Tim and Richard are still going strong on the ion gun front.
Posted their design and progress. Looks pretty cool. I can’t
wait to see the result.
Yesterday I got the 40 kV wire, the LabJack and the ceramic high voltage
stand offs. SmallParts back
ordered the ceramic balls – figures. So I spent the day trying to decipher
and learn LabVIEW… Man, what a frickin’ complicated program. But
I’m coming along okay. It takes some getting used to, being dataflow and
graphical. Normally I despise graphical programming languages, but it
really makes sense with LabVIEW. We’ll see.
Not much else going on. Tomorrow is the peace march in SF – today was
Chinese new year, and they bowed out in favor of the traditional celebration.
Millions of people marched all over the world today, though. Sorry to
bring politics in here, but it’s something important… So tomorrow is
basically hosed. Brent is coming over tomorrow night or Monday, so we’ll
mess around in the lab a bit. I got some 15 kV 1 G ohm resistors, so we’ll
crank up the power supplies and do a load test. Have been thinking quite a
bit about the gas subsystem. Need to think much more.
Well, I got a copy of LabVIEW today. No, I didn’t pay 2G’s for it, I
got it from an Angel. Thanks, BTW. Ye gods, yet another complicated
and horribly useful program to figure out. But it’ll be worth it.
Fusor forum is still running hot. Seems to be a lot of people getting
into building these beasts. Kerry Bonin has a new
site that I just found. Looks
like they’re going to be having a lot of fun soon. Must be nice working in
a group <heh>. Looks like there’s at least three people involved and
all of them smart.
this amateur lab. This is a picture of Richard Hull and Tim Raney in a
planning session for development of an ion gun. <heh> Very cool.
Another amazing thing about the web – i.e. community. Phil and now Richard
and Tim doing serious research on amateur ion gun development. Again, very
Me? Well, I’m still straggling along. Tonight I’m going to
construct a new cage out of the stainless steel pieces I got a while back.
The problem with the mild steel cage I currently have – besides having to keep
it in a desiccated environment so it won’t rust – is the question of a magnetic
circuit. The mild steel cage forms an incredibly complicated magnetic
circuit, which means I don’t stand a snow ball’s chance in analyzing this short
of using Deep Blue – not anything remotely possible. Secondly, the
magnetic permeability significantly changes the magnetic fields which extend
outside the cage which are used to bottle up the electrons. The second
follows from the first, but it’s significant in that the field flux lines are
concentrated in the mild steel, not distributed where I want them. D’oh!
But I’m still going to use this cage for my first experiments. I want
to see if I can use this cage as a normal, glow discharge fusor, just to see
what it can do. It’ll be neat to see if I can produce neutrons from it.
Should be able to, with no problems. We’ll see.
Ordered the high voltage cable for the Bertan power supply. Geesh.
What a frickin’ monster. One inch thick, 60 kV cable. Very cool,
though. It’ll be here "sometime". Couldn’t get a hard date out of
Del, but who knows. I’ve got more than enough to do in the mean time.
So… Off to work after a glass of wine…
finally got all the gaskets and bolt fittings. Well, mostly. But I
did the first vacuum test tonight after getting home from work. To the
left is the chamber now complete – well, sans any electron or ion gun. The
red plastic is covering up the view ports so I don’t scratch them. Just
click on the picture for a larger view.
If you look at the larger picture, you can tell that there are three bolts on
the main 14.5" flange missing above the electrical feed through on the bottom
hemisphere. Directly opposite, where the cold cathode ion gauge is
attached, another three bolts are missing. I can’t get the bolts in, due
to the flange configuration – something that I thought would happen. I’ll
have to see if I can get some double threaded bolts so I can get these puppies
bolted down firmly.
any event, the vacuum test went well. I got the chamber down to 2×10-6
torr. There were a few fits and starts as I tightened the zillion seals on
the chamber, but after everything tightened up it dropped like a stone. I
turned off the turbo and the pressure held for about 15 minutes before I had to
close down the shop for the night. The fore line pressure on the
roughing pump held at 1 millitorr. Very cool. I think this will do
Now the real work will start – building ion guns, setting up the high voltage
and gas lines and…
have the semblance of the beast. Ye gods. My fingers are numb from
screwing in a thousand (or so) 12 point screws. Not to mention removing
the vacuum tight seals from all the flanges and such. I can barely type
because my fingers have no feeling. Oh well, it was worth it. The
picture on the left is the beast as it
looks mostly assembled. Click on the picture for a larger view.
When it rains, it pours. To top off all the other shit that happened
since 9/11 the space shuttle disintegrated during the
landing descent yesterday. This tragedy underscores the tremendous
risk Astronauts take while they are doing their job. It reminds us about
what exploration actually is – pushing the engineering envelope beyond our
current industrial understanding. And the dangers involved. My heart
goes out to the people who loved them. My salute and deepest respect to
those with the tremendous courage it takes to ride the fire into the future.
You are all truly brave souls to which we owe our future.
Well, Phil has got the ion gun design
working on his fusor. <heh> Very cool. Runs with less
power, more easily controlled and still has higher neutron counts. Gotta
love this stuff, eh?
I did some DWF renderings of the clone of the multipactor ion gun
patent and posted them on the
fusor.net forum. Phil mentioned he was
looking at a multipactor design, and this was likely the patent. Hopefully
it’ll be of help.
Got SIMION 7.0 today. Not a bad program at all. The demo is
incomprehensible to someone like me, so I was glad to see the real version
actually worked like I thought it would – I kept banging my head against
whatever they did to cripple the freely downloadable version. The manual
is a satisfyingly thick, 1.25" of 8.5 x 11 paper entity, chock full o’ detail
about using the program. This thing is an order of magnitude less in price
than something of comparable utility to the Field Precision offerings.
They also have terrific student discounts, so rock on.
We’ll see how long it takes me to start modeling even simple things. It
would be most excellent to have an analytical model of the chamber so I can play
mind games with myself. <heh> Delusions of adequacy, I know.
Every one of these analytical/visualization tools are non-trivial to use because
it’s a non-trivial system. But I should be able to get a simple grid
modeled with a single ion. Dave Cooper has promised to upload a SIMION
Model which does just that, so that’ll be cool to see. So at least the
diligent and talented can reproduce this We’ll see how well I make out.
Well, the fusor.net forum is really
heating up (remember, I’m a geek, so scale "heating up" accordingly). Phil
Fostini started off the
discussion by making a wonderfully generous offer of an ion gun to those
that helped him design them from the parts he was making available.
Garrett Young and Phil are busily designing their first version. I think
the entire process is pretty cool. A while ago Garrett was pushing for a
more distributed fusor equivalent to ITER – amateurs colluding with each other
to share knowledge and resources in this amateur research. So far, people
seem to be responding. <heh>
From what I can tell, though, the first version will likely work. The
design, however will need some focusing electrodes I think. I did some
quick sketches in CPO-3D and it’s clear that of the ions created, most will hit
the BeO insulator – assuming a point ion source with momentum directed in a cone
towards the accelerating electrode. I’m not sure, but the accelerating
electrode may quickly become a decelerating electrode. I’m also thinking that the electric
field from the fusor cathode may not have much effect through the BeO
insulator with a small hole down the center. I’ve been trying to model
this with CPO-3D, but I haven’t had much time to do so. I’ll try some more
It could well be that the BeO insulator will block the decelerating effect of
the accelerating electrode (i.e. once past the electrode, the ions will be
re-attracted back towards the now decelerating electrode). So the scheme
might actually work. I do think that unless focused in some way, it’ll be
hard to get more than a small percentage of the generated ions to go down the
hole in the BeO insulator. But even if they only get 10% of the ions, it
will still be very cool.
And lord knows the second version of the ion gun will be far, far better.
<heh> I just love this stuff.
Well, I’m feeling much better about things. Usually a warning sign to
small furry animals who might be innocently underfoot. Garret Young asked
a while ago on the fusor BBS "where’s the science". This got me worrying
more about things that I had already worried about a lot. Science is
asking questions, forming theories, making predictions, constructing and
performing experiments, gathering data, analyzing the results and comparing
results with predictions.
I posted an article a while ago on the news group
sci.physics.fusion regarding ion acoustic standing waves in a spherically
contained plasma. Basically, I wanted to find out what research had been
done in this area. It’s been sitting there for several days without a
reply. So I posted a more detailed message in
sci.physics.plasma, hoping that perhaps that was a more appropriate
newsgroup. The posting hasn’t showed up yet. There might be some
problem with the moderator’s email, as nothing has shown up since Dec 24th.
Oh well. What’s strange about the lack of reply to my sci.physics.fusion
posting is just that. Usually when someone posts something really stupid
on these forums, someone is always ready to point out the idiocy – sometimes
nicely, most of the time with a rather sharp pointy stick. But nothing.
Strange. Hopefully my posting to the plasma newsgroup will produce some
response and some pointers. I’ve been spending a lot of time trying to
find out all I can about analyzing and modeling these types of standing waves,
but to no avail. It’s very strange.