So we can see a perspective from above, as well as end-on, a luxury most don't have. Here's what that looks like. (click the pic)
- View from above of a cylinder grid
For what it's worth, I expected more like sheet beams, but the real thing has some emergent behaviour that resists that sort of oversimplification. We even tried warping the rods closer and further apart to force that -- no good. And it works best with straight, evenly spaced grid rods.
So as a partial investigation of what was going on, we built a pinhole charged particle/X ray camera using a few mg of ZnS:Ag from Eljen to make the screen, a 2" copper pipe for the camera body, and a .030" hole in a lead piece soldered on the end for the pinhole. It's on a wobble stick so we can move it around. There seem to be two images overlaid, one from X rays and one from charged particles, and various parts of the pic get brighter or dimmer from different points of vew of the camera -- some of what it sees is beaming, not like light reflected from a simple object.
And in the case of charged particle beams, unlike photons, they don't go straight -- the fields in the tank (created by the electrodes and the particles themselves) bend them.
- Pinhole camera, end on view
At some point I plan to put an electromagnet on this camera so I can see the charged particle image shift from the X ray one. As well as separate based on polarity and energy/mass.
The orange glow you see is alumina insulation for the extractor electrode bias lead for the ion source.
The circles you see above the ion source on the left are artifacts from the 3 pieces of glass (one thick lead glass) the picture was taken though. The alternative is bad pixels from X rays hitting the camera CCD (and me!), so I live with that.
Just to make things more interesting (or is that incomprehensible?) here's another pic with the cylinder grid a little differently positioned along its axis.
- Rays with different grid position, still from center of grid, but....
Sorry about the noise in this picture -- was learning how to use this camera in low light at the time.
- Spiral cylinder grid attempt
Here is an attempt at a spiral wound grid. Not very good at all -- it's too big, doesn't form the recyling rays and you can see all the trash hitting the glass viewport.
This really belongs in a forum I'll create soon -- "it almost worked" which should be very educational as a failed but good try is often better for learning than having it
all just fall into your lap. It's been a popular category in some other web efforts of mine.
