A student investigates a radioactive mineral specimen using a Geiger-Müller (GM) tube connected to a counter.
The count-rate is first measured with no absorber between the specimen and the GM tube.
The measurement is then repeated with three different absorbers placed in turn between the specimen and the GM tube.
The table below shows the results of the investigation:
| Absorber placed between specimen and GM tube | Count-rate (counts per minute) |
|---|---|
| None (air only) | 3200 |
| Thin paper | 2150 |
| 4 mm aluminium sheet | 580 |
| 3 cm lead block | 35 |
Explain how the data in the table supports the conclusion that the mineral specimen emits three different types of radiation: alpha (α\alphaα), beta (β\betaβ), and gamma (γ\gammaγ).