2. Physics 490 – Project Lab Lab B2: Radioactive Decay, Counting Statistics, and the Geiger Tube Jack Young Richard Breazeale Ryan Phelan

3. Counting Statistics - Topics Read and interpret the Chart of the Nuclides. Observe the difference between α, β, and γ decays. Observe the properties of the Gaussian and Poisson distributions.

4. Chart of Nuclides

6. α, β, and γ Decays α decay β decay γdecay γ decay

7. Measuring Decays The Geiger-Muller tube and associated equipment

8. Science Workshop

9. Science Workshop Settings

10. Excel – Statistical Analysis

11. Science Workshop

12. Science Workshop - Model

13. Science Workshop - Spreadsheet

14. Science Workshop - Parameters

15. Science Workshop - Plot

16. Science Workshop – Curve Fit

19. The Poisson Distribution  The Poisson distribution can be obtained from the binomial distribution if we let the number of events n go to infinity, where the most probable number of successes x remains constant so that p goes to zero.

20. Binomial Theorem The Poisson distribution describes the large-n limit (k large or small). We define the average number of events as x and the average number of events per measurement p so that x = np. If n is large compared to k and p is very small compared to 1, we can approximate as follows: Poisson Ditribution

21. The Poisson distribution is applied generally to situations where only a few events are counted. It is equally valid when large numbers of events are counted, but the Gaussian distribution can be used then, and it is easier to use. Substituting x for np, the Poisson distribution becomes:

22. Poisson Distribution Poisson distributions with different mean values.

23. The End