On a sunny day (Tue, 7 Aug 2018 19:29:36 -0500) it happened "Tim Williams"
<tiwill@seventransistorlabs.com> wrote in <pkddhd$l90$1@dont-email.me>:
><jurb6006@gmail.com> wrote in message
>news:ac36082f-19fa-46fa-8a17-5fb90a83a93b@googlegroups.com...
>> >"and I then proposed to heat the cathode with hot plutonium. "
>>
>> Then it would need lead shielding. Too much work.
>
>Hardly: plutonium is primarily an alpha emitter. Also, he probably meant
>Pu238, the stuff NASA uses in RTGs (or they did, back when there was
>available production of the stuff), which is short enough lived to be useful
>this way, and definitely all about the alphas. (If any other Pu were used,
>it would have to be neutron based -- fission powered -- and in that case,
>yes, it would be a steaming mess of radiation.)
>
>The solution is foiled by a different mechanism. All those alphas have to
>go somewhere, and a hot cathode guarantees thermal diffusion into the vacuum
>is the primary route. You might get an unreliable gas rectifier or
>thyratron, but not a usable vacuum triode or the like. :-/
>
>Tim
Use an indirectly heated cathode.
Reply by ●August 7, 20182018-08-07
>"All those alphas have to
go somewhere, and a hot cathode guarantees thermal diffusion into the vacuum
is the primary route."
Yeah, and thinking abut it, acetylene would throw a bunch of CO2 in there unless it was some sort of heat exchanger. Maybe a tubular type such as used in modern furnaces.
Probably easier to just use a LASER.
Actually tubing could be filled with pumped coolant and a simple current passed to radiate the heat. Works at the Tokamak.
Reply by ●August 7, 20182018-08-07
On Wednesday, 8 August 2018 01:29:37 UTC+1, Tim Williams wrote:
> <jurb6006@gmail.com> wrote in message
> news:ac36082f-19fa-46fa-8a17-5fb90a83a93b@googlegroups.com...
> > >"and I then proposed to heat the cathode with hot plutonium. "
> >
> > Then it would need lead shielding. Too much work.
>
> Hardly: plutonium is primarily an alpha emitter. Also, he probably meant
> Pu238, the stuff NASA uses in RTGs (or they did, back when there was
> available production of the stuff), which is short enough lived to be useful
> this way, and definitely all about the alphas. (If any other Pu were used,
> it would have to be neutron based -- fission powered -- and in that case,
> yes, it would be a steaming mess of radiation.)
>
> The solution is foiled by a different mechanism. All those alphas have to
> go somewhere, and a hot cathode guarantees thermal diffusion into the vacuum
> is the primary route. You might get an unreliable gas rectifier or
> thyratron, but not a usable vacuum triode or the like. :-/
>
> Tim
If you're chucking out a megawatt you can afford to include a vacuum pump in he amp.
NT
Reply by Tim Williams●August 7, 20182018-08-07
"Bert Hickman" <bert-hickman@comcast.net> wrote in message
news:JNGdnVGkQLezT_TGnZ2dnUU7-cvNnZ2d@giganews.com...
I've always wondered what the plate curves of those things look like. They
make extraordinary claims. I don't see how they're going to get a low
voltage drop for switching operations.
As we still don't have cold-cathode 300Bs in TO-247 packages, I have other
doubts about such technology; but, given that these are very much in the
domain of military secrets and "munitions", I can see there might be reason
for that. (Speaking of EMP protection, you could just as well wire one as a
blocking oscillator and generate an offensive quantity of ESD, intense
enough to be called EMP as such.)
Tim
--
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Design
Website: https://www.seventransistorlabs.com/
Reply by Tim Williams●August 7, 20182018-08-07
<jurb6006@gmail.com> wrote in message
news:ac36082f-19fa-46fa-8a17-5fb90a83a93b@googlegroups.com...
> >"and I then proposed to heat the cathode with hot plutonium. "
>
> Then it would need lead shielding. Too much work.
Hardly: plutonium is primarily an alpha emitter. Also, he probably meant
Pu238, the stuff NASA uses in RTGs (or they did, back when there was
available production of the stuff), which is short enough lived to be useful
this way, and definitely all about the alphas. (If any other Pu were used,
it would have to be neutron based -- fission powered -- and in that case,
yes, it would be a steaming mess of radiation.)
The solution is foiled by a different mechanism. All those alphas have to
go somewhere, and a hot cathode guarantees thermal diffusion into the vacuum
is the primary route. You might get an unreliable gas rectifier or
thyratron, but not a usable vacuum triode or the like. :-/
Tim
--
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Design
Website: https://www.seventransistorlabs.com/
Reply by ●August 7, 20182018-08-07
>"and I then proposed to heat the cathode with hot plutonium. "
Then it would need lead shielding. Too much work.
Reply by Cursitor Doom●August 7, 20182018-08-07
On Tue, 07 Aug 2018 17:14:16 +0000, Jan Panteltje wrote:
> Anyways same idea as you now come with was brought forward,
> and I then proposed to heat the cathode with hot plutonium.
Well, I should imagine a scheme like that would introduce an unacceptable
amount of noise. ;-)
Nice to see you back, Jan!
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Reply by Jan Panteltje●August 7, 20182018-08-07
jurb6006 wrote
>In the words of the late Steve Brown "Let's stop fistfucking around here and do it".
>
>So make your own tube. I was thinking for the plate - a cement mixer. Chain link fence for a grid. Not sure about the cathode,
>whether to heat it with a LASER or acetylene.
>
>Then you need to go to the nastiest bar in town and find some "boosters" who are people who will "obtain" things for you. Tell
>them to get you some of the transformers off the poles.
>
>Then you take your pee wee 5,000 watt per channel amp and a transformer to drive the grids of the REAL output stage.
>
>And don't worry about the missing transformer off the pole, make this thing run off 16 Kv directly. (or whatever voltage it is)
Long ago, in this group, same question was asked,
maybe by same OP?
Anyways same idea as you now come with was brought forward,
and I then proposed to heat the cathode with hot plutonium.
Maybe google still has it, otherwise I could search my own database for it.
OP is just a troll.