From CRT to Electron Gun

6 10 2011

This post is dedicated to Steve Jobs. Hero, and inspiration to all.

All photos.

I bought a second CRT; broke the vacuum by drilling an unused pin; scored it and smashed it!

Now we have an electron gun:

I installed it in the chamber and wired it up:

Here you can see down the beam line to the hot cathode.

I taped a piece of broken phosphor screen on the viewport so I can see the electron beam:

But something is not working, no beam.

Time to troubleshoot.

Advertisements

Actions

Information

11 responses

6 10 2011
kcdodd

Look up oxide-coated hot cathodes, which are sensitive to being exposed to air.

6 10 2011
Mark Suppes

The cathode was not heated in air.Although it was exposed to air at room temp.

6 10 2011
yonemoto

Taped to the inside or the outside? You sure those electrons are getting through the viewport?

6 10 2011
Mark Suppes

It’s attached so the electrons would directly hit the phosphor powder.

6 10 2011
yonemoto

is the phosphor powder oxygen senstive? This guy uses fluroescent lamp powder:

http://www.sparkbangbuzz.com/crt/crt6.htm

6 10 2011
yonemoto

oh nm, it’s obvious from the pics.

6 10 2011
Steve

You need a positive connection to the phosphor, It has a conductive coating, otherwise the coating / conductor charges negatively and repels the incoming electrons. Perhaps copper tape would make the best connection.
Steve.

7 10 2011
tomschuring

i always thought the front of the screen ‘pulled’ the electrons to it via a grid once the were focussed by the electron gun.

on the inside of the screen there should be a conductive grid, and the holes in the grid is what you see on a tv screen as ‘pixels’
not 100% sure though

7 10 2011
MikeH

I was curious about this problem so i did some websurfing. While I didn’t find an answer your quandary, I did find an interesting website, which I am passing along in case you didn’t know about them. No idea of the $ involved in having a electron gun made for your application, but maybe an engineer at the firm would be willing to help you troubleshoot your improvised solution.

http://www.kimballphysics.com/electron-gun-systems/technology/product-overview

13 10 2011
Remy Dyer

Hmm. What vacuum are you getting?

I’m not sure about the exposed insulation and heat shrink – might they outgas enough to add a virtual leak?

5 12 2011
Just Look at this Print « Prometheus Fusion Perfection

[…] I tesed out the electron gun and I didn’t see a beam on the phosphor. I wanted to rule out the possibility that there WAS […]

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s




%d bloggers like this: