An industrial health and safety technician is testing two radioactive waste canisters, Canister A and Canister B, to determine their primary emission types for storage labelling. A Geiger-Müller (GM) tube detector is positioned at a fixed distance of 1.5 cm1.5\text{ cm}1.5 cm from each canister, and counts are recorded for a duration of 120 s120\text{ s}120 s using different absorbing materials.
The table below shows the technician's measurements:
| Source | Count in 120 s120\text{ s}120 s with no absorber | Count in 120 s120\text{ s}120 s with thin card | Count in 120 s120\text{ s}120 s with 3 mm3\text{ mm}3 mm of aluminium | Count in 120 s120\text{ s}120 s with 5 mm5\text{ mm}5 mm of lead |
|---|---|---|---|---|
| Canister A | 5200 | 82 | 80 | 81 |
| Canister B | 9800 | 9650 | 83 | 82 |
| None | 81 | 83 | 80 | 82 |
Explain why there is a reading recorded when no canister is present.
State why the technician must keep the distance between the canister and the detector constant throughout the measurements.
Using the data from the table, identify and explain the primary type of radiation emitted by: (i) Canister B
Using the data from the table, identify and explain the primary type of radiation emitted by: (ii) Canister A
