[diyengineer]

Noob Question

Question: The shelf life of these tubes is what on average? A year? less? more?

What actually happens? Carbon dioxide tube you flow the gas through the tube and the electricity excites the gas, blah blah. I didn't think there was a gas that actually "remained" under pressure.

Someone set me straight

[zax15uk]

The shelf life is the same as the operating life, and should be several years or more but due to manufacturing variability and quality control it can often be as short as 6 months.

Power degradation occurs during use, but not only from depletion of the gas but also from electrode deterioration. In storage the degradation would be caused by a vacuum leak or more likely permeation of the seals, resulting in the gas mixture being contaminated.

The gases used are typically He (76%), N (14%) and CO2 (10%) and a few other additives to improve tube life and improve lasing. These are stored in the tube at low pressure (vacuum), around 0.02 atm or 14 torr.

Zax.