A theory on the sensitivity of a silicon surface-barrier detector including a thermal charge-diffusion effect

A theoretical model of the x-ray responses of silicon surface-barrier (SSB) detectors was developed under a configuration of a widely used detector structure for plasma x-ray diagnostics. The model consisted of a signal contribution from thermally diffusing charge created in the field-free substrate region within a diffusion length from the depletion layer. This was accompanied signal contributions coming from charge created in the depletion layer. The model was found to predict a large signal contribution from the charge-diffusion effect on the SSB responses to high-energy x-rays.