Running purge_det on GEM data 

Before you can run purge_det, you must download the appropriate grouping file and rename or copy it to groups_def.dat 

GEM grouping files are available here . 

The file purge_det.dat must already exist in the directory where you are doing the analysis. This file must be prepared so that its contents are appropriate to your experiment. The contents of purge_det.dat are described here .

The file spec.bad must not already be present in the same directory - if it is there then you must delete it before running purge_det.

The .RAW data files must be made available before you run purge_det. If you are at ISIS then the data files can be accessed over the network. If you are not at ISIS then this probably means that the data files need to be on a disc on your computer. You can either take the .RAW files away on a CD-rom, or FTP them to your computer (they must be FTPed as binary).

It is recommended to run purge_det from a command prompt window, not by double-clicking on the program's icon. This has the advantage that if the program encounters an error then the error messages are retained.

At the end of running purge_det you should check that the number of good spectra is reasonable. A value of zero indicates that all spectra will be excluded from the analysis, and  that something has gone seriously wrong. It is reasonable to expect that more than half of the detectors will yield good spectra.

Last updated on 08 May 2006 by Alex Hannon (a.c.hannon@rl.ac.uk)