Band Intensities

The Band Intensities window is provided to allow the intensities and widths of selected wavelength bands to be viewed as they change with time or position on the detector.

The steps for defining a band are as follows (using the Ar Ly-alpha line as an example):

• Click on the Add. button in the Bands panel. The Set Line Band Parameters dialog will be displayed:

• Change the name to Ly-alpha.
• Set the profile type to Gauss or Voigt. If a Voigt profile is chosen, a value for the Voigt parameter should also be entered. The parameter controls the ratio of the width of the Lorentzian contribution to the width of the Gaussian contribution.
• Click on the Set using Viewer button. The Time-Resolved Spectra window will show a spatially integrated spectrum with a range selection tool superimposed on it. Drag the lines of the selection tool by holding down the left mouse button while moving the mouse. The x values of the lines are shown in the toolbar of the Time-Resolved Spectra window. Position the tool to include the entire band. It will help to expand the region of the spectrum containing the band, as shown below. When satisfied, press the Enter button. To cancel, press the Esc button.

• To set the background, first select the type of background. For the Ly-alpha line, a background described by an exponential function is chosen. Add points to use to fit the exponential by clicking on the Add. button to display the Add Continuum Points dialog. A range of points or individual points can be added. For the present line, 3 points are chosen. For each point, click on the Select with mouse. button to again display the spatially integrated spectrum. This time a single point selection tool is superimposed. Move the selection line to the desired point and press the Enter key, then click on the Add key in the Add Continuum Points dialog (see below). This procedure can be repeated as many times as needed for both single points and ranges of points.
• Click on the Done button.

• When satisfied, click the OK button in the Set Line Band Parameters dialog.

If two or more bands have been defined, ratios of bands may also be specified. To specify a ratio:

• Click on the Add. button in the Ratios panel. The Set Line Ratios Parameters dialog will be displayed:

• Enter a name for the ratio.
• Select the bands for the Numerator and click on the right arrow key next to the Numerator box.
• Select the bands for the Denominator and click on the right arrow key next to the Denominator box.
• Click on the OK button when finished.

The parameters used to define the bands and ratios can be saved by choosing File | Export Band Analysis Parameters from the menu bar of the main window. The file is saved with the extension 'sbp'.

A previously saved file can be imported by choosing File | Import Band Analysis Parameters from the menu bar of the main window.

The Band Intensity Viewer window displays the integrated intensity for the band as well as the intensity found from fitting a Gaussian to the band and the width of the fitted line. Ratios of the integrated intensities and fitted intensities are shown for the specified band ratios. The values shown correspond to the selected Spectral data, time and position values selected in the combo boxes. For calculations with spatially resolved spectra, the integrated intensity, fitted intensity or width can be plotted against pixel position by choosing the plot type in the Select plot quantity combo box and clicking on the right arrow button. For simulations having both spatially resolved spectra and multiple time steps, plots can be made either against pixel position or against time. The x axis quantity, and the value of the time or position for the plot, are chosen in the controls above the graph.

The intensity and width results can be saved to a file by choosing File | Write Intensity Results from the menu bar on the Band Intensity Viewer window. The file is written in xml format and has the extension 'vrs'.

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