[ARC5] DARPA announces new program to improve vacuum tube performance----really!

[Tim]

Hi Bruce - One of the main codes was "EBQ" used to model electron flow in a
vacuum. (Electron Beam Charge)  We used it extensively to model electron
flow in imaging tubes, microchannel plate image intensifiers, streak tubes
etc.  We did a lot of work to try FEA's (Field Emission Arrays) as low
voltage area photocathodes in those applications as well.  fun stuff....
Tim
N6CC

On Tue, Aug 11, 2015 at 4:08 PM, Bruce Long via ARC5 <arc5 at mailman.qth.net>
wrote:

> Back in the mid 1980's IIRC the military made available a very large pot
> of cash to do two things, to write software to do the electron ballistics
> needed to design high performance vacuum tubes such as traveling wave tubes
> magnetrons and gyrotrons, and to financially support college professors and
> grad students to turn out new generation of tube designers.
> From what i can tell this has worked out well.  Since that was a
> generation ago, this seems to me to be an effort to bring forth the next
> generation of devices and designers.
> Similarly many years ago I heard of work modernizing vacuum device design
> using semiconductor fabrication techniques.  For example use silicon
> anisotropic etching to create a bed of nails, field emission electron
> emitter to replace the filament thereby enabling high performance
> vacuum-electron devices using more or less conventional semiconductor and
> nano-fabrication techniques.
> Because the electron emitter-grid-plate spacing can be made very small and
> very uniform these hypothetical devices would work with transistor type
> operating voltages but- in the specific case I remember- much better RF
> linearity and overload performance.
> So i have no idea wheeze all of this is going to go but I like the idea
> that people are still thinking about designing and making useful devices
> that employ electrons flowing in a vacuum
> bruce
>
>       From: J Mcvey <ac2eu at yahoo.com>
>  To: Bruce Long <coolbrucelong at yahoo.com>; Ian Wilson <
> ianmwilson73 at gmail.com>; Peter Eijlander (PA0PJE) <pa0pje at xs4all.nl>
> Cc: "Arc5 at mailman.qth.net" <Arc5 at mailman.qth.net>
>  Sent: Tuesday, August 11, 2015 6:46 PM
>  Subject: Re: [ARC5] DARPA announces new program to improve vacuum tube
> performance----really!
>
> You can't make this stuff up!
>
>
>
>      On Tuesday, August 11, 2015 6:29 PM, Bruce Long via ARC5 <
> arc5 at mailman.qth.net> wrote:
>
>
>  OK somewhat off topic and you are never going to use one of these new
> tubes in a receiver project but still - I think- of interest:
> DARPA wants to transform vacuum electronics for superior communications,
> data transmissions
> |   |
> |   |  |   |   |   |   |   |
> | DARPA wants to transform vacuum electronics for superio...The notion of
> vacuum electronics may sound ancient in high-tech terms but a new program
> from the scientists at the Defense Advanced Research Projects Agency
> aims... |
> |  |
> | View on www.networkworld... | Preview by Yahoo |
> |  |
> |   |
>
>
>
> The tube shall rise again.
> bruce  KJ3Z
>
>
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