Development of very-thick transparent GEMs with wavelength-shifting capability for noble element TPCs

A new concept for the simultaneous detection of primary and secondary scintillation in time projection chambers is proposed. Its core element is a type of very-thick GEM structure supplied with transparent electrodes and machined from a polyethylene naphthalate plate, a natural wavelength shifter. Such a device has good prospects for scalability and, by virtue of its genuine optical properties, it can improve on the light collection efficiency, energy threshold and resolution of conventional micropattern gas detectors. This, together with the intrinsic radiopurity of its constituting elements, offers advantages for noble gas and liquid based time projection chambers, used for dark matter searches and neutrino experiments. Production, optical and electrical characterization, and first measurements performed with the new device are reported.

Automated summary

The proposed device introduces a new concept for detecting primary and secondary scintillations simultaneously in time projection chambers. It offers good scalability and optical properties, improving performance of conventional gas detectors. With inherent radiopurity, it is advantageous for dark matter searches and neutrino experiments.