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ArcticMyst Security by Avery

DIY Radiography






Joined
Dec 11, 2011
Messages
4,364
Points
83
I suggested road kill a few weeks ago. Organic material might be interesting nudge nudge
:can: :can:

I've had my eye out, but up here in the frozen wastelands there's nary a hint of wildlife right now, living or dead.

I don't remember if I wrote about it here or on 4HV (looks like just 4HV) but I'm working on upgrading the HVDC supply too. I did some initial experimentation with a tertiary isolated wehnelt bias supply and it was favorable, albeit underwhelming in terms of image benefits. X-ray flux was increased by at least 50% though. I then started working on passive means of providing the wehnelt bias instead of the clunky switchmode supply, as the enhanced output wasn't worth the effort. Initial tests with bias resistance weren't very favorable, as it vaporized my resistors, hehe. I am looking to try zener based biasing and I also have some high power ceramic resistors, both of which came in the mail today. I'll report back on how it goes when I can do the modifications.

It's worthy of note that originally Voltage Regulator Glow-Tubes were used for this purpose, and while they aren't very expensive today, they are large, fragile, and have poor current requirements and even poorer voltage selection compared to their modern equivalent; zener diodes. I was most surely tempted to grab some VR tubes and give that a go though. The major dissuading factor was the minimum current requirement for appropriate voltage tubes being to high by at least a factor of 2, and if I wanted to series up lower voltage tubes which had the right current reqs I'd need a ton of space!
 




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