Neutron Club Application - Cade Neely

Current images of fusor efforts, components, etc. Try to continuously update from your name, a current photo using edit function. Title post with your name once only. Change image and text as needed. See first posting for details.
Post Reply
User avatar
Cade Neely
Posts: 28
Joined: Mon Dec 30, 2019 9:06 pm
Real name: Cade Neely
Location: Southern Indiana

Neutron Club Application - Cade Neely

Post by Cade Neely »

Here is my neutron club application. For in-depth information on the various systems/progress please view the various posts I have made. An explanation of the system's details can be found in the update post right before this one. As always, questions or comments are welcomed.

(Sorry some of the images are upside down. The interface is being weird.)



Data

Voltage: 28kv average

Started time once the voltage cleared 20kv. During the run the lowest voltage was 22kv and the max was 36kv. Wandered around this range but the voltage averaged at 28kv.



Current: 2.5-3.5ma

Current stayed pretty constant during the run. When the gas dump from the syringe occurred (see update post) the current shot up to 6-7ma before I had a chance to back off the needle valve and voltage.



Pressure: 15-20 microns

Because Pirani gauges are gas dependent, the pressure registered was about two times higher than it was. These values are adjusted approximately for hydrogen. I believe it has been stated in the forums that small reactors run at higher pressures than larger ones.


Time of Run: 19 minutes

As stated above, the time started when 20kv was reached.


Neutron Detection

I am using a bubble neutron detector from bubbletech with a calibration of 25 bubbles per mrem. The detector is placed approximately 1 cm from the chamber wall. At the end of the run, 26 bubbles were counted.
Attachments
Image of Claimant by device
Image of Claimant by device
Fusor during fusion run
Fusor during fusion run
Fusor
Fusor
60kv supply on control panel
60kv supply on control panel
Control panel looking like a scientist's nest as usual
Control panel looking like a scientist's nest as usual
IMG_3469.jpg
Detector setup
Detector setup
Bubble Detector after run
Bubble Detector after run
Bubble Detector
Bubble Detector
User avatar
Liam David
Posts: 518
Joined: Sat Jan 25, 2014 5:30 pm
Real name: Liam David
Location: PPPL

Re: Neutron Club Application - Cade Neely

Post by Liam David »

Congrats on the neutrons!

The bubbles look as one would expect and the run parameters look good, so I think you'll have no problem being added to the club. Using the calculator (https://www.gammaspectacular.com/fusion_calculator.html), it looks like you're getting an average of 2.9e3 n/s:

Capture.PNG

The rate seems a little low for the voltage and current, but that could be the result of many things.

I like the sturdy wood frame and control box, and see that you've got an oil mist filter on the rough pump--good going. The remote operation is also a plus and rarely seen.

A couple bits of advice, that in no way diminish your achievement:
  • Move your bubble detector away from the chamber by a few more cm. This accomplishes two things: 1. Bubble detectors are sensitive to heat and I'd imagine your chamber is getting a little toasty, especially after 19 minutes. 2. The neutron emission region isn't a point but is instead distributed in various ways throughout the device. This can greatly affect the apparent neutron rate if you're measuring too close and assuming isotropy. For a better idea of the true neutron rate, you'd have to be in the far field, although this is more challenging at lower neutron rates.
  • Make sure you're isolating your turbo from vibrations from your rough pump. There's nothing that turbos hate more, short of an air inrush.
  • Try adding some cooling to the chamber. A computer fan can go a long way and water cooling (submersible pump+water reservoir+cooling pipes/blocks) can help a lot. Think beam-target fusion...
  • I think one of the (if not the) major things decreasing your neutron rate is gas purity. Try developing a configuration that allows you to pump out the whole gas line and get rid of as much plastic as possible. In a previous post you mention a base pressure of ~4e-6. Is this still the case? Do you have to throttle the turbo?
  • The wood frame is nice, just be careful as you start to increase the voltage. Wood can be somewhat conductive at high voltages, especially when it's damp (even from just ambient humidity) or has particulates on the surface.
If you've got time, could you reupload the photos on your old posts? They got lost in the forum move and it would be great to have them for future reference.

Great work, I hope you keep working on your system!
User avatar
Richard Hull
Moderator
Posts: 14992
Joined: Fri Jun 15, 2001 9:44 am
Real name: Richard Hull

Re: Neutron Club Application - Cade Neely

Post by Richard Hull »

A well done report, Cade. You have done fusion. Liam did a great follow-up on your data, as supplied. Thanks Liam.

Liam's advice, especially about holding the BTI a bit more distant from the chamber is great advice. I would also suggest you place it under or below the chamber to avoid heated rising over the BTI.

Liam, I added a additional kudo to your elite member status. We appreciate your continued posting and assisting others.

Cade, I will add your name to the list of neutron club fusioneers.

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
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
User avatar
Cade Neely
Posts: 28
Joined: Mon Dec 30, 2019 9:06 pm
Real name: Cade Neely
Location: Southern Indiana

Re: Neutron Club Application - Cade Neely

Post by Cade Neely »

Hey Liam, thanks for your comments. You have given me much to work on. During that run the chamber reached 300 degrees which caused the detector to heat up. I wondered at the time if this hindered the counts, it probably did.

What do you mean by isolating the turbo pump? The turbo appears to be operating normally.

As for cooling, I have a fan that I removed from the system to make room for my janky bubble detector rig. I will add the fan back into the system.

On the note of gas purity, I one hundred percent agree. Much of the reduced purity comes from operator error. The more I run the fusor, the higher the purity of gas I obtain. Yes, I still have to throttle the turbo back; the throttle valve is barely open. The only “plastic” in the system is the vinyl tubing for the flow restrictor. The drying tube is quartz glass placed inside plexiglass. The plexiglass is not exposed to vacuum, it only shields the quartz glass tube from mechanical trauma. The base pressure of the system is no longer 4e-6. I think there may be a leak (physical or virtual) around the new feedthrough. (The leak was not present before the new feedthrough was installed) The new base pressure is 5e-5.

I would like to update my posts with the pictures but I am unsure how to do so. Could you explain?


Thank you Richard. I am honored to join such an elite group of people. One note, in the recent additions you put that I was in the elite neutron club. I hope to be there soon but I am not there yet. Just wanted to point that out; don't want to get credit for something I have not achieved.
User avatar
Richard Hull
Moderator
Posts: 14992
Joined: Fri Jun 15, 2001 9:44 am
Real name: Richard Hull

Re: Neutron Club Application - Cade Neely

Post by Richard Hull »

Corrected the listing to just the neutron club fusioneers. Thanks

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
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
User avatar
Liam David
Posts: 518
Joined: Sat Jan 25, 2014 5:30 pm
Real name: Liam David
Location: PPPL

Re: Neutron Club Application - Cade Neely

Post by Liam David »

I mean isolate as in reducing the transmission of vibrations to the turbo. Vibrations won't prevent your turbo from operating normally, it will just make the bearings wear a lot faster. I have a similar model pump to yours and I would not put it on the same shelf as a turbo. I'd also recommend a longer foreline hose. These are dependent on how much the forepump vibrates; put your hand on the turbo while the system is running--you shouldn't be able to feel the rough pump vibrations. If you do, make some changes, and if not, then there's no problem.

The best thing you can do for your gas purity is to remove that vinyl tubing. Vinyl outgasses terribly and I'd be surprised if the gas line was pumped out to <100 torr. The second thing is either removing the dryer, as Matt suggests, or better yet, adding a valve that bypasses your needle valve to pump out the dryer for a long time, perhaps while heating it. The drierite can store a lot of junk that can do more harm than wet gas. The endpoint would be a chamber pressure that changes very little with the gas lines open vs closed.

To get a better idea of your gas purity/pressure situation, could you give an approximate chamber pressure in the following states? Ballpark is good enough:

Throttle open, gas line closed
Throttle open, gas line fully open (back to valve 1, no deuterium)
Throttle cracked, gas line closed
Throttle cracked, gas line fully open (back to valve 1, no deuterium)

The last of these will most determine how clean everything is. Even if you could get to 1e-9 torr with the throttle open and gas lines closed, it doesn't do you much good when opening the gas line and cracking the throttle brings you to 1e-4.

For re-uploading the pictures on an old post you'll have to get an admin to temporarily allow editing old posts.

Thanks, Richard.
Post Reply

Return to “Images du Jour”