Radiation (counts/minute) for various radioactive sources with various shielding
The following data was collected using radioactive sources found in our lab. It shows the count rate (counts per minute, cpm) detected by our geiger counter as various types of shielding are used. The first four sources are known sources.
The last three (unknowns A, C, and E) are radioactive sources whose identity is unknown. They are part of a set labeled "Becquerel Chemicals" produced by the Damon Scientific Company, which has gone out of business as far as I know. Each sample is permanently sealed inside a small, transparent, plastic box.
Your task: decide what kind (or kinds) of radiation is/are being emitted by unknowns A, C, and E.
| Source | Sr-90 | Tl-204 | Co-60 | Po-210 | Unkn A | Unkn B | Unkn C |
| Radiation type | beta | beta | gamma | alpha | |||
| Shielding | |||||||
none |
5152 | 5432 | 2119 | 198 | 2728 | 2865 | 523 |
2 sheets paper |
4796 | 4025 | 2092 | 28 | 2492 | 2627 | 461 |
1 piece plastic |
2704 | 34 | 2046 | 26 | 969 | 1009 | 210 |
1 piece Aluminum |
2137 | 22 | 1993 | 23 | 635 | 643 | 156 |
1 piece lead |
22 | 22 | 1773 | 20 | 22 | 24 | 80 |
Comments? Questions??
Robert Clark