Design of an Automated Liquid Nitrogen Filling System for Germanium Clover Detectors

High-purity germanium (HPGe) clover detectors offer high resolution for gamma ray detection and identification. To prevent leakage current caused by thermal excitation, these detectors must be kept at cryogenic temperatures using liquid nitrogen. At the Cyclotron Institute at Texas A&M, the Hyperion HPGe detector employs 14 dewars arranged around the system. These must be manually filled every 4 hours using a funnel, which poses safety risks and is physically impractical. To improve safety and reliability, this project introduces an automated LN₂ filling system. Using an Arduino Uno, PT-100 temperature sensor, solenoid valves, and cryogenic tubing, the system detects fill completion via thermal feedback. Custom PCBs and a Python-based GUI were developed to enable remote operation, offering both manual and automatic control with real-time monitoring and built-in safety interlocks. This design reduces the need for overnight labor and ensures consistent thermal conditions across the detector array. Alongside the system development, preliminary testing on a separate HPGe detector was conducted to evaluate its suitability for future spectroscopy experiments