FLArE

Simulation code for R&D of the FLArE detector

Setting up on lxplus

The LXPLUS service at CERN (lxplus.cern.ch) provides a cluster of machines for interactive computing as well as access to the HTCondor batch system for job submission. Provided you have a valid CERN computing account, you can access LXPLUS following these instructions:

1. Visit the list of services at the CERN Resources Portal, and search for boxes: LXPLUS and Linux, AFS Workspaces, EOS/CERNBox.
2. Subscribe to LXPLUS and Linux
3. Subscribe and setup your AFS Workspaces: you can have up to 10GB in /afs/cern.ch/user/<initial>/<username> and up to 100GB in /afs/cern.ch/work/<initial>/<username>. You can set these limits from the Settings in the "AFS Workspace".
4. Subscribe to EOS/CERNBox and login to cernbox: https://cernbox.cern.ch/. This will allow you access to /eos/user/<initial>/<username> with up to 1TB of space.

Users are recommended to setup code in their AFS Workspace areas and use their EOS/CERNBox for long term data storage. A simple script is provided to setup the relevant software dependencies in the LXPLUS environment.

source lxplus_setup.sh

To compile the code

• Create a new directory to contain the executables (assume the path is /path/to/build)
• Assume the path to the source code is /path/to/source
• To compile, you need to go to the build directory cd /path/to/build
• And then cmake -S /path/to/source -B /path/to/build
• Finally make

The minimal software requirements are:

• Geant4 v4_10_6_p01c
• ROOT v6_22_06a
• HEP_HPC v0_14_01
• HDF5 v1_10_0+

These are automatially satisfied once the lxplus_setup.sh script is sourced. There is no longer an explicit GENIE dependency. However, the input GENIE ghep files need to be converted in the gst format (plain ROOT tree). The conversion can be perfomed with the native GENIE utility gntpc.

Run the simulation

Once the code has been compiled, the simulation can be run by passing a macro file to the FLArE executable:

./FLArE /path/to/macro.mac

Several examples of macros are available in the macros directory. The detector geometries can be easily imported by including one of the macros in macros\geometry_options. If no macro is passed as argument, the default is macros\vis.mac which simply displays the current geometry.

Single particles

There are several .mac macros in macros\single_particle directory: LAr_e-_mono.mac, LAr_mu-_mono.mac, etc. As denoted by the name, they're used to simulate single e-/mu-/... particles inside the FLArE volume. To run a simulation, just do ./FLArE macros/single_particle/LAr_e-_mono.mac. If you want to modify the energy you intend to simulate, modify the parameters inside the mac scripts.

Neutrino events

Neutrino events are generated by reading nu-Ar interaction vertexes from GENIE output files and transposing the final states particles in Geant4. These GENIE gst files are available for all users in \eos\user\m\mvicenzi\genie. Example macros can be found in macros: numu_genie.mac, nue_genie.mac, nutau_genie.mac.

Macro commands

Geometry

Event generators

Analysis

How to save an event display with high resolution using the DAWN Event Display

There is this tutorial for use at the October 2003 Fermilab Geant4 Tutorial.

• Add /vis/open DAWNFILE to the mac file, after running a pass of simulation you'll find a ".prim" files suitable for viewing in DAWN.
• Run ~/dune_data/app/dawn_3_91a/dawn -d filename.prim, and it will generate a high resolution picture with the format of EPS.

Some initial results

cern indico 1

cern indico 2