Stepping in everyone’s toes
( but for a good cause….)
Eduardo do Couto e Silva
Software Meeting – January 2001
1
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
2
Integration
Science Database
Calibration
Monte Carlo
On line/ off line
reconstruction
Towers
Beam Tests
Cosmic Ray Tests
Integrated
Hardware/Software
Subsystems
Hardware/Software
Database (s) ?
3
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 ?
4
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 ?
5
An example…
Detector Construction
(subsystem level)
Integration
Dead channels
Leakage current
FILTER
Local coordinates of strips
Sensors
Ladders
Kapton
Converter
Cables
MCM
GTRC
GTFE
Trays …
Both sides must be able to search and query all information
Database
6
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
7
Instrument Response Functions
( on GROUND)
1. Monitor electrical properties of detectors and determine
effects from temperature, vibrations and vacuum
environment
2. Mechanical survey to obtain local spatial coordinates of
sensitive elements and determine effects from
temperature, vibrations and vacuum environment
3. 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 ?
4. Detailed program for study of background rejection with
data and Monte Carlo simulation
8
Immediate Tasks
1.
2.
3.
4.
5.
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).
9