Impact of the surface density of paraTerphenyl films on the Vacuum Ultra Violet light conversion efficiency

Abstract This work studies the efficiency of paraTerphenyl (PTP) films for converting Vacuum Ultra Violet (VUV) light, as a function of their thickness. The PTP films were coated on microscope glasses using the vacuum evaporation technique. The arrangement of the glasses within the evaporation chamber was done to ensure different levels of PTP deposition, with those closer to the center having higher mass values. Surface density measurements were conducted by pre- and post-deposition weighing of the glasses. Relative measurements of the conversion efficiency with respect to a reference sample were done in a vacuum monochromator with a deuterium lamp. The goal of this set of experiments is to understand the impact of PTP thickness on film conversion efficiency. Furthermore, the study employs Profilometry and Optical Microscopy measurements to verify if structural and morphological effects can impact the efficiency of the film. Results indicate that PTP resembles TPB by showing a small change in efficiency due to surface density variations, inside the explored range of thickness.