This wiki explains how to view electron-proton collision events. To analyse events for such studies, install Jas4pp program (assumes “bash”):

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.

Then copy the detector geometry file to the local directory where the file “jas4pp” 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]

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

Please read FpadSoft

— Sergei Chekanov 2016/01/22 20:36