Beta Particles
Uploaded by madsquirrel on Mar 16, 1999
Aim:
I will investigate how the field strength varies the deflection of Beta Particles.
Preliminary Work
I started my preliminary work because, when I started my measurements using 2 coils used in experiments to deflect electrons from and electron gun. While testing for the deflection of beta particles, I found that beta radiation was scattered in a very large cone, I can not get any readings with amount of beta radiation scattering.
So I would have to construct some type of shielding for this investigation, this is so I can measure the deflection more easily. The angle at which the beta particles are being scattered is 48o.
Deciding on the Type of Shielding
I will test for the best shielding. The best properties of the shield will be; it can be malleable to form different shapes and can be punctured, can stop radiation at a small thickness.
Equipment
Strontium 90 beta source
GM tube + counter
Different thickness of different metals
Clamps, bosses and clamp stand to hold the source and the material being tested.
Method
1. Set-up equipment as in the diagram
2. Record the thickness and the material being used.
3. Record 5 readings of the radiation count, and record them in a table
4. Replace material being tested with different material or a different sized material.
5. Repeat steps 2 to 4 as required.
Results
The background radiation reading is 2, 4, 6, 4, 5, 2. The average count is 3.8 (1dp).
Conclusion
This shows that aluminium stops radiation at 3.5 mm, this would be difficult to use because, this thickness of Aluminium is not malleable and the aluminium is not soft enough to puncture. Lead can stop radiation at very thin thickness', also lead is very malleable and is soft enough to puncture. I will use Lead shield at 0.6mm thick, since it is the most abundant thickness' available and it is the easiest to form to any shape I want.
Deciding how the shielding can be used.
I want to have a tight beam of beta particles in this investigation, so I will use my knowledge on what would be the best way to shield the source.
An unshielded source
The source is unshielded and has beta particles spreading out. Angle Theta is the angle which the beta particles are scattered through. The path of the beta particles is not a straight line, but a curve because the beta particle are deflected by the moles in the air. The points A B are the furthest points where beta ration is...