LD Online Help

NOTE: The program has again received significant feature upgrades and the help here pages have been updated. Make sure you download and start using Version above 847.

(Some images are from older versions and will be substituted at a later point)

These help pages describes the general procedure of analyzing DEER results in terms of distance distributions using the “LongDistances” program by Christian Altenbach. It is recommended to play extensively with simulated data to gain experience where the expected results are known. Another good set of examples are the files that ship with Deeranalysis 2013 by Gunnar Jeschke (select the “tutorial” folder).

The program is designed to quickly analyze DEER data. Often the default settings are sufficient and many aspects are fully automated. For advanced analysis, everything can be tuned manually, of course.

Overview

General layout: The panels on the right are always visible showing the full raw data, selected data, fitting result and Tikhonov regularization, and are updated as settings change on any of the tabs. (Some example screens and descriptions can be found here)

User interaction takes place on the various tab pages on the left. On the right are three graphs and one chart. Top: The raw data currently under analysis in white. The back calculated simulation based on the regularization results are shown in either purple (tikhonov, if a fit is not available) or red (valid fit). Below is the same graph, but only showing the selected data after background correction according to the current settings. Below is the distance graph, showing the two fits (purple or red). The vertical cursors show the estimated confidence boundaries according to Jeschke. The chart below shows the relative chi² (normalized to the estimated noise variance in the data) of the residual for both types of fits, the lower the better, best is (theoretically) 1! Some assumptions need to be made about the noise in the data. The current noise estimation is from the difference in the late data and a back-calculated tikhonov fit using alpha=0.1 (can be changed on the settings tab). (A chi² value <1 indicates that the data noise estimate is poor probably due to an incorrect "noise alpha" value). If a fit is not available, the value is shown as NaN ("Not a number"). The bottom left shows the file currently processed and the text box in the lower right show relevant status information, such as fitting statistics.

Tip strips and context help

Most controls and indicators have a small tip strip providing additional information when the mouse is hovered over them. In addition, many items have extensive context help.

To enable context help, press ctrl+h (or "menu..help..show context help") and further information is shown in the context help window when hovering over a control or indicator.

The detailed help is mainly arranged by the pages of the main tab control. Click on the relevant entry to get more information.

• Quick Instructions <--- Start Here!

• Data tab

• Select tab

• Background tab

• Distances tab

• L-Curve tab

• Errors tab

• Internal data tab

• Output tab

• Settings tab

• About tab

Reference:

• Algorithm details

• File Formats

• Distribution Shapes