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THEMIS Solid State Telescope (SST) Instrument Suite PER The THEMIS SST, IDPU and II&T Teams. Personnel and Organization. SST Organizational Chart ( all UCB unless noted ): Davin Larson - Lead Ron Canario - Electrical Robert Lee - Mechanical Thomas Moreau – Design/Testing (Postdoc)
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THEMIS Solid State Telescope (SST) • Instrument Suite PER • The THEMIS SST, IDPU and II&T Teams
Personnel and Organization • SST Organizational Chart (all UCB unless noted): • Davin Larson - Lead • Ron Canario - Electrical • Robert Lee - Mechanical • Thomas Moreau – Design/Testing (Postdoc) • Jianxin Chen – FPGA programmer (Outside contractor)
MRD Functional Requirements • The Tough requirements • Energy Threshold - ~30 keV (at room temperature; determined by noise. Improves at lower temperature) • Energy Resolution - ~10-12 keV ( at room temp; improves at lower temperature) • Magnetic Cleanliness <1 nT at location of magnetometer <2 nT at 2 meter
SST Status at I-PER • Requirements and Design: • No major changes to Requirements since M-CDR (see Changes Since M-CDR and PFR Status for details). • Procurement: • All parts procured with exception of detector stacks for P4, P5 and P6. Detector stack delivery delayed due to inadequate Aluminum layer on “O” detectors. • Probe 1 Flight Sensors • Have gone through 1 Vibration test – Failure in mechanical structure • Rebuilt but not retested. • Have gone through TV but rework may invalidate tests • Probe 2 Sensors • Includes ALL Mods • Passed Vibration • Passed Thermal Vac • Final Calibration scheduled: 2005-5-3 • Probe 3 Sensors • Awaiting detector tests before final assembly • Vibe scheduled for 2005-05-6
SST Changes Since M-CDR • Changes to Mechanical and Electrical Designs: • Sensors • Mechanical Housing strengthened. • Additional light baffling and blacking added. • FET added to prevent preamp saturation during Sun Pulse. • Minor Mods to attenuator mechanism to improve reliability • DAP board • Minor changes to analog housekeeping. • FPGA mods added to control Sun Pulse Blackout. • Attenuator position feedback method changed to allow use of harness wires for sun pulse control. Still Open • If SMA supply is on: should have no impact on measured housekeeping value. • If SMA supply is off: Voltage will drift high due to 5k pull up resistor.
Electrical Assembly & Test Mating (w/ pictures) Magnetic Characterization CPT Mechanical Assembly & Test Vibration Magnetic Characterization CPT 2004-12-28 Thermal Vac Magnetic Characterization CPT (?) 2005-01-03 Calibration Assembly test sequence
Sensor Vibration History • ETU #1 passed Qual vibration; but resonance had been improperly notched. • ETU #2 Mechanical failure during 2nd Qualification vibration • ETU #2 support structure added (band-aid approach) • ETU #2 with support structure Passes Qual level Viibration test • Flight units 01 and 02 (with band-aid) vibe tested • Sensor 1 passes • Sensor 2 has structural failure (epoxy delaminated) • Electrical systems on both units survive • Outer casing strengthened and replaced on all units (ETU#2 ETU#3) • ETU #3 passes Qualification level vibe • Flight units delivered for suite level testing (without revibe) • Flight sensors 03 and 04 have passed vibration.
Sensor Test History • During independent SST system tests of F1 and F2 discovered: • Current surge when the Amptek 225fb comes out of saturation following a sunpulse. (~100 mA for ~50 ms) • Does not affect the operation of the SST. • Current pulse perceived as a problem to other instruments. • Solution: add FET to turn off detector during sunpulse. • Inadequate light baffling in the sensor – corrected on all sensors • Flight detectors were more sensitive to light than expected. Inadequate Al layer on ‘O’ detectors. (detectors acceptable - not optimal) • All mods are made on all sensors with exception of FETs in sensors F01 and F02 (currently in suite testing) • Plan for F01 and F02 is to do rework following suite testing.
SST Vibration Testing (Pictures of Probe 2 units)
SST Acceptance Level Dynamic Test • Per UCB THEMIS Document THM-SST-PRC-002 • All 3 Axes • Sine Survey, 0.5 G, 5 – 2000 Hz • Sine Strength per Swales TM2430-RevD, 29 November 2004 • Random • Per Swales Document TM2430-RevD • 12.51 G RMS • 1 min duration per axis • All Vibration Testing Performed at Quanta Laboratories • Retesting (if required) • ‘Workmanship Shake’ • Validate any design changes following original Flight build shake • Validate rework of any failures on previous vibration test • Entire vibration protocol, single axis only Acceptance Sine Strength Specification SST Flight Unit Acceptance Level Random Specification
SST Acceptance Level Dynamic Test
SST Acceptance Level Dynamic Test • Deviations from Test Specification (Notching/Force Limiting/Aborts) • None • SST First Natural Frequency: 213 Hz (Requirement: >75 Hz) • Good Sine Survey Consistency from Unit to Unit (within 10 Hz) • Retesting due to Hardware Redesign • Reinforcement plate bond failure led to stress fracture formation on SST 001 support structure • Resolution: Support structure redesigned and strengthened in high stress areas • Flight-like ETU passed qualification level dynamic test performed on 2 Feb 2005 • Flight Unit Status • Flight Units for Probe 1 scheduled for 2nd vibration test upon completion of suite level testing • Flight Units for Probe 2 completed vibration testing on 22 April 2005 • Flight Units for Probe 3 scheduled for vibration testing on 6 May 2005 X-Axis Testing Y-Axis Testing Z-Axis Testing
SST Sensor Thermal Testing Status • Actual profile for Sensors 01 and 02. • Sensor 1 had no major problems • Sensor 2 had failure of Attenuator mechanism due to GSE cable short.
Dual 26 pin feed through DaqPad PCB- Not used Router DAP SST GSE Thermal Isolators Am241 HP triple supply +5V, -5V, +2.5 Door- Heater Test box Triple supply SMA: +3.9V, Heater:+25V SST Thermal Vac test diagram • All Sensor testing is done with a DAP board and GSE equipment.
SST Sensor Thermal Testing measurements • SST Sensors • Two sensors tested simultaneously in “Themis snout” using thermal isolators • 2 (4 if time permits) full cycles – Hot: +50 C Cold: –50 C 4 hours at each soak • First cycle has additional non op soak at +55C and –65C • Thermal Vac tests are aided with DAP/GSE external to chamber • All counts, noise, HKP values are recorded with GSE • The following variables are monitored and recorded continuously for each sensor (using DAQPAD at 1 sec resolution) • (2x2) Preg current (voltage across 0.3 Ohm) • (2x2) Nreg current (Voltage across 0.6 Ohm) • (2x1) Internal thermistor temperature (Vtherm - Powered by DAP) • (2x1) Heater current (voltage across 2 Ohm resistor) • (2x1) External thermistor temperature (Vth– Biased by GSE DaqPad • Also recorded: • (1) Analog housekeeping channel • (1) Reference voltage • Attenuator • Actuated manually (automatically on Probe 2 and later). • Close time / open time measured with a scope • Thermocouple temperatures recorded by TV facility • DAP Board – Tested with IDPU
CP Tests • SST Sensors testing in Thermal Vac • Electrical – DFE assembly • Detector functionality • Detector gain (location of Am241 60 keV peak) • Baseline determination • Test Pulser response (calibration of test caps) • Noise characterization vs. Temperature • Bias current vs. Temperature • Thermistor checkout & calibration • Cross Talk • SPB FET functionality over temperature range (not yet done on P1 sensors) • Mechanical • Attenuator Mechanism and feedback test. • Heater strip de-lamination testing • Thermostat cycle test (would like ~2 dozen cycles) • Kinematic Flexure testing • Pre/Post testing • Magnetic characterization • Magnetic dipole and quadrapole moments
Mag cleanliness • A magnetic test Fixture was built to determine the magnetic properties of the sensors. • Precise magnetic moments (dipole, quadrapole, octapole. etc.) are determined for each sensor prior to and following Vibe and TV tests. • Magnetic field maps are produced at 2 meter radius to determine the DC field at the location of the Magnetometer.
Magnetic Test results (probe 1) Requirement: <1 nT at 2 meter radius - NOT MET Sensor 01 Sensor 02 Peak field ~1.2 nT Peak field ~0.9 nT Magnetic Field map is determined for each sensor at 200 cm All Magnet cages have been measured and paired to reduce the DC field strength as seen at the location of the magnetometer for each probe
Magnetic Test results (probe 1) At location of magnetometer: <1 nT at location of Magnetometer - OK Sensor F001 Sensor F002 ~Location of magnetometer The field strength at the location of the magnetometer is <1nT
F1 Testing To-Date • Sensors • Detectors • Light sensitivity • Leakage current measurement • Magnetic cleanliness. • Vibration. • Thermal Vacuum testing. • Attenuator operation. • Cable buzzing. • Mass properties • DAP board • Functional (Board-Level) Test. • SST (DAP and Sensors) • Calibration with Sources • SST -IDPU (Suite-Level Integrated Instrument) • Attenuator operation • Noise tests • ETC communication • Suite-Level CPTs (DC- and AC-Functional, pre- and post-EMC, etc.). • Suite-Level EMI/EMC Test (see IDPU Presentation).
SST Functional Tests • Detector live test (using Am241 source, verify wire bond connection) • Internal Test Pulser Test. • External Test pulse test. • Actel Operation • Memory test • Analog Mux operation • Bias Voltage operation • Baseline restoration • Attenuator operation and feedback through DAP • Noise measurement • Sun pulse recovery tests • Light leakage tests • Magnetic moments measurement • SPB FET Functionality
Calibration • Sensors tested individually using the both the ETU DAP board and on the Flight Dap board • DAP board calibrated separately using external test pulse generator. • Flight Board calibrated separately using external test pulse generator. (must be repeated) • DAP/Sensor suite calibrated using Am 241 source. • DAP/Sensor suite to be calibrated using electron and ion gun (Not yet done on Flight Units)