Incontro Nazionale di Astrofisica delle Alte Energie Roma

Incontro Nazionale di Astrofisica delle Alte Energie – Roma, 15 -16 maggio 2003 Caratterizzazione spaziale del Tracker di GLAST Silvia Rainò INFN - BARI Roma, 15 -16 Maggio 2003 Incontro Nazionale di Astrofisica delle Alte Energie

Overview v GLAST experiment v The Large Area Telescope: GLAST-Tracker v Space tests: results on Engineering Model v Conclusions Roma, 15 -16 Maggio 2003 Incontro Nazionale di Astrofisica delle Alte Energie 2

Gamma Ray Large Area Space Telescope GLAST is an important part of the continuing quest to broaden our view of the universe. w explore Nature’s highest energy processes (10 ke. V – 300 Ge. V) w observe, with unprecedented detail, cosmic phenomena of extreme violence - LAT: ~20 Me. V - >300 Ge. V - GBM: correlative transient observations ~20 ke. V – 20 Me. V Roma, 15 -16 Maggio 2003 Incontro Nazionale di Astrofisica delle Alte Energie 3

Glast observatory Gamma Ray Burst Monitor (GBM) Large Area Telescope (LAT) Spacecraft Launch Vehicle Launch Location Orbit Altitude Orbit Inclination Orbit Period Launch Date Roma, 15 -16 Maggio 2003 Delta II – 2920 -10 H Kennedy Space Center 575 Km 28. 5 degrees 95 Minutes September 2006 Incontro Nazionale di Astrofisica delle Alte Energie 4

Large Area Telescope 4 x 4 modular array 3000 kg, 650 W g Si Tracker pitch = 228 m 8. 8 105 channels 18 x-y planes 20 Me. V – 300 Ge. V Cs. I Calorimeter hodoscopic array (8 layers) 6. 1 104 channels Roma, 15 -16 Maggio 2003 e+ ACD Segmented scintillator tiles e. Grid mechanical backbone Incontro Nazionale di Astrofisica delle Alte Energie 5

Large Area Telescope Single Photon Angular Resolution 3. 5 o @ 100 Me. V 0. 15 o @ 10 Ge. V g Wide Energy Range: 20 Me. V - >300 Ge. V Wide Field of View (> 2 sr) Point Source Sensitivity: < 6 x 10 -9 ph cm-2 s-1 (est. performance: < 3 x 10 -9 ph cm-2 s-1) Source Localization: 0. 3’ – 1’ e+ Good Energy Resolution DE/E ~ 10%; 100 Me. V – 10 Ge. V ~ < 20%; 10 Ge. V – 300 Ge. V Roma, 15 -16 Maggio 2003 e- Low dead time: < 100 ms/event Large Effective Area (Aeff )peak > 8, 000 cm 2 Incontro Nazionale di Astrofisica delle Alte Energie 6

Tracker Tower 1 top tray (converter 3% X 0) 11 thin-converter trays (3% X 0) 4 thick-converter trays (18% X 0) 2 no-converter trays 1 bottom tray (no-converter) Roma, 15 -16 Maggio 2003 Incontro Nazionale di Astrofisica delle Alte Energie 7

Space tests ACD Tray Tower TKR LAT CAL w withstand the mechanical solicitation during launch and first orbit phases Dynamic tests w operate satisfactorily at the temperatures expected during the mission Thermal tests Roma, 15 -16 Maggio 2003 Incontro Nazionale di Astrofisica delle Alte Energie 8

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 v July 8: v July 22: v August 5: Roma, 15 -16 Maggio 2003 EM tower assembled Vibration testing completed Thermal-vacuum testing completed Incontro Nazionale di Astrofisica delle Alte Energie 9

Dynamic test Test Sequence: 1. Modal survey: normal mode search 2. Random vibration 3. (Low frequency test + quasi static acceleration) 4. Modal survey: normal mode check Modal survey: ü Low amplitude sine sweep test, performed at the beginning & end of the test sequence ü Evaluates the transfer function of the item ü Allows to find any structural damage occurred during the test Roma, 15 -16 Maggio 2003 Frequency range 20 2000 Hz Sweep rate 2 oct/min Target Amplitude 0. 25 g 0 -pk Incontro Nazionale di Astrofisica delle Alte Energie 10

Dynamic test Random Vibration: ü Allows to study the structural response of the item when subjected to the launch environment ü depends on the rocket used for launch Frequency (Hz) ASD Qualification Level (g 2/Hz) ASD Acceptance Level (g 2/Hz) 20 0. 026 0. 013 20 -50 +6 d. B/oct 50 -800 0. 16 0. 08 800 -2000 -6 d. B/oct 2000 0. 026 0. 013 Overall 14. 0 grms 10. 0 grms Roma, 15 -16 Maggio 2003 Incontro Nazionale di Astrofisica delle Alte Energie 11

Vib test: experimental set-up accelerometers Shake table LDS V 864 LT @ Centrotecnica s. a. s (MI) Roma, 15 -16 Maggio 2003 Incontro Nazionale di Astrofisica delle Alte Energie 12

Modal survey EM tray - thin converter type (W=3%X 0) m 830 g 1 st resonant mode 0 815 Hz 2 nd resonant mode 0 1860 Hz ESPI Vibration TEST Roma, 15 -16 Maggio 2003 Incontro Nazionale di Astrofisica delle Alte Energie 13

Random vibration EM Trays tested at successively higher excitation levels: 7 grms 10 grms 14 grms White noise check among two successive random Roma, 15 -16 Maggio 2003 Incontro Nazionale di Astrofisica delle Alte Energie 14

Thermal tests Strain gauges positioned on the Si surface of the tray 1 m 3 Climatic chamber in INFN - PG site Terni, Dip. Ingegneria dei Materiali Lab. View based DAQ system Strain gauge on Si Wheatstone bridge configuration Roma, 15 -16 Maggio 2003 Reference strain gauge on quartz (CTE 0 ppm/°C) Incontro Nazionale di Astrofisica delle Alte Energie 15

Thermal test on EM 4 cycles -30°C ÷ +50 °C d. T/dt = 20 °C/hr Plateau 5 hr Roma, 15 -16 Maggio 2003 Incontro Nazionale di Astrofisica delle Alte Energie 16

Thermal test results Strain vs time strain T=30°C: 200 12 MPa Stress vs T = trasf· ESi , ESi= 13 GPa max= 28 MPa (SF= 7. 5) Roma, 15 -16 Maggio 2003 Incontro Nazionale di Astrofisica delle Alte Energie 17

Conclusions Summary v Test plans have been developed for all dynamic and thermal tests on trays and towers and are in the release cycle now v Positive results for the tests on EM trays Further work v June-July 2003: assembly and test of EM tower: w Dynamic and thermal-vacuum in Alenia Globalstar, Rome v Revise flight test plans with updated information resulting from EM tests v Assembly & test of Flight items (October 2003 ): w Test on 342 trays w Cosmic rays test w Assembly & test of 18 towers (16 flight+ 1 qual + 1 spare) Roma, 15 -16 Maggio 2003 Incontro Nazionale di Astrofisica delle Alte Energie 18

Roma, 15 -16 Maggio 2003 Incontro Nazionale di Astrofisica delle Alte Energie 19

Tracker Tray SSD’s Bias. Circuit Structural Tray Panel Converter Foils Bias. Circuit SSD’s Roma, 15 -16 Maggio 2003 Incontro Nazionale di Astrofisica delle Alte Energie TMCM 20

Tray Test flow overview Tray factory (panels) Ladder factory Vibration test Electrical test Tray assembly: ladders and MCMs on trays Electrical test before MCMs encapsulation Tray functional test Tray thermal cycles Stacked cosmic rays Tower assembly Roma, 15 -16 Maggio 2003 Incontro Nazionale di Astrofisica delle Alte Energie 21

Cosmic rays test Tray stacked in single/double view Roma, 15 -16 Maggio 2003 Incontro Nazionale di Astrofisica delle Alte Energie 22

Tower Test Flow Overview Tower assembly Sine sweep Tower functional test Vib test sequence Random vib Quasi static Sine burst Tower functional test Sine sweep Thermal-vacuum & functional test Roma, 15 -16 Maggio 2003 Incontro Nazionale di Astrofisica delle Alte Energie 23

Tower vib levels Sinusoidal vibration Sine burst TKR Acceptance (g) Qualification (g) Lateral (X) 3. 7 4. 6 Lateral (Y) 3. 7 4. 6 Axial (Z) +6. 8/-1. 8 +8. 5/-2. 25 • 2 half level 5 sinusoidal cycles @ 25 Hz: • 1 full level • 2 half level Random vibration Modal survey Frequency range 20 2000 Hz Sweep rate 2 oct/min Target Amplitude 0. 25 g 0 -pk Roma, 15 -16 Maggio 2003 Frequency (Hz) ASD Acceptance Level (g 2/Hz) ASD Qualification Level (g 2/Hz) 20 0. 01 0. 02 20 -50 +5. 9 d. B/oct 50 -800 0. 06 0. 12 800 -2000 -5. 9 d. B/oct 2000 0. 01 0. 02 Overall 8. 7 grms 12. 3 grms Duration 1 min/axis 2 min/axis Incontro Nazionale di Astrofisica delle Alte Energie 24

Tower thermal-vacuum cycles Qualification Acceptance Ranges -30°C 50°C -20°C 45°C # of cycles 12 4 Temp. rate 20°C/hr Pressure 10 -5 Torr Duration @ plateau 12 hr 4 hr Total Duration 384 hr + stabilization 58 hr + stabilization Roma, 15 -16 Maggio 2003 Incontro Nazionale di Astrofisica delle Alte Energie 25

Bottom tray Roma, 15 -16 Maggio 2003 Incontro Nazionale di Astrofisica delle Alte Energie 26