Re: Tek 7000 Series deflection plate precision?


Don Black <donald_black@...>
 

Maybe an image orthicon rather than a vidicon? They have an electron multiplier as part of the tube. I think you might find one to try but I hope there aren't too many IOs destroyed for the project.

Don Black.

On 21-May-13 12:13 AM, cleyson@... wrote:
 

I think one of the biggest problems you're going to have is
focusing the beam down small enogh to make it usable. If you're
going to use a CRT electron gun you would be better off using
magnetic focus and possibly deflection.

It might be worth trying an old one inch diameter Vidicon
camera tube if you can find one. Better still try to get
hold of a complete camera, that way you get the deflection
coil drive electronics as well. In addition, it might be easier
taking the faceplate of the front of a camera tube rather than
taking a gun assembly out of a CRT.

BTW it was Brad's idea of a custom design CRT that made me
think of the Vidicon.

Chris

--- In TekScopes@..., "cheater00 ." wrote:
>
> Brad,
> you need a way to put a photomultiplier in there somewhere. Won't do a
> lot of good otherwise.
>
> Have a look at Ben Krasnow's links, he has a very down to earth
> explanation of what's what.
>
> At his BOM, which is around the $1000 mark, a school can already
> afford one of those if it is so inclined.
>
> Cheers,
> D.
>
> On Mon, May 20, 2013 at 3:14 PM, Brad Thompson wrote:
> > On 5/20/2013 8:32 AM, cheater00 . wrote:
> >> Hi guys,
> >> could someone chime in on how precise the deflection in a Tek 7000 can be?
> >>
> >> I'm very new to vacuum tubes and the idea of electrostatic deflection,
> >> so please bear with any stupid questions...
> >>
> >> My main consideration is: with modifications, would it be suitable to
> >> jury rig an SEM (Scanning Electron Microscope)?
> >>
> >> I am trying to do something inspired by Ben Krasnow's SEM design. If
> >> you don't know it, he has some info here on how he made an SEM
> >> himself:
> >>
> >> http://benkrasnow.blogspot.de/2011/03/diy-scanning-electron-microscope.html
> >> http://benkrasnow.blogspot.de/2011/03/diy-scanning-electron-microscope_26.html
> >
> >
> >
> > Hello--
> >
> > A concept that I've kicked around for a while comprises a scanning
> > electron microscope that would be inexpensive enough to offer
> > high-school science departments. Please understand that I'm
> > not familiar with electron microscope technology and the
> > concept may be technically impractical, financially unsupportable
> > or otherwise hopelessly flawed.
> >
> > Imagine a custom-designed "cathode ray" tube that has a fixed
> > target located in place of the phosphor screen. Make the target
> > "interesting"-- e.g., a well-used coin with a small smear of
> > bacteria on the surface (metallized). The tube would include an
> > oscilloscope-tube-like electron gun and electrostatic-deflection
> > plates and a collection means for electrons deflected by the
> > target.
> >
> > Use an oscilloscope or dedicated interface box to provide
> > controllable beam deflection, amplification of the scattered
> > electrons, and display of the recovered image. Further signal
> > processing by a PC might be needed.
> >
> > My hunch is that the specialized specimen-containing tubes could be
> > mass produced at relatively low cost, since the target is not
> > replaceable and thus eliminates the need for vacuum apparatus.
> >
> > In the lab, students could explore the coin's surface and study
> > the effects of varying deflection voltages, etc.
> >
> > Comments welcomed.
> >
> > 73--
> >
> > Brad AA1IP
> >
> >
> >
> >
> > ------------------------------------
> >
> > Yahoo! Groups Links
> >
> >
> >
>


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