themis mission cdr 1 ucb, june 16, 2004 themis t ime h istory of e vents and m acroscale i...
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THEMIS Mission CDR 1 UCB, June 16, 2004
THEMISTIME HISTORY OF EVENTS AND MACROSCALE INTERACTIONS DURING SUBSTORMS
RESOLVING THE MYSTERY OF WHERE, WHEN AND HOW AURORAL ERUPTIONS START
THEMIS Mission Critical Design Review – SST Instrument MaterialTHEMIS Mission Critical Design Review – SST Instrument MaterialJune 16, 2004June 16, 2004University of California, BerkeleyUniversity of California, Berkeley
THEMIS Mission CDR 2 UCB, June 16, 2004
SST SubsystemMission Critical Design Review
Davin Larson - Lead
Thomas Moreau – Design/Modeling
Ron Canario - Electrical
Robert Lee – Mechanical
Jianxin Chen (Baja) - Actel
Jim Lewis – GSE
Robert Abiad – ETC design
THEMIS Mission CDR 3 UCB, June 16, 2004
Overview
Solid State Telescopes:• Measure Energetic Electrons and Ions• Energy Range:
– H+: 25 keV to 6 MeV (possible ~3 MeV)
– Electrons 25 keV to ~800 keV
• Angular Coverage:– Theta
– 4 look directions (+55, +25, -25, -55)– Resolution: ~ 30 deg FWHM
– Phi– 32 sectors– Resolution: ~20 deg FWHM
• Geometric Factor: ~0.1 cm2-ster (~1/3 of WIND)• Pinhole Attenuator: Cuts geometric factor by 64
THEMIS Mission CDR 4 UCB, June 16, 2004
Sensor Unit Schematic
FoilCollimator
Thick Detector
Sm-Co Magnet
Attenuator
Al/Polyamide/Al FoilOpen Detector
Foil Detector
Attenuator
Open Collimator
THEMIS Mission CDR 5 UCB, June 16, 2004
REQUIREMENT SST DESIGN
IN-1. The Instrument Payload shall be designed for at least a two-year lifetime
Compliance. Lifetime has been considered in all aspects of SST design (parts, performance degradation, etc). Primary Impact: Attenuator added to protect detectors from “radiation”.
IN-2. The Instrument Payload shall be designed for a total dose environment of 33 krad/year
(66 krad for 2 year mission, 5mm of Al, RDM 2)
Compliance. All parts screened for total dose. Radiation testing planned if TID is unknown.
(All major parts tested to 50 krad.)
IN-3. The Instrument Payload shall be Single Event Effect (SEE) tolerant and immune to destructive latch-up
Compliance. Most parts screened for SEE. Radiation testing planned if LET is unknown.
IN-7. No component of the Instrument Payload shall exceed the allocated mass budget in THM-SYS-008 THEMIS System Mass Budget.xls
Compliance.
Sensor: 554 gm x2 (Measured)
Harness: 141 gm x2 (1.73 meter)
(DAP Board tracked with IDPU)
IN-9. No component of the Instrument Payload shall exceed the power allocated in THM-SYS-009 THEMIS System Power Budget.xls
Compliance.
DFE + DAP: 1200 mW (Estimate @ 10 kHz count rate)
IN-13. The Instrument Payload shall survive the temperature ranges provided in the ICDs
Compliance.
DAP: –40 to 65
DFE: -65 to 100 (Heater required to survive eclipse)
IN-14. The Instrument Payload shall perform as designed within the temperature ranges provided in the ICDs
Compliance.
DAP: –30 to 40
DFE: -55 to 70
Mission Requirements
THEMIS Mission CDR 6 UCB, June 16, 2004
REQUIREMENT SST DESIGN
IN-16 The Instrument Payload shall comply with the Magnetics Cleanliness standard described in the THEMIS Magnetics Control Plan
Compliance?. THM-SYS-002 Magnetics Contamination Control Plan. Budget for SST Magnets is <2 nT @ 2 meters. (Compliance if SST budget is increased, still meets overall system budget)
IN-17 The Instrument Payload shall comply with the THEMIS Electrostatic Cleanliness Plan
Compliance. THM-SYS-003 Electrostatic Cleanliness Plan. Box electrically isolated.
IN-18 The Instrument Payload shall comply with the THEMIS Contamination Control Plan
Compliance. THM-SYS-004 Contamination Control Plan (Partially driven by SST)
IN-19. All Instruments shall comply with all electrical specifications
Compliance. THM-IDPU-001 Backplane Specification.
IN-20. The Instrument Payload shall be compatible per IDPU-Instrument ICDs
Compliance. THM-SYS-105 ESA and SST Electronics Card (ETC) Specification. Verification Matrices to be completed.
IN-21. The Instrument Payload shall be compatible per the IDPU-Probe Bus ICD
Compliance. THM-SYS-111 SST-to-Probe ICD. Verification Matrices to be completed.
IN-23 The Instrument Payload shall verify performance requirements are met per the THEMIS Verification Plan and Environmental Test Spec.
Compliance. THM-SYS-005 Verification Plan and Environmental Test Specification preliminary draft. Verification matrix to be completed.
IN-24 The Instrument Payload shall survive and function prior, during and after exposure to the environments described in the THEMIS Verification Plan and Environmental Test Specification
Compliance. THM-SYS-005 Verification Plan and Environmental Test Specification preliminary draft. Verification matrix to be completed.
Mission Requirements
THEMIS Mission CDR 7 UCB, June 16, 2004
REQUIREMENT SST DESIGN
IN.SST-1. The SST shall perform measurements of the tailward-moving current disruption boundary speed using the finite gyroradius technique
Compliance. Provided by Full Distribution Functions (FDFs).
IN.SST-2. The SST shall measure the time-of-arrival of superthermal ions and electrons of different energies emanating from the reconnection region to determine RX onset time.
Compliance. 3 second time resolution of FDFs
IN.SST-3. The SST shall obtain partial moments of the plasma electron and ion distributions in the magnetotail plasma sheet
Compliance. Partial moments produced by ETC board.
IN.SST-4. The SST shall obtain measurements of ion and electron distribution functions with one spin resolution (<10sec required)
Compliance. Full distribution functions at 1 spin resolution obtained in burst mode.
IN.SST-5. The SST shall measure energetic electron fluxes as close to Earth as 6RE geocentric, at all local times.
Compliance. Attenuator lowers flux sufficiently to avoid saturation at this distance
IN.SST-6. The SST shall measure energetic ions in the solar wind, at the magnetopause and in the magnetosheath.
Compliance.
Science Requirements
THEMIS Mission CDR 8 UCB, June 16, 2004
REQUIREMENT SST DESIGN
IN.SST-7. The SST shall measure energetic particles over an energy range of 30-300keV for ions and 30-100keV for electrons found in the magnetotail plasma sheet .
Compliance.
Electrons: ~25 keV to ~800 keV
Ions: ~25 keV to ~2 MeV (possibly 6 MeV)
IN.SST-8. The SST energy sampling resolution, dE/E, shall be better than 30% for ions and electrons.
Compliance.
Intrinsic energy resolution is ~6 keV with 1.5 keV binning. Measured full system resolution is 8 keV @ 30 keV
IN.SST-9. The SST shall be capable of measuring differential energy flux in the range from: 10^2 to 5x10^6 for ions; 10^3-10^7 for electrons (keV/cm2-s -st- keV) whilst providing adequate counts within a 10 second interval.
Compliance. Max counting rate estimated at 50,000 cps (per detector). Two geometric factors:
G1 ~ 0.1 cm2-ster
G2 = G1/64.
IN.SST-10. The SST shall measure over 90 deg. in elevation with a minimum resolution of 45 deg.
Compliance.
Elevation: +/- 60 deg, Resolution:~37 deg.
IN.SST-11. The SST shall have an azimuthal resolution of 45 deg.
Compliance.
Azimuthal resolution = 22.5 deg
IN.SST-12. The SST shall supply the high energy partial moments at one spin time resolution.
Compliance.
Performed by ETC board
IN.SST-13. SST calibration shall ensure <20% relative flux uncertainty over the ranges defined above.
Compliance. Measured pre-flight;
Verified by in-flight calibration.
Performance Requirements
THEMIS Mission CDR 9 UCB, June 16, 2004
ETC BoardDCB
Block Diagram
SensorUnit 1
(2 DFEs A&B)DAP Board
(Data Acquisition & Processing)
Bac
kpla
ne
SensorUnit 2
(2 DFEs A&B)
IDPU
SST Instrument:•2 Sensors with attenuators (4 DFEs)
•2 Cable bundles
•1 DAP Board (inside IDPU)
PCB(Power Control Board)
Other Boards
~1.7 m cable (x2)
DFE = Detector Front End Hea
ter
Pow
er
&
SM
A P
ower
THEMIS Mission CDR 10 UCB, June 16, 2004
Sensor Cross Section
Each sensor unit is a:• Dual-double ended solid state
telescope• Each double ended telescope
(1/2 sensor) has:– Open collimator– Pinhole attenuator paddle
– Reduces count rate during periods of high flux
– Reduces radiation damage from intense fluxes of low energy ions
– Magnet (Open side)– Filters out electrons <400 keV – Leaves ion flux nearly
unchanged
– Triplet stack of SSDs– DFE board
– Preamp / shaping electronics
– Thin Polyamide Foil– Filters out ions <~350 keV – Leaves electron flux nearly
unchanged
– Another attenuator paddle– Foil Collimator
THEMIS Mission CDR 11 UCB, June 16, 2004
Detector Pixelation
Detectors similar to STEREO/STE• Produced at LBNL/Craig Tindall PI
Active area
Guard ring
10 mm
5 mm
Additional Pixels not used for Themis
300 microns thick
THEMIS Mission CDR 12 UCB, June 16, 2004
Typical Electrical Connection Between Detector and Flex-Circuit
SST Mechanical Design
Kapton Flex-Circuit
Detector (pixelated side)
Wirebond Loop
(NOT to scale – actual loop height < 300 micron)
THEMIS Mission CDR 13 UCB, June 16, 2004
SST Mechanical Design
Detectors (4)
Spring Clamp
Spring Plate (2)
Detector Board Composition (exploded view)
PEEK Spacer (4)
BeCu Gasket (3)
Kapton Flex-Circuit (4) AMPTEK Shield
KaptonHeater
Thermostat
DFE Board Subassembly
THEMIS Mission CDR 14 UCB, June 16, 2004
SST Mechanical Design
DFE Board Subassembly Relative Positions (2 per sensor)
AMPTEK Shielding
Detector Stack Subassembly
Multi-Layer Circuit Board (62 mil thickness)
Foil Frame
Thermostat
THEMIS Mission CDR 15 UCB, June 16, 2004
SST Mechanical Design
Magnet-Yoke AssemblyCo-Fe Yoke (2)
Sm-Co Magnet (4) (currently not visible)
Aluminum Magnet Cage
THEMIS Mission CDR 16 UCB, June 16, 2004
SST Mechanical Design
Attenuator Assembly
Attenuator (4)
Cam (2)
SMA Lever (2)
THEMIS Mission CDR 17 UCB, June 16, 2004
SST Mechanical Design
Actuators and Position Switches
Honeywell SPDT Hermetically Sealed Switch (2)
SMA Actuator (2)
THEMIS Mission CDR 18 UCB, June 16, 2004
SST Mechanical Design
Support Structure
(front section)
Kinematic Flexure (2)
Rigid Mounting Flange
THEMIS Mission CDR 19 UCB, June 16, 2004
SST Mechanical Design
Bi-Directional Fields-of-View
THEMIS Mission CDR 20 UCB, June 16, 2004
SST Mechanical Design
Sensor Orientation Relative to Spacecraft Bus
THEMIS Mission CDR 21 UCB, June 16, 2004
THEMIS Mission CDR 22 UCB, June 16, 2004
SST Mechanical Design
Sensor Unit Mounting Using Kinematic Flexures• Each sensor mounted to spacecraft panel at
three points– One rigid mounting flange– Two mounting flanges with kinematic flexures
• Allows relative motion due to CTE differences between sensor structure and spacecraft panel– Predicted expansion differential along instrument
axes with 120 ºC temperature gradient:– X-Axis: 0.006” (0.15 mm)
– Y-Axis: 0.013” (0.33 mm)
• Flexure dimensions sized to keep maximum bending stresses below 6061-T6 yield strength– Factor of Safety (F.S.) > 1.4 per NASA-STD-5001
THEMIS Mission CDR 23 UCB, June 16, 2004
SST Mechanical Design
Attenuator Actuation – CLOSED position
Honeywell Switch (extended-position)
SMA Actuator (extended)
Honeywell Switch (compressed-position)
SMA Actuator (retracted)
THEMIS Mission CDR 24 UCB, June 16, 2004
SST Mechanical Design
Attenuator Actuation – OPEN position
Honeywell Switch (compressed-position)
SMA Actuator (retracted)
Honeywell Switch (extended-position)
SMA Actuator (extended)
THEMIS Mission CDR 25 UCB, June 16, 2004
SST Mechanical Design
Attenuator Control – CLOSED to OPEN (INITIAL)
CLOSEAttenuator
OPEN Attenuator
PCB
+5V
SST Sensor
+5V
GNDGND
MonitorMonitor
PCB
SPDT Switch
FREE COMPRESSED
C C
NC NC
NONO
FRONT SMA(ACTIVE)
BACK SMA
HIGHLOW
THEMIS Mission CDR 26 UCB, June 16, 2004
SST Mechanical Design
Attenuator Control – OPEN to CLOSED (INITIAL)
PCB
+5V
SST Sensor
+5V
GNDGND
MonitorMonitor
PCB
SPDT Switch
CLOSEAttenuato
r
OPEN Attenuator
COMPRESSED FREE
C C
NC NC
NONO
FRONT SMABACK SMA(ACTIVE)
LOWHIGH
THEMIS Mission CDR 27 UCB, June 16, 2004
SST Mechanical Design
Attenuator Mechanism Cycling Test• Run over 40,000 cycles• Pivot shaft (303 Stainless) showed significant
abrasion damage on contact surfaces with sapphire bearings• Subsequent shafts to be treated as follows:
– Titanium Nitride (TiN) coating to increase hardness
– Tungsten Disulfide (WS2) coating for dry film lubrication
• Required SMA stroke reduced from 3.5 mm to 3 mm for additional operating margin (maximum stroke: 4 mm)
• Mechanism test will be performed again with modified components on ETU (late April 2004) with minimum target of 150,000 cycles• Target values based on 10 times expected
number of actuations on-orbit• Cycle counting will not be necessary for flight
components
THEMIS Mission CDR 28 UCB, June 16, 2004
SST Mechanical Design
Analysis Results - Modal Analysis• ALGOR FEMPRO Version 13.30
– First Mode @ 600 Hz
– Second Mode @ 1200 Hz
– Third Mode @ 1550 Hz
• Modal frequencies > Delta II minimum levels
Finite element model with mass simulators
THEMIS Mission CDR 29 UCB, June 16, 2004
SST Mechanical Design
Analysis Results – Quasi-Static Acceleration• ALGOR FEMPRO Version 13.30• 40g load along each instrument axis
– X-axis maximum stress: 3040 psi– Y-axis maximum stress: 1730 psi– Z-axis maximum stress: 1440 psi
• F.S. > 1.4 above yield strength for 6061-T6
X Axis Load Y-Axis Load Z-Axis Load
THEMIS Mission CDR 30 UCB, June 16, 2004
SST Mechanical Design
Electronics and Cabling• DAP Board
– Located within IDPU– Type 6U card– Radiation shielded with 5mm of aluminum– Will be discussed in further detail in IDPU section
• Harness (per sensor)– Approximate length of 1.73m x 64 gm/m – Composition:
– 13 x 36 AWG coaxial cables - 6 Signals, 6 Test, 1 Bias voltage– 3 x 28 AWG wire - 2 Door monitors, 1 Temperature– 3 x 24 AWG (TT) - Door Open/Close power & return– 2 x 26 AWG (TP) - Heater supply– 3 x 26 AWG (TT) - Preamp Power
– 26 pin HD Cannon at each end
THEMIS Mission CDR 31 UCB, June 16, 2004
SST Sensor
Mass Summary:
Sensor mass= 553.5 gm
Cable mass (173 cm) = 141 gm
Total x2= 1389 gm
THEMIS Mission CDR 32 UCB, June 16, 2004
SST Sensor Mass Estimate
SST Mass EstimatesItem Mass
[g]Items/unit Mass [g] Actual Mass % %
SensorsMagnets 9.6 4 38.4 6.7Yoke 33.2 2 66.4 11.6Magnet and Yoke Cage 16.7 1 16.7 2.9Retainer plates and fasteners 1.4 4 5.7 1.0Sub total Magnet Assembly 127.2 22.2Housing 20 mil (front and back) 107.1 1 107.1 18.7Bottom closeout 62.5 mil 14.3 1 14.3 2.5Collimators (with baffles) 14.4 4 57.7 10.1Attenuator cover 18.6 2 37.2 6.5Thermal Spacer 0.3 6 1.9 0.3Baseplate Washer 1.6 3 4.9 0.9Housing fasteners 0.8 16 12.2 2.1Sub total Housing 235.3 41.0Attenuator (axle/4 paddles/2 cams, 2 levers,2 bearings, 8 set screws)10.6 1 10.6 1.9HM Switch Assembly (mounting plate, spring, nut plate, plunger, set screw, screws)9.8 2 19.6 3.4HM Switch (w/ aux lever) 5.8 2 11.7 2.0SMA actuator (nanomuscle, T-bone, nut plate and screws) 4.6 2 9.2 1.61/2 Winchester w/o wire 1.7 2 3.3 0.6Sub total Attenuator 54.4 9.5Connector (26 pin DD w/ nut plate) 9.2 1 9.2 1.6Internal wires 10.0 1 10.0 1.7DFE board (unloaded) 10.3 2 20.6 3.6DFE EEE parts 5.7 2 11.4 2.0Amptek 225FB 2.3 6 14.0 2.4Amptek Shield Cover (2mm Brass) 18.0 2 36.0 6.3Detectors 0.0 8 0.0 0.0Detector Stack 10.0 2 20.0 3.5Polyamide Foil & Holder 1.9 2 3.7 0.7Thermostat 7.8 2 15.6 2.7Heater Patch 2.2 2 4.3 0.71/2 Winchester w/o wire 1.7 2 3.3 0.6screws and pem nuts 1.1 8 8.5 1.5Sub total DFE assembly 156.6 146.7 27.3
Sensor Total: 573.5 573.5 553.5 gm 100.0 100.0
THEMIS Mission CDR 33 UCB, June 16, 2004
SST Mechanical Design
Nitrogen Purge Connection• Nitrogen line is connected to SST purge fitting during pre-flight
operations to purge instrument interior
• Gas supplied at 5 psig– Regulated and filtered flow rate of 1 liter/hour
Supply fitting
Vent
THEMIS Mission CDR 34 UCB, June 16, 2004
Electronics Block Diagram
Signal chain: 1 of 12 channels shown
ADC
FPGACoincidence
Logic &Accumulators
Memory
DACThresh
Gain
PD
BLR
A225FBPreampShaper
DFEBoard x4 DAP Board
Test Pulser
Bias Voltage
x12
x 3
THEMIS Mission CDR 35 UCB, June 16, 2004
T Out
+4.5 V
-2.5 V
O Out
-35 V
F Out
F Test in
T Test in
O Test in
Current DFE Design
~200 A Polysilicon + ~200 A Al
pn
np
np
pn
~200 A Polysilicon
T
F
O
300 micron thick detectors
225FB
225FB
225FB
Outside Grounded
Pixelated side ~1200 A Dead layer
THEMIS Mission CDR 36 UCB, June 16, 2004
DFE Schematic
THEMIS Mission CDR 37 UCB, June 16, 2004
DFE Schematics
Detector Front End Schematic
–Single Channel
THEMIS Mission CDR 38 UCB, June 16, 2004
Preamps/Shaping
Using Amptek 225FB (6pin sip Hybrid - special request)Characteristics:
• ~6 keV electronic noise (with 1.5 cm2 detector)• ~2.5 uS shaping time (time to peak)• ~26 mW (Increases with negative supply voltage) • 100 Krad (still needs ~2mm Cu shield)• Operating range: -55 to +125 C• Dual supply allows negative output pulses
B
THEMIS Mission CDR 39 UCB, June 16, 2004
DFE Layout
ETU board layout (version 2). • A225FBs have 2 mm Cu radiation
shielding• Caps/Resistors have ~0.5mm Al
shielding• Detectors located near Preamps• Flexible, rugged design
3- A225FBs
Cu shield
Detector Stack
Version 3 (Flight) is nearly indistinguishable from Version 2
THEMIS Mission CDR 40 UCB, June 16, 2004
ETU DFE Assembly
A225FB
Detector Stack
26 Pin HD
A sideA sideB side
Winchester connector to Attenuator
Assembly/testBracket
Shield/Heater not shown
THEMIS Mission CDR 41 UCB, June 16, 2004
ETU DFE Assembly
DFE In Test Box
THEMIS Mission CDR 42 UCB, June 16, 2004
DFE/Mechanical Mating
DFE assembly and housing/attenuator assembly can be adjusted/tested separately and then mated.
ETU Issues: Intermittent shorting of one diode - resolved
THEMIS Mission CDR 43 UCB, June 16, 2004
Progress Summary
DAP (Data Acquisition & Processing) Board Summary• ETU #1
– 3 of 12 channels loaded
– Fully functional with some issues:– Oscillation of threshold DACs (fix: compensate)– Commercial MUX not functioning at +/- 5V (fix: use flight MUX)– Baseline restore locks up occasionally (fix - found)– Pulse generator not linear at low end– Various Minor problems (i.e. all diodes loaded backwards)
• ETU #2 (same PWB with some different components)– 12 of 12 channels loaded
– Board to be used for thermal vac and testing of ETC
• ETU #3 (could potentially be flight quality)– Layed out and in production
– Should fix all known problems except pulse generator linearity
THEMIS Mission CDR 44 UCB, June 16, 2004
Peak Digitizer Schematic
THEMIS Mission CDR 45 UCB, June 16, 2004
DAP Layout
Layout:•Started: ~2004-01-05•Finished: ~2004-03-24•Two Boards built up
•1 partially loaded•1 fully loaded
•Rev 2 in progress
THEMIS Mission CDR 46 UCB, June 16, 2004
Power EstimatesSST Power Estimates Current
2.5 5 5 5+2.5V D
(mA)+5V D (mA)
-5V A (mA)
+5V A (mA)
Power mW
DFE electronicsA225FB (assumes 2.5 volt negative ref) 1.800 3.450 26.25
x 12 21.600 41.400 315.00
IDPU electronicsADC channelsOP462 2.200 2.200 22.00CA3080A 0.075 0.075 0.75MAX907 1.400 7.00LTC1604 0.955 0.650 0.955 12.80Gate transistors 0.016 0.08subtotal 0.955 2.925 4.646 42.63ADC subtotal x 12 11.460 35.100 55.752 511.56
Threshold (quad)AD5544 0.000 0.050 0.25OP462 2.200 2.200 22.00subtotal 2.200 2.250 22.25TH subtotal x 3 0.000 6.600 6.750 66.75
LT1217 1.000 1.000 10.00
Test Pulse & Bias controlAD5544 0.000 0.000 0.050 0.25OP462 0.000 2.200 2.200 22.00TP&BC subtotal 0.000 2.200 2.250 22.25
Bias Voltage circuitAD648 0.680 0.680 6.80
POR 0.200 1.00FPGA (actel) 0.000 48.000 240.00SRAM (128K) 0.000 0.00
1173.36
Total 0.000 59.660 67.180 107.832 1173.36 mW
Estimated Power Consumption: ~1200 mW
THEMIS Mission CDR 47 UCB, June 16, 2004
ACTEL Development
• Designed by Jianxin Chen – Baja Technologies• First installed 2004-04-12 (Now on Rev 4)• Functionality:
• Controls 12 ADCs– Monitor / Count threshold events - Working– Monitor peak detect signal - Working– Produce convert strobe - Working– Coincidence detection - Working (further testing still needed)– Readout ADC (energy) - Working
• Psuedo-logrithmic energy binning– ADC measurement used as address of LUT to increment
accumulators (LUTs and accumulators stored in SRAM) - Working
• Data Readout (controlled by ETC board) - Working• Command Data Interface (CDI) (loads tables) -Working• Test Pulser control – Working (not optimum design however)• Noise measurement – not yet implemented
– Periodic conversions to measure “noise”
• Analog Housekeeping control – Working
THEMIS Mission CDR 48 UCB, June 16, 2004
Progress Summary
GSE Equipment• GSE software
– Working great!
• Calibration Vacuum Chamber– Now Operational
– Minor problems (ports smaller than desired)
• Ion gun– Arrived early but damaged in shipment
– Beam misalignment makes it difficult to obtain low energy H
– Being fixed this week.
• Electron gun– Adapter ring to accommodate smaller ports is in shop.
• Misc. Cabling, fixtures, feedthroughs etc.– Done
THEMIS Mission CDR 49 UCB, June 16, 2004
Progress Summary
Differences between ETU Sensor #1 and Flight units:• Flight Thermostat will switch at –50C (instead of –25C)• Heater pads will be lower power (on order)• Heater wires to be electrically shielded (if needed)• Thin foil mounted on support structure instead of circuit
board (done for ease of assembly)• Minor mods to DFE board and flex circuits (out for fab now)• Collimator baffles affixed with screws instead of epoxy• Flight detectors to be used (instead of STEREO spares)
No major design changes!
Ready to begin production of flight units (pending outcome of thermal/vac tests
THEMIS Mission CDR 50 UCB, June 16, 2004
ETU Sensor Testing
ETU Sensor with Cd109 source
88 keV photons
Test Pulser22-25 keV photons
<7 keV FWHM Resolution
THEMIS Mission CDR 51 UCB, June 16, 2004
ETU Sensor Testing
ETU Sensor with Am241 source
59.5 keV photons
Test Pulser14 & 17.5 keV photons (not resolved)
<7 keV FWHM Resolution
THEMIS Mission CDR 52 UCB, June 16, 2004
ETU Sensor & DAP Testing
Am241 Source
59.5 keV photons
Test Pulser14 & 17.5 keV photons
<8 keV FWHM Resolution
GSE display of complete SST unit (DFE+DAP) data flow
THEMIS Mission CDR 53 UCB, June 16, 2004
SST System Performance
0
20
40
60
80
100
120
0 20 40 60 80 100 120 140 160
Pulse Size (~keV)
Mean Bin
FWHM (Bin x10)
FWHM (keV x10)
Response is (reasonably) linear
~5 keV Noise
<8 keV noise
ETU Sensor#1 with DAP ETU#2 Response
(Test performed with external pulser)
THEMIS Mission CDR 54 UCB, June 16, 2004
Progress Summary
ETU Update (since PCDR)• Attenuator cycle testing
– shaft hardening/lubing didn’t help much
– Sapphire bearings replaced with ball bearings
– Attenuator cycle test #2b started June 7, 2004
– >50,000 cycles as of June 11, 2004
• Functional and characterization tests completed.• Vibration (16g) Qualification Test on June 11, 2004
– Mechanical functional : Passed ! (No obvious failures)
– Electrical functional : TBD
– Electrical characterization: TBD
• Thermal Vacuum Tests– Scheduled for late June 2004 (after spin-plane booms)
THEMIS Mission CDR 55 UCB, June 16, 2004
PDR RFA Responses
RFA #: UCB-6 Instrument: SSTRFA Title: SST Operating Temperature Review: UCB Instrument EPR Date of Review: October 15-
16, 2003 Reviewer: Shelley Organization: SelfRecommended Action:Take all practical steps to reduce average operating temperature of
the SST instrument or at least its sensor elements.Rationale:The thermal analysis indicated an average operating temperature
of 25C with a wide variation around that average. For noise levels consistent with the desired performance of this instrument, operating temperatures should be closer to 0-10C.
Response:Nominal operating temperature is –20 C and can be adjusted
pending future testing.
THEMIS Mission CDR 56 UCB, June 16, 2004
PDR RFA Responses
RFA #: UCB-7 Instrument: SST
Review: UCB Instr EPR Date of Review: Oct 15-16, 2003
Reviewer: McCarthy Organization: U. Wash.
Recommended Action:Reconsider the following design decisions:a. Changing the sweep magnet to better exclude 250-400 keV electrons.
- Done – 50gm/sensor mass penalty
b. Operating the detectors at an average temperature 0 C instead of 25 C. - Done
c. Increasing the ion energy range to include the 6 MeV calibration point. – Final decision still pending test results
d. Use of high-Z materials (tungsten) near the detectors should be evaluated in terms of locally generating bremsstrahlung x-ray background. – Baffles are BeCu. SmCo magnets shielded by Al.
e. Sun glints not only temporarily blind the particle detectors, but preamp can saturate and require additional time to recover. This effect to be measured, especially with their thinner dead layers. No Change yet
THEMIS Mission CDR 57 UCB, June 16, 2004
PCDR RFA: INST-06
TITLE: Temperature Dependence of Net Residual Field from SST Yoke
REQUESTED BY: Ed Shelley, Michael McCarthySPECIFIC REQUEST: Stray field from SST magnetic system can
be expected to have a temperature dependence due to mechanical changes in gap. This can exceed effect due to magnetic coefficient of SmCo. As a minimum, measure field in gap as a function of temperature. Note: stray fields may not scale with total field. If it does, this is not likely to be a problem, since effect in gap is on order of or less than 1%
RESPONSE: We tried to measure the ETU gap field over a temperature range of –50 to +40 C. We found an apparent 14% increase in field strength over this range. We do not expect the stray field to vary in the same manner. A test of stray field temperature dependence is in progress.
THEMIS Mission CDR 58 UCB, June 16, 2004
Magnetics Testing
Magnet Cage assembly #1• Measured Py for 19 magnets (All values were very close)• Selected 4 magnets for assembly #1• Measured dipole and quadrapole moments of assembly• Found significant residual dipole moment along x-axis• Contribution of dipole and quadrapole nearly equal at 2 m• Conclusion: Px and Pz of individual magnets are important
THEMIS Mission CDR 59 UCB, June 16, 2004
Magnetics Testing
Magnet Cage assembly #2• Measured Px, Py & Pz for 15 magnets• Selected 4 magnets for assembly #2• Measured dipole and quadrapole
moments of assembly #2• Still Found significant residual dipole
moment:• P=[ -0.244, -0.343, -0.012] nT-(2m)^3
• Q= B (nT) at 2 m
Angle in x-y plane
-0.034 -0.389 -0.009
-0.389 0.018 ?
-0.009 ? 0.016
•B(dipole @ 2m) = .84 nT•B(quad @ 2m) = .60 nT
THEMIS Mission CDR 60 UCB, June 16, 2004
Magnetics Testing
Sent Magnet Cage assembly #2 to UCLA for testing• Results are virtually the same• Contribution of dipole and quadrapole fields are similar at 2 m:
• B(dipole @ 2m) = .88 nT• B(quad @ 2m) = .59 nT
• The sum of both contributions exceeds requirement (0.75 nT @ 2m)
-350
-300
-250
-200
-150
-100
-50
0
50
100
150
0 100 200 300 400 Series1
Series2
Series3
THEMIS Mission CDR 61 UCB, June 16, 2004
THEMIS Mission CDR 62 UCB, June 16, 2004
PCDR RFA: INST-07
TITLE: Wire Bond Testing RFA CODE: INST-07REQUESTED BY: Joe Osche, Michael McCarthy, Henry
HeetderksSPECIFIC REQUEST: Wire bonds may fail. Test and qualify wire
bonding on detector. Install redundant wire bonds to increase reliability.
RESPONSE: Redundant bonds will be made on all flight detectors. Qual test Procedure: Wire bonds are made on a test detector prior
to and following the wire bonding of all detectors in a stack. Destructive pull tests are performed on these test bonds to qualify the bonds in the associated detector stack.
This test procedure was followed during the assembly of ETU stack #4 (However, redundant bonds were not made despite our requests to do so.)
Wire bonds must also pass vibration tests along with the sensor unit. (Qualification vibe test on 6-11-2004 results: TBD).
THEMIS Mission CDR 63 UCB, June 16, 2004
PCDR RFA: INST-08
TITLE: Thermal Twisting of Flexure Mounts RFA CODE: INST-08
REQUESTED BY: Henry Heetderks, Michael McCarthy
SPECIFIC REQUEST: The slots on the "quasi-kinematic" feet should be orthogonal to a line drawn to a common point. (In the case with one fixed foot, the other two should point toward it.) Heetderks thinks P. Turin recognizes this and will get it fixed. Correct flexure mounts to eliminate thermal twisting.
RESPONSE: A FEA was performed on the current design to quantify the stresses developed in the feet flexures due to the non-perpendicularity of the bolt-to bolt lines and the flexures combined with the max temperature excursion expected. The results showed a maximum stress of 4600 lb/in2 which is a factor of seven below yield for aluminum. Thus, we see no reason to modify the design, given that the required changes would cause problems with part geometry and would necessitate relocating the SSTs on the spacecraft panel, potentially causing FOV clearance issues.
THEMIS Mission CDR 64 UCB, June 16, 2004
PCDR RFA: INST-09
TITLE: Testing of Detectors RFA CODE: INST-09REQUESTED BY: Joe OscheSPECIFIC REQUEST:
• Risk of detectors not working. Perform and document a test for the performance verification of the detectors prior to placing them in the instrument.
RESPONSE: (We will do this )• Wire bond tests (see RFA-08)• LBL responsibilities:
– Leakage current test– Breakdown voltage test– Depletion voltage test
• SSL responsibility: (after assembly in stack)– Short/Open circuit test – Diode test– Leakage current test (including light sensitivity)
THEMIS Mission CDR 65 UCB, June 16, 2004
PCDR RFA: INST-10
TITLE: Fairing Debris RFA CODE: INST-10
REQUESTED BY: Michael McCarthy
SPECIFIC REQUEST: • Include a fairing cleanliness requirement to mitigate debris
dropping into uncapped detectors apertures.
RESPONSE:• We will write a detector surface cleanliness requirement.
Swales will use this requirement to determine the fairing cleanliness requirements.
– <10 Angstrom condensate (NVR < 0.1 g/cm2)
– <1% obscuration (Level 500 cleanliness)
– No large debris
THEMIS Mission CDR 66 UCB, June 16, 2004
PCDR RFA: INST-11
TITLE: SST Sensitivity to Sun Glints RFA CODE:INST-11
REQUESTED BY: Michael McCarthy
SPECIFIC REQUEST: • As part of the cal/checking procedure, the instrument should be
checked for sensitivity to sun glints and degree of solar blindness.
RESPONSE: We will do this. (BTW: Detectors are known to be very sensitive to light and will not function properly in direct sunlight.)
• Prior to installation in sensor, detector stacks will be tested for leakage current as a function of incident light to verify correct application of Aluminum layer on open detectors.
• Sun pulse recovery times will be measured on the ETU.• A stray light leakage test is planned.
THEMIS Mission CDR 67 UCB, June 16, 2004
PCDR RFA: INST-12
TITLE: SST Analog-Actel Interface RFA CODE: INST-12
REQUESTED BY: Henry Heetderks
SPECIFIC REQUEST: The current interface between the analog electronics and the Actel in the SST will give multiple transitions at the Actel when the slow analog signals change. This is probably OK but should be recognized in the design. I.e. if you were using a counter in the Actel to keep track of the number of particles by counting transitions of the peak detector, you will get an answer which is way too high. Abiad is an expert on this. Verify that there is not a problem with this interface.
RESPONSE:• We have verified there is no problem with this aspect of the
interface. The possibility of multiple transitions in the comparator output was recognized prior to the Actel design specification and had been accounted for.
THEMIS Mission CDR 68 UCB, June 16, 2004
PCDR RFA: INST-R11
TITLE: SST Flexure Stresses RFA CODE: INST-R11
REQUESTED BY: Michael Sholl
SPECIFIC REQUEST: Show that thermal stresses in SST mounting base flexures are not too high under a 120 degrees C temperature delta.
RESPONSE:
Please see response to RFA-08
THEMIS Mission CDR 69 UCB, June 16, 2004
PCDR RFA: INST-R12
TITLE: SST Shutter Imbalances RFA CODE: INST-R12
REQUESTED BY: Michael Sholl
SPECIFIC REQUEST: Make a statement on allowable SST shutter imbalance to prevent rattling during launch.
RESPONSE: • The Attenuator Assembly axis of inertia shall be within
0.9 mm (0.035 inch) of the rotational axis.
P.S. The shutter was observed to remain closed throughout the ETU vibration test (6-11-2004).
THEMIS Mission CDR 70 UCB, June 16, 2004
SST Mechanical Design
SST MECHANICAL INTERFACES
THEMIS Mission CDR 71 UCB, June 16, 2004
SST Mechanical Design
Interface Between SST Sensors and Spacecraft Bus• THM-SYS-111: Probe to SST Interface Control Document
– Summarizes mechanical and thermal interfaces with spacecraft
• THM-SST-ICD-001-B: Interface Control Drawing– Page 1: Overall unit dimensions, mounting footprint, and field-of-view
requirements– Page 2: Purge access and non-flight hardware dimensions– Page 3: Sensor orientation relative to spacecraft bus– Page 4: Sensor external thermal finish
THEMIS Mission CDR 72 UCB, June 16, 2004
SST Mechanical Design
THM-SST-ICD-001-B: Interface Control Drawing – Page 1
THEMIS Mission CDR 73 UCB, June 16, 2004
SST Mechanical Design
THM-SST-ICD-001-B: Interface Control Drawing – Page 2
THEMIS Mission CDR 74 UCB, June 16, 2004
SST Mechanical Design
THM-SST-ICD-001-B: Interface Control Drawing – Page 3
THEMIS Mission CDR 75 UCB, June 16, 2004
SST Mechanical Design
THM-SST-ICD-001-B: Interface Control Drawing – Page 4
THEMIS Mission CDR 76 UCB, June 16, 2004
SST Mechanical Design
SST TEST REQUIREMENTS
THEMIS Mission CDR 77 UCB, June 16, 2004
SST Mechanical Design
Unit Level Test Requirements
• Attenuator Mechanism Cycling– ETU target of 150,000 cycles (10x expected on-orbit maximum value)
• Vibration– Per THEMIS Instrument Payload Environmental Verification Plan and
Test Specification THM-SYS-005B – Sine burst, random, sine sweep – Updated test levels to be provided by Swales in place of GEVS
(Qualification @ 15.8g)
• Thermal-Vacuum– Per THEMIS Instrument Payload Environmental Verification Plan and
Test Specification THM-SYS-005B– Sensor alone
8 CyclesTemperature range: -60 C to +40 C
– Sensor w/ DAP in IDPU2 CyclesTemperature range: -30 C to +40 C
THEMIS Mission CDR 78 UCB, June 16, 2004
SST Mechanical Design
THEMIS Environmental Test Matrix
COMPONENT (ITEM)
QU
AN
TIT
Y
SU
PP
LIE
R
ALI
GN
ME
NT
MO
DA
L S
UR
VE
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ST
AT
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RA
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OM
VIB
RA
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N
SIN
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IBR
AT
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AC
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PR
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F T
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CLA
MP
BA
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SH
OC
K
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/PR
ES
SU
RE
PR
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MA
SS
PR
OP
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S
ME
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FU
NC
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LIF
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ES
T
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FA
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RIF
ICA
TIO
N
CO
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UC
TE
D E
MIS
SIO
NS
CO
ND
UC
TE
D S
US
CE
PT
IBIL
ITY
RA
DIA
TE
D E
MIS
SIO
NS
RA
DIA
TE
D S
US
CE
PT
IBIL
ITY
TH
ER
MA
L V
AC
UU
M (
# C
YC
LES
)
TH
ER
MA
L B
ALA
NC
E
TH
ER
MA
L A
IR (
# C
YC
LES
)
TH
ER
MA
L LI
MIT
S
(OP
ER
AT
ING
, DE
PLO
Y)
TH
ER
MA
L P
RE
DIC
TS
TH
ER
MA
L T
ES
T L
IMIT
S (
QU
AL)
LI
MIT
S +
/-10
C V
AC
; +/-
15C
AIR
TH
ER
MA
L T
ES
T L
IMIT
S (
AC
C)
P
RE
DIC
TS
+/-
10C
VA
C; +
/-15
C A
IR
ES
C A
ND
GR
OU
ND
ING
DC
MA
GN
ET
ICS
AC
MA
GN
ET
ICS
BA
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T
RA
DIA
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OP
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AT
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HO
UR
S
FA
ILU
RE
FR
EE
HO
UR
S
WO
RS
T-C
AS
E A
NA
LYS
IS
COMMENTSInstrument Payload 6 UCB T9 T10 T10 T10 T10 6 -30 to +45 -40 to +50 -40 to +55 M3 T14 1000 100 SST Sensor 2 UCB T1 A2 T4 T5 A7 M1 T7 T9 2 -65 to +40 -52 to +13 -75 to +50 -65 to +30 T11 M2 A 100 A
notes:T1 0.25g sweep from 5 Hz to 2000 HzA2 Analysis to show margin on Yield at 2.0 x limit load; and Ultimate at 2.6 x limit loadT3 Test conducted at 1.25 x limit load T4 ETU tested to Qual; F1 tested to Protoflight; F2-F6 tested to Acceptance. Levels from coupled loads analysisT5 ETU tested to Qual; F1 tested to Protoflight; F2-F6 tested to Acceptance (sine profile in thm-sys-005)T6 ETU tested with SC shock testA7 Analysis to show margin at 2 x maximum pressure differential (launch ascent profile in thm-sys-005)M1 Mass, CG and MOIs measuredT7 At least 10 x number of actuations during the mission life, unless mechanism is on Limited Life Items ListT8 SPB Motor to go through Life Test - operation after 6 months (TBR)T9 Safe-to-Mate and compliance to ICD prior to Integration
T10 Per MIL-STD-461C (levels in thm-sys-005) T11 Grounding checked for each component prior to integrationM2 DC Magnetics measured prior to Instrument Payload integrationM3 AC Magnetics measured in mag facility at Probe Level
T12 Total Dose and SEE Testing at part level if necessaryT13 60C for 48 hours prior to TV w/ integrated payloadT14 Contamination Verification w/ TQCM during Instrument Payload Thermal Vac
CONTAMINATION OTHERHARDWARE MECHANICAL ELECTRICAL THERMAL
THEMIS Mission CDR 79 UCB, June 16, 2004
Solid State Telescope
Thermal
Christopher Smith
Thermal Engineer
510-642-2461
THEMIS Mission CDR 80 UCB, June 16, 2004
SST
• Mounts directly to the corner panel on three 1/8 inch isolators
• Has four open apertures that are sometimes obscured by attenuators
• Must operate at 10 Deg C or less
THEMIS Mission CDR 81 UCB, June 16, 2004
SST Geometry Model
Alodined
Aluminum
AZ 2000 IECW
Ebanol
Black Body /
Alodined Aluminum
THEMIS Mission CDR 82 UCB, June 16, 2004
SST Model Inputs
• Optical materials– Ebanol– AZ 2000 IECW White Paint– Alodined Aluminum
• Thermophysical materials– Aluminum, 6061– ULTEM
• Heaters– Two 5 watt heaters per sensor head controlled by redundant
thermostats– Set points –50 and -42
• Conductors– 3 ULTEM isolators to corner panel, 0.0078 < G < .0133 W/C
each
• Power Dissipation– 0.135 W Watts Nominal per Sensor
THEMIS Mission CDR 83 UCB, June 16, 2004
SST Case Sets
THEMIS Mission CDR 84 UCB, June 16, 2004
SST – Nominal Plots
-70
-60
-50
-40
-30
-20
-10
0
10
20
30
40
0 50K 100K 150K 200K 250K 300K
SST - Alodine and AZ 2000 IECW White Paint, 10 W Heater (04/12/04)SAA 103 Hot Aperture Closed - SAA 103 Hot - SAA 90 Cold - SAA 77 Cold - SAA 77 Cold Low Power
Tem
pe
ratu
re
Time
SST1 TOP SST1 COLLIMATOR SST 1 INTERNAL CORNER PANEL SST2 INTERNAL SST1 HEATER SST2 HEATER SST1 TOP
SST1 COLLIMATOR SST1 INTERNAL CORNER PANEL SST2 INTERNAL SST1 HEATER SST2 HEATER SST1 TOP SST1 COLLIMATOR
SST1 INTERNAL CORNER PANEL SST2 INTERNAL SST1 TOP SST1 COLLIMATOR SST1 INTERNAL CORNER PANEL SST2 INTERNAL
SST1 TOP SST1 COLLIMATOR SST1 INTERNAL CORNER PANEL SST2 INTERNAL
THEMIS Mission CDR 85 UCB, June 16, 2004
SST – Top and Bottom to Sun Plots
-80
-70
-60
-50
-40
-30
-20
-10
0
10
20K 30K 40K 50K 60K 70K 80K 90K 100K 110K 120K 130K
SST - Alodine and AZ 2000 IECW White Paint, 10 W Heater (04/12/04)SAA 0 Cold - SAA 180 Cold
Tem
pera
ture
Time
SST1 TOP SST1 COLLIMATOR SST1 INTERNAL CORNER PANEL SST2 INTERNAL SST1 HEATER
SST2 HEATER SST1 TOP SST1 COLLIMATOR SST1 INTERNAL CORNER PANEL SST2 INTERNAL
THEMIS Mission CDR 86 UCB, June 16, 2004
SST Results Table
THEMIS Mission CDR 87 UCB, June 16, 2004
SST – Coldest Heat Map
THEMIS Mission CDR 88 UCB, June 16, 2004
SST Hottest Heat Map
THEMIS Mission CDR 89 UCB, June 16, 2004
Design Details
Thomas Moreau
THEMIS Mission CDR 90 UCB, June 16, 2004
Detector system• Measure electrons and protons > 20 keV
Geometrical analysis• Collimator aperture• Solid state detector size• Thin foil
– Stop protons < 350 keV
• Magnet system– Deflect electrons < 400 keV– Not to disturb particle trajectories out of the magnet gap– Low stray magnetic field at the position of the magnetometers
• Attenuator System– Reduce count rate during high flux– Reduce radiation damage (especially to open side)
Sensor Considerations
THEMIS Mission CDR 91 UCB, June 16, 2004
Detector System
Detectors stacked in “Triplet” sequence:• Foil (F) | Thick (T) | Open (O)
• Area used 1.32 0.7 cm2
• Front detectors F and O are 300 m thick while T is 600 m (with two detectors back to back)
• Detectors associated with a system of coincidence/anticoincidence logic
OTF OTF
OTF OTF
F T O
THEMIS Mission CDR 92 UCB, June 16, 2004
Collimator System
3D numerical model (GEANT3) of the collimator with detectors/foil
• Collimator baffle offers 42 23 rectangular full field-of-view
• Be-Co knife-edges intercept out-of-beam low-energy particles and reduce scattered light
• Aluminum housing shielding (0.5 mm) stops normally incident protons < 8 MeV and electrons < 400 keV
• Al/Polyimide/Al (LUXÉL) three layer foil (~1500Å/4m/1500Å) absorbs protons < 350 keV while permitting electrons ~20 keV to penetrate
• Geometric factor ~ 0.1 cm2sr
THEMIS Mission CDR 93 UCB, June 16, 2004
Telescope Response
Monte-Carlo simulation• 3D ray tracings are performed: a clean
electron-proton separation is obtained
• Particles’ angular distributions are determined ( 27 14 FWHM)
• Efficiency plots of the electron-proton detectors are determined for different energies
THEMIS Mission CDR 94 UCB, June 16, 2004
Magnet System
Magnetic circuit design• 4 permanent magnets (Dexter
Magnetic Technologies) + 2 yokes (Vacuumschmelze, Germany)
• Two oppositely oriented dipoles
• Stray fields < 1.5 nT at 2m distance
Magnet gap
THEMIS Mission CDR 95 UCB, June 16, 2004
Particle tracing simulations
Magnet System
400 keV (e)
30 keV (e)
30 keV (p)800 keV (e)
THEMIS Mission CDR 96 UCB, June 16, 2004
Tests and Calibration
Thomas Moreau
THEMIS Mission CDR 97 UCB, June 16, 2004
Tests Magnet System
• 2 magnet assemblies assembled for prototype• Spot-checks of measured magnetic field versus those
obtained from the analytical calculations are done: small discrepancy due to the misalignment of vector magnetization and the non-uniformity of magnetization
• The discrepancy of magnetic properties between 4 magnets of each assembly is minimized
• Magnetic induction in the center of the gap is measured ~2.23 kG (in agreement with 2.24 kG of the model)
• Mapping of the magnetic field strength at SSL and additional measurements at IGPP/UCLA are done: magnetic moments of each assembly are characterized (used to derive the stray fields)
• To save weight, yokes will be shaved until they went to the saturation (to be done)
THEMIS Mission CDR 98 UCB, June 16, 2004
Tests and Calibration
Need to characterize the sensor response in terms of: • Species (electron, proton, oxygen and helium ions)• Energy: - determine the detection threshold for a particular
channel- determine the energy thresholds for the coincidence
counting rate channels - to provide the look-up tables
• Angle: - determine the off-axis response (including information on the response to scattered particles)
• Dead time
Other goals:• Determine the electron and proton detection efficiency of individual
counting rate channels
• Sun pulse recovery
• Use the calibration data to verify and adjust the mathematical model
THEMIS Mission CDR 99 UCB, June 16, 2004
Calibration Set Up
• Initial calibrations at SSL, Ba-133, Bi-207, Cd-109 and Cs-137 conversion electron sources will be used to determine channel energies over the range 62 keV to 1060 keV
• Low-energy (up to 50 keV) and detection efficiency calibration for both electrons and protons will be done at the new SSL acceleration facility
• Additional energy and detection efficiency calibration with both electrons and protons with a high-energy accelerator (above 300 keV) if needed
THEMIS Mission CDR 100 UCB, June 16, 2004
SST GSEJim Lewis
THEMIS Mission CDR 101 UCB, June 16, 2004
SST/DAP GSE Block Diagram
SSTSensor
GSE workstationBenchLVPS GPIB via USB
Ethernet
GSE software: basedon Mike Hashii’sSTEREO GSE tools
6U GSEInterface
Board+
Niosembeddedprocessor
Ethernet router
Lab network
DAP_HSK
SST TLM
SST CMD
SST CLK
SST SectorClk
SST TLM ENA
3-axis servoamplifier
Manipulator
Electronor ion gun
HVPS
Vacuum chamber
PCI motioncontroller
DAPPower
Data
PWR
Digital MultimeterGPIB
Ethernet
THEMIS Mission CDR 102 UCB, June 16, 2004
SST/DAP GSE Software
Capabilities:• Scripted or interactive entry of CDI, GPIB, and manipulator
commands
• Simulates ETC board to command DAP and acquire telemetry
• Real-time display of counter histograms, raw hex telemetry dumps, analog housekeeping values, manipulator status
• Monitoring of CDI commands to mirror DAP memory operations and validate correct DAP FPGA operation
• Telemetry and log messages archived to disk for later examination and processing
• Device control– GPIB programmable LV and HV power supplies, digital multimeter– Internal PCI motion controller, external servo amp and motor drive– TCP/IP interface to 6U VME GSE Interface Board for sending CDI
commands, acquiring telemetry and analog housekeeping values
THEMIS Mission CDR 103 UCB, June 16, 2004
Contamination Control
• Standard cleanliness procedures will be followed• The sensor units will have a dry Nitrogen purge
system and red tagged covers (removed at last possible opportunity)
• Nitrogen purge can be removed for transport (<24? hours) with sensor in sealed containers.
• Red tape to cover apertures during spin balance• Sensor contamination from fairing during launch –
still open issue• Attenuators should be in the closed position during
satellite manuevers.
THEMIS Mission CDR 104 UCB, June 16, 2004
Vacuum Chamber Refurb
Not really a refurb!
ReGen valve
Roughing valve
Cryo pump
Compressor
Gate valve
Convectron -1
Ion chamber
Ion Chamber valve
IG-1
IG-2
VacuumChamber
New Purchase
Convectron -2
Turbopump
Backingpump
Turbo controller
Scroll Pump
Vent valve
THEMIS Mission CDR 105 UCB, June 16, 2004
Ion Gun Specifications
10/6/2003
List of Specs
1 energy range 1KeV to 50 KeV2 energy width 0.5% over full range or 50eV, whichever is greater3 energy stability 1% over full range for 20 minutes
4 particle flux 1000 to 100000 particles/s/cm2
5 beam cross section 4 cm diameter6 beam flux stability <2% for 20 minutes7 beam flux variation <20% over cross section
8 species H+, He+, Ne+, O+, N+, Ar+, (Kr+)9 mass resolution distinguish above species10 system footprint not to exceed 9' x 4' (preference, not required)11 power requirement 120VAC
12 cooling requirements preferably air, but H2O OK
13 lead time 4 to 5 month14 vacuum system req ability to interface to 250 l/s turbo pumping system
THEMIS Mission CDR 106 UCB, June 16, 2004
Ion Gun Schematic
THEMIS Mission CDR 107 UCB, June 16, 2004
Detector Schedule
THEMIS Mission CDR 108 UCB, June 16, 2004
Schedule
THEMIS Mission CDR 109 UCB, June 16, 2004
Schedule
THEMIS Mission CDR 110 UCB, June 16, 2004
Schedule
THEMIS Mission CDR 111 UCB, June 16, 2004
End of Presentation