Minilab: Radiation VS Shielding for Unknown Isotope #204

Introduction:
This unknown radioactive sample is quite old (approximately 30 years old), so its activity is low. You should compare the effect of shielding on this radiation using the data in the lab entitled "Shielding" - which gives shielding data for known isotopes.

Data

Background count: 20 cpm

 
Shielding
Radiation, cpm
none
97
2 sheets paper
61
1 piece plastic
32
1 piece Al metal
27
1 piece lead
22

 

Procedure
First correct for background radiation: subtract the background radiation from each value above. Next decide what type of radiation Unknown #204 is emitting.


Questions? Comments??
Robert Clark