Stepping in everyone’s toes ( but for a good cause ….)

1. Stepping in everyone’s toes( but for a good cause….) Eduardo do Couto e Silva Software Meeting – January 2001

2. LAT Performance/Calibration • Ensure faultless operation of integrated hardware on GROUND prior to launch • Test and verify hardware (including environmental testing) • Provide support to validate tools and strategy developed for LAT on-orbit and offline calibration, monitoring and debugging • Characterize the performance of the LAT via Instrument Response Functions and validate background estimations from Monte Carlo simulations. • Develop in-house expertise (as much as possible) for backup needed in case subsystem’s schedules are compromised by unforeseen situations

3. Integration Monte Carlo On line/ off line reconstruction Science Database Towers Calibration Beam Tests Cosmic Ray Tests Subsystems Hardware/Software Integrated Hardware/Software Database (s) ?

4. Ground testing is part of the overall calibration plan(Let’s raise some issues…) • What will be provided by subsytems (hardware/software) ? • What is needed to ensure that upon delivery all subdetectors are working and how this info will be stored and used as a reference ? • What will be needed at the tower(s) level from BTEM, BFEM, future tests beams and calibrations with cosmic rays ? • How do we interface with on-line,offline reconstruction and Monte Carlo developments ? • How to combine, maintain and update the information from different institutions and SLAC (database) ? • What will be the our input to the data science software ?

5. Performance & Database • The construction database will be continuously developed by the subsystems locally at their institutions and data will certainly be available on the web. • How does one transfer only the relevant data needed for integration while keeping the possibility of searching and querying construction information in case problems appear ? • Shall we have a central database ? If so, can we maintain it ?

6. An example… Detector Construction (subsystem level) Integration Sensors Ladders Kapton Converter Cables MCM GTRCGTFE Trays … Dead channels Leakage current Local coordinates of strips FILTER Both sides must be able to search and query all information Database

7. Database – What are we looking for ? (let’s plan for it) • Shall handle needs for integration (future beam tests and cosmic ray tests). • Shall interface with subsystems production database • What will be the inputs to the in-flight calibration software? • What will be the inputs to the off-line calibration software? • What will be the inputs to the Science database

8. Instrument Response Functions ( on GROUND) • Monitor electrical properties of detectors and determine effects from temperature, vibrations and vacuum environment • Mechanical survey to obtain local spatial coordinates of sensitive elements and determine effects from temperature, vibrations and vacuum environment • Characterize performance as a function of angles (how many ?) , energy (now many bins and how wide ?) and front/back sections of tracker (efficiencies?). What do the likelihood analyses need ? • Detailed program for study of background rejection with data and Monte Carlo simulation

9. Immediate Tasks • Define the group of people involved in integration and their roles (on the works by the GLAST management). • Define and build an integration database at SLAC with input from all subsystems (SCS is already ready to help–need green light). • Define tentative Instrument Response Functions (groundwork has been done by evaluation of science capabilities and by the integration engineers). • Define role of BTEM and BFEM data for integration to evaluate efforts needed for the software development (some groundwork done by the BTEM/BFEM groups). • Define minimum requirements for reconstruction and Monte Carlo simulations and prepare a working version with the GAUDI framework and GEANT4 (on the works by the software group).