Gas laser and a dedusting unit thereof

A gas laser comprising:

• a tube containing a gas mixture including a laser gas, the tube comprising a cylindrical inner wall;
• a discharge unit disposed in said tube and having two elongated electrodes defining an electrical gas discharge gap therebetween for providing an electric gas discharge between said electrodes which generates laser light;
• a circulation means disposed within said tube creating a gas flow substantially transverse to said electrodes;
• and
• a dedusting unit mounted along the inner cylindrical wall of the tube such that a portion of the gas flow within the tube,passes through the dedusting unit;
• wherein the dedusting unit comprises an elongated U-shaped channel extending parallel to the electrodes, the two opposing walls of the U-shaped channel being perforated and disposed substantially transverse to the direction of the portion of the gas flow within the dedusting unit.