MPGD 2026

Fabrication and Preliminary Characterization of Laser-Ablated GEM Foils for Rapid Prototyping Applications

Not scheduled

20m

Masarykova Kolej Congress Centre, Czech Technical University in Prague

Poster Production techniques

Speaker

Daniel Estevao (Universidade de São Paulo)

Description

Gaseous Electron Multipliers (GEMs) are conventionally manufactured through photolithographic and chemical etching processes, which are highly effective for large-area production but can become costly and less practical for small-scale prototyping and laboratory testing. To address the local demand for rapid and low-cost GEM fabrication, an alternative production route based on laser ablation is being investigated.
In this work, GEM foils featuring an active area of 5 × 5 cm² are fabricated using an LPKF ProtoLaser U3 system to produce the micro-hole pattern through controlled laser ablation. Target geometries were defined based on standard GEM dimensions, aiming for hole diameters of approximately 70 µm and pitches near 140 µm. By optimizing laser processing parameters, it is possible to obtain holes with controlled geometry.
Optical and electron microscopy analyses were used to characterize the fabricated structures. Preliminary measurements show entrance diameters around 80 ± 2 µm and exit diameters near 70 ± 2 µm, with pitches of approximately 145 ± 1 µm. The resulting hole profiles exhibit a slight conical shape characteristic of the laser ablation process.
To further enhance hole quality, post-processing chemical treatments were investigated to remove re-solidified copper residues formed along the hole edges during laser machining. A PCB-inspired photolithographic process based on dry-film photoresist and UV exposure was also employed to define the electrode pattern and isolation border of the foil, followed by the integration of a phenolic frame for mechanical support.
Preliminary fabrication results demonstrate the feasibility of producing laser-ablated GEM structures with controlled geometrical features suitable for detector applications and rapid prototyping of small-area foils. Electrical characterization of the fabricated foils is currently in progress and will be presented.