NPDGamma Online Analysis  Version: NPDGData2005-04-29

2.3.1 Run Files and Names

File Name	Contents
runXXXX-0.dat	Guide Field Data
runXXXX-1.dat	Proton Beam Data + other diagnostic
runXXXX-2.dat	Detector difference signals only
runXXXX-3.dat	Detector sum signals, Monitor signals, RFSF signals, and other miscellaneous

The XXXX stands for the run number. When opening a run it is enough to select one of these four files. The others will then be opened automatically. The file runXXXX-0.dat is currently not opened in the on-line analysis program.

To open a run, select the File menu (see section 2.2.1 The Menu Bar ) and choose Open (Run file) .... The program will pop up a dialog box, asking you to select a file.

Figure 2.3.1: File open dialog

In the dialog box, select the directory in which the run is located

***************************************************
NOTE: if you select this file from either the hazel
directories /data0 or /data1 do not double click on the
directory name--only select it once!
If you double click on the directory name, ROOT will
attempt to read the entire information content of all
files located in that directory and, for reasons I
don't quite understand, this is really slow, because 
of the number of files in these directories.
***************************************************

For correct display of the plots, caculation of diagnostic data and correct analysis it is necessary to make sure that the correct TOF Data and Pedestal Window Settings have been applied.

If you are working on fiver, the run files will be located in the /archive backup directory. Sometimes the backup drives that are mounted under this directory fill up while the experiment is taking data. It then takes some finite amount of time to switch the backup drives. In this case, some of the files may only be available on hazel.

If you are running the analysis program on hazel the files are located in either of the /data0 or /data1 directories. These directories contain all runs that have been taken since the start of the commissioning. They therefore contain a large number of runs and when opening runs from these directories it is better to know the run number you are trying to open and type it into the file-open-dialog, rather than double-clicking on these directory names (see waring in section Run Files and Names).

If you want to work on a different computer you have to manually copy the runs you want to analyze from the directories mentioned above.

When opening a run and if the program can find all of the necessary miscillaneous files it will traverse the data in that file and extract/calculate some initial information about the run and the conditions under which it was taken. Figure 2.3.3 below shows the file information that is displayed in the log tab when a new run is opened. The quantities that are calculated during this process are used for the calculation of monitor ratios, neutron beam polarization and in the asymmetry analysis. It is important to make sure that the correct pedestals and monitor ratios for the unpolarized neutron beam are loaded (see section 2.4 Generating Miscellaneous Files).

Figure 2.3.3: Run File Information

If the program can not find the necessary miscillaneous files it will produce warnings and continue to open the run files. It will then perform the calculations without taking pedestals and monitor data ratios into consideration which will lead to bogus values for beam polarization and possibly wrong asymmetry. Sometimes, if one calculates noise asymmetries for example, these warnings can be ignored, but it is in general better to use the correct pedestal runs.