Transcript C R I A
Cosmic dust Reflectron for Isotopic Analysis (CRIA) Progress Review April 30, 2007 Laura Brower: Project Manager Drew Turner: Systems Engineer Loren Chang Dongwon Lee Marcin Pilinski Mostafa Salehi Weichao Tu 1 Agenda • Organization • Background • Operational Concept • System Design & Requirements • Subsystem Design • Project Management Plan 2 Organizational Structure Customer Z. Sternovsky Administration Manufacturing Professional M. Rhode (CU) System Engineer Project Manager L. Brower Student Lead D. Turner CU Advisors X. Li S. Palo Professional M. Lankton (LASP) Structures Professional P. Graf Thermal Electronics Student Lead M. Pilinski Student Lead M. Salehi Student Lead W. Tu Professional S. Steg (LASP) Professional B. Lamprecht (LASP) Professional V. Hoxie (LASP) Materials Ion Optics Detector Student Lead D. Lee Student Lead L. Chang Student Lead D. Turner Professional G. Drake (LASP) Experienced Graduate K. Amyx (CU) Professional G. Drake (LASP) 3 Agenda • Background • Operational Concept • System Design & Requirements • Subsystem Design • Project Management Plan 4 Dust in Space! Space dust provides important clues on the formation and composition of our solar system as well as other stars. Several instruments have been launched on past missions to analyze the flux and composition of space dust in-situ. 5 Time-Of-Flight (TOF) Mass Spectrometers • Dust is ionized against a target and accelerated through an electric field to a detector. • Ion mass is inferred from Time-Of-Flight. 6 CDA CIDA Time-Of-Flight (TOF) Mass Spectrometers • Large target area • Low mass resolution • High mass resolution • Small target area 7 CDA CIDA Large Area Mass Analyzer 8 Large Area Mass Analyzer • TOF Mass Spectrometer • Large target area comparable to CDA. • High mass resolution comparable to CIDA. • Lab prototype constructed and tested. 9 LAMA: What is still needed for dust astronomy? Several tasks have yet to be completed: DTS • Dust triggering system not yet implemented. • No decontamination system. • System has not yet been designed for or tested in the space environment. •No interface for dust trajectory sensor (DTS) 10 Cosmic dust Reflectron for Isotopic Analysis LAMA (A cria is a baby llama) CRIA 11 Project Dan Motivation Baker (~6ft tall man) Scale down LAMA to a size better suited for inclusion on missions of opportunity. LAMA (struc support) CRIA models Improve the Technological Readiness Level (TRL) of the LAMA concept from TRL 4 to TRL 5. CRIA LAMA 12 Agenda • Background • Operational Concept • System Design & Requirements • Subsystem Design • Project Management Plan 13 Cosmic dust Reflectron for Isotopic Analysis 3-D View 14 CRIA: Mass Analyzer Primary Subsystems IONIZER Target 15 CRIA: Mass Analyzer Primary Subsystems ANALYZER (Ion Optics) Annular Grid Electrodes Ring Electrodes Grounded Grid Target 16 CRIA: Mass Analyzer Primary Subsystems DETECTOR Detector 17 CRIA Concept: Operation incoming dust particle Example Dust Composition Key Species-2 Species-3 Target Increasing mass Species-1 Example Spectrum 18 CRIA Concept: Operation negative ions and electrons accelerated to target target material also ionizes dust impacts target and ionizes (trigger t0) Example Spectrum t0 19 CRIA Concept: Operation positive ions accelerated towards grounded grid (trigger t1) Ions of Species-1, Species-2, Species3, and Target Material Example Spectrum t0 t1 20 CRIA Concept: Operation Positively charged particles focused towards detector Example Spectrum t0 t1 21 CRIA Concept: Operation Species-1 ions arrive at detector Ions of the same species arrive at the detector at the same time with some spread Species-1 arrives at detector Example Spectrum t0 t1 t2 22 CRIA Concept: Operation Species-2 ions arrive at detector Species-2 arrives at detector Example Spectrum t0 t1 t2 t3 23 CRIA Concept: Operation Species-3 ions arrive at detector Species-3 arrives at detector Example Spectrum t0 t1 t2 t3 t4 24 CRIA Concept: Operation Target material ions arrive at detector m/Δm: mass resolution Target material has characteristic peak Example Spectrum t0 t1 t2 t3 t4 t5 25 Agenda • Background • Operational Concept • System Design & Requirements • Subsystem Design • Project Management Plan 26 System Level Diagram Supporting Electronics •High voltage supply •Oscilloscopes •Computer •Power source Thermal Control Line Key Power High Voltage Heat Data •Heaters •Thermocouples Structure (Gray area) Mass Analyzer Instrument Electronics •Charge Sensitive Amplifier •Voltage dividers Ionizer Analyzer (Target) •Annular electrodes Detector •Ring electrodes •Grounded grids 27 Minimum Success Criteria • Achieve working instrument with mass resolution of at least 100 m/Δm (Req: 1.TR2) • Achieve TRL-5: Working prototype tested in relevant environments (Req: 1.TR4) Remember: Working with Preflight Model only from this point on! -Designed originally in context of flight to help pave the way to TRL > 5, and ultimately to a possible mission of opportunity -Requirements have been categorized based on this into Preflight only (PF), Flight only (F), or Both (B) -We must only verify PF and B requirements 28 Level 1: Requirements Flowdown Top Level Requirements Level 2: System Requirements - Functional Requirements - Performance Requirements Analyzer Ionizer - Design Constraints - Interface Requirements Each includes: -Functional Reqs Detector -Performance Reqs -Design Constraints Level 3: Electronics/CDH -Interface Reqs Subsystem Requirements Structural/Mechanical Level 4: Component Requirements Thermal 29 Key Performance Requirements 1.TR8 & 1.TR9: Adequate Data Set Operational lifetime Instrument Size Instrument Mass 2.PR3: Mass Resolution Ion optics configuration Electrode voltages 2.PR4: Target Cleaning 3.6.PR3: Electronics Op. Temps Power budget Thermal design Thermal design: limiting range Target material 30 Agenda • Background • Operational Concept • System Design & Requirements • Subsystem Design • Project Management Plan 31 Structures Subsystem Lead: Marcin Pilinski Speakers: Marcin Pilinski Analyzer Structures Detector Thermal Ionizer Electronics/ CDH External Structure Fabrication Plan 32 Structure: Requirements Overview Requirement Description 3.4DC1 Scaling of Ion optics by 5/8th of LAMA ion optics 3.4DC6, 3.4DC7, 3.4DC8 Electrically isolate high voltages 3.4DC2 Fundamental frequency = 50 Hz 3.4DC3, 3.4DC4 Yield FOS 1.5, Ultimate FOS = 2.0 in 42g load 3.4DC5 Structure mass < 15 kg 3.4DC10, 3.4DC11 Light cannot enter instrument except at aperture 33 Structure: Major Design Trade 30 cm Cylindrical 40 cm Cylindrical 40 cm Hexagonal Aperture Requirement Not Met Medium Material Cost Meets aperture requirement High Material Cost Meets Aperture requirement Low Material Cost [80%] in-house manufacturing* [9 kg] [40%] in-house manufacturing [13 kg] [80%] in-house manufacturing [14 kg] [40 cm] external envelope [48 cm] external envelope [53 cm] external envelope [80] manufactured parts [80] manufactured parts [116] manufactured parts 34 Cylindrical Structure: Overall Characteristics Unique Parts Total No. of Mnf. Parts Mass 26 80 13 kg Fasteners 200* *Not including instrument-spacecraft interface *All blind fasteners will be vented 35 Hexagonal Structure: Overall Characteristics Unique Parts Total No. of Mnf. Parts Mass 45 116 14 kg Fasteners 300* *Not including instrument-spacecraft interface *All blind fasteners will be vented 36 Structure: Parts Summary Annular Electrode Mount Annular Electrode Support Annular Electrodes Ring Electrodes Ring Electrode Standoffs Grounded Grid Target Hexagonal Base Detector 37 Structure: Parts Summary Light Cover CSA Box Side Panels Channel Supports Annular Electrode Support 38 Structure: Assemblies Annular Electrode Assembly Main Housing Assembly Target Assembly Detector Assembly 39 Structure: Annular Electrode Assembly Wiring Channel (G-10) Annular Electrode Mount Annular Electrode Standoff (G-10) Annular Electrodes (BeCu 17200) 40 The photo-etched grid • • • • BeCU C17200 ~7 mils in thickness $800 manufacturing cost (includes spare) Mitigates grid wrinkling and eases integration 41 Structure: Annular Electrode Assembly 42 Structure: Main Housing Assembly Channel Supports Ring Electrodes Voltage Divider Box Side Panels Ring Electrode Standoffs (Noryl) Light Covers (G-10) Side Panel Brackets 43 Structure: Main Housing Assembly 44 Structure: Target Assembly Inner/Outer Target Electrode Standoffs (Noryl) Grounded Grid Silver Coated Target Hexagonal Base 45 Inner/Outer Target Electrodes Structure: Target Assembly 46 Structure: Detector Assembly Detector Lid Top/Bottom Detector Grid Clamp Detector Detector Grid Detector Housing Cylinder 47 Structure: Main Assembly Detector Assembly Main Housing Assembly Target Assembly Annular Electrode Assembly 48 Cable Layout Heater/CSA High Voltage – Ion Optics 49 Cable Layout: Solder Access 50 Cable Layout: Annular Electrodes 51 Cable Layout: Ring Electrodes 52 Cable Layout: Target Electrodes 53 Cable Layout: Grounded Grid 54 Cable Layout: Target 55 Cable Layout: Heater/CSA Power (twisted-shielded) Output (coaxial) Input (coaxial) 56 Mechanical Ground Support Equipment Interfaces • Remove-before-flight cover • Thermal Vacuum/Vibration Adapter Plate 57 Integration &Testing Features • • • • Removal of Detector Assembly for Storage Electrical Access Reconnecting the CSA Panel removal for internal access 58 FEM Design Check Results Max Displacement = 0.122 mm Min Factor of safety = 3.8 59 Manufacturing • Total Manufacturing Time: ~450 student-hours • 5 critical/difficult components totaling in ~200 student-hours Number of Parts Per Tool 2-axis mill 3-axis CNC mill lathe band-saw 1 19 8 Manufacturing Hours for Number of Unique Parts >30 to 40 hours 8% >20 to 30 hours 15% 10 hours or less 46% 101 >10 to 20 hours 31% 60 Structure: Upcoming Work • Complete Finite Elements Structural Analysis – Fundamental mode – Ultimate and Yield Stresses – Fastener pull-out strength • Review Design and Produce Mechanical Drawings 61 Detector Subsystem Lead: Drew Turner Speakers: Drew Turner Analyzer Structures Detector Thermal Ionizer Electronics/ CDH Detector Design 62 Detector: Driver Requirements Requirement 2.PR2 2.PR3 3.3.IR1 3.3.IR2 3.3.IR3 Description The instrument shall be able to detect a cloud of 10,000 elementary charges after initial dust vaporization [must have sufficiently high gain] The instrument shall measure the mass composition of dust particles with a simulated mass resolution of at least 100 m/Δm The detector shall be mounted in a detector casing [interface with structure] The detector shall electrically interface with the CDH system [computer to store data] The detector shall electrically interface with the voltage dividing system 63 MCP-MA34/2: Microchannel Plate Detector from Del Mar Ventures •Two MCPs in chevron stack enclosed in casing with leads for wiring (voltage and signal) •Need to be used in vacuum •Same as used for LAMA 64 Detector Testing • Functional tests in vacuum chamber • UV testing – MCP’s sensitive to UV light (table below) Source: Wiza, J. Nuclear Instruments and Methods, 1979 – Want to know how deep space UV background affects detector – Test with a UV source in vac chamber 65 Analyzer Subsystem Lead: Loren Chang Speakers: Loren Chang Analyzer Structures Detector Thermal Ionizer Electronics/ CDH Electrode Design Voltage Supply 66 Analyzer: Requirements Requirement Description 3.4.DC1 Scaling of Ion optics by 5/8th of LAMA ion optics 3.2.PR2 - PR4 Electrode voltages shall be within +/- 10 V of the specified values from SIMION simulation. A voltage divider box shall provide the necessary voltages to the various subsystems. All electronics shall maintain a voltage accuracy of 0.5% on the electrodes. 3.5.IR2 3.5.PR2 67 Electrode Voltages Ion Optics Configuration • • • Simulations done by Keegan Amyx using SIMION 5 annular and 8 ring electrodes Exact values for electrodes determined ranging from ~1 - 6 kV kV, DC 66kV, DC R1 Electrode Power: • • Power in preflight model provided by lab HV supply. Required electrode voltages can be provided by system of voltage dividers. R2 Electrode Electrode 68 Voltage Divider - Resistors • Ohmite SlimMox-104 thick film resistors. • Custom resistor values exceed budget, will use standard values. 8.64 mm • Rated for 10 kV DC operating voltage, -55 110°C temperature. 27.43 mm 22.86 mm • Non-exact values will introduce some error in voltage. 69 • Use of series circuit configuration results in reduction in: •Discrete resistors needed. •Power required. •Resistor value. • Cascading errors inherent in series configuration can be addressed by70 adding smaller corrector resistors during calibration. Voltage Divider - Configuration • Resistors for annular, ring, and target electrodes arranged in 3 parallel lines. • Resistors for each electrode type arranged in series. • Voltage precision of +/- 3 V. • Power Draw 0.15 Watts. • Requires 46 discrete resistors. Ring Electrodes Annular Electrodes Target Electrodes 71 Ionizer Subsystem Lead: Dongwon Lee Speakers: Dongwon Lee Analyzer Structures Detector Thermal Ionizer Electronics/ CDH Target Selection 72 Ionizer : Requirements Requirement Number 3.1.FR1 Description 3.1.FR7 The target shall be made of a high-z material, where high-z is defined as having atomic mass greater than 100 AMU The target shall be thermally conductive 3.1.FR8 The target shall be electrically conductive 73 Ionizer • Material : Ag (silver) • Silver Plating follow ASTM-B-700 – Type I : Purity 99.9% min. – Grade B or C : Bright – 10 μm copper coating between silver plating and Al substrate Vendor : Ano-plate, NY Parameter Value Inner φ 0.14 m Outer φ 0.40 m Thickness 100 μm Vendor website : www.anoplate.com – Cost : $250 + shipping 74 Substrate • Applying 5 KV on the Ionizer surface • Soldering to Substrate Silver Coated Substrate 5KV 75 Thermal Subsystem Lead: Mostafa Salehi Speakers: Mostafa Salehi, Laura Brower Analyzer Structures Detector Thermal Ionizer Electronics/ CDH Multi-Layer Insulation Target Heater Design 76 Thermal Requirements Requirement Description 3.6.FR1 Power allocation is 20 W 3.6.PR1 Target shall be heated to 100oC 3.6.IR1 Target heater shall be electrically insulated from the target 3.6.IR3 Target heater shall be thermally insulated from the instrument 4.6.IR1, 4.6.IR2 The backside of the target heater shall be covered in a low emissivity material 77 Design Reference Mission NGSTP Apogee: 200 Re Orbit plane: perpendicular to Sun-Earth line Magnetopause CRIA (in halo orb) Vsw 20-35 Re = RL 10-14 Re Sun +/- 20 Re Re Earth Moon L2 -5 °<β <15° ~240 Re Earth’s Magnetotail Hot Case: •External structure of instrument in complete view of Sun •CRIA sees 223 K (-50oC) Cold Case: •Spacecraft carrying instrument completely shades it from Sun 78 •CRIA sees temperature of 7K Power for Target Heater 25 W 15 W 10 W Minco Heater Max Power 26.18 W Input Resistance 5.5 ohm Size ~2” diameter Lead AWG 24 6W MINCO Kapton covered thermofoil heater -25 W required to heat target to 100C assuming worst case environment of 7K -Lower power heaters take longer to heat target -25 W heater will heat to 100C in 2 hrs at min environment testing temp of -50C Temperature Sensing and Heater Control Controller Type Manual On/off Sensor Type Thermocouples 79 Target Heater Configuration • The heater is wrapped in a thin Kapton coating • An additional layer DuPont Kapton FN (Kapton type: 150FN019) provides the electrical insulation sufficient to shield the heater from the target at 5 kV. ¼ cm Al target substrate 0.5 mm Target Kapton FN (Kapton type: 150FN019) Minco Heater • Similar heater configuration may be used to heat electronics 80 Electronics/CDH Subsystem Lead: Weichao Tu Speakers: Weichao Tu Analyzer Structures Detector Thermal Ionizer Electronics/ CDH Electronics Design Triggering Power Consumption System Monitoring 81 Electronics: Requirements (key pre-flight ones) Requirement 3.5.PR1 3.5.PR2 3.5.PR3 3.5.PR4 4.5.DC1 4.5.DC2 4.5.DC3 Description The voltage ripple on any of the electrodes shall not exceed [0.1%] of the applied voltage All electronics shall maintain a voltage accuracy of 0.5% on all the electrodes All electronics used in design shall operate in a vacuum environment without failure The instrument shall be able to detect charge signals on the target, grounded grid, and the detector grounded grid for data triggering The master electronic box shall be located outside of the instrument body (assumed to be with/near s/c electronics) The voltage divider box shall be located inside the instrument body beneath the target substrate The CSA box shall be located inside the instrument body close to the charge detector 82 Electrical Block Diagram (Preflight Design) Inside Electronics Lab Supporting Electronics CRIA Amplifier Box Coax CSA POWER Max: <25 W Coax CSA DET CSA Oscilloscope (500 MHz) CSA Coax Target HV wire Ring Electrodes HV wire Annuli Electrodes HV wire Divider Box (+6kV) HV wire HV wire Detector (-1~2 kV and -100V) CSA (6V, 14mW) HV Supply 1 (+20kV) 0.15W HV Supply 2 (-3 kV) 0.6pW Voltage Supply ~24W Decontam. Heater (11.5 V, 24W) 83 Key Electronic Subsystems -Triggering System • TR1-Trigger On Target (biased voltage: 5 kV) Cf 5 kv Target A250 CRIA Amplifier Box DET TR2 CSA TR1 CSA TR3 CSA TR4 CSA Voltage Source • TR2 and TR3-Trigger On Grid (Grounded) Cf Grid A250 84 Triggering System • TR4-Trigger On Detector – Include both biased voltage and grounded voltage MCP V1 V2 grounded 85 Triggering Test • Object: To determine which place is the best to get the triggering signal from. • Setup: CSA box and its connections Dimensions: 1 X 2 X 3 inches Signal Input Coax A250 Power Input SMA Twisted wire pair (+6V& ground) SMA Coax 86 Signal Output Triggering Test • Test Procedure – One CSA, move among different trigger-option places – At each place: • CSA Noise Floor Test (for determining trigger S/N) • Trigger Test – Laser-simulated impact – To determine whether resulting signals are detectable above the noise floor • Relocate CSA Box 87 Agenda • Background • Operational Concept • System Design & Requirements • Subsystem Design • Project Management Plan 88 Analysis Tools PROFESSIONAL ANALYSIS TOOLS SIMION analysis of time of flight, effective target area, and dynamic range. TR2, FR2, PR1, PR6 SolidWorks analysis of mass, structural integrity, thermal properties TR3, FR4, PR4, IR1 Thermal Desktop analysis of heat transfer PR5 89 How to Reach TRL 5 TRL 5: test CRIA in a relevant environment Required for TRL 5: • Vacuum Testing – Test performance of CRIA (measure m/Δm) using laser ablation of target to simulate dust impacts • Thermal Vacuum Testing – Monitor temperature response of structure, detector, voltage divider electronics, etc. during Thermal Balance Test and Thermal Cycle Test • UV Testing – Test signal response of detector exposed to UV Additional Testing • Vibration Testing – Shake/vibe based on NASA criteria for launch 90 Vacuum Testing Test Matrix Test Type Component Description Measure/ Record Functional Target Heater Heat target to 100C Target substrate temp Performance Instrument Simulate dust w/laser ablation Obtain spectra, monitor voltages Location: CU campus, Z. Sternovsky’s lab Operating Pressure: 10^-5 Torr Cost: $0 to operate vacuum Schedule: expect 1 week of testing in Oct, budget 1 month of testing Pre-testing Tasks: •Instrument checkout (test resistors, etc.) Lab Support Equipment: •2 HV Supplies (power detector) •Oscilloscope 91 Thermal Vacuum Testing Test Matrix Test Type Component Description Measure/ Record Functional Target Heater Heat target to 100C during -50C thermal balance test Target substrate temp Thermal Balance Instrument Steady state at Monitor instr temps Thermal Cycle Instrument -50C, +40C Cycle between -50C, +40C Monitor instr temps Location: LASP (MOBI or BEMCO) Operating Pressure: <10^-5 Torr Cost: Budgeting $1000 for oper equip / personnel time Schedule: expect 2-3 days of testing in Nov, budget 1 month of testing Lab Support Equipment: •Low voltage power supply Pre-testing Tasks: •Instrument checkout •Clean Room practices during assembly •RGA, TQCM, possibly BOT 92 Schedule 93 Pre-Flight Cost Budget 94 Special Thanks: • • • • • • • • • • • • • LASP for providing internal Funding and Support CU Aerospace Engineering Sciences Dept. Funding and Support Keegan Amyx Chelsey Bryant Josh Colwell Ginger Drake Paul Graf Vaughn Hoxie Bret Lamprecht Mark Lankton Mike McGrath Steve Steg The Heidelberg dust group And of course: Xinlin Li, Scott Palo, and Zoltan Sternovsky 95 Questions? 96 Backup Slides 97 Design Reference Mission Launch Phase (1 mo.) Checkout Science Phase (2+ years) Time Launch Phase Launch to L2 Enter 35,000 km orbit around L2 Aperture Cover removed from instrument Science Phase 29 Days 32 Hours Nominal Science Mode Power down non-essential equipment Cleaning Mode Nominal Science Mode Cleaning Mode Turn off target heater Perform Start target checkouts heater 98 System Level Diagram Electronics: Master Box •Analog/Digital Converter Thermal Control Structure •Data storage •Kapton Heaters •Aluminum •Step-up transformer •Aluminum foil tape •Insulating materials •Voltage divider with controller •Temp sensor •Connections •Temperature control device •Multi-layer insulation •Breakouts •Interface w/ DTS (flight model) •Interface w/ external electronics and power supply •Aperture cover (flight model) Mass Analyzer Ionizer Electronics: Inside Instrument •Charge Sensitive Amplifiers •Detector electronics •Silver coated target at +5kV Analyzer Detector •Annular electrodes •Microchannel Plate •Ring electrodes •Grounded grids •High voltage wiring 99 High Voltage Safety • Electrodes will be held at high potentials (~6 kV), but very low current. Total power estimated to be < 0.3 Watts. • Typical resistance of a human body roughly 105 Ohms. Worst case scenario ~ 103 Ohms (wet or broken skin). • Maximum electrical current exposure roughly 6 amps. Risk mitigation measures: •Ensure that CRIA is powered down when electrode contact is possible. • Ensure that instrument exterior is grounded to prevent charge accumulation from self-capcitance. 100 Previous Instrument Comparison Instrument Measurement Type Instrument Type Parameters Measured Mass Range (g) Surface Area (m2) SDC In-Situ PVDF Flux > 10-12 0.125 Stardust Sample return Aerogel collector Composition - 0.1 CDA In-Situ Time-of-Flight Parabolic Target Composition 10-16 - 10-10 0.1 CIDA In-Situ Time-of-Flight Reflectron Composition 5 x 10-14 - 10-7 0.005 101 Work Breakdown Structure CRIA Management System Engineer Scheduling Requirements Budget Verification / Test Plan Risk Assessment Task Management Structures External Structure Material Selection Fabrication Plan Detector Detector Design Analyzer Electrode Design Voltage Supply Operational Concept Ionizer Target Selection Thermal Electronics/CDH Multi-Layer Insulation Electronics Design Target Heater Design Triggering Thermal Control Power Distribution System Monitoring 102 FEM Part Name Material Mass load Ring Electrode 0.172273 kg 42g Aluminum 6061-T6 FEM MIN Max Stress 2516.84 N/m^2 1.27445e+007 N/m^2 Strain 5.00783e-007 0.000612643 Displacement 0 mm 0.12209 mm 103 Part Material Manufacturing Number of Parts Total Mnf. Hours Hexagonal Base 6061-T6 3-axis CNC mill 1 40 Channel Support 6061-T6 2-axis mill 6 20 Target Substrate 6061-T6 Lathe and 2-axis mill 1 15 Grounded Grid Inner Standoff G-10 2-axis mill 1 5 RBF cover 6061-T6 2-axis mill 1 10 Ring Electrode Standoff Noryl 2-axis mill 48 30 Side access panel 6061-T6 3-axis CNC mill 1 15 Side panel 6061-T6 3-axis CNC mill 5 25 Side panel bracket 6061-T6 2-axis mill (3-axis preferred) 6 20 Inner target electrode 6061-T6 Lathe and CNC mill 4 15 Outer target electrode 6061-T6 Lathe and CNC mill 4 15 Inner target electrode Fixture 6061-T6 2-axis mill 6 10 Outer target electrode fixture 6061-T6 2-axis mill 6 10 Target Substrate Standoff G-10 Band-saw 2 5 Testing Adapter Plate 6061-T6 2-axis mill 1 15 Annular Electrode Standoff G-10 2-axis mill 6 20 Annular Electrode Mount 6061-T6 3-axis CNC mill 1 40 Annular Wiring Fixture G-10 2-axis mill 1 5 CSA box 6061-T6 2-axis mill 1 5 CSA lid 6061-T6 2-axis mill 1 10 Detector Housing 6061-T6 Lathe and 2-axis mill 1 Detector grid inner clamp 6061-T6 Lathe and 2-axis mill 1 10 104 5 Detector grid outer clamp 6061-T6 Lathe and 2-axis mill 1 5 Physical Properties of Silver Properties Silver Atomic Weight 107.868 Density 10.49 g/cm^3 at 20 °C Specific Heat 0.24 kJ/kg Thermal Conductivity 428 W/m K at 20 °C Electrical Resistivity 14.7 n Ohm m at 0 °C Typical Emittance (ε) 0.02 Typical Absorptance (α) 0.07 α/ε 3.5 - Other consideration : Gold, Radium 105 Insulator material • Material : G-10 – Electrical Insulation – Thermal Insulation – Low Machining Difficulty – Low Outgassing Properties Noryl G 10 TML (%) 0.1 0.35 CVCM(%) 0.0 0.02 Dielectric Strength 19 15~19 Thermal Expansion(10^5in/in/°F) 3.3 0.6 Thermal Conductivity 0.2 0.3 Tensile Strength(psi) 9,600 40,000 Machining Moderate Low (KV/mm) (W/m-k) • Vendor : Plastic International Difficulty 106 Material Properties for Analyzer Subsystem Material CVCM TML Dielectric Strength Typical Electrical Conductivity [KV/mm] Mass Density [g/cm3] /Resisitivity[ ohm] - 58~50 % 19.7 Compare to Cu - Vespel scp5000 >1E15 - 1.43 Delin >1E15 ohm - 1.53 Al 6063 Noryl n/a 0 0.1 Tensile Strength (psi) Thermal Expansion [muin/in/F]@2 0 °C 19 ksi 33 23.4 kpsi 24 ohm 500AF 107 Electrode Design Design to Goal: Design Selection: • 5 annular electrodes • 8 ring electrodes Relative Performance (ie. Mass Resolution) of Analyzer Subsystem 120 100 Percentage (%) •Mass resolution (ie Relative voltage accuracy) •Electrical conductivity •Low emissivity •Machinability 80 60 40 20 0 2 (10 rings) 3 (8) Material Selection: • Aluminum T-6061 or 6063, polished • Emissivity (0.02) 3 (16) 4 (14) 5 (8) 8 (10) No. Annular Electrodes Design Selection 108 Electrode Design 109 Resistor Values (Ring) Resistance (MΩ) Resulting Voltage (V) Absolute Voltage Error (V) Discrete Resistors Required 10.5 5874.0 -2.0 2 63.5 5112.0 -1.0 4 68.0 4296.0 -1.0 4 74.5 3402.0 -3.0 4 40.5 2916.0 -2.0 2 44.0 2388.0 -3.0 2 48.5 1806.0 0.0 4 57.5 1116.0 -2.0 4 93.0 3 110 Resistor Values (Annular) Resistance (MΩ) Resulting Voltage (V) Absolute Voltage Error (V) Discrete Resistors Required 9.5 5886.0 1.0 3 20.0 5646.0 1.0 1 12.5 5496.0 -1.0 3 6.5 5418.0 -1.0 4 2.5 5388.0 -2.0 2 449.0 4 111 Resistor Parameters SLIM-MOX 104 • Temperature Range: -55 - 110°C • Power Rating: 1.5 W • Operating Voltage: 10 kV DC 112 Electrode Arcing Mitigation Lower arcing limit • • • at 1.55 Torr Electrodes are separated by 2 mm gaps. The strongest electric field (~3 x 106 V/m) occurs between the innermost ring electrode and the grounded grid. 107 Arcing will occur if electrodes turned on between 1.55 468 Torr (approx. 3 - 43 km altitude). This is well above the operational pressure for CRIA. at 468 Torr Breakdown Electric Field Electric Field (V/m) • Upper arcing limit 105 100 CRIA operating pressure, 10-5 Torr Pressure (Torr) 103 Max. Arcing Risk at 4.169 Torr 113 Arcing • Electric field required for arcing in a neutral dielectric given by Paschen’s Law. Nonlinear function of pressure and gap distance. 114 Expected Impacts 115 For randomly tumbling object. Per NASA Technical Memorandum 4527, p.7-3 Detectors Various MCP’s Specs from Del Mar Ventures 116 MCP Detector: Configurations • Chevron Configuration: High voltage difference Metal anode Output signal • Z-stack Configuration: High voltage difference Metal anode Output signal 117 MCP Detector Efficiencies Table from Wiza, J.L. “Microchannel Plate Detectors.” Nuc. Inst. and Methods, Vol 162, 1979. E(10000 parts @ 5keV) = 8.011e-12 J E(deep space UV~100nm) = 1.464e-16J E(deep space X-rays) = 1.464e-18J 118 THERMAL ANALYSIS The heat flow at each node is given by: N dTi N mi .ci . C ji .(T j Ti ) R ji .(T j4 Ti 4 ) Qi dt j 1 j 1 Where: mi : The node’s lumped mass ci : The node’s specific heat T : temperature t : time Cji: The conductive links Rji: The radiative links Qi: The power dissipation at the node 119 •Both steady state and transient runs can be performed on this model Target Heater Design Design to Goal: Transient Thermal Analysis •Heat target to 100°C (based on CDA experience) Cylinder Surface Target Surface 150 Thermal Analysis: •Cold Case simulation •Cylinder/ target start at 0 Kelvin •100°C reached ~15 hr •LASP support from Bret Lamprecht, using AutoCAD Thermal Desktop shows 23.5 W power required Temperature (C) 100 50 0 -50 -100 -150 -200 -250 -300 0 5 10 15 20 25 30 Time (hr) Total Power Required: 23.5 W Options for Reducing Power: •Segment target area and heat in cycles 120 Thermal Control • MinCo Kapton heater – – – • Thin semitransparent material with excellent dielectric Internal adhesive, max temperature 200oC Radiation resistant to 10^6 rads if build with polyimide insulated leads Honeywell Thermal Switch – – – – MINCO Kapton covered thermofoil heater Temperature ranges for Honeywell Thermal Switch: From -73oC to +371oC Operational: -54o C to 148.9oC Non-Operational: -65o C to 177oC Mounted to the target substrate Honeywell Series 7000 Thermal Switch 121 Thermal • Temperature Sensors Model Material Dimension S651PDY24A (100 Ω) Polyimide with Miniature spot foil sensor with backing wire-wound RTD 2 or 3 PTFE element leads Temperature (7.6 × 7.6 -200 to 200°C mm) Lead length: 600 mm •Temperature Controller Mounted to surfaces, alongside heaters or on top of them Minco controller model CT325 Control Supply method power sensor input On/off 4.75–60 VDC Sensor input Controlled out put PD: 100 Ω platinum RTD Same as supply power 122 Thermal Control Device - Full power on below setpoint - power off above setpoint. - Electronic on/off controllers offer faster reaction time and tighter control than thermostats. on/off controllers have a differential (hysteresis or dead band) between the on and off points to reduce rapid cycling and prolong switch life. - With on/off control, temperature never stabilizes but always oscillates around the setpoint. 123 Thermal Insulation MLI Layer Description: Design to Goal: •Reduce thermal swings •Electrically dissipative •Germanium Black Kapton •Aluminized Kapton •Dacron netting •Double Aluminized Kapton Design Selection: •Cover external structure with Germanium Black Kapton Multi-Layer Insulation Hot Case: •With MLI CRIA sees reduced heating power of min, 1 W, max 11 W (instead of min 26W, max 343 W) •Assumed MLI ε=0.03, 13 layer MLI Cold Case: •No solar power input •With MLI CRIA sees temperature of 7K – no change 124 Thermal Insulation • Multi Layer Insulation (MLI) 1. Multi layer insulation closely spaced layers of aluminized Mylar or Kapton 2. Insulation reduces the rate of heat flow per unit area between two boundary surfaces and prevents a large heat influx 125 Q (T1 4 Tn4 ) (n 1)( 1 1 1 n 1) Thermal Definitions Properties for transmission: Absorptivity, α: ability for the surface to absorb radiation. Emissivity, ε: ability for the surface to emit radiation View factor, F12: relates fraction of thermal power leaving object 1 and reaching object 2 126 Transient Thermal Analysis Radiation Heat Flux : Q12 A1F12 (T1 T2 ) where : σ is the Stefan-Boltzmann constant, and F12 is the view factor between the surfaces of both bodies F12The view factor is the fraction of radiation leaving dA1 intercepted by dA2 1 F12 A1 A1 A2 Cos(1 )Cos( 2 ) dA1dA2 2 L s where F12 is the view factor, A1 and A2 are the areas of the different materials surfaces, θ1 and θ2 are the angles between the normal of the surface and Ls, the shortest distance between them 127 Instrument Monitoring • Temperature Sensor: Decontamination • Voltmeter: Housekeeping (High voltage and low voltage) Physically separated electronic box • Ammeter : Housekeeping :Total current in high voltage supply 128 Mass Resolution (m/m) • Mass resolution describes m m m FWHM peak width FWHM: full width at half maximum the ability of the mass spectrometer to distinguish, detect, and/or record ions with different masses by means of their corresponding TOFs. • m/m will be effected by: – Sampling rate m/m= t/2t CRIA: dt=2ns – The energy and angular spread of emitted ions – Electronic noise 129 Sampling Rate • The flight time for ions is approximately: t[ s] 0.86 106 m[amu] then m / m t / 2t t (10) 3.9 ns ; t (100) 12.3 ns ; t (300) 21.3 ns ; • Required m/Δm>100, however, the instrument can achieve m/Δm=350. For not missing narrow, we want m/Δm=350 • We want to resolve the C peak (m=12) with high accuracy • dt=2ns would give us 2 measured points for the C peak. The number for m=100 and m=300 would be 6 and 10. • Then, sampling rate=500MHz 130 CSA Selection: A250 • Features : Ultra low noise, Low power, Fast rise time $500/each • A250 Connection Diagram 131 Application Specific Integrated Circuit (ASIC) • Developed in cooperation with the Kirchhoff Institute for Physics of the Heidelberg University, Germany • Tests performed • The front-end (CSA and logarithmic amplifier) • The transient recorder (32 channels with 10 bit ADCs and 1-K sample SRAM). 132 Size Range of Detectable Dusts • For a two year mission with a 0.1 m2 dust detector at 1 AU records only about one particle of 10^-13 g (0.2um radius) per day and one particle of 10^-10 g (2um radius) per two weeks, respectively. • Assumption: For a decent mass spectrum, at least 10^4 ions need to be generated upon the impact on the target. 133 The smallest detectable radius The largest detectable radius • Verification Plan -Detector Functional Test : Combination of detector performance tests usually performed each time the detector is powered on with high voltage to confirm the detector is operating nominally. -Short-Form System Functional Test : Abbreviated version of Long-Form Functional Test, performed when the detector is power on without high voltage to confirm most electronic and software function. -Long-Form System Functional Test : Conducted before and after each environmental test to verify all functional and electrical interface requirements for every phase of the mission. 134 System Level Risk Assessment Sources Events Solar UV Material Outgassing Prelaunch Contamination Micrometeroid Radiation / Plasma Mechanical Malfunction Detector damaged Contaminated spectra Contaminated spectra Detector damaged Instrument charging Target area damaged Electronics malfunction Inaccurate spectra / no spectra recorded Noise in spectra Arcing Mitigation UV reflective electrodes On/Off detector mode Technol. Risk Risk Level Vaporize contaminants with heater Aperture Cover Use clean room Shielding in annular electrode design Use rad-hard electronics and rad protect electronics Low Medium Medium Use low outgassing mt’ls UV impact on detector unknown High Low •Technology •Materials limits known unknown •Heater temp range can be large •Common practice •High probability of impacts High •Instrument •No risk charging not mitigation understood 135 Possible Questions • What is the elemental composition of cosmic dust? • What is the dust flux and its mass dependence? • What direction is the dust coming from? • What are the differences in composition and size between interstellar and interplanetary dust? 136 Pre-Flight Cost Budget 137 138