NuDOT rat-pac fork

Simulation code for NuDot

This fork contains geometry, scripts and settings for the Bo cryostat optical simulation

Checking out

• using git flow pattern (more info: https://www.atlassian.com/git/tutorials/comparing-workflows/gitflow-workflow)
• git clone https://github.com/NuDot/ratpac-nudot.git
• git checkout develop (this moves you to the develop branch)

Dependencies

• ROOT 6 (tested with v6.08/02)
• Geant4 (tested with v4.10.03)
• scons

building

• instructions in doc/installation.rst
• make sure ROOT and geant4 environment variables set
• ./configure
• scons

Running the Bo Optical Simulation

• ./bo_total_autorun.sh [runpath] [new]

This script runs the two optical simulations (plate-to-PMT with 420nm light and source-to-plate with 128nm light). The output is a simulated PE spectrum which is saved to output/[runpath]/pespec.root. The parameters for the simulation (number of events and positions to test) are set within the bash script, and can be modified.

The [new] flag forces a re-run of the plate-to-PMT simulation. If this option is ommitted, and if the file output/[runpath]/weights.txt file already exists, the script will skip the plate-to-PMT simulation and use the existing weight values for the source-to-plate simulation.

Additional material parameters are set in data/OPTICS.ratdb. The simulation geometry files are in data/bo_final/ and data/bo_src/ for the plate-to-PMT and plate-to-source simulations respectively. Both files should have the same geometry elements, but in the plate-to-PMT simulation, the PMT volume is sensitive, while in the source-to-plate simulation, the TPB plate is sensitive.

Adding a feature

• git checkout develop
• git checkout -b [username]_[featurename]
• do something awesome
• to put your code onto develop: git checkout develop; git merge [username]_[featurename]
• delete the branch

Chroma Interface Optional

This copy has an extremely developmental feature: an interface to Chroma, which simulates photon transport on a GPU. Current state is that it is not really working.

But to build with it anyway:

• go into ./configure and change USECHROMA=1
• one needs to have zmq and google protobufs
• one also needs to clone and install the ratchroma interface ...

Geometry

Optical Detector

• Needed to add new type of Sensitive Detector class for optical detectors
• RAT optical detectors too tied to PMTs
• Created GLG4SimpleOpDetSD. No fancy physics. If opticalphoton hits it, then a hit gets made. (later we can maybe configure this.)
• To add it, include opdet_lv_name in GEO RAT db table.
• Also, in GDML give each physvol instance a name with a number. This number will be used to assign the opdet a channel number.
• example:

[In GEO table]
{
name: "GEO",
valid_begin: [0, 0],
valid_end: [0, 0],
gdml_file: "nudot.gdml",
opdet_lv_name: "volSiPM",
}

[in GDML file]
...
    <physvol name="OpDet1">
      <volumeref ref="volSiPM"/>
      <position name="posSiPM1" unit="cm" x="0" y="0" z="0"/>
    </physvol>
    <physvol name="OpDet2">
      <volumeref ref="volSiPM"/>
      <position name="posSiPM2" unit="cm" x="0" y="0" z="10"/>
    </physvol>
...

RAT (is an Analysis Tool), Public Edition

---

RAT is a simulation and analysis package built with GEANT4, ROOT, and C++, originally developed by S. Seibert for the Braidwood Collaboration. Versions of RAT are now being used and developed by several particle physics experiments.

RAT combines simulation and analysis into a single framework, which allows analysis code to trivially access the same detector geometry and physics parameters used in the detailed simulation.

RAT follows the "AMARA" principle: As Microphysical as Reasonably Achievable. Each and every photon is tracked through an arbitrarily detailed detector geometry, using standard GEANT4 or custom physics processes. PMTs are fully modeled, and detected photons may be propagated to a simulation of front-end electronics and DAQ.

This generic version is intended as a starting point for collaborations looking for an easy-to-learn, extensible detector simulation and analysis package that works out of the box. Once acquainted with RAT, it is easy to customize the geometry elements, physics details, data structure, analysis tools, etc., to suit your experiment's needs.