Speaker
Description
Liquid noble gas detectors for neutrino and rare-event searches often rely on efficient detection of vacuum-ultraviolet (VUV) scintillation light while minimizing radioactive backgrounds from nearby materials. To improve the detection of VUV photons, wavelength shifters are required to convert scintillation light into the visible range. At the scale of next-generation experiments such as DUNE, DarkSide-20k, and LEGEND-1000, conventional approaches based on passive structural materials combined with wavelength-shifting coatings become increasingly difficult to implement.
A complementary strategy is to replace components with optically active materials that contribute directly to light conversion or scintillation. Among these, poly(ethylene naphthalate) (PEN) is a particularly promising candidate due to its intrinsic wavelength-shifting and scintillation properties, mechanical robustness, and long-term stability at cryogenic temperatures such as liquid argon.
We present recent developments in optically active PEN components, both filament-printed and injection-molded. In addition, commercially available PEN films were subjected to advanced cleaning and handling procedures and were subsequently qualified through extensive optical and radiopurity characterization for LEGEND. A dedicated cryogenic VUV spectrofluorometer was commissioned to measure wavelength-shifting behavior under realistic operating conditions. We outline the next steps in the development and qualification of optically active materials for future liquid noble gas detectors such as LEGEND-1000.
This work is supported by the U.S. DOE, and the NSF, the LANL, ORNL and LBNL LDRD programs; the European ERC and Horizon programs; the German DFG, BMBF, and MPG; the Italian INFN; the Polish NCN and MNiSW; the Czech MEYS; the Slovak RDA; the Swiss SNF; the UK STFC; the Canadian NSERC and CFI; the LNGS and SURF facilities.