Building the new beam device
Posted: Mon Jun 20, 2011 9:17 pm
Well, the beam device project is coming along, just at the mockup stage now. Still a few more things to do before it sees a vacuum station, but it's coming along. I finished the remote positioner (or I think I did, but tests will tell). Here's what it looks like:
For the moment, I have a piece of Ti sheet I punched out in there. Should be good enough for intial tests, but I of course have fancier things in mind for later. The first test will probably be with a phosphor screen to deal with focus and aiming issues which are expected to be kinda marginal at first -- I'm not an owner of Simion and so on, just going by the seat of the pants here.
This will go into the front hole of the cross depicted here. The top gets a window, the back gets an 8 pin lv feedthrough for diagnostices, and the tubing couplers will accept whatever beam tubes we wind up making (probably a few revs there -- so it's nice not to have to buy gaskets for every test).
This setup should be versatile enough to do a few things and get some learning in. I can put a beam tube into one of the couplers, and if I like, a HV feedthrough into the other one so as to use split supplies for more volts in beam->target mode. Or I can use two beam pipes for beam on beam stuff. The movable target holder can hold whatever target, with whatever holes and has an extra spot to connect to the lv feedthrough for diagnostics -- for example, I can sweep a target with a hole in it across the beam and see both the stuff that doesn't hit the hole and the stuff that gets through on another target behind this on the other coupler.
Assuming the Phillips book is correct, we should be able to see on the order of a million (to ten million) neutrons/second per microamp with such a setup, using DT, or about 1/100 of that (still pretty respectable) with just D. Should be a hot rod. We're bulking up on shielding materials just in case!
Next is modding a gas inlet valve as described elsewhere here...I'll put that in the bottom adapter that goes to the pump station. This not being my first, I'm willing to take it at the right speed and get all the parts pretty close before worrying about getting to vacuum on it, I'll save a few gaskets that way. But it won't be long now anyway.
For the moment, I have a piece of Ti sheet I punched out in there. Should be good enough for intial tests, but I of course have fancier things in mind for later. The first test will probably be with a phosphor screen to deal with focus and aiming issues which are expected to be kinda marginal at first -- I'm not an owner of Simion and so on, just going by the seat of the pants here.
This will go into the front hole of the cross depicted here. The top gets a window, the back gets an 8 pin lv feedthrough for diagnostices, and the tubing couplers will accept whatever beam tubes we wind up making (probably a few revs there -- so it's nice not to have to buy gaskets for every test).
This setup should be versatile enough to do a few things and get some learning in. I can put a beam tube into one of the couplers, and if I like, a HV feedthrough into the other one so as to use split supplies for more volts in beam->target mode. Or I can use two beam pipes for beam on beam stuff. The movable target holder can hold whatever target, with whatever holes and has an extra spot to connect to the lv feedthrough for diagnostics -- for example, I can sweep a target with a hole in it across the beam and see both the stuff that doesn't hit the hole and the stuff that gets through on another target behind this on the other coupler.
Assuming the Phillips book is correct, we should be able to see on the order of a million (to ten million) neutrons/second per microamp with such a setup, using DT, or about 1/100 of that (still pretty respectable) with just D. Should be a hot rod. We're bulking up on shielding materials just in case!
Next is modding a gas inlet valve as described elsewhere here...I'll put that in the bottom adapter that goes to the pump station. This not being my first, I'm willing to take it at the right speed and get all the parts pretty close before worrying about getting to vacuum on it, I'll save a few gaskets that way. But it won't be long now anyway.