2. Alpha Beta Gamma Practical

Question 1

Describe the method for alpha beta and gamma practical

Answer 1

1. Measure the background count for 2 minutes using Geiger Muller tube, counter and stop clock.
2. Place the radioactive source near the Geiger Muller tube and measure the amount of ionising radiation that it detects in a fixed time with no absorbing materials.
3. Place paper, aluminium and lead between the tube and source and repeat

Question 2

Why is it important to repeat the measurements?

Answer 2

For reliability and to calculate the average

Question 3

What could cause the measurements to be different?

Answer 3

The detector might not detect all the radiation and as radiation is a random process levels can fluctuate

Question 4

What problems would be caused if we measured how much radiation was detected in 1 second or 10 seconds instead of 1 or two minutes?

Answer 4

This would cause smaller values and the fluctuation will be quite large, making the results harder to compare

Question 5

Safety precautions?

Answer 5

Radioactive sources should be kept in a lead lined box
Should be picked up using long handled tongs
Don’t point them at people and keep your distance
Reduce exposure time by not keeping the sources in the room for very long

Question 6

Why should you measure the background radiation?

Answer 6

To check whether all the radiation has been absorbed, and detect whether the value remaining is due to the source or background radiation

Question 7

How do you find out the type of radiation emitted by the source?

Answer 7

Look at the big drops in the values

If there was a big drop when paper was put in front, then its alpha etc.

Question 8

Why is the distance between detector and source the same for each experiment?

Answer 8

Control variable as distance affects the exposure to radiation and could decrease or increase the count