Investigating Beta Particle Backscatter from Foil Materials

[exequor]

I am designing an experiment to investigate how the number of beta particles scattered backwards depends on the thickness of a foil and the proton number of the foil material. I have an idea of what I will do, i.e. I will have the beta particles fired at the foil and place a GM tube next to the source the get the number of particles scattered backwards. i will change the thickness of the foil, and would also change the type of foil (aluminum, tin and some other material).

What source can i use for emitting the beta particles?

 

[Cyclotron Boy]

Salt substitute is made of Potassium Chloride. 0.00118% of the K is a beta emitter at 1.3 and 1.5MeV. Otherwise, you will have to go with a commercially produced beta emitter.

 

[Astronuc]

Where will you be doing this experiment? Most academic departments (Nuclear Engineering or Health Physics) should have a supply of common radionuclides.

You might want to use something like Sr-90, half-life of 29 years, no gamma., and maximum beta energy of 0.546 MeV. It is a pretty common radionuclide.

I would recommend if at all possible, putting the beta source and scattering surface in a vacuum, with the GM just outside. If you do this, be careful that you don't blow out the window of the detector (if thin window, that is).

Otherwise put the scattering foil, source and detector close together. The problem with the latter setup is that you will get a broader distribution of angles.

As Cyclotron Boy inidcated, K-40 is also good because of the long half-life and high max. beta energy.

 

[exequor]

Where will you be doing this experiment? Most academic departments (Nuclear Engineering or Health Physics) should have a supply of common radionuclides.

I won't be carrying out the actual experiment, instead I am just designing one. The extra information is helpful because I have to look at safety and precautions too.

I would recommend if at all possible, putting the beta source and scattering surface in a vacuum, with the GM just outside. If you do this, be careful that you don't blow out the window of the detector (if thin window, that is).

What would happen if the detector is inside the vacuum? Would it do more damage to the detector as opposed to the detector being outside the vacuum?

Otherwise, you will have to go with a commercially produced beta emitter.

Would this include the Sr-90 that Astronuc talked about?