Cheep fusor II update

[Charles Elkins]

I have not had much time to work on it this semester due to my class load.

I have come up with a few new ideas to try and will set up this new Fusor to test them all. It’s going to have Two HV feed-throughs, one on bottom, one on top, and a shielded viewing window. One, maybe two 8-wire low voltage feed through to control actuators or acquire data from inside the Fusor. I have some pure titanium wire so I can also make a titanium sublimation pump to get the vacuum into the ultra high range(the same mount can be used to make mirrors to). It will also have a provision for a 1kw microwave heater operating at 2.45 GHz. I also still need to figure out how to reflect or guide the microwaves around inside the chamber. I just got a cart to construct my new Fusor on, and piled all my parts on it but I will not be able to work on it this weekend.

If there are any experiments and I mean any, no matter how outlandish, that yall would like to test and can be conducted within a 10” Fusor/vacuum chamber please let me know so I can make any adjustments to my machine before I start drilling holes in things.

Thanks Charles.

[waltsphotos]

Charles,

I would love to take up your offer to have you test some ideas.

all of the tests I would like to do wouldn't require any major adjustments to your machine(like addional holes needed for equipment).

feel free to contact me direct by email through the fusor forums.

first set of tests I would like are: [1] inner grid 1" outer grid 2" [2] inner grid 2" outer grid 4" [3] inner grid 1" outer grid 4" (grid design and meterial should be the same for all grids) would like test data to show: vaccum pressure, voltage, current, nutrons, time, and anything else that you can think of to measure and record.

(there is a post called "testing and equipment; beyond just counting nutrons" where I was trying to make the case to create monthly projects for this community where as a community we would agree on what and how to test fusors, and report results. I hope you will join me in such a project)

~Walt

[Richard Hull]

Before one goes slapping a microwave maggy on a fusor, consider safety issues as the viewport becomes possibly lethal without proper shielding. The average fusor is not tuned properly to the radiation and one will need to worry about reflected energy back into the maggy and other issues that might prove a bit of a sticky wicket.

Richard Hull

[Charles Elkins]

I was originally going to have a mirror set up like half a periscope with the camera looking down a lead lined pipe. The design required thick port glass and the mirror to be mounted in a holder etc. Using the prism doesn’t need the holder and all the glass is one piece so there is no chance of it getting out of alignment. I plan on making a simple frame that holds it against the side and seals the glass with a 1.75” o-ring. I am not planning on directly viewing this experiment except in demo mode under 10kv and with air/nitrogen in the chamber.

So far my thoughts on the Microwave is to reflect the beam threw the core two or three times then have it go into dump-channel so its energy can be dissipated safely.

[Starfire]

A word of caution Charles;-

See;-
viewtopic.php?f=6&t=2648&hilit=Cataracts#p15989

Carl corrected me as the magnetron he was using was not a MO configuration

But It can not be stressed enought - don't play with Magnetrons - DO NOT BE NAIVE

once you go blind - you are blind forever.

[Carl Willis]

I don't see much concern about the microwave idea, safety-wise, provided of course one is not "naive" in this area. Viewports--if present--must be covered carefully with chicken wire to eliminate leakage. Richard was right to raise some concern there because if you don't short out the port with a metal screen, you have a nice little eye-popper. Think about that aqueous humor boiling like a Jello salad, and consider the benefits of some good mesh screen.

On the practical, non-safety-related, execution of the idea, there are certainly some challenges. For instance, coupling microwave power into the fusor: ideally, this would be done with waveguide above the cutoff frequency. But then you have to figure out how to attach rather large waveguide to the vacuum chamber. Perhaps you could run the magnetron attached to an external cavity, and couple the power in via a slot dipole / vacuum window. Also, predicting the standing-wave mode structure inside a complicated chamber like a fusor is difficult. It is practically unknown where your E fields will be strongest, and whether they will do any good there. Judicious application of microwave fields and magnetic fields in the same place can provide ECR heating of electrons, and the concomitant surge in efficient ionization.

I think the microwave idea is a good enough experiment for starters. If putting 900 W of maggie power into a fusor cavity has a profound impact on operation, that's a very valuable contribution. Of course, results here will lead to new ideas for advancement. I'm not sure you should be in a hurry to take orders for others' experiments just yet. Seek advice on the refinement of the microwave idea if you need it, put it together, and share the outcomes. I think that seems to be an innovation you are interested in.

-Carl

[Charles Elkins]

I have an idea to fill a tube with water, it would have a vent, and be 2" to 3" thick so I take photos of the chamber with the Microwave on and not fry my camera CCD. Allowing me to take nice unobstructed photos of the core.

I only plan on viewing the chamber with out the camera when it’s running in standard demo Fusor mode with a normal core electrode, and under 10kv.

I don’t have a neutron detector and plan on measuring the decay of a Silver sample to determine the if neutron activity is occurring.

Also when I do fire up the microwave and have the Fusor at full power I plan to be far way 60feet or more remotely controlling and monitoring the experiment. The whole Fusor will be lined with lead sheathing and inside a lead box.

[Nanos]

I was under the impression that Indium with Cadmium would make a better choice than Silver.

And I thought lead wasn't a good choice ?

I do like the idea of a water filled window, I await replies on the suitability of that from others.


I'm just a beginner myself by the way, just got hold of some aluminum angle to make up a frame, made some flooring out of old scaffolding boards to place it all on, and of course, tidied up so I got a little bit of space to build the thing in! (At the moment its next to the wardrobe, going to put some plasterboard up between it and the fusor due to concerns about firerisk.)

[John Futter]

Charles

step 1 get a good vacuum with what you have got ie 2 x 10-7 millibar or better with diff pump or turbo.

2 the microwave idea has merit i like the water window to mitigate the RF escaping and causing eye damae or what have you.

3 you may need a field stirrer to place an RF hot spot where you need it.

4 lead shielding is not very effective against neutrons try water or wax with borax added - much more effective neuts are absorbed / slowed by light elements such as hydrogen and boron. At 10 Kv any metal chamber will stop xrays - the window may not unless it is lead glass or uranium glass.

5 Activating silver requires alot of neuts to be measurable - get yourself a neutron counter plenty of good oil on this, on this site as to what works.

6 be safe have fun

[Charles Elkins]

I have a new announcement. My wife is pregnant! We found out the good news the weekend before last and verified it with blood test to see how far along she was. The expectant due date is in late September early October.

Back to the Fusor, the lead is to stop X-rays in non-fusion experiments. When I run the Fusor to create neutrons I plan on running it remotely. This seems to be the best way to prevent exposure to neutrons. Though the output should be low I am paranoid of radiation and would prefer no avoid all the exposure that I can. It looks more and more that I will have to get a neutron counter I will probably order a bubble detector or come up with some way to construct one. I have been looking at how house hold microwaves deal with the RF and decided that field stirrer/stirrer blade would be the best way to dissipate the energy inside the machine. I have a diff pump that will be backed up by two rotary pumps. It will likely be some time next year before I start experiments with deuterium. I am hoping to do demo experiments by this summer with this new machine.
Thank you all for your wonderful feedback! It has really helped a lot with the design of this machine hopefully I will avoid a lot of trial and error learning.