source is of the order of hundreds µm with the primary energy of ∼50 keV.