September 4, 2007 - Cosmic Telescope: Difference between revisions

From New IAC Wiki
Jump to navigation Jump to search
Oborn (talk | contribs)
No edit summary
Oborn (talk | contribs)
No edit summary
Line 20: Line 20:
|75 degrees
|75 degrees
|}<br>
|}<br>
;Binomial distribtuion
: best example is a coin toss, its either heads or tails
: mean (<math>\mu</math>) = number of tries <math>n</math>(coin flips) * probability of success<math>p</math> (head, 1/2)
:standard deviation(<math>\sigma</math>) = <math>np(1-p)</math>
; 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.
;Gaussian/Normal Distribution
: Full WIdth at Half Max (FWHM) = width of the distribution at half the value of the maximum probabilty (distibution peak) = <math>\Gamma</math>
:standard deviation (<math>\sigma</math>) = <math>\frac{\Gamma} {2.354}</math>
:error = <math>0.675 \sigma</math>


{| border="1" cellpadding="20" cellspacing="0"
{| border="1" cellpadding="20" cellspacing="0"
Line 62: Line 46:


The cosmic ray telescope sounting experiment appears to be following Poisson statistics.
The cosmic ray telescope sounting experiment appears to be following Poisson statistics.
[http://www.iac.isu.edu/mediawiki/index.php/Statistics_for_Experimenters See Statistics ofr Experimentalists]

Revision as of 16:16, 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


Time Start Time Stop Time elapsed (hour) Singles Count (on top) Coinc. Counts Coinc. per hour [math]\displaystyle{ \sqrt{N} }[/math] [math]\displaystyle{ (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


Mean [math]\displaystyle{ \mu }[/math] = 138 counts per hour

Instrumental Uncertainty =[math]\displaystyle{ \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]\displaystyle{ \sqrt{138}= 11.7 }[/math]) counts per hour.

The cosmic ray telescope sounting experiment appears to be following Poisson statistics. See Statistics ofr Experimentalists