Abstract: A CO2 beam source includes a discharge tube in which a laser gas serves as a laser medium, a fan for supplying the laser gas into the discharge tube via a supply element and for removing the laser gas from the discharge tube via a removal element in a closed laser gas circuit, and a catalyst for catalysing oxidation of dissociation products formed upon excitation of the laser gas. The catalyst includes precious metal nanoparticles applied to a substrate. The catalyst is arranged with clearance from the discharge tube in the flow direction of the laser gas within the closed laser gas circuit in order to reduce deposition of degradation products formed in the discharge tube upon excitation of the laser gas compared to an arrangement within the discharge tube. A temperature of the at least one catalyst during operation of the CO2 beam source is at least 60° C.

Abstract: A back surface contact solar cell has a wafer with an anti-reflection layer on the front surface, with an emitter and a back surface field on the back surface, and with contacts, produced using laser ablation, on the back surface, wherein the pitch is at most 800 micrometers. Furthermore provided is a method for producing such a solar cell.