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Registered Member #96
Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4059
Yes, this is the same problem I had. Interesting idea: what about using a linear device like an LED array? Calibrate elsewhere and then measure it using optical fibre eg TOSLINK cable. Known length of cable should be pretty accurate.
Registered Member #59353
Joined: Sun Apr 17 2016, 02:08PM
Location: France
Posts: 84
the idea of optical fiber is interesting, but for economic reasons, I will be content with vintage analog voltmeter with a simple resistance voltage divider and transmit coaxial cable.
Registered Member #543
Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992
paulj wrote ...
the idea of optical fiber is interesting, but for economic reasons, I will be content with vintage analog voltmeter with a simple resistance voltage divider and transmit coaxial cable.
Take care that you do not have more current going into your voltage divider than into your tube! When your power supply can supply only a few milliamps this can be a serious issue!
In practice, you may find that the current drawn by the voltage divider has the effect of pulling down the voltage available to the anode, so do your Ohms Law calculations carefully before deciding what to do! :)
Registered Member #230
Joined: Tue Feb 21 2006, 08:01PM
Location: Gracefield lower Hutt
Posts: 284
Ho boy I hope you were no where near that uSv/hr is not the correct range to be on uSv/min or uSv /sec would be much better --read quicker to a determination. I see that the output was still going up as you turned it off
Registered Member #96
Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4059
Indeed. Been there, done that. Also low energy X-rays are even more damaging. There is a good reason why the window on some commercial tubes is made from beryllium, it is to block the useless X-rays below 9keV and changing the window eg for tungsten changes the pass energy.
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personnal X Ray machine
