Neon signs last a long times – years – how about HeNe laser tubes?
The operating lifetime of a typical HeNe laser tube is greater than 15,000 hours when used within its specified ratings (operating current, proper polarity, and not continuously restarting). Under these conditions, end-of-life occurs when the oxide “pickling” layer of the cathode can gets depleted. Larger diameter (1.5 or 2 inch) tubes last the longest – up to 50,000 hours or more. Small diameter (0.75 or 1 inch) tubes have the shortest lifetime – 10,000 hours or so. Since even 10,000 hours is still very long – over 1 year of continuous operation – HeNe laser lifetime is not a major consideration for most hobbyist applications. Chances are that even a surplus laser will still have thousands of hours of life remaining. However, the shelf life of the tube depends on types of sealing method used in the attachment of the optics.
