  Poly Ethylene Naphthalate (PEN) is an industrial polymer plastic which is
investigated as a low background, transparent, scintillating and wavelength
shifting structural material. PEN scintillates in the blue region and has
excellent mechanical properties both at room and cryogenic temperatures. Thus,
it is an ideal candidate for active structural components in experiments for
the search of rare events like neutrinoless double-beta decay or dark matter
recoils. Such optically active structures improve the identification and
rejection efficiency of background events, like this improving the sensitivity
of experiments. This paper reports on the production of radiopure and
transparent PEN plates These structures can be used to mount germanium
detectors operating in cryogenic liquids (LAr, LN). Thus, as first application
PEN holders will be used to mount the Ge detectors in the LEGEND-200
experiment. The whole process from cleaning the raw material to testing the PEN
active components under final operational conditions is reported.
