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Archived - First neutrons from Slovakia!

Posted: Sun Oct 21, 2012 3:59 pm
by Michal
Hello, I'm a high school student from Slovakia and I already gave a
short description of fusor in my earlier post. Since then, with my
supervisor from Comenius University, we made new HV feedthrough which
resulted in much better stability of the discharge. Although we are
limited by voltage to 20 kV by our power supply, we managed to achieve
fusion and get some neutrons.

Our vacuum chamber is made from standard components. We use standard connectors and seals with aluminium ring which cause some problems with X-rays because aluminium is not good material for blocking X-rays. We managed to solve these problems by adding extra shield fromlead glass.

We´ve been using rotary and turbomolecular pump for achieving high vacuum. With this
apparatus we managed to achieve minimal pressure of about 2.10-3 Pa. Pressure was measured by the Thermocouple and the Penning vacuum gauge.

For preparing deuterium gas we used electrolysis of heavy water. Heavy water was electrolyzed by Polymer Electrolyte Membrane electrolyzer. This electrolyser causes some probles because water from oxygen side passed to hydrogen side. This problem was solved by adding a bubler for cathing water on hydrogen side. For purifing deuterium gas we used zeolite dryer, and between this dryer and electrolyser we put bubler with diffusion pump oil to prevent drying of electrolyser. Rate of deuterium production was kept higher than its consumption by fusor. Excess deuterium was released to atmosphere through another bubler with oil. Slow constant purging of the system was used also in order to improve
purity of deuterium gas. Then we put this deuterium into recipient by using precise leak valve.

The most problematic part was high voltage feedthrough and central electrode. Feedthrough was made from alumina tube with outer diameter of 10 mm and stainless steel rod. Smaller diameter of alumina caused sparking which was interfering with the neutron detector. Another essential thing was purity of central electrode. The electrode was first made from molybdenum, and later from tungsten. Both metals were cleaned by an electrolyte where they acted as anodes. For cleaning of molybdenum we used chromo-sulphuric acid. This acid is highly toxic and dangerous which was one of the reasons why we changed to tungsten. Tungsten was cleaned in 13% solution of sodium hydroxide. In both cases, stainless steel cathode was used during the cleaning process.

As a neutron detector, we used LiI crystal mounted on VA-S-50 Universal
scintilation probe. The whole setup was build by RFT company, East
Germany. As a moderator, we use polyethylene sphere with diameter of 10
cm. We measured background of 60 to 70 cpm because of high noise of
detector. With moderator and fusor running we measured about 80 to 100
cpm. Reference measurements with running fusor and without moderator
didn't show increased intensity of counts. The measurements were up to
2000 seconds long. In the figure, black errorbars show deviation
of 3 sigma, red ones shows 5 sigma. Sigma (standard deviation) was
calculated as square root of counts detected.

Do you find this to be reliable proof of fusion for “neutron club” membership?

Best wishes,

Michal Racko, under supervision of Michal Stano, PhD

Re: Archived - First neutrons from Slovakia!

Posted: Mon Oct 22, 2012 3:11 pm
by Richard Hull
This looks creditable to me, but before I go much beyond here and log your name into the neutron club, I would like for others in the admin area and fusion successes to chime in on this.

Data presentation and error bars look good. This is certainly a very edge point for fusion possibilities.

Could we see an image of the detector and moderator you used?

Richard Hull

Re: Archived - First neutrons from Slovakia!

Posted: Mon Oct 22, 2012 3:34 pm
by Michal
Of course, here is the image.

Re: Archived - First neutrons from Slovakia!

Posted: Mon Oct 22, 2012 4:54 pm
by Carl Willis
This looks like a credible "Neutron Club" entry to me.

There are photos, descriptions, and statistically-significant neutron counts as confirmed with a classic moderator-removal experiment.

It would be nice to know more about some of the unique components in Michel's apparatus, especially the electrolysis system. Relative to most Neutron Club fusors, not many details on the subsystems of this one have been described yet. I hope Michal will provide more of those details so that other people can understand the "nuts and bolts" of his approach.

A background count on the LiI:Eu detector of 60-70 cpm is very high. It should be possible to raise the LLD on the detector electronics (or alternately lower the PMT voltage) to eliminate most of these counts, and incidentally improve the detection limit for neutrons. As I've never had the pleasure of working with radiation instrumentation from the German Democratic Republic, I can't offer any more specific advice for how to accomplish this tune-up.

All in all, very nice work, Michal.

-Carl

Re: Archived - First neutrons from Slovakia!

Posted: Tue Oct 23, 2012 10:44 am
by Richard Hull
I have added Michal's name to the neutron club membership. Thanks for you input Carl. Thanks Michal for the picture of the detection gear and welcome to the Neutron club. I had to search the membership list for a last name. I hope I got it right.

Richard Hull

Re: Archived - First neutrons from Slovakia!

Posted: Tue Oct 23, 2012 4:02 pm
by Michal
Thank you for adding me to the neutron club.
It is my mistake that I´m logged just as "Michal". My surname is "Račko" in my native language, or just "Racko". Please rewrite it from Michal Krzeminski to Michal Racko.
Also, if you could, please add there my supervisor. His name is Michal Stano, PhD.
Our country is Slovakia, could you correct it as well please?

The high background was caused by wrong adjustment of discriminator. But my supervisor managed to adjust it better. The background is now about 10 counts per 100 seconds so next experiments should have more accurate results.

Now I have just one more detail photo of deuterium supply. I´ll take other ones when I´ll be in the laboratory. In the photo you can see zeolite, which is used for gas drying.

Best wishes,
Mike

Re: Archived - First neutrons from Slovakia!

Posted: Wed Oct 24, 2012 10:30 am
by Richard Hull
I have made all the corrections and additions. Sorry about the mixup.

Richard Hull

Re: Archived - First neutrons from Slovakia!

Posted: Fri Oct 26, 2012 6:27 am
by RobertTubbs
I would like to extend my congratulations aswell.

I too am very interested in that PEM electrolysis setup, I had gone the Hoffman-apparatus route a few years ago and since then these PEMs have become widely available. Their small size in contrast to Hoffmans makes for a potentially much smaller investment into the D2O for the same result.

At your leisure if you could post a number of good photos of the electrolysis setup and any modifications to the cell itself that you've made that'd be quite valuable.

Regards,
RT

Re: Archived - First neutrons from Slovakia!

Posted: Sun Oct 28, 2012 5:35 pm
by Michal
Thank you,

Here is a video of the electrolysis system:
http://www.youtube.com/watch?v=NOcb5eFU ... e=youtu.be
The dryer is made not from zeolite but from silica gel.
PEM cell was made in Germany. It is a single cell.
It works with voltage of 2,5 V and current of about 0,5 A.

Here is another video of the fusor:
http://www.youtube.com/watch?v=-Bq45jRQ ... e=youtu.be

The neutron detector can be heard in a background.

My mentor will take other, more detail, photos tomorrow.

Michal Račko