Caratterizzazione spaziale del Tracker di GLAST

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Caratterizzazione spaziale del Tracker di GLAST
Incontro Nazionale di Astrofisica delle Alte
Energie Roma, 15-16 maggio 2003

• Silvia Rainò
• INFN - BARI

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Overview

• GLAST experiment
• The Large Area Telescope GLAST-Tracker
• Space tests results on Engineering Model
• Conclusions

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Gamma Ray Large Area Space Telescope
GLAST is an important part of the continuing
quest to broaden our view of the universe.

• explore Natures highest energy processes (10
  keV 300 GeV)
• observe, with unprecedented detail, cosmic
  phenomena of extreme violence

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Glast observatory
Gamma Ray Burst Monitor (GBM)
Large Area Telescope (LAT)
Spacecraft
Launch Vehicle Delta II 2920-10H Launch
Location Kennedy Space Center Orbit
Altitude 575 Km Orbit Inclination 28.5
degrees Orbit Period 95 Minutes Launch
Date September 2006
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Large Area Telescope
4 x 4 modular array 3000 kg, 650 W 20 MeV 300
GeV
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Large Area Telescope
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Tracker Tower
1 top tray (converter 3 X0)
11 thin-converter trays (3 X0)
4 thick-converter trays (18 X0)
2 no-converter trays
1 bottom tray (no-converter)
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Space tests
LAT
Tower
Tray
TKR
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Work in progress

• Space test activity now concentrated on the
  assembly and test of the Engineering Model Tower
• Test plans have already been defined
• Dynamic test 12 EM panels successfully tested
• Thermal test 2 EM trays cycled w/out any damage
  to silicon

EM Tower Plan Schedule

• July 8 EM tower assembled
• July 22 Vibration testing completed
• August 5 Thermal-vacuum testing completed

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Dynamic test

• Test Sequence
• Modal survey normal mode search
• Random vibration
• (Low frequency test quasi static acceleration)
• Modal survey normal mode check

• Modal survey
• Low amplitude sine sweep test, performed at the
  beginning end of the test sequence
• Evaluates the transfer function of the item
• Allows to find any structural damage occurred
  during the test

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Dynamic test

• Random Vibration
• Allows to study the structural response of the
  item when subjected to the launch environment
• depends on the rocket used for launch

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Vib test experimental set-up
accelerometers
Shake table LDS V864LT _at_ Centrotecnica s.a.s (MI)
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Modal survey
EM tray - thin converter type (W3X0) m ? 830 g
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Random vibration
EM Trays tested at successively higher excitation
levels
7 grms ? 10 grms ? 14 grms
White noise check among two successive random
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Thermal tests
Climatic chamber in INFN - PG site Terni, Dip.
Ingegneria dei Materiali
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Thermal test on EM
4 cycles -30C 50 C dT/dt ? 20
C/hr Plateau 5 hr
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Thermal test results
Strain vs time
? ??? ? 12 MPa
?T30C ??? ? 200 ??
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Conclusions

• Summary
• Test plans have been developed for all dynamic
  and thermal tests on trays and towers and are in
  the release cycle now
• Positive results for the tests on EM trays
• Further work
• June-July 2003 assembly and test of EM tower
• Dynamic and thermal-vacuum in Alenia Globalstar,
  Rome
• Revise flight test plans with updated information
  resulting from EM tests
• Assembly test of Flight items (October 2003 ?)
• Test on 342 trays
• Cosmic rays test
• Assembly test of 18 towers (16 flight 1 qual
  1 spare)

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Tracker Tray
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Tray Test flow overview
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Cosmic rays test
Tray stacked in single/double view
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Tower Test Flow Overview
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Tower vib levels
Sinusoidal vibration
Sine burst

• 2 half level
• 1 full level
• 2 half level

5 sinusoidal cycles _at_ 25 Hz
Random vibration
Modal survey
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Tower thermal-vacuum cycles
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Bottom tray