Originally posted by Imageman ts not a bulb its a xenon flash tube an altogether different thing, you wont find one down at the hardware store
Not only that, but the xenon tube is triggered by very high voltage - poking around in there with your fingers can be lethal.
If you are handy with a soldering iron, you could *try* to substitute a xenon flash tube from a discarded flash unit. Most of the tubes are interchangeable electrically, but finding the right shape tube to physically fit can be a challenge.
If you attempt this, be absolutely sure to discharge the high votage capacitor that's hiding nearby!