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Registered Member #96
Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4061
heh.. is it just me or are vacuum devices (aka valves) making a 21st century comeback? first it was the vacuum based heat pumps a while back, then nano versions of the CRT (aka SED). what next, a solid state voltage multiplier? (in fact this is relatively simple and has been done, used a setup very much like a photomultiplier tube IIRC but with isolated dynodes, they got something like 100KV from a little device no bigger than a PMT)
Interestingly, the next "big thing" in thermionics is the nanotube display, same sort of idea as a plasma screen but the tubes sit "end on" and emit electrons in a vertical beam at the fluorescent screen. the main feature being the low voltage and current needed (under 1V!) and nearly unlimited lifetime as the main failure mode of conventional CRTs is emission loss due to the degradation of the active material on the heater.
Registered Member #543
Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992
Diamonds are where it's at with radiation detectors just now. A metal diamond sandwich with a bias voltage across it can detect any radiation that can produce electron hole pairs in the diamond, which means any particles with an energy greater than 5.5eV, the diamond' band gap. It seems that the mobile charges drifting in the diamond actually reduce its resistance, which is quite different to the operation of PIN diode detectors.
They are said to be enormously robust, and have been used for measurement in Nuclear Weapons Effects Simulators by Sandia.
I've not heard of any amateur constructors making a diamond detector, and am tempted to give it a go when I feel I have understood it better.
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Thermionic solar cells?
