Hi guys,(adsbygoogle = window.adsbygoogle || []).push({});

Need a spot of help as i cant seem to find where to go next :(

Ok, so there is a source which emits beta particles (currently unknown whether they are positrons or electrons). It can move at an angle +/- 90 degrees to the GM tube. I need to find an expression for the energy of the particles related to the angle the apparatus is at. Here are the equations given to me:

[tex]E = m_{0}c^2 [\sqrt{1+(\frac{p}{m_{0}c})^2} - 1][/tex] (1)

[tex] r = \frac{R}{\tan(\frac{\Theta}{2})}[/tex] (2)

Where

r = the radius of the electron/positron circle.

R = the radius of the circle used for the source/GM tube setup.

I also have the following equation:

[tex] F = \frac{mv^2}{r} = qvB[/tex] (3)

Combining (2) and (3) gives me:

[tex] \frac{R}{\tan(\frac{\Theta}{2})} = \frac{mv}{qB}[/tex]

I cant see where to go next...any ideas? Cheers :)

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# Homework Help: Beta decay - derive an expression relating source angle to energy

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