themis instrument pdr 1 ucb, october 15-16, 2003 sst subsystem preliminary design review davin...

THEMIS Instrument PDR 1 UCB, October 15-16, 2003

SST SubsystemPreliminary Design Review

Davin Larson, Thomas Moreau,

Ron Canario, Robert Lee, Jim Lewis

UCB


Overview

Solid State Telescope (SST)• Requirements and Specifications• Block Diagram• Mechanical Design

– Detectors– Collimation– Magnets– Attenuator (aka shutter, door)– Detector placement / FOV issues– Mass estimates

• Electrical Design– AFE – (Analog Front End) (aka: DFE)– ADC board (aka: DAP)– Power Estimates

• Testing and Calibration• Schedule• Issues


Science Requirements

• SST-1: The SST shall perform measurements of the tailward-moving current disruption boundary speed using the finite gyroradius technique (4.1.1.2, 4.1.1.5).

• 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 the Rx onset time (4.1.1.3, 4.1.1.5).

• SST-3: The SST shall compute the partial energy moments due to the superthermal ions and electrons in the magnetotail plasma sheet (4.1.1.3, 4.1.1.6, 4.1.1.7, 4.1.1.9, 4.1.1.10).

• SST-4: The SST shall obtain measurements of ion and electron distribution functions with one spin time resolution (<10sec required) (4.1.1.2, 4.1.1.3).

• SST-5: The SST shall measure energetic electron fluxes as close to Earth as 6RE geocentric, at all local times. (Radiation belt science- tertiary objective – achieved by nominal design).

• SST-6: The SST shall measure energetic ions in the solar wind, at the magnetopause and in the magnetosheath (Dayside science – secondary objective – achieved by nominal design).


Performance Requirements

• 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 (SST-1, SST-2).

• SST-8: The SST energy sampling resolution, dE/E, shall be better than 30% for ions and electrons (SST-1, SST-2).

• 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. (exact values TBD) (SST-1, SST-2)

• SST-10: The SST shall measure over 90o in elevation with a minimum resolution of 45o (SST-1, SST-2, SST-3, SST-4).

• SST-11: The SST shall have an azimuthal resolution of 45o (SST-1, SST-2, SST-3, SST-4).

• SST-12: The SST shall supply the high energy partial moments at one spin time resolution (SST-3)

• SST-13: SST calibration shall ensure <20% relative flux uncertainty over the ranges defined above (SST-1, SST-2).


Block Diagram

SensorUnit

(2 DFEs)SSTDAPBoard

(aka: ADC)

ETCBoard

DCBSensorUnit

(2 DFEs)

IDPU


Sensor Units

Each sensor unit is a:• Dual-double ended solid state telescope• Each double ended telescope (1/2 sensor) has:

– Triplet stack of silicon solid state detectors– Foil (on one side)

– Filters out ions <~350 keV – Leaves electron flux nearly unchanged

– Magnet / Open side– Filters out electrons <300 keV – Leaves ion flux nearly unchanged

– Mechanical Pinhole attenuator– Reduces count rate during periods of high flux– Reduces radiation damage (caused by low energy

ions) during periods of high flux

– Collimators– Preamplifier / shaping electronics


Sensor Unit Schematic

Collimator

Foil DetectorThick DetectorOpen Detector

Magnet Attenuator

Lexan/AlFoil


Sensor Units


Mechanical Design

Block Diagram Overview

Sensor Components• Detectors (& Associated Electronics)• Attenuator (aka shutter, door)• Detector Placement / FOV issues • Collimation• Magnet

Other Stuff• Cables• ADC Board

Mass Estimates


Detector Pixelation

Detectors similar to STEREO/STE• Produced at LBNL/Craig Tindall PI

Active area

Guard ring

10 mm

5 mm


Detector Stacking

Current Design

Thick{

Open

Foil

~200 A Dead Layer

Pixelated side ~1200 A Dead Layer

+35 V

n

p


Mechanical Presentation

Robert K. Lee


SST Mechanical Design

Solid State Telescope (SST)• Mechanical Requirements• Mechanical Design

– SST Sensor Unit

– Attenuator Actuation

– Attenuator Control

• Electronics and Cabling• Sensor Orientation Relative to Spacecraft Bus• Thermal Summary• Mass Summary



Mechanical Requirements• SWALES Mechanical Verification Specification 1c• Radiation shielding thickness driven by dose depth curve• Total subsystem mass < 1.2 kg

– Two SST sensors

– DAP electronics board with shielding

– Harness

• Nitrogen purge required• Attenuator actuation must complete motion < 1 minute• Attenuator used approximately 20 times per day



SST Sensor Unit• DFE Detector Board Subassembly• Magnet-Yoke Subassembly• Attenuator-Actuator Subassembly• Collimators• Support Structure• Bi-Directional FOV

Attenuator Actuation• Linear Actuators• Position Switches

Attenuator ControlElectronics and Cabling

• DAP Board• Harness

Sensor Orientation Relative to Spacecraft BusMass Estimate



Detector Stack Composition (exploded view)

DFE Detector Board Subassembly

Detectors (4)

Spring Clamp (2)

Spring Plate (2) PEEK Spacer (3)

BeCu Gasket (3)

Kapton Flex-Circuit (4)

AMPTEK Shielding


Typical Electrical Connection Between Detector and Flex-Circuit


Kapton Flex-Circuit

Detector (pixelated side)

Wirebond

(not shown to scale)



DFE Detector Board Subassembly Relative Positions (2 per sensor)

AMPTEK Shielding

Detector Stack Subassembly

Multi-Layer Circuit Board (62 mil thickness)



Magnet-Yoke AssemblyCo-Fe Yoke (2)

Sm-Co Magnet (4)

Aluminum Magnet Cage



Attenuator Assembly

Attenuator (4)

Sapphire Bearing (2)

Cam (2)

Actuator Yoke (2)



Actuators and Position Switches

Honeywell SPDT Hermetically Sealed Switch (2)

NANOMUSCLE SMA Actuator (2)



Two Collimators Per Side

Electron Side

Ion Side



Four Collimators Per Sensor

Ion Side

Electron Side

Electron Side

Ion Side



Support Structure (back section)

Electrical Connector

Bottom Closeout Panel

Housing (back section)



Support Structure (front section)

Housing (front section)



Bi-Directional Fields-of-View



Attenuator Actuation – OPEN position

Honeywell Switch (extended-position)

NANOMUSCLE Actuator (extended)

Honeywell Switch (compressed-position)



Attenuator Actuation – CLOSED position

Honeywell Switch (compressed-position)

NANOMUSCLE Actuator (retracted)

Honeywell Switch (extended-position)



Attenuator Control – OPEN position

R~5Open

AttenuatorClose

Attenuator

PCB

+5V

SST Sensor

+5V

GNDGND

MonitorMonitor

PCB

SPDT Switch

NANOMUSCLE



Attenuator Control – CLOSED position

R~5

PCB

+5V

SST Sensor

+5V

GNDGND

MonitorMonitor

PCB

NANOMUSCLE

SPDT Switch

OpenAttenuator

Close Attenuator



Attenuator Control – Switch Activation

Cam Radius

Cam Rotation Angle

Switch Roller during compressed-position

Switch Roller during extended-position

Switch Travel Length

Switch Toggle/Transition

Note: Sketch NOT drawn to scale


Linear Actuators• NANOMUSCLE Shaped Memory Alloy (SMA)• Single direction 125 gram pull-force

– < 40 gram required force => F.S. > 3.0

• Operating temp range: -70°C to +75°C

Extended Position

Retracted PositionRelative Size



Position Switches• Honeywell miniature hermetically sealed switches• Single-Pole-Double-Throw circuitry• Operating temperature range: -65°C to +121°C• Exceeds MIL-S-8805 shock and vibration requirements

Extended Position Compressed Position


Roller



Sensor Orientation Relative to Spacecraft Bus• FOV is still being resolved


Thermal Summary - Heat Transfer

Power Dissipation

•6 Amptek 225s = 72 mW per sensor.

•Steady state shadow temperature of -61 °C

Conduction

•Corner panel reaches –60 °C in long eclipse

•Isolated from corner panel with 1/8 inch G10 spacers.

Radiation

•All surfaces covered with low ε VDA tape

•Apertures and collimators dominate the heat leak



Thermal Summary - Temperature Limits

•Steady state predictions from UCB based on corner panel temperatures from Swales

•Cold prediction from 3 hour eclipse orbit

•Hot prediction from hottest orbit and attitude

•Average operating temperature around 25 °C

•Better predictions await more complete instrument thermal models

Survival (°C)Predictions

(°C)

Margin

(°C)Eclipse-Op

Science-Op Cold Hot Cold Hot

-65 -55 40 +65 -61 35 4 5



Temperature Monitoring and Control

•Modified Interface Monitoring

•Probe Bus will monitor the SST temperature on one of the SSTs

•Instrument Monitoring

•IDPU will process thermistors near the detectors

•Heaters

•No operational heaters are required

•Survival heaters will keep SST above Eclipse-Op limits

•Two heater services provided by the probe bus

•Primary service thermostat closes at –58

•Secondary service thermostat closes at -63




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 to each detector stack at 1 liter/hour



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– Approximate length of 1.2m– Composition:

– 10 coaxial cables (36 AWG)– 4 twisted wire pairs (26 AWG)– 4 single wires (36 AWG)


Mass Summary

SensorsUnit Mass

[g]Units/SST Mass [g] # units

Total Mass [g]

Magnets 6.6 4 26.2Yoke 20.2 2 40.3Magnet and Yoke Cage 10.0 1 10.0Foil Collimator (Electron) 12.0 2 24.0Open Collimator (Ion) 6.0 2 12.0Housing 20 mil 57.0 1 57.0Bottom closeout 20 mil 4.0 1 4.0Attenuator (1 axle/4 paddles/2 cams) 10.0 1 10.0AFE board (loaded) 0.8 gm/cm2 57.0 cm2 45.6 2 91.2Amptek Shield Cover 9.0 2 18.0Detector Stack 12.0 2 24.0HM Switches 6.0 2 12.0SMA actuator 3.0 2 6.018-8 SS Fasteners 0.4 80 32.0

Sensor Total: 366.7 2 733.4

Cables:7 Coax; 5 twisted pairs 44.0 gm/m 1.3 m 57.2 2 114.4Connectors 15.0 4 60.0

Cable Total: 174.4 2 348.8

IDPU electronicsDAP board 1.0 gm/cm2 368.0 cm2 368.0 1 368.0Shield board 0.1 gm/cm2 368.0 cm2 36.8 1 36.8Edge Shielding 69.3 cm3 187.1

IDPU Total: 591.9 1 591.9

Total: 1674.1




Questions/Comments?


Design Details

Design Details

Thomas Moreau


Detector system• Measure electrons and protons > 20 keV

Geometrical analysis• Collimator aperture• Solid state detector size• Thin foil

– Stop protons < 350keV

• Magnet system– Deflect electrons < 200 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


Detector System

Detectors stacked in “Triplet” sequence:• Foil (F) | Thick (T) | Open (O)

• Area used 1.0 0.5 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


Opto-Mechanical System

48 28

Section view of the wide aperture

Section view of the

narrow aperture

28Critical one-bounce scatter

Most of stray light from an out-of-field source are eliminated by a proper design


Collimator System

3D numerical model (GEANT3) of the collimator with detectors/foil

• Collimator baffle offers 48 28 rectangular full field-of-view

• Tungsten 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:Si/Lexan/Al:Si three layer foil (1449Å/3.877m/1353Å) absorbs protons < 350 keV while permitting electrons ~20 keV to penetrate

• Geometric factor ~ 0.11 cm2sr


Telescope Response

Monte-Carlo simulation• 3D ray tracings

• Angular response 37 22 FWHM

• Efficiency plots

for electron and proton


Magnet System

Magnetic circuit design• 4 permanent magnets + 2 yokes• Two oppositely oriented dipoles• Stray fields < 10 nT at 1m distance

Magnet gap

Magnetic flux density

Permanent magnet [Samarium-Cobalt 18 MGOe]

Yoke[Vacoflux 50 Iron-Cobalt alloy]


Particle tracing simulations

Magnet System


Electrical Design

Block Diagram

DFE–Analog Front End (aka: AFE)• Functions: Preamp/Shaping

• Schematics

• Parts

• Layout

• Testing

DAP board (aka: ADC)• Functions: Baseline restoration, Peak detect, ADC, Logic

• Schematics

• Parts

• Layout (currently incomplete)

• Testing

• Actel Specs

Power Estimates


Electrical Systems

Ron Canario


Electronics Block Diagram

Signal chain: 1 of 12 channels shown

ADC

FPGACoincidence

Logic &Accumulators

Memory

DACThresh

Gain

PD

BLR

A225FPreampShaper

Det/PreampBoard

ADC/ACTEL Board

Test Pulser

Bias Voltage


Detectors

Thin dead layer (PIPS like) detector

Fabricated by LBNL (PI: Craig Tindall)


DFE Schematics

Analog Front End Schematic


Preamps/Shaping

Using Amptek 225F (6pin sip Hybrid)

Characteristics: • ~6 keV electronic noise (with 1.5 cm2 detector)

• ~2.5 uS shaping time (time to peak)

• ~12 mW at +5.0Volts

• 100 Krad (still needs ~3mm Al shield)

• Operating range: -55 to +125 C


DFE Layout

Preliminary board layout. (possibly adequate for ETU)• A225Fs have 3.5 mm radiation

shielding• Caps/Resistors have ~0.5mm

shielding• Detectors located near Preamps

A225Fs

Al shield

Detector Stack

15 pin D


SST Schematic


DFE Schematic


DAP Schematic


ADC Schematic


Quad Converter Schematic


ADC Schematic


Test Pulse Schematic


Bias Supply Schematic


Controller Schematic


DAP Layout

Preliminary layout suggests the SST/DAP board will fit on a 6U card

ACTEL

12 identical channels


DFE Testing

Figure 4AmpTek output in response to a much wider input pulse


DFE Testing

• Split ground planesPositive vs Neg A225F Out

0

200

400

600

800

1000

1200

0 50 100 150 200

Input (mv 0tp)

Ou

tpu

t (m

v 0t

p)

Positive Output (WP)

Negative Output (WP)

Positive Output

Negative Output


ACTEL Development

Noise measurements

Test Pulser control

ADC Readout

Data Binning

Coincidence

Data

Analog Housekeeping control


SST GSEJim Lewis


Power / Thermal / Mechanical

Power• Provide regulated voltages • Facilitate current measurements

Mechanical• 6U VME support (without Wedge-locks)• Portable and Rugged for transport• Open rack for access while under test• Connectors are acceptable for flight interconnection


Electrical Interface

Mechanical interface to signals• Before DCB & ETC, GSE connectors as defined for SST-to-

IDPU• Afterwards data is taken through DCB.

Analog Housekeeping• 1 analog housekeeping output (shared backplane ANA HSK

signal)

Electrical Quality• GSE Interface circuitry must be flight grade


Command and Telemetry Handling

Commands (to DCB)• Sends CDI 24-bit commands per ICD specification• User command interface in STOL• Reads STOL command files• Compatible format with IDPU GSE and MOC GSE

Commands (before DCB) are CDI

Telemetry• Before DCB & ETC, data is taken directly by GSE h/w• Afterwards data is extracted from packet telemetry.


Data Manipulation

Input data or outputs from calculations can be displayed, saved to disk, and/or plotted with library routines.

Plot data over user-defined energies and angle.

Convenient access to data for offline processing (FTP, HTTP, etc.)

Supports “screen print” capability


Errors and Responses

GSE software monitors serial instrument data stream for missing or corrupted data. All detected anomalies are logged, counted, and displayed in user interface.


Mission Requirements

Compatibility with next level integration• Uses ITOS, LabWindows, C• PC standards (same platform through all mission phases)


Testing and Calibration

• GSE Devolopment • Vacuum Chamber Refurb• Ion Gun (Peabody Scientific)


SST

GSE workstation

LVPSequivalent

GPIB via USB

RS232Manipulator/HVPScontrol workstation

Ethernet

GSE software: basedon Mike Hashii’sSTEREO GSE tools

GSEInterface

Board

Multiport Ethernet Hub/Firewall

Optional uplink to lab network

ANA HSK

SST TLM

SST CMD

SST CLK

SST SectorClk

SST TM ENA

ACS-Tech80Servo control card

GPIB

PWR

3-axis servoamplifier

Manipulator

Electronor ion gun

HVPS

Vacuum chamber

New components Existing components


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.

Satellite manuevers should be done with attenuator in the closed position.


Vacuum Chamber Refurb

ReGen valve

Roughing valve

Cryo pump

Compressor

Gate valve

Convectron -1

Ion chamber

Ion Chamber valve

IG-1

IG-2

Vacuumchamber

Convectron -2

Turbopump

Backingpump

Turbo controller

Roughing pump

Vent valve


Vacuum Chamber refurb

9/11/2003

item description vendor p/n price($) note1 Cryo Pump CTI 8160001sys 14200.00 Cryo-Torr 8 / 8200 Compressor System, complete2 Cryo temp indicator CTI 8043459G001 1372.00 Cryo head temp monitor3 chamber gate valve MDC 304005-05 2825.00 8" port, 1-1/2" rough port, ANSI ASA6 flanges4 gate valve hardware MDC 190177 74.00 hex head bolts for ASA6 flange5 Turbo-V 301 Navigator Varian 9698828 7280.25 complete system w/ controller, N2 250 L/s, 120VAC, ISO NW1006 turbo air cooling kit Varian 9699299 297.60 very convenient7 turbo inlet screen Varian 9699302 76.608 SH-100 Scroll pump Varian SH01001UNIV 2450.00 backing pump for turbo, 120VAC, 60Hz, oil-free9 exhaust silencer Varian SH0100EXSLR 83.0010 scroll pump power cord Varian 656458203 free 15A/125VAC, 6' length11 adapter nipple MDC 832008 225.00 ISO NW100 to ISO NW80 reducer12 reducing cross MDC 825043 290.00 ISO NW80 to NW40 KF13 Ion Chamber valve MDC 306005 1500.00 4" port manual swing gate valve, ISO NW100 flange14 roughing valve MDC 312029 340.00 2-3/4" CCF, metal seal bonnet, manual15 vent valve Varian 9515085 325.00 Rt angle valve, NW16 KF, manual16 regen valve MDC 310073 245.00 NW25 KF, metal seal bonnet, manual17 vacuum gauge controller Granville-Phillips 307502-C10-T1 2095.00 307, dual IG/rough gauge capability, IEEE 48818 ion chamber rough gauge Granville-Phillips 275316 180.00 Convectron gauge(1), range atm to 8e-4 Torr, NW40 KF19 chamber rough gauge Granville-Phillips 275316 180.00 Convectron gauge(2), range atm to 8e-4 Torr, NW40 KF20 ion chamber ion gauge Granville-Phillips 27453 470.00 BA Nude IG(1), all metal case, NW40 KF21 chamber ion gauge Granville-Phillips 27453 470.00 BA Nude IG(2), all metal case, NW40 KF22 rough gauge cables Granville-Phillips 303040-10 90.00 Dual Convectron cable, 10'23 ion gauge cable Granville-Phillips 307046-CR 140.00 BA IG cable24 ion gauge cable Granville-Phillips 307046-CR 140.00 BA IG cable25 misc.plumbing 2000.00 fittings, rough lines, switches, etc.26 cleaning chamber Pullbrite(510 659-9770) 750.00 soak, scrub, and electropolish27 half nipple Varian INH1000400 100.00 ISO NW100 weldable to chamber 28 in house fab SSL shop 1325.00 25 hr @ $53.00/ hr

Total 39523.45


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


Ion Gun Schematic


Schedule

ID Task Name0 THEMIS SST1 LINKS

12

13 SST Design

14 Initial Concept

15 SST Spec

16 ETC Spec

17 SST Mech Dwgs

18 AFE Electrical Design

19 ADC Electrical Design

20 ACT Electrical Design

21 ACT Specification

22 ACT Development

23 ACT Electrical Design

24 SST Parts

28 SST FLT DETECTOR FAB

36 SST ETU Sensor Head

37 ETU Mech Fabrication

38 AFE ETU Layout Card

39 AFE ETU PWB Fab

40 AFE ETU Assy

41 AFE ETU Prelim Test

42 SST ETU ADC Board

43 ADC ETU Layout Card

44 ADC ETU PWB Fab

45 ADC ETU Assy

46 ADC ETU Prelim Test

47 SST ETU Test

48 SST ETU Complete

49 SST GSE

50 SST GSE Development

51 Vacuum Chamber Refurb

Larson

Larson

Abiad

Robert Lee

Ron Canario[50%]

Ron Canario

10/14

Dorothy Gordon

Ron Canario

Robert Lee

Jeanine Potts

UCB

Helen Yuan

Moreau

Jeanine Potts

UCB

UCB-T2

Ron Canario

Larson

2/17

Lewis

Marquardt

A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D J F M2002 2003 2004 2005

themis instrument pdr 1 ucb, october 15-16, 2003 sst subsystem preliminary design review davin...

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