First light on second, smaller, setup

[Doug Coulter]

Nothing super special, but I just got to "let's light up some deuterium" on the new smaller setup. There's a lot more to do. The HV power is a NST right now, and this modern one thinks any significant current draw means it should shut down for my safety....
The new magnetic ion source works better than expected and is very controllable, just lashed up in there with a clip to a feedthrough for power (you can see the clip in the video).
No data acq yet, the main thing new and special is a better camera, mic and mount. Just making sure this works at all, and a little testing on the ion source being able to control the main grid current.
The video was shot with a lot more gas than is actually needed - this (according to the meters) works well below the point where there's no glow outside the ion source, but the main grid current is going up and down with the ion source drive, so I'm going to call this a conditional success on the path to where I want to go - measuring the ability to trap ions and then drive them into forced recirculation and collisons while avoiding the tank walls and most scattering.

https://youtu.be/uDCIlhR6mps

[Doug Coulter]

It seems I'm doing more building than storytelling so far on this one...but I'm catching up.
Some progress on the build here.

current state

The big HV supply is wired and mildly tested. That thing is a monster and I'm treating it a little gingerly.
On the right of the tank is the stand to mount a camera looking right down the middle - the camera isn't on there as I used it to take the picture. The mirror lets me look when the camera isn't there
to show me it's little video preview.

Some re arranging in progress to get this all to fit, and to make things adjustable without putting my arm into the HV...
A nice LV power supply with a stereo audio amplifier to use for geiger and neutron counters is sitting on the bench, but will be put in that rack along with another
3u panel that will hold a raspi-4 (on the way here).
I've been writing the code for that pi and for the couple of LG8T (nano clone, but faster) boards that will feed the pi with data to put in the DB and to plot.
There will be a lot more words on that - I've made some interesting and worthwhile changes to the basic fusor data aq and control design.
Hopefully I can get the data aq for the more-complex ion trap parameters, which now also include AC frequency and amplitude (and will add waveform at some point).
But there are endless details yet - for example tapping into the pressure gage with it's crazy nonlinear output, and wiring up the gas outlet solenoid for remote control (I had it already as
front panel buttons and switches long ago, but...)

Things take a little longer when I have to block out time for this to accommodate the delay of heating that building first, and then getting some work done there so it's not wasted.

[Doug Coulter]

I don't normally like to take things apart and do major work on them - which invokes outgassing and leak hunting most often, but this basic setup has to be some approximation of right to get the data I want. To just see if it works, laying the ion source on the tank floor is fine, with a clip lead for power, but for real work...it needs to look more like this. It's now screwed to the Al backplate we made awhile ago that O ring seals to a somewhat dinged CF flange...that was interesting, working with those 4-40 steel screws (put through threade 10-32 holes, because they were there) in the presence of that super loud magnet - I wound up making a plastic phillips screwdriver to hold them down till I could screw them in as the magnet would yank them out of the holes...but it's done now, with a more-real power connection, just a slipover bit of ceramic. You can see where the grid is going to screw on. This will probably want more like a 2" OD grid if my guess at the desired geometry is right, we'll see. If that's the only thing that needs to change (or, well, that and the Faraday probe placements) I can do that through the window.
So it looks like this on the sloppy machine shop bench.

From one angle

from the other side