Speaker
Description
TPB is the standard wavelength shifter used in liquid argon/xenon experiments to convert scintillation light from deep UV to visible wavelengths, where typical photodetectors have non-negligible light detection efficiency. While TPB offers high light conversion efficiency, its use presents challenges: it is an organic powder that is difficult to deposit as a thin film on substrates like glass or reflector films, particularly for stable performance in cryogenic conditions as a wavelength shifter. As a result, deploying TPB over large detector volumes is difficult, highlighting the need for novel materials for the next generation of experiments.
PEN, a polyester easily manufactured as thin sheets, could simplify the coverage of large volumes with wavelength shifters. Previous measurements have shown that commercial grades of PEN have approx. 50% light conversion efficiency relative to TPB. Encouraged by these results, we conducted a large-scale measurement of a 4 m² PEN + ESR reflector combination foil in a liquid argon environment, using a two-tonne LAr dewar to assess its stability over two weeks. This step is crucial for validating PEN as a viable substitute for TPB. In this poster, I will describe the measurement setup and present the initial results on the stability of PEN as a wavelength shifter in liquid argon.
