Daniel Klasing Neutron Club Application

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Silviu Tamasdan
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Re: Daniel Klasing Neutron Club Application

Post by Silviu Tamasdan » Thu Nov 23, 2017 1:51 am

Daniel Klasing wrote:
Thu Nov 23, 2017 12:42 am

I'm afraid you are correct about my He-3 counter. The guy who sold it to me said that's how much moderator I would need. He must have been mistaken.
I'm pretty sure I got my system from the same person. There are a lot of good points about that system, but needs some work and adjustment to make it work properly. It seems in my experience to detect neutrons properly with a sufficient amount of moderator. In my case that's 4 inches of HDPE and 12 quarts of mineral oil (motor oil) all surrounding the corona tube.
The Faraday cage is an excellent point too. Do you think maybe a cylinder of paraffin wax wrapped in a grounded tin foil shell would work?
In my case I use a copper tube 1" diameter (from Home Depot, plumbing section) in which I inserted the neutron tube wrapped in a few layers of plastic wrap to make a tight fit. The copper tube has one end closed with a copper cap soldered on, and the other end has the SHV connector threaded through a hole in another similar cap. The copper cylinder is electrically connected to ground. I haven't run extensive tests yet but I think it should provide enough screening. Will post in the relevant section of the forum when I have more data.
Yes bottle under the table is helium, and according to the supplier it is at least above 80% purity. I don't exactly have access to a mass spectrometer, so I don't know the exact purity, but its a whole lot cheaper then the laboratory grade stuff, and it seems to be working just fine.
That was a superfluous question of my part. As you're not using the helium during the actual fusion attempts the purity shouldn't matter. Much.

BTW, I don't know which version of the application program (pulsecounter.exe) you are using. If yours has in the setup section parameters for the sampling frequency, delay at starting of the counting and minimum pulse size then you have the latest version I know of. If not, you can request the latest version from the vendor, or I can send it to you. There is presumably another version in the pipeline that will add more features (though those would be targeted more at gamma spectroscopy and not really useful for neutron counting).
There _is_ madness to my method.

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Dennis P Brown
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Re: Daniel Klasing Neutron Club Application

Post by Dennis P Brown » Thu Nov 23, 2017 4:38 am

Daniel, you need to both understand and better address Richard's points. The bubble detector (BD) results you obtained appear to have issues - mainly, those bubbles appear to be due to heat rather than neutrons (as you know after running a fusor for awhile, it gets rather hot.) That is why I asked you about the distance and location of your bubble detectors. The calibration is not an issue. Please understand that heat on a bubble detector has caused issues for others and even has destroyed BD's.

So, to address the main concerns Richard raised: your power level are too low (particularly, the voltage for your effort - which is extremely low for detectable fusion using most systems used/available); you can't address that power supply issue directly except get a better supply (that is higher voltage - need at least 20 kV and 10 ma for most detector systems - higher voltage & current would be better - be advised, getting voltages near/above 20 kV with these currents gets very dangerous.)

Otherwise, a long exposure can help the BD build up a clear signal. But do be advised that a long exposure can cause the BD to overheat if pre-cautions are not taken. Too much heat can destroy a bubble detector. Keep that in mind and be careful about this issue - I would suggest that you use a heat shield (just a thin Al foil shield between the fusor and BD) and possibly forced air cooling for the bubble detector (A He-3 detector is not as affected by heat.)

Best to re-set the bubble detector (I assume there are instructions included with the BD on how to do that), be certain the BD is both heat shielded (neutrons go right though even thick metal like it isn't even there) and at a safe location (not too close so it does not get too much heat) that keeps it cool (again, forced air, maybe) when running another long test (twenty minutes or more is a long time near a fusor's main section - that can cause issues with heat and cause bubbles to form and grow that have nothing to do with neutron detection (again, Richard's concern relative to the bubble detector results you obtained - you MUST address these concerns to be consider & accepted for addition to the Neutron Club.)

As for a He-3 detector, that is not a system that is easy to get working relative to noise issues and proving a clear signal - especially for a very low flux system like your's. However, it is well worth the effort to learn how to use such a detector and how to deal with these issues (see a number of recent posts - Finn, Silviu and earlier posts.) But that should be another thread and unless you really understand how to operate such a detector with all its issues, not a system that can readily prove fusion.

Aside: Daniel, detecting neutrons is not an issue that is easy using electronic means and causes many people trouble (I was no exception as were many others) - also, bubble detectors were not intended for fusors and as such, must be used cautiously. Keep at it and learn about detectors and fusor power supplies and I am certain that you can meet Richards requirements with your excellent fusor. Please don't get discouraged and do continue to post your efforts so we can help you address your questions and achieve your goal. Best of luck.

Jon Rosenstiel
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Re: Daniel Klasing Neutron Club Application

Post by Jon Rosenstiel » Thu Nov 23, 2017 7:44 pm

Below is what I normally see when using a bubble detector. Compared to the images of your BTI's note that the bubbles are smaller in size and are fairly evenly distributed throughout the detector's volume.

Jon Rosenstiel

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Richard Hull
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Re: Daniel Klasing Neutron Club Application

Post by Richard Hull » Thu Nov 23, 2017 10:16 pm

Thank you Jon for posting a clean image of bubbles all through the volume of your tube. I submit one of my close-ups as well.

It is very difficult for me to imagine 15kv fusion at those currents and pressures.

Richard Hull
bub position.JPG
Here is how I mounted my BTI. Under the fusor so that heat rising would not affect or create bubbles.
brand new BTI...Small bubble over entire volume 300k n/s.
Here, the bubbles are larger but still over the entire volume. Detector 6 months old.... >1 million n/s
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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