An automatic liquid-nitrogen filling system for use with solid-state X-ray detectors

An automatic system for the filling of liquid nitrogen-cooled X-ray detectors is described. A novel feature of the system is the pre-cooling of the transfer tube from the nitrogen source to the detector when filling is initiated. This avoids some problems inherent in commercially-available systems. The control electronics center around an inexpensive microcontroller chip. This allows for the inclusion of safety features, whilst keeping the circuit construction very simple and straightforward.