Xenon strobe sensitive to ambient light?

[rads]

I have a strobe light which is sold as a safety device for attaching to a diving suit to attract attention whilst lost and adrift.
I think the actual flashing bit is a xenon discharge tube (out of my depth here).
When I test the strobe in ambient light it works normally. flash rate once every 3 seconds or so.
If I turn out all the room lights the flash rate dramatically reduces (approx. once per 30 seconds) and becomes erratic.
I can see no sign of a light sensor, and I can't believe it is design intent to stop the thing working in the dark, when it could be argued it is most needed.
Any electronics reason why ambient light should effect the function?

 

[tiki]

Hi rads,
sometimes some manufacturers use plastic encapsulating material for their components, which seem to be opaque, because they are black. But IR may be let through, see packagings of consumer IR-transmitters/receivers.
First, try to wrap a thick cloth around the electronics (not the tube itself), if you see the same effect...
Second, there is a effect of light induced ionization, which can have effects on the flashing sequence itself, if the tube is fired "over the top". But this effect is normally negligible, especially in Xenon tubes. Otherwise, the flashing lights should be controlled independent of slight variations the tube characteristics.
tiki

 

[nbucska]

It is possible that the ambient light generates some curent via photoelectric emission and it may reduce the voltage the tube fires at. Try to filter out the UV with regular glass to verify it. <nbucska@pcperipherals.com>

 

[busbar]

Good xenon-flash (and others) site:

http://misty.com/people/don/index.html

 

[Jayell59]

Apart from something interfering with the electronics, eg condensation reducing the trigger voltage level I suspect the manufacturer of the flash tube has not done his job properly and the tube has indeed got to depend on photo electric effects for normal operation.It could be that the manufacturer has never tested the tube in the dark or is perhaps ignorant of the cause!
Gas tubes mostly have some small radioactive component within to insure consistent firing by maintaining a residual small degree of ionisation within the tube.
A thorium composition in the electrode structure would help.I believe some manufacturers have added tritium gas to the Xenon to overcome this particular problem as well.Fitting a substitute tube from another manufacturer will surely remedy the problem.
John Lundy lumalite@alphalink.com.au
Australia

 

[IRstuff]

This a very ancient thread, but seems to me, there is a sound design rationale for reducing the flash rate in the dark. That's to minimize the impact to your eyes' dark accommodation.

In high ambient, a high flash rate does not affect your vision, while in the dark, a high flash rate will kill your dark vision PDQ. TTFN