UV mercury low-pressure lamp with amalgam deposit

An ultraviolet mercury low-pressure amalgam lamp comprising:

• a tube having a first end and a second end;
• a first electrode positioned in the first end of said tube;
• a second electrode positioned in the second end of said tube, whereby, when the lamp is energized, a discharge path is formed between said first and second electrodes;
• at least one amalgam deposit adjacent to one of said first and second electrodes outside the discharge path between said first and second electrodes;
• at least one constriction disposed in the tube;
• and
• a thermally resistant plate arranged between the at least one amalgam deposit and a helical-wound filament of one of said first and second electrodes,
• wherein the at least one amalgam deposit is positioned behind the constriction with respect to the discharge path such that the at least one amalgam deposit is shielded by the constriction from direct thermal radiation emitted by the electrodes.