4.6 GEMSQRAW: GEMSQRAW / GSQ

To run the program type gemsqraw . Alternatively the program may be run in a simplified way by typing say gsq 10352 103466 where these two numbers are a sample and vanadium run number respectively. If the vanadium data have already been processed, then just type gsq 10352 and time will be saved by not processing the vanadium data again.

The purpose of this program is to produce a quick visualisation of the data. The program calculates a focused and normalised (sample/vanadium) spectrum for each existing detector bank. If desired, suitable backgrounds can be subtracted from the sample data and/or the vanadium data. The program is able to read data for a run which is still in progress, without any need to update or save the run. Vanadium data which have been smoothed by use of the ATLAS suite may be used by the program. This has the advantages that the result is obtained more quickly and has a better appearance, due to the removal of vanadium Bragg peaks. The smoothed vanadium data must be stored in the vansm subdirectory. The x-axis of the output can be either d-spacing, d, or momentum transfer, Q. Click here for a plot of typical glass data, or here for a plot of typical crystal powder data. The focussed data can be saved to a file named like GEM06914.SQR.

After execution, the focussed and normalised data are stored in a WorkspaceArray called bank. Each element of bank corresponds to a GEM detector bank - for example you can make a plot of the data for bank 5 by typing d bank[5] 0 10 (this will plot the data over the x-axis range from 0 to 10). The WorkspaceArray bank may be copied to another WorkspaceArray (called sio2 for example) by typing sio2=bank. (At the time of writing, GEM's bank zero does not exist, but when it becomes available its data will be stored in bank[8].)

GEMSQRAW normalises the data for each run to the number of microAmp-hours. As well as being able to read .RAW data files, GEMSQRAW is also able to read .SUM files produced by the NORM program of the ATLAS suite.

Last updated on 18 Sep 2002 by Alex Hannon (a.c.hannon@rl.ac.uk)