Difference: 20151129_MSciSpectrocopyLab (8 vs. 9)

Revision 909 Feb 2016 - AshleaKemp

Line: 1 to 1

META TOPICPARENT	name="StewartBoogertSpectroscopy2015"

Fixing errors

Line: 44 to 44

Finally a quadratic term was fitted for the background of the image, which has the equation:

$\begin{equation} f(x) = b_{0} + b_{1} x + b_{2} x^2 \end{equation}$

These are plotted below

Changed:

<
<

>
>

The quadratic can be seen to improve the fit to the background of the data as shown below:

Changed:

<
<

>
>

The three different fits produced parameter values of:

Parameters

Gaussian + circle

Skewed Gaussian + Circle

Skewed Gaussian + circle + Quadratic background

Line: 76 to 76

$\begin{equation} L(x;\gamma, x_{0}) = \frac{A}{\pi} \frac{\gamma/2}{(x-x_{0})^2 + (\gamma/2)^2} \end{equation}$

Both of these fits are shown with the data in the plot below:

Changed:

<
<

>
>

Paramater	Skewed Gaussian + Circle + Quadratic Background	Voigt + Circle + Quadratic Background
Gauss Amp	1.077	-1.48±(1.39e05)

Line: 122 to 122

$\chi^2$ per dof

1587

968

969

Some of the grating setting are shown below

Changed:

<
<

>
>

Halogen Lamp

For the halogen lamp the above fit parameters were used to set the wavelength of each frame, these were then plotted as shown below:
The below plot shows the linear and squared plots and it can clearly be seen to improve at larger and smaller wavelengths, however not much change in the center.

Changed:

<
<

>
>

When the cubed parameters were used, the plot did no seem to improve, as the image shows

Changed:

<
<

>
>

This may be due to an incorrect point which the cubed plot fits better to however is further from the true value

-- AshleaKemp - 27 Nov 2015

View topic | History: r11 < r10 < r9 < r8 | More topic actions...

Copyright © 2008-2023 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