Apparatus for Making a Deuterated Target

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Mark Rowley
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Apparatus for Making a Deuterated Target

Post by Mark Rowley » Fri Jun 18, 2021 2:32 am

Slowly assembling an apparatus to make some deuterated targets. This is somewhat based on Timothy Koeth’s arrangement shown in this link:

http://www.nuclearphysicslab.com/npl/np ... eparation/

Key differences being the use of induction to heat the material, PEM cell deuterium, and a heating vacuum that’s initially not going to get below 10mTorr. It’s highly desirable to get the vacuum deeper than 1mTorr however I’m not quite ready to hook up the diff pump until confidence is established with the quartz tubing. So for now, 10mTorr will be it. Im assuming the less pure result will still be considerably better than a non-deuterated piece. Subsequent testing will definitely answer the question.

Still have a few things to make before this is operational. Custom flange, quartz tube end cap, custom “quick connect” fitting, safety enclosure, and the induction heater arrangement.

Here’s a crude assemblage of parts which loosely represents the arrangement I’ll be using.

BA73DDF7-938B-4ED0-9C73-5EB7A83D364A.jpeg
Vacuum inlet on the right.

As this progresses I’ll periodically update.

Mark Rowley

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Richard Hull
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Re: Apparatus for Making a Deuterated Target

Post by Richard Hull » Fri Jun 18, 2021 3:46 am

Great work in "leading the way"... I can hardly wait for the results!

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
Retired now...Doing only what I want and not what I should...every day is a saturday.

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Re: Apparatus for Making a Deuterated Target

Post by Mark Rowley » Fri Jun 18, 2021 4:31 am

Since I’m limited to 100-200mL of deuterium, I may discard the voluminous T fitting (circled) and feed gas through the exposed left end of the quartz tubing.
F606DAB7-9643-4620-A5D9-2009E8A992BB.jpeg
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Richard Hull
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Re: Apparatus for Making a Deuterated Target

Post by Richard Hull » Fri Jun 18, 2021 5:13 pm

I was a bit worried about the volumes involved when I saw the syringe there. Even with tanked Deuterium, keeping the volume limited in the feed system is the thing to do or shoot for.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
Retired now...Doing only what I want and not what I should...every day is a saturday.

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Dennis P Brown
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Re: Apparatus for Making a Deuterated Target

Post by Dennis P Brown » Fri Jun 18, 2021 9:08 pm

Once you pump down, you close off the system and allow the deuterium to raise the system to its desired pressure, that extra 'T' isn't going to have much an impact; calculate the total volume for "zero torr". Then the volume of gas in the syringe - I bet the amount in the syringe is well above 10 mTorr for the final volume. Likely you will use far less than that syringe volume.

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Re: Apparatus for Making a Deuterated Target

Post by Mark Rowley » Fri Jun 18, 2021 9:24 pm

Quite true Dennis. In fact it’s way more than enough to put it well above 1000mTorr. I’m more or less caught up with Tim’s end goal of positive pressure. Not something I’m planning on doing (and cant with a syringe), but establishing 1atm would be a second best.

Lots of room for experimentation.

Machining is going faster than expected. Good possibility of a first run in a couple of days.

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Re: Apparatus for Making a Deuterated Target

Post by Mark Rowley » Tue Jun 22, 2021 3:27 am

Finally finished with the machining end of things. Custom made parts are the gas inlet fitting with o-ring and the quartz tube “quick connect” flange assembly. Not shown is an interchangeable 0.75” hose barb / KF25 flange for the vacuum. Hose barb fitting is used with the Yellowjacket roughing pump and the KF25 in case its ever hooked up to the diff pump.

The next bit of construction involves building a stable mounting bracket for the assembly, a protective safety shield to cover the quartz tube, and the electrical hook ups for the induction coil.

Note: The quartz tube shown in the picture is for fitting purposes. The tube used during operation will be more than double the length.

A268644F-F6A9-4FF6-9418-33659B860DC9.jpeg

D063092B-DA24-42F3-9AE5-85FD3D57437E.jpeg

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Re: Apparatus for Making a Deuterated Target

Post by Mark Rowley » Wed Jun 23, 2021 9:25 pm

As somewhat expected, the induction heater isn’t sufficiently heating the thin titanium strips. Some improvements were gained with different coil configurations but nothing good enough to hit 1k deg C. No big deal though, constructing an adequate tube furnace is remarkably simple. I’ll be detailing the build in a few days.

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Re: Apparatus for Making a Deuterated Target

Post by Mark Rowley » Sat Jun 26, 2021 10:34 pm

While waiting on parts time was spent fabricating two thermal dissipators for the quartz tube. The hope is that they can cool the tube enough to prevent damage to the o-rings on each side. During operation the dissipators will be cooled with forced air. If they don’t work then it’s just a matter of ordering a longer quartz tube.

A571C82F-9C73-43BA-9500-320AFD5E1009.jpeg

CB4083A5-9DB5-4848-99B5-57026C56171D.jpeg

952749D7-3AFB-4CBF-A24E-FDC53E089B80.jpeg

F1690AEC-E020-4E59-9E0A-EB5927F58C65.jpeg

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Re: Apparatus for Making a Deuterated Target

Post by JoeBallantyne » Sun Jun 27, 2021 12:03 am

Very nice work Mark.

It would be cool to see a video of that tube furnace in operation.

Joe.

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