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News from Argentina

Posted: Mon Jan 22, 2018 7:04 pm
by Roberto Ferrari
Hi fellows,
After many years lurking around on the Fusor consortium, our system is taking form.
Down South hemisphere, all Hi Tech parts became more expensive than in the North hemisphere. Flying them almost 10,000 km and paying Customs typically brings the price up to a factor 2.5/3.
And, yes, procrastination also adds up…
With German Mülller, friend and partner in some technological activities, we are assembling our small 2.75” cross fusor.
Vacuum and deuterium supply almost done. Now we need to devote time and brain to high voltage supply and electrical measurements.
Neutron quantification almost none; just planning to measure activity on silver sheets.
See picture of setup.
We appreciate and aknowledge the many comments and suggestions received along the years from a so excellent team!
Fusor_I_RandG_01.jpg
PS: note fancy clamps from Andrew Robinson!

Re: News from Argentina

Posted: Mon Jan 22, 2018 9:40 pm
by Jerry Biehler
I dont know what range the baratron you have there is but the more sensitive ones need to be in a vertical position to read accurately.

Re: News from Argentina

Posted: Mon Jan 22, 2018 9:47 pm
by Roberto Ferrari
Hi Jerry

Good point, thanks!
That one is 100 torr but we have also 10 torr FS.
We will manage to put an elbow or swap positions with the viewport, now at cross lower port.

Re: News from Argentina

Posted: Mon Jan 22, 2018 10:07 pm
by Dennis P Brown
First off, nice fusor! (Aside, do you have a Geiger Counter to check on the X-ray threat?)

Second, activation of silver requires a high neutron output so don't be discouraged if you do not succeed in that neutron detection methodology.

Finally, what voltage and current can you supply?

Re: News from Argentina

Posted: Mon Jan 22, 2018 10:43 pm
by Roberto Ferrari
Hi Dennis,

Thanks for your comments.
We have an old pancake Ludlum Model 2.
Also assembling a gamma spectrometer but at slow pace.

About HVPS we will try first with a low power one, as Mr. Rapp did. He succeded activating silver.
And working in modifying an old X-ray equipment, 100 kV 100 mA.
Lead sheet is in its way to our lab.

Re: News from Argentina

Posted: Mon Jan 22, 2018 11:46 pm
by Dennis P Brown
Wow, that is some power supply - 10,000 watts!!! Amazing. You have some massive input wiring, I bet for that monster.

Cables for 100 kV are rare and expensive. Diodes for that range are not too rare, at least, but expensive. Maybe you can string a large number of 20 kV/one amp diodes available from China to save money. They are less than $3 each.

Are you considering just operating at 50 kV or so making the cable/insulator feed thru and diodes issues easier and cheaper (you should seriously consider operating all diodes/resistors under oil (cheap synthetic motor oil works very well. I do that.))

Also, the input variac to handle that wattage, if they can be located, would be highly expensive, I'd think as well.

Re: News from Argentina

Posted: Tue Jan 23, 2018 12:27 am
by Jerry Biehler
Ok, you should be fine. Its the ones around 2 torr or less that are position critical.

Re: News from Argentina

Posted: Tue Jan 23, 2018 12:44 am
by Roberto Ferrari
Jerry:
Thanks, good to know that.
Dennis:
We have an almost complete X-ray equipment.
Xformer is under oil, silicon diodes also.
We plan to run on the negative half only, with a variac for 220 V (our mains voltage) 20A.
As ballast resistor we plan to use a water one, avoiding to open the xformer container. Still managing to couple those conical terminals to our HV feedthrough.
As a matter of fact, the HV feedthrough limits the voltage to approx. 30 kV.

Re: News from Argentina

Posted: Tue Jan 23, 2018 12:06 pm
by Dennis P Brown
A water based ballast resistor is an excellent idea. You make your own? Is it a Cu based solution or are you just using highly purified water?

Why does the HV feed-thru limit you to 30 kV? Is that its rated max? Not that it matters - in a small chamber 30 kV will probably give you plenty of neutrons.

Re: News from Argentina

Posted: Tue Jan 23, 2018 12:25 pm
by Roberto Ferrari
Hi Dennis,
Following Mr. Rosenstiel’s suggestion, our water resistor will be a plastic tube with water and a little of copper sulphate.
Yes, the maximum rated voltage for our HV feedthrough is 30 kV.