7E: Tower test plans GLAST Large Area Telescope: Tracker Subsystem Gamma-ray Large Area Space Telescope GLAST Large Area Telescope: Tracker Subsystem 7E: Tower test plans Nicola Mazziotta University and INFN Bari - Italy mazziotta@ba.infn.it

Outline Overview Tower vib plan Tower thermal plan Test schedule Summary Reference LAT Documents: LAT-MD-00408, LAT Instrument Performance Verification Plan LAT-SS-00788, LAT Environmental Specification LAT-TD-01005, Thermal Test Results on Thick Converter Mock-up Trays LAT-TD-01249, Thermal Test Results for Pre-Engineering Model Trays LAT-PS-01584, LAT Tracker Tray SSD Ladder Panel Assembly Procedure LAT-TD-00155, Tower Vibration Test Plan LAT-TD-01840, Tower Thermal Test Plan

Tower matrix Item Quantity High freq sine Sweep 20-2000 Hz Random Vibration White noise Low freq sine Sweep 5-50 Hz Functional Thermal Vacuum Test site Tower A (Qual) 1 X,Y,Z axis Qual  Italy Tower B (Spare) Acc 1-16 Towers (Flight) 16

Qual test flow (LAT-MD-408)

Acc test flow (LAT-MD-408)

Low frequency sine sweep Tower vib levels Low frequency sine sweep White Noise Frequency (Hz) ASD WN Level(g2/Hz) Overall grms Duration (min) 20 ÷ 2000 10-4 0.45 1 Random vibration Frequency (Hz) ASD Acceptance Level (g2/Hz) ASD Qualification 20 0.01 0.02 20-50 +5.9 dB/oct 50-800 0.06 0.12 800-2000 -5.9 dB/oct 2000 Overall 8.7 grms 12.3 grms Duration 1 min/axis 2 min/axis High frequency sine sweep Frequency range 20  2000 Hz Sweep rate 2 oct/min Target Amplitude 0.5 g0-pk

Tower vib set up Accelerometers set up (TBR): 3 axial on the shaker table (control accelerometer) 3 axial on the center of the bottom tray lower surface 3 axial on the center of the top tray upper surface 3 axial accelerometer +X sidewall center of the thermal boss tray number 12; 3 axial accelerometer +Y sidewall near the center of the tray number 10; 3 axial accelerometer +Y sidewall center of the thermal boss of the tray number 1; 3 axial accelerometer +Y sidewall center of the thermal boss of the tray number 19; 3 axial accelerometer -X sidewall center of the thermal boss of the tray number 10; 3 axial accelerometer -Y sidewall near the center of the tray number 10, on the center plane;

Tower A vib sequence For each axis Step Description Test Level LPT 1 LPT 1 Mounting 2 Fixture calibration High frequency sine sweep 0.5 g0-pk 3 Normal mode search 4 Pre-random vibration White noise 0.45 grms 5 Random vibration -6 dB Qual 6 Post/Pre-random vibration 7 -3 dB Qual 8 9 0 dB Qual 10 Post-random vibration 11 Normal mode check 12 13 Low frequency test Low frequency sine sweep Qual 14 Dismounting 15 16 Test completion

B&Flight Towers vib sequence For each axis Step Description Test Level LPT 1 Mounting 2 Fixture calibration High frequency sine sweep 0.5 g 0-pk 3 Normal mode search 0.5 g0-pk 4 Pre-random vibration White noise 0.45 grms 5 Random vibration -6 dB Acc 6 Post/Pre-random vibration 7 -3 dB Acc 8 9 0 dB Acc 10 Post-random vibration 11 Normal mode check 12 Dismounting 13 14 Test completion

Tower A thermal levels 8 Cycles Thermal-Vacuum cycling/Qual level Ranges -30°C  50°C # of cycles 8 (12) Temp. rate 20°C/hr Pressure 10-5 Torr Duration @ extreme 12 hr Total Duration 256 (384) hr + stabilization @ T room 8 Cycles (Tab. 2 LAT-MD-408)

B&Flight Towers thermal levels Thermal-Vacuum cycling/Acc level Ranges -20°C  35°C # of cycles 4 Temp. rate 20°C/hr Pressure 10-5 Torr Duration @ extreme 4 hr Total Duration 54 hr + stabilization @ T room

Tower covered with a thermal blanket during T-V cycles. 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.

Tower thermal sequence Step Description Level CPT 1 (Strain gauges and) Thermocouple set up 2 Chamber set up 3 (Strain gauges calibration) 4 Thermal vacuum cycles  CPT/LPT Qualification/Acceptance CPT/LPT 5 Dismounting 6 7 Test completion

Summary Work in progress: Number of thermal qualification cycles LPT definition CPT definition Use of strain gauges for T-V test ???