The mercury arc lamp or burner is the light source for most fluorescence microscopy. In order for these arc lamps to function optimally, they need to be used properly. The following points should be observed for their use:
  1. When an arc lamp is brand new and first fired up, it should be left on for two hours, whether observing specimens or not. This is to allow the arc to establish arcing points on the electrodes to which the arc will always go and keep the arc stable when the lamp is fired in the future.
  2. The lamp should properly aligned to: a) allow for the brightest fluorescence, and b) to make sure that the real and mirror images of the arc are not overlapping which may cause overheating (possible explosion hazard).
  3. The lamp should always be cold when it is turned on. Never turn an arc lamp when it is warm. This causes clouding of the glass in the bulb and both considerably shortens the life of the burner and decreases the burner's brightness. When the glass is clouded, the burner will heat up more and the lamp is more likely to explode.
  4. Once a lamp is turned on, it should be left on for a minimum of twenty minutes (thirty is preferable). This allows it to warm up properly and will help prevent premature wearing out (clouding) of the burner.
  5. Rated life of mercury arc lamps is as follows:



    HBO 50W : 100 hrs

     HBO 100W: 200 hrs

     HBO 200W: 400 hrs

    After a lamp has reached its rated life in hours, it should be inspected for cloudiness. If you have turned a 100W burner on only 10 times for 20 hr periods and otherwise cared for it properly, it may not be cloudy and last for many hours beyond its rated life. It is a good idea to inspect it often during this period, however. Other than firing the burner when warm, turning the lamp on and off repeatedly (many warmups and cooldowns) is probably the worst contributor to shortening the life of burner.

  7. I (Matt Schibler, X59783) can teach you how to replace and/or align your mercury arc lamps if you do not how to do this correctly.

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