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Electron ion collier studies
This wiki explains how to view electron-proton collision events. To analyse events for such studies, install Jas4pp program:
wget http://atlaswww.hep.anl.gov/asc/jas4pp/download/current.php -O jas4pp.tgz tar -zvxf jas4pp.tgz cd jas4pp source setup.sh # takes 5 sec for first-time optimization
The last command optimizes Java packages for the Python language. Now you are ready to run over any file with truth-level and datector-simulation files, such as LCIO and ProMC. This program allows you:
- Downloading and searching HepSim data
- Processing ProMC files from HepSim
- Running over SLCIO files with Geant4 simulated / reconstructed events.
- Data analysis (jets, physics vectors, histogram packages)
- Visualisation of reconstructed events using Wired4 display
We will use e-p events shown in http://atlaswww.hep.anl.gov/hepsim/index.php?c=emp&e=141&t=all. The full simulation files are located under the tag “rfull001”, which corresponds to SiD simulations.
Visualizing events with Jas
First, install FPadSoft. Then copy the detector geometry file to the local directory where the file “fjas” is:
wget http://atlaswww.hep.anl.gov/hepsim/soft/detectors/sidloi3.tgz -O - | tar -xz;
This creates a directory “sidloi3”. This detector corresponds to “rfull001” tag used for the reconstruction of events in http://atlaswww.hep.anl.gov/hepsim/index.php?c=emp&e=141&t=all.
Now we can visualize the detector as [File]-[Open data source]-[HepRep] XML and select file “sidloi3/sidloi3.heprep”. This is how to do this using the command line:
jas4pp sidloi3/sidloi3.heprep
Now you should see the detector layout.
Next, we will read the simulated events: Open any *.slcio file you copied from HepSim using the menu [File]-[Open data source]-[LCIO] For e-p events, use this LCIO file from rfull001.
wget http://mc.hep.anl.gov/asc/hepsim/events/ep/141gev/lepto6ard_dis5q2//rfull001/lepto6ard_dis5q2_0001_pandora.slcio
Then click a small button [Go] (top menu bar). It will process events. Then select again [File]-[New]-[Wired 4 view]. If you want to see how data records are organized inside the slcio file, do this [File]-[New]-[LCSim Event browser]
Event display
Here are images of ep collision with a scattered electron identified using the PFA. The images were done using DIS ep samples http://atlaswww.hep.anl.gov/hepsim/info.php?item=159. Reconstructed electron energy from PFA: E=16.92 GeV “EVGEN” energy: 16.90 GeV
Now to analyse full simulations
Please read FpadSoft
— Sergei Chekanov 2016/01/22 20:36