Launching Ultrathin Foil Floating Capabilities at the Princeton Space Physics Lab, Nina Arcot, G1 and Grace Gong, UG '22 (3956977)
The SWAPI (Solar Wind and Pickup Ions) instrument on NASA’s IMAP (Interstellar Mapping and Acceleration Probe) mission uses ultrathin (~10 nm) carbon foils for coincidence measurements. Other space plasma, energetic particle, and energetic neutral atom instruments further use such foils to make time of flight (ToF) measurements. To install a foil in an instrument, the foil must first be floated onto a metallic flight grid using a technique known as foil floating. Variations in foil floating can affect the quality of foils, thereby affecting the performance of space instruments. Specifically, the water and isopropyl alcohol used in the floating process can lead to contamination, and any thickness nonuniformities will further reduce detector performance and efficiency. This work included the creation of a foil floating station and procedure for the Princeton Space Physics Lab, as well as microscopic analysis to characterize foil samples. Atomic force microscopy (AFM) data showed that the foil thickness exceeds what is theoretically expected, with greater increases in foils that have been floated. X-ray photoelectron spectroscopy (XPS) data showed that there is oxygen present on the surface of the foils but not on the inner layers. Both of these provide a greater understanding of the contamination that arises through the foil floating process, which can lead to procedure modifications to improve the quality of foils. This will allow the Space Physics Lab to optimize their foil floating capabilities, which will improve space mission outcomes.