Software for Flash Matching

ICARUS implementation of OpT0Finder. To get started, go to README under flashmatch/Base.

Requirements

• ROOT version >= 6.22
• Python >= 3.6

How to build

source configure.sh
make -j

Per-shell (i.e. when you re-login), you have to run source configure.sh. No need to re-build unless you would like to (e.g. maybe you modified the source code).

Example

Coming soon...

What is Flash Matching?

In our detector we assume particle interactions produce signals in both TPC and PMT. Typically an interaction signal reconstructed from PMT signal is represented by recob::OpFlash and a corresponding representation from the TPC side is a cluster of particles that are produced from the same interaction (or the same root particle, such as a neutrino = neutrino interaction, a cosmic ray, etc.).

recob::OpFlash carries two information: a timing in the detector clock + photo-electron (PE) spectrum over PMTs, which is an estimate of photo-electron counts detected by each PMT. Although this is not a strict definition, we consider recob::OpFlash to represent one interaction without a granularity of particles in the same interaction. This is a good assumption as a photon detection timing resolution is several to 10 nano-seconds (prompt light time constant is ~6ns, and time of flight is several ns while particles finish traveling in similar time scale). In order to match with a recob::OpFlash, TPC interaction unit should be a set of particles that consists one interaction.

That's a long introduction... but finally! A flash matching is a reconstruction process in which reconstructed interactions (which unit is discussed above) from TPC and PMT are matched :)

What is OpT0Finder?

OpT0Finder is a mini-framework for developing and running flash matching algorithms. The top-level program execution is handled by flashmatch::FlashMatchManager. If you want to just try running the code and learn by examples, you can skip this section and maybe look at [this] toy-simulation example. In below, I ignore flashmatch namespace when specifying C++ class under that scope.

In OpT0Finder, TPC and PMT interactions are defined as QCluster_t and Flash_t respectively. So FlashMatchmanager is a code to find the right match between sets of QCluster_t and Flash_t. Though this is not a strict requirement, in general the matching is done by producing a hypothesis Flash_t, which is an expected PE per PMT based on QCluster_t, and comparing the similarity between the hypothesized and reconstructed (input, provided) Flash_t. In doing this, FlashMatchManager execute 5 types of algorithms.

• TPC interaction filter ... optional, can exclude some QCluster_t at run time before running matching
• PMT interaction filter ... optional, can exclude some Flash_t at run time before running matching
• Match prohibit ... optional, can exclude a certain QCluster_t and Flash_t from matching
• Hypothesis algorithm ... required, used to generate a hypothesis Flash_t from QCluster_t.
• Match algorithm ... required, used to match hypothesis Flash_t and reconstructed (input) Flash_t.

Big picture: how does FlashMatchManager work?

FlashMatchManager works in 4 big steps:

1. Configure parameters
2. Register a list of QCluster_t = TPC interactions
3. Register a list of Flash_t = PMT interactions
4. Run flash matching

That's it! So, in principle, only 4 function calls.

You can look at dat/flashmatch.cfg as an example. By now you should be able to understand the FlashMatchmanager configuration. If you are interested in learning about algorithms, you can find README and the source code under flashmatch/Algorithms directory. For FlashMatchManager itself, the code is under flashmatch/Base directory.

Learning more details?

The framework base is defined under flashmatch/Base and the algorithms can be found flashmatch/Algorithms. Take a look at README there!