Particle Physics Group



Processing data from the tracker prototypes

This describes how to analyse the data taken with the scope from one cell of a prototype. The data are taken with labview ( which produces a large ascii file of all digitised signals. The file names look like raw_141108_153459.txt or 141108_153459.txt.

1) Run the labview program that analyses the signals and extracts the useful numbers (anode, cathode times, signal peaks and areas). The vi you need is:


This produces a smaller text file (named like raw_141108_153459sum.txt) with the useful signal quantities: times and amplitudes.

2) To convert the text file to a root ntuple, you need the program:


The usage of this is "txt2root filename.txt", for example if you are in the top level directory, type:

$ pwd

$ ./Text2root/txt2root raw_141108_153459sum.txt
txt2root> reading file: raw_141108_153459sum.txt
txt2root> Thanks to Andres Osorio!
txt2root> The run parameters are:
lvlc     dtbc    dtac    lvl1a   lvl1a           dtaft   dtbft   lvlsk   dtsk
50.000  -1.000  5.000   -30.000 -80.000 4.000   -1.000  -20.000 1.000
txt2root> Processing events...
txt2root> Total number of events: 1074

This produces in the current directory a file raw_141108_153459sum.tree.root and outputs some statistics such as thresholds and total number of events.

3) The next step is to analyse the root data and produce histograms. For this you need the macro:


To use it, run (in this example, from the same directory):

$ ./AnalysisGeiger/analyseData raw_141108_153459sum.tree.root > 141108_153459.log

The macro produces in the current directory a file raw_141108_153459sum.hist.root with all the histograms. If the current directory has a subdirectory called Plots, then some plots will be saved in it.

In this command I have redirected the standard output to a log file. It will contain some messages and root fitting statistics, but also the important numbers of efficiencies, means and rms's of distributions etc. Some of these means and rms's are also saved into a file Data.txt in the current directory, which contains a table of the numbers and is appended (not overwritten) every time you run the macro. For more information, read the code of

The txt2root code is standard and should not be modified (unless the file format of the labview text file changes).

If you wish to edit the macro that analyses the data and books histograms, you can download the files into your working directory:

$ cd SomeDir
$ cp /afs/ .
$ tar -xzvf software.tar.gz

$ ls
software.tar.gz  sw

$ ls sw/
AnalysisGeiger  Text2root

$ cd sw/AnalysisGeiger/

$ ls 
analyseData  GeigerCellData.hh  GeigerCellData.o  Makefile

The file contains the data analysis and histograms, you can change them or add your own. Then make the executable again:

$ make
g++           -DHAVE_CONFIG_H -O2 -g -Wall   -I/home/irina -pthread -m32 
-I/opt/root/root5.18.00/root/include -I./ -I/opt/root/root5.18.00/root/include  
g++           -o analyseData GeigerCellData.o -L/opt/root/root5.18.00/root/lib 
-L/opt/root/root5.18.00/root/lib -lCore -lCint -lRIO -lNet -lHist -lGraf -lGraf3d 
-lGpad -lTree -lRint -lPostscript -lMatrix -lPhysics -pthread -lm -ldl -rdynamic

and run it in the same way as shown above. Good luck!


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Last modified Thu 20 November 2008 . View page history
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