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Gamma-ray Large Area Space Telescope. Status of the EM Thermal Tests. GLAST Large Area Telescope: Tracker Subsystem. INFN - Bari. 1 m 3. Si Strain gauge . Wheatstone bridge configuration (Labview). Reference Strain gauge on quartz. Thermal tests on pre-EM trays: set-up.
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Gamma-ray Large Area Space Telescope Status of the EM Thermal Tests GLAST Large Area Telescope:Tracker Subsystem INFN - Bari
1 m3 Si Strain gauge Wheatstone bridge configuration (Labview) Reference Strain gauge on quartz Thermal tests on pre-EM trays: set-up Procedures: LAT-TD-1037; Pre-EM Results: LAT-TD-1249 Service box
Pre-EM trays: some results Stability @ plateau: dT/dt < 3°C/hr Tchamber Tsilicon Silicon temperature delay 45 min plateau 5 hr
EM Tray thermal levels On orbit temperature range -15°C 30°C The maximum temperature is to be confirmed T-C: Thermal cycle (dummy trays) T-V: Thermal vacuum (live tray) Trays to be cycled/time: > 4 (TBD)
EM Tray thermal sequence The EM dummy trays will be tested at ambient pressure into the service boxes
Thermal-vacuum chamber in Alenia Spazio Globalstar, Rome Experimental set-up Tower Adapter plate Flex cable TEM EM Tower:TV Test Plans • TEM: • Voltage supply • Thermistors read-out
EM Tower thermal set up Tower covered with a thermal blanket during T-V cycles. The tower has a large number of thermocouples in the read out cables that can be acquired by using the TKR DAQ system. • Additional thermocouples (TBR): • +Y sidewall center of the thermal boss of the tray number 1; • +X sidewall center of the of the tray number 1, on the center plane; • +Y sidewall center of the thermal boss of the tray number 19; • +X sidewall center of the of the tray number 19, on the center plane; • -X sidewall center of the thermal boss of the tray number 10; • -Y sidewall near the center of the tray number 10, on the center plane The temperature control point for the cold part of the cycle will be the coldest thermocouple, while the control point for the hot part of the cycle will be the hottest one.
TV plan & procedures:open items • Maximum tray temperature 50 Vs 60 °C • The mystery of Jeff Wang and T-V simulation • Thermal balance: what is that? • TEM: is it ready? • Thermistors: voltage or resistance modes?