One of the pillars of the T-REX project is the software. This is because one of the key points of the T-REX concept relies on the use of the precious information provided by Time Projection Chambers to qualify events as signal or background. In order to do that with the maximum efficienty, we need sophisticated software tools that are capable of recognising the patterns of the signal events in the data. Although each of the different Rare Event Searches will have their specific needs, a series of generic software tools are being developed to stress synergy. This particular effort is called RESTsoft, a software for Rare Event Searches with TPCs.
More specifically, RESTsoft is a collaborative software effort to provide a common framework for adquisition, storage, simulation, treatment and analysis of data taken with gaseous Time Projection Chambers (TPCs). RESTsoft is conceived for Rare Events applications in which access to detailed topology of the events in gas is required, in order to develop advanced anaylisis tools and discrimination/identification algorithms. Therefore the software provides a set of classes to store complete generic event models of TPC events, and generic tools to manipulate the event’s information.
RESTsoft has natural links to third party software:
- GEANT4 for the physics of the primary interactions of particles in the conversion gas. Alternative packages can be invoked for specific applications, e.g. SRIM for ions.
- MAGBOLTZ/GARFIELD for the physics of drift and diffusion of primary charge in a TPC. GARFIELD++ for the detailed microphysics of the amplification avalanche process.
- ROOT for generic analysis tooling, I/O, etc. As a general rule, all RESTsoft classes are ROOTified.
RESTsoft has a modular structure, which allow to combine and customize the software to the specific use/application. Briefly:
- It contains a software core to store detailed event information at different stages of the analysis or simulation process (physical event information, DAQ event information,…). It also contains holders for important information like detector geometry, gas type, readout geometry, DAQ type and configuration, etc…
- It contains electronics-specific acquisition software that reads data from binary files acquired with AFTER electronics (a versatile DAQ specifically designed for micromegas detectors by the T2K experiment) into RESTsoft core DAQ event holders.
- It contains wrapping software that links to GEANT4 type of code to simulate events from external particle and internal radioactivity produced interactions in the TPC gas. It includes a GEANT4 application optimized for the simulation of a low energy TPC with a customizable basic geometry and methods for generation of events of interest in Rare Event Searches, as well as simple tools (ROOT macros) for fast output analysis.
- It contains low level analysis tools that extract customized information and observables out of DAQ events, for further higher level analysis.
- It contains customizable routines to reproduce the detector response of a TPC on the DAQ event, like drift and diffusion of the primary cloud and digitization in a given readout pattern.
- It contains routines to simulate charge amplification and mesh transmission in the micromegas according to phenomenological models or experimental curves. A more detailed study is also available (see next item).
- It contains routines to study the microphysics of the detection in the readout plane (Micromegas mesh transmission and amplification). This is so far carried out as a stand-alone workline not yet integrated in the common frame.
- It contains customizable routines to reproduce amplifier pulses so as to produce realistic raw DAQ data from simulations.