AFM pictures of the surfaces of glass RPC electrodes damaged by water vapor contamination

We present surface pictures of the damaged electrodes from the Glass Resistive Plate Chambers (GRPCs) taken by an Atomic Force Microscope (AFM). For the test, a set of chambers were operated with freon mixed gas (damaged) and freonless gas (not damaged), contaminated with 1000 to 2000 ppm of water vapor. In the AFM pictures, clear differences in damage are seen between the electrodes in the chambers with the freon mixed gas and the freonless gas; a combination of freon and water vapor caused the damage.