Science/Engineering/Technical forums

Things are going on slowly
Magnet has been flipped and put on its new stand.
Acceleration tube still to go on top with terminal above.
more pics when this happens

Must have been fun doing that turn -- last pic I saw, all the lifting hooks were on what is now a side....good show you still have all your fingers and an un-dinged magnet!

Progress is painfully slow --a bit like elephants mating --all done at a high level with lots of ranting and groaning, and takes two years to get a result.




The white bit in the middle is the 50kV break we are working on the 200kV break. The three Al disks are the terminal shelves for the electronics and alternator. All of this to be able to run 200kV away from earth.

Of course a bit of plastic and wire mesh is needed to keep the braindead safe
The parrot cage goes over the top of the terminal

Ahh, so your outfit has "meeting-itis" like most? Sad, but the norm. Still, I'd love to be able to play with stuff on that scale, I might even be willing to put up with that for the chance.

I once had a customer, CEO of a well-run private firm (he just owned it flat out) who said anyone running a meeting should wear a gun and put their hand on it once in awhile.
So one time, I actually did that. Boy that meeting got to resolution quick!

I take it it's just the stuff at the top that needs to be a couple hundred kv off ground?
Last time I played with a mere 125k I had way too much interesting "fun" so I don't think it's just the brain dead who might want that screen there.

Okay there's progress
Today we tested all the electronics while waiting for the accel tube insulators to arrive.
We put in a PETP homemade break thats good to 30kV to test the terminal electronics under arc over conditions ( you know the usual conditioning of the ionsource and einzel assembly).
I did load the gas bottle with CO gas yesterday but for this test we are using air so an N2 beam was dialed up on target
The terminal needs a tidy up ie shortening cables and tying them up but all is working there are 10 uP's up there controlling the HVarc supply V+I, the solenoid magnet supply with read back of current, the leak valve motor, the neg 5kV Einzel supply that is referenced to terminal. all of this via fibre optic cables from the control rack to the terminal

Pic shows Andreas fine tuning the beam on target


This pic of charge integrator showing 19uA of N2 on target

A thing of beauty to a certain sort of eye (mine, for example). I take it you're using the nifty spark plug fed deflection plates to fine-aim post-acceleration?

I always wonder why the bulk of acceleration isn't done post ion selection/steering (magnet), as was pioneered in CRT's a long while back with post deflection acceleration, but that's me, and in this case I doubt power efficiency is that big a deal for you. It would be for me. Space charge limits? At 19uA they wouldn't seem too severe?

Of course, all that makes things more complex, maybe not justified when you're just trying to get something to work at all.

Beautiful upgrade John...

I only hope I see my portion of my aunt's trust soon so can I can turn one of our bedrooms into a lab.

Right now I have literally no place to work except a tiny little fold-out table. That just won't do.

Congrats on a great job, Bill Washburn

Doug
yes the sparkplugs are on the steerers and quadropoles. first you steer the beam to get it dead centre of the quadropole then you use the quads to focus the beam downto 1mm dia or less on target. the beam is then raster scanned onto the target Dejour.
we have used post deflection accelerarion but you still need pre deflection acceleration to get enough energy to be able to mass select to sure that for instance you are inplanting U235 not U238 or B10 not B11.
the ion beam form the ion source is around 2-3mA but slits, apertures etc cut down the number of ions. suits us as a copper beam of 3+ at 50kV acceleration would give 450 watts /sq/cm if the full 3mA hit the target ie meltdown of the target.

OK, I get it now. Cool! I was thinking more of selecting between easier things -- like D+ vs D2+ for example (2::1 c/m ratio), where those limits aren't so difficult as real isotope separation. Comes from thinking more about my own problems here than yours, I guess, oops! And yup, at mA currents and those voltages, there's going to be a bit of target melting going on unless "heroic" measures are taken indeed, and maybe even then. I'd guess using an implant beam as an annealing heater is not very smart?

In fact, that cooling problem is probably the driver for an "inside out" fusor design I've seen as a neutron generator. Not really a fusor, but a beam on target device. Cylindrical ion source in the center of a big pipe, and the pipe is the target, all spread out for low watts/sq cm -- and all the heat shows up conveniently outside the thing through the thin pipe walls for easy cooling. I've thought of making one to play with activations as a side project, since we now have those cheap ebay turbos and I have a handy cave to put it in. But I'll walk first, then run -- MarkB has made me some nice quartz beamline parts for a more conventional borehole type design I'll use to learn a bit more first.

Again painfully slow but the Acelleration column went in today and is under vacuum