That source is the same one I have. It is sold (oops, leased) together with a length of wire to be used for grounding. So obviously some charge partition will happen. In air most of it will leak away due to the tremendous ionization of nearby air by the alpha particles. For instance I keep the source in the insulating sleeve that it came in, and yet if I touch it after a while of it sitting undisturbed I don't get any electric shocks at all. It would be fun to estimate how much charge really builds up on it however I don't have a measuring instrument with a high enough input impedance (just a few digital multimeters of the usual 1Mohm value). An electrometer - the kind with 2 gold foils suspended in a vacuum - would be useful here. I bet that if the source were in a vacuum it would build up some static voltage, more than in air. But then the total charge would be small.
And this brings up to the question of powering a fusor. Definitely not. We both know that what drives a fusion reaction is not voltage alone but voltage and current, in other words power. And the current that such a source generates is very small, probably nanoamperes at best (left as an exercise to calculate for an activity of 5mCi). As a corollary, calculate the activity of a 210Po source needed to power a fusor (200W or more) :)
Gamma spectrum of a Polonium/Beryllium neutron source
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stamasd
- Posts: 102
- Joined: 29 Oct 2017, 02:12
Re: Gamma spectrum of a Polonium/Beryllium neutron source
Last edited by stamasd on 20 Nov 2017, 13:35, edited 2 times in total.
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Sesselmann
- Posts: 1392
- Joined: 27 Apr 2015, 11:40
Re: Gamma spectrum of a Polonium/Beryllium neutron source
Yes, I agree,
We can calculate the capacitance of the source and then if you know the activity you can calculate how many positive charges leave the source per second (activity), and assuming a high vacuum with minimal leakage, the charge can be calculated.
Idealising the source to a 1" Sphere it's capacitance would be 2.8 pF (http://deepfriedneon.com/tesla_f_calcsphere.html)
The capacitance of the 1" sphere 2.8 pF which equates to 1,750,000 charges, to leave the sphere, each alpha particle carries away 2 charges. So if the activity of the Nuclespot is 185 MBq. it would only take a fraction of a second before the fun starts.
Steven
We can calculate the capacitance of the source and then if you know the activity you can calculate how many positive charges leave the source per second (activity), and assuming a high vacuum with minimal leakage, the charge can be calculated.
Idealising the source to a 1" Sphere it's capacitance would be 2.8 pF (http://deepfriedneon.com/tesla_f_calcsphere.html)
The capacitance of the 1" sphere 2.8 pF which equates to 1,750,000 charges, to leave the sphere, each alpha particle carries away 2 charges. So if the activity of the Nuclespot is 185 MBq. it would only take a fraction of a second before the fun starts.
Steven
