A Temperature Dependent Study of the Calibration of Timepix4 Assemblies

Timepix4 hybrid pixel detector ASICs are used by the LHCb collaboration to construct the Timepix4 telescope. The temperature dependence of Timepix4 assemblies has been studied to outline the considerations required when cooling down the telescope "planes" to improve performance. The assemblies were studied with temperatures measured on the ASIC that varied between around 25 °C and 40 °C, in a 0% humidity environment. It was found that cooler sensors have a lower leakage current, but their breakdown and depletion voltage is a function of more than just temperature, and as such doesn't show one uniform dependency. It was shown that the digital to analogue converters of the ASIC have a measurable but negligible temperature dependence. The threshold equalisations demonstrated a negligible change between the maximum and minimum temperatures on the per pixel local threshold, however the number of pixels that could not be equalised increased as temperature decreased.