Electrical Contact Improvements to the MCP Detector at the Princeton Space Physics Laboratory

Abstract

The Princeton Space Physics Lab uses a commercial MCP detector to monitor the 2D flux of their ion beam. This type of detector uses Micro-Channel Plates to multiply a single incoming particle into an avalanche of electrons, which is detected by a resistive anode to determine the position of the original particle in 2D space. The detector's structural assembly provides support to the delicate MCPs and delivers voltage to the MCPs and resitive anode. In 2024, PSPL reverse engineered their commercial MCP detector with the goal of building their own set of detectors in-house, but the attempt was unsuccessful because certain crucial components had insufficient electrical contact between them. My senior thesis project aimed to improve the design of the reverse engineered detector, specifically by creating reliable electrical contact, and then manufacture a new, working detector. The beryllium copper components responsible for poor contact were eliminated: the spring plate was replaced with a stainless steel ring that compressed the MCP stack with a spring force and the anode holders were replaced with aluminum mounts that strapped down the anode with copper strips. All new parts were manufactured by me in the MAE/SEAS machine shop. During the design process, an error in the circuit of the MCP voltage dividing box was discovered, which may have also contributed to the issues with the reverse engineered detector. The new detector was cleaned, baked out, and then installed in the Main Chamber of PSPL. It did not produce any counts using the original box, but it began reading counts at 1975 volts with the new box. A gain curve was graphed going up to 2275 volts, which was determined to be the saturation point.