This and linked documents will lay out the requirements, inter-relationships and testing procedures for each of the major science software components.
Science Software comprises several components
Prompt processing of instrument data through to Level 1 event quantities
Provide near real time monitoring information to the IOC
Monitor and update instrument calibrations
Create high level science products from Level 1 for the PI team
Reprocessing of instrument data
Provide access to event and photon data for higher level data analysis
Bulk production of Monte Carlo simulations
Interface with mirror PI team site(s) (sharing data and algorithms)
Interface with the SSC (sharing data and algorithms)
and is broken down into WBS units to illustrate the workplan. The top of our WBS is 4.1.D.
Existing requirements documents arranged in the WBS structure are:
D.1 Sources, Sim and Recon*, which in turn contains pointers to
D.1.1 Sources*
D.1.8 Trigger Simulation*
D.1.9 Background Rejection*
D.2 Analysis Tools*, containing pointers for some specific areas
D.2.7 Geometry*
D.2.9 Code and Release Management*
D.4 Science Tools*
D.6 Calibrations*
D.7 PDR Support*
The simulation takes input distributions of photons or background particles, follows their path through GLAST and simulates any interactions with the device. The simulation phase outputs "raw data" that is interchangeable in form to real data, but adds Monte Carlo truth to the record. Reconstruction takes the raw data and attempts to recover the initial properties of the incident particle, and to tag it as signal or background.
The sources are particle flux generators which are the input to the simulation. These model the characteristics (origin, energy) of the signal photons as well as background cosmic rays, albedo and heavy nuclei used for calibrations.
The flight trigger code, made to run in the offline environment and any analysis that goes with the understanding of the trigger code and support of its design.
Algorithms, tuned to different science goals, which identify incident particles as background, allowing the remaining interactions to be identified as signal photons.
Lower-level requirements for analysis. See also Science Tools.
The geometry will be described by an ascii file representing the instrument and its required surroundings (eg spacecraft, gondola etc). Utilities will be supplied to extract the information from the input file with interfaces to the simulation packages (eg GEANT4 and Gismo) to create the geometric volumes. An interface to the reconstruction to extract needed geometrical quantities will be supplied. The utilities will also be available to other clients as needed: event display, user analysis, etc
An ongoing effort to optimize and track the high level performance of the instrument and code through the PSF and effectve area measures. This is intended as a diagnostic for the performance of the simulation and reconstruction, providing a way to track its performance vs time. These are the code benchmarks telling us the code has not wandered away from us.
Utilities and procedures needed to reliably tag the versions of code that form releases and to validate the performance of those releases. Other utilities and facilities of general use will be grouped under this aegis.
The high level tasks required to extract science from the reconstructed data and MC. These include the various utilities to manipulate the Level 1 data and perform the required analyses, such as GRB detection, sky maps and so on.
Co-located with the IOC to perform near-real time data reconstruction from the instrument and provide feedback to Operations from high level subsystem-correlated instrument response, as well as input to the instrument calibration process. It will also perform bulk MC production. It will provide the Level 1 reconstructed photons that will be used for science and passed on to the Science Support Center. It will perform re-reconstructions as needed.
These include the subsystem instrumental calibrations and alignment as well as higher level calibrations of overall instrument response.
The previous version of this document may be found here.
This document has been prepared to avoid confusion such as ... (text, audio).
R.Dubois Last Modified: 08/13/2001 22:54