- Found peak using second derivative of data. Double differential used as it enables us to find some hidden peaks.
- Picked a cut off point for second derivative of data to give a range, and , where the values inside the range would be considered a peak
- Used equation,

- RMS was obtained by the equation,

- FWHM can be obtained by .

- Peak locator algorithm used for camera angle at 1.50mm:

- First attempt at error bars, setting y error as the square root of the count:

- Error bars are tiny due to incorrect assumption that data follows a poison distribution.

- Gaussian function used:

- Chi squared function used:

- Cd spectrum at 06.50mm with Gaussian fits, error bars and Chi squared values:

- Array of test parameters passed to fucntion : test_array_Cd650 = [[8E6, 150, 30, 3E5], [1.6E7, 270, 30, 3E5], [1.6E7, 520, 30, 3E5]]
- Chi squared values are huge as expected due to poor fit. Once errors and fit equation are correct, Chi squared should reduce.

- gaussian_fit.py.txt: Gaussian, erro, chi squared pyhton code

I | Attachment | History | Action | Size | Date | Who | Comment |
---|---|---|---|---|---|---|---|

png | Cd_0650_gaussian_errors_chi.png | r1 | manage | 48.9 K | 04 Nov 2016 - 12:21 | WilliamBurrows | Cd spectrum at 06.50mm with Gaussian fits, error bars and Chi squared values |

png | Improved_Cd_0650_Gaussians_lowest.png | r1 | manage | 19.6 K | 04 Nov 2016 - 10:17 | WilliamBurrows | Zoomed in look at the lowest Cd peak at 06.50mm |

png | Improved_Cd_0650_Gaussians_lowest_errorbar.png | r1 | manage | 22.1 K | 04 Nov 2016 - 10:17 | WilliamBurrows | First attempt at error bars, setting y error as sqrt of count |

png | PeakAt1.50mm.png | r1 | manage | 95.1 K | 03 Nov 2016 - 20:39 | JamesAngthopo | Peak locator algorithm used for camera angle at 1.50mm |

txt | gaussian_fit.py.txt | r1 | manage | 6.1 K | 04 Nov 2016 - 13:50 | WilliamBurrows | Gaussian, erro, chi squared pyhton code |

Physics Webpages
•
RHUL Webpages
•
Campus Connect
•
Royal Holloway, University of London, Egham, Surrey TW20 0EX; Tel/Fax +44 (0)1784 434455/437520

Topic revision: r5 - 04 Nov 2016 - WilliamBurrows

Copyright © 2008-2022 by the contributing authors. All material on this collaboration platform is the property of the contributing authors.

Ideas, requests, problems regarding RHUL Physics Department TWiki? Send feedback

Ideas, requests, problems regarding RHUL Physics Department TWiki? Send feedback