1. 1 Japan-US collaboration to develop the “End-to-End simulator” Tsunefumi Mizuno Mar 12, 2003

2. 2 Overview of the “End-to-End simulation” In most past X-ray and gamma ray observatory missions, observations were done in the pointing mode and the instrumental response had rarely been simulated in the temporal axis (e.g., ASCA, Chandra, XMM, and EGRET). Due to its large field of view (~20% of the whole sky) and scanning observational mode, GLAST Large Area Telescope is extremely different in its construction and operation, and requires a thorough simulation in the time axis as well as in the spatial and spectral axes. The simulation framework, called “End-to-End simulation,” is required to have following features. The simulator must run very fast and can simulate the detector response and background dynamically. It has high flexibility; we can change the source generator, detector simulator, digitization, reconstruction, etc. easily and independently.

3. 3 Framework structure Master manager written in python Orbit information location and altitude (cut off rigidity) observation date (solar activity) satellite direction (source position) Calibration information bad channel list energy resolution Source generator Egret 3 rd catalogue Cosmic-ray Detector MC simulator BFEM Simulator EGRET Simulator LAT Simulator Digitization Data formatting Reconstruction Visualization Mapping histogramming data flow

4. 4 Works to do (Mizuno’s thought) BFEM simulator Compare with a stand-alone BFEM simulator and data ->Validate the framework in one position and time and test the performance (speed). EGRET simulator Compare with EGRET Crab data and Beam test data ->Validate G4 simulator Develop the digitizer, formatter and reconstruction program. Compare with EGRET data ->Validate framework in any position and time and re-analyze the EGRET data. LAT simulator Update geometry information. Develop the interface program with XML geometry description -> Update detector geometry automatically. Run simulator in EtoE framework -> Study performance. Develop the digitizer and formatter -> Study the trigger rate, response and background, etc.

5. 5 Task list and assignment Master manager (H. Tajima and others) Orbital information, coordinate translation (T. Kamae and others) EGRET catalogue generator (done) CR generator (T. Mizuno and others) BFEM simulator (done) EGRET simulator (to be assigned) LAT simulator (to be assigned) Digitizer/formatter for BFEM (done) Digitizer for EGRET (to be assigned) Digitizer/formatter for LAT (to be assigned) Reconstruction for BFEM/LAT (use the existing program developed by software team) Reconstruction for EGRET (to be assigned) Visualization, GUI interface (T. Kamae, H. Tajima and others)