R&D of Commercially Manufactured Large GEM Foils

TL;DR

This paper reports on the development and characterization of large-area GEM foils manufactured commercially by Tech-Etch, demonstrating their electrical and geometrical quality suitable for detector applications, and exploring production of even larger foils.

Contribution

It introduces a new commercial production process for large GEM foils using the single-mask technique, expanding availability beyond CERN.

Findings

Tech-Etch successfully produced 10x10 cm² and 40x40 cm² GEM foils.

The foils exhibit excellent electrical properties and uniform hole diameters.

Larger 50x50 cm² foils are under production, with ongoing efforts for meter-long sizes.

Abstract

Many experiments are currently using or proposing to use large area GEM foils in their detectors, which is creating a need for commercially available GEM foils. Currently CERN is the only main distributor of GEM foils, however with the growing interest in GEM technology keeping up with the increasing demand for GEM foils will be difficult. Thus the commercialization of GEM foils has been established by Tech-Etch Inc. of Plymouth, MA, USA using the single-mask technique, which is capable of producing GEM foils over a meter long. To date Tech-Etch has successfully manufactured 10 $\times$ 10 cm$^2$ and 40 $\times$ 40 cm$^2$ GEM foils. We will report on the electrical and geometrical properties, along with the inner and outer hole diameter size uniformity of these foils. Furthermore, Tech-Etch has now begun producing even larger GEM foils of 50 $\times$ 50 cm$^2$, and are currently looking into how to accommodate GEM foils on the order of one meter long. 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, as well as single-mask GEM foils produced at CERN. They also show good hole diameter uniformity over the active area.