Fusor V Chamber

[Richard Hull]

UPDATE - I am now in possession of the chamber seen in the images of the original posting in this thread. It will be on static display at HEAS 2010. It's a real beauty!

The specs are as follows.

Ports

11- 2.75" conflat ports
3 - 4.5" conflat ports
1 - 6" conflat port
2 - 8" conflat ports
2 - 10" conflat ports
1 - 16.25" sealed off base conflat port

Attached and fitted goodies that road along with the chamber for free as delivered. All of these are new and unused.

2 - 4.5" conflat quartz view ports
1 - nude ion gauge - in new condition
1 - 531 TC gauge tube
1 - 12 pin plug ceramic feed through on base

This chamber is electropolished though, now, that is rather moot as it has been open to air for a year or two.

Already blanked off for me and tested are the bulk of the 11-2.75" ports and the only free 4.5" port. (The other two have the quartz viewports in them.)

The chamber is brand new and never installed. It was part of a fab line that was to be installed, but never got delivered due to the economic downturn.

Now it is time to put some lipstick on this pig and plug some of the holes in her.

May I now be given the internal fortitude to actually get this thing pumped down and on line. Fusor IV will remain intact until this gal is virtually ready to go on-line. I have a feeling that like all beautiful gals this one is going to be high maintenance.

Richard Hull

[DaveC]

Richard -

Now is the time to slap on a boatload of blanks and get 'er mounted to a base and begin the initial pumpdown. Actually should be fun. ( I say this at a comfortable distance from the work.....)

Seriously, I have seen some issues with corners where ports make an entrance. You've got an abundance of corners in the chamber. Some glow discharge runs with the view port in place, might be very informative, as to whether some sort of shielding is needed and on which port intersections.

Nice piece of gear....

Dave Cooper

[Richard Hull]

As this was a finished piece ready for a fab line, I assume it has already been helium tested. I don't think they would have electropolished a chamber that might need a bit more touch-up in the weldment department.

Now, how well can I seal those open ports?

Richard

[Richard Hull]

This is being written long after this bold idea died a much deserved death. By 2012 I realized this pig would devour Deuterium like a vacuum cleaner. It was just a ridiculous effort that was still born after a burst of excitement. I sold the entire chamber to a local member of HEAS who, like me, was impressed with it. As of December 2019 he has had it for 7 years and it sits in his lab exactly where we set it down in late 2012.

Due to its size and mass, it sits where ever you put it very well. In the area of getting it to work, it also is still sitting nicely and is going no where!

Fusor IV has filled all these past years and is now to be retired (2020) after 16 years of fabulous service.

Around the first of the year, I am now at the other extreme in building fusor V.... The current rage in fusors is to use a single 2.75 conflat cross as the entire fusor chamber!

Fusor V is right around the corner........

Richard Hull

[ian_krase]

Outgassing -- because it's huge and has lots of internal surface area?

That is quite gigantic. Needs a big viewport door.

[Paul_Schatzkin]

Well, that solves that mystery...

I was wondering why I was seeing all these posts and images from 2010 when you'd just started talking about F-V recently. Now I get it.

That's some paperweight you had going there.

--P

[Richard Hull]

I repaired the photos in this FAQ last night! I am only 3 posts away from declaring a 100% repair in the construction forum of all of my attachments images and diagrams. (Thanks to the bold and aggressive work of Rex and others supplying me with a clickable list of defective URLs of yesteryear.) As noted , I have already 100% cleaned up the high voltage forum FAQs and the radiation and neutrons FAQs. Again, these are only all of my post's attachments. As I have done 99% of the FAQ over time, This really is an undertaking. The rather rare attachments of others in the FAQs various threads, remain broken. I continue my work tonight.

Richard Hull

[Scott Moroch]

I am by no means disagreeing with the statement: would "devour Deuterium like a vacuum cleaner."

However, it is worth noting that larger systems maintain star mode at lower pressures. The fusor Tim Koeth and I built (larger than that chamber) maintains star mode between 2-4 mTorr. My 9" spherical chamber is around 12-16mTorr. These smaller fusors seem to operate in the 25-45 mTorr range.

I would argue that you may not necessarily be burning through deuterium in a larger system.

With a well-assembled vacuum system (with a UHV chamber like that), it is also possible to isolate the chamber completely and run at a fixed pressure. This is obviously not the case if you have significant outgassing or leaks.

Scott

[Richard Hull]

True enough on all points, but I was not going to forge ahead on waning excitement versus the horrors that would surely lay ahead associated with a device that was mostly HOLES!
Apparently, the HEAS member and friend who paid my steep price for it seems to have had the gleam in his eyes fade, as well. Of course, admittedly, he has never pulled a vacuum in anything during his lifetime. Can you imagine his learning curve??! I'm just glad to see it gone. Another vacuum technology lesson learned the hard way.......Bigger is not necessarily better. The old "mine is bigger than yours" can get costly if you are to enter the game.

Richard Hull

[Jim Kovalchick]

Lots of big chamber bashing going on of late. My last fusor was relatively big, and it made some nice neutrons. U of Wisconsin has done lots of impressive science with great big IEC chambers.

I think it is easy for amateurs to over reach with big chambers that aren't properly matched by the right other aspects such as gas/ion supply, vacuum equipment, and power supplies.

I think it really comes down to what does one want to accomplish and what can one afford.

[Richard Hull]

I have actually had for the last 18 years in my lab two ten inch Braun 304 SS hemispheres and $700 dollar Lesker purchased, new 12 inch diameter CF rings in the original packing. I purchased these co-jointly with the 8" CF rings for fusor IV. Even those 8" rings would wait another 3 years before becoming part of fusor IV Again, looking ahead with big ideas for the ultimate 10" fusor!! There they sit buried in a far corner of the upstairs storage area in my lab to this day. All of that was when I worked and used the 2001 Braun and Lesker prices. Look at the prices today. I keep thinking if someone wants the challenge I would sell the lot for $800 at HEAS, but I demur for some unknown reason.

I would never bash a big chamber, just the big chamber that I showed in the original post here. If I ever built the 10" fusor it would be sensibly ported as fusor IV has been.

Richard Hull