Difference between revisions of "September 4, 2007 - Cosmic Telescope"

From New IAC Wiki
Jump to navigation Jump to search
Line 49: Line 49:
  
 
Instrumental Uncertainty =<math>\sigma = \sqrt{\frac{\sum (x_i - \bar{x})^2}{N-1}} = 12.12</math> counts per hour
 
Instrumental Uncertainty =<math>\sigma = \sqrt{\frac{\sum (x_i - \bar{x})^2}{N-1}} = 12.12</math> counts per hour
 +
 +
Your instrumental uncertainty is approximately equal to the Poisson sigma (<math>\sqrt{N}</math>)

Revision as of 15:57, 5 September 2007

Plateau Zeroing
Time Start Time Stop Time elapsed (min.) Thresholds on both Scintillators Singles Count (on top) Coinc. Counts Coinc. per minute Angle measure
1:35 pm on 8/31 1:10 pm on 9/04 5725 min 225 626816 1654 .2889 75 degrees


Binomial distribtuion
best example is a coin toss, its either heads or tails
Poisson Distribution
standard deviation ([math]\sigma[/math]) = root of the mean ([math]\sqrt{\mu}[/math])
use in counting experiments
the distribtuion approximates the Binomial Distribution for the special case when the mean ([math]\mu[/math]) is a lot less than the number of attempts to measure ([math]n[/math]) because the probability of the event occurrring is small.
In the cosmic ray telescope experiment the mean number of detected cosmic rays is much smaller than the number of cosmic rays passing by.
Time Start Time Stop Time elapsed (hour) Singles Count (on top) Coinc. Counts Coinc. per hour [math]\sqrt{N}[/math] [math](x_i-\bar{x})^2[/math]
1:20 pm 2:20 pm 1 5694 127 127 11.3 121
2:20 pm 3:20 pm 1 4896 136 136 11.6 4
3:20 pm 4:20 pm 1 4655 151 151 12.2 169


Instrumental Uncertainty =[math]\sigma = \sqrt{\frac{\sum (x_i - \bar{x})^2}{N-1}} = 12.12[/math] counts per hour

Your instrumental uncertainty is approximately equal to the Poisson sigma ([math]\sqrt{N}[/math])