Research and Development of Commercially Manufactured Large GEM Foils

TL;DR

This paper reports on the development and characterization of large-area GEM foils manufactured commercially using single-mask techniques, demonstrating their electrical and geometrical suitability for future particle physics detectors.

Contribution

It introduces a commercial process for producing large GEM foils with uniform properties, overcoming size limitations of previous manufacturing methods.

Findings

GEM foils have excellent electrical properties.

Hole diameter uniformity is consistent across large areas.

Suitable for future nuclear and particle physics applications.

Abstract

With future experiments proposing detectors that utilize very large-area GEM foils, there is a need for commercially available GEM foils. Double-mask etching techniques pose a clear limitation in the maximum size of GEM foils. In contrast, single-mask techniques developed at CERN would allow one to overcome those limitations. However with interest in GEM foils increasing and CERN being the only main distributor, keeping up with the demand for GEM foils will be difficult. Thus the commercialization of GEMs has been established by Tech-Etch of Plymouth, MA, USA using single-mask techniques. We report on the electrical and geometrical properties, along with the inner and outer hole diameter size uniformity of 10 $\times$ 10 cm$^2$ and 40$\times$40 cm$^2$ GEM foils. The Tech-Etch foils were found to have excellent electrical properties. The measured mean optical properties were found to reflect the desired parameters and are consistent with those measured in double-mask GEM foils, and show good hole diameter uniformity over the active area. These foils are well suited for future applications in nuclear and particle physics where tracking devices are needed.