The Target Chamber Manipulator

The Target Chamber Manipulator (TCM) system allows users to remotely control the angular positions of multiple detectors in the high vacuum 30R end station of the 1.7 MV tandem Pelletron accelerator. Previously, in order to accumulate data from a surface barrier detector at various angular and radial positions, the vacuum chamber was first filled with 1 atmosphere of dry nitrogen, then opened to atmosphere so that the detectors would be repositioned by hand. Evacuating the chamber required several more hours. The entire process took approximately 6 hours to complete, this added substantial time to those experiments requiring frequent repositioning of the detectors. To mitigate this problem and reduce vacuum failure risks from excessive cycling, a TCM system was designed and built at SUNY Geneseo. The system uses LabVIEW to control stepper motors to move the detectors in the chamber. Prior to the summer of 2021, jamming between the drive chain and the main sprocket occurred regularly, and excessive friction between the sprocket and chain occurred intermittingly, inhibiting motion. During the summer of 2021 the TCM was improved by increasing its efficiency and accuracy. The mechanical integrity of the TCM was enhanced by machining the sprocket to better tolerances and 3D printing an alignment tool, which allowed for consistent and reproducible angular alignment. While using a newly constructed electronics control system that simplifies interfacing from the TCM to the computer, time required to perform a Rutherford backscattering spectroscopy experiment will now be significantly reduced from multiple days to just a few hours. Funded in part by a grant from the DOE through the Laboratory for Laser Energetics.