You are here:

Physics/Americium battery


I had a question about voltage levels of electricity derived from Americium in a vacuum.

If you were to take a common (smoke detector) americium source and aim it at a piece of metal (I would use Titanium) 1 mm away, and enclose the entire assembly in a vessel and pump out the air. If you could measure the voltage, What would the approximate voltage be?

I understand that your answer will be approximate, but that will be good enough.

I understand that the current would be in the nanoamp range, but was curious about what the voltage might be.

According to
the americium in a smoke detector gives off .9 micro-curies of radiation, all in the form of alpha particles.

From this you can easily figure out the number of alpha particles leaving the americium each second. Knowing the charge of one alpha particle, and making a reasonable estimate of the fraction of alpha particles that leave the americium and hit the titanium, you could easily determine the current between the two plates. If both were electrically isolated, this flow of charge would result in a buildup of charge on each of these plates.

The capacitance of parallel plates is a fairly simple formula, and can be easily found. Once you know the charge buildup between the plates, knowing the capacitance will give you the voltage.

I could do the math myself, but I'll leave it to you.

This is all I wish to say on this matter.


All Answers

Answers by Expert:

Ask Experts




I can help with understanding physics that does not involve eggs. I will NOT help with academic or professional questions, which are NOT limited only to homework. Please do not waste your time by asking a question that comes out of ANY kind of academic, professional, or business matters.


Have been fascinated by physical laws ever since I learned, at age seven, that magnets work under water. My study continued through college and has not ceased even after I retired.

B.A. in Physics (with honors) from University of California at Berkeley.M.A. in Physics (with honors) from University of Texas Austin.

©2016 All rights reserved.