Solar Cell Radiation Environment Analysis Models (SCREAM)

Transcription

1 Solar Cell Radiation Environment Analysis Models (SCREAM) 2017 Space Environment Engineering & Science Applications Workshop (SEESAW) Scott R. Messenger, Ph.D. Principal Space Survivability Physicist

2 Space Radiation Environment for Solar Arrays Ionizing and nonionizing radiation electrons protons solar UV p + p + e - p + e- e - COVERGLASS ACTIVE CELL e - SUBSTRATE Omnidirectional (directional?) Energy Spectra (electrons & protons & plasmas) Nuclear activation (secondary production) Prompt effects (EMP, gammas, neutrons) p + p + PANEL p + e - p +

3 Outline Space Solar Cell Modelling Displacement Damage Dose (DDD) Model SCREAM SCREAM Success Stories TacSat4 GPS-IIR SV41 Low Thrust Trajectories (DDD accumulation) Summary 3

4 Integral Fluence(cm -2 ) Normalized Maximum Power Normalized Maximum Power Space Solar Cell Degradation Prediction: The Problem To generate ground irradiation data necessary to predict the effect of a space particle energy spectrum on a solar cell This is accomplished by reducing the ground data to a characteristic dataset 1.E+16 1.E+15 1.E+14 1.E+13 1.E+12 1.E+11 1.E+10 1.E+09 1.E+08 1.E+07 1.E+06 Electron & Proton Spectra for TacSat4 TACSAT4 Orbit (700 x km, 63.4 o, 1 year) THIS FIGURE IS FOUO 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 Particle Energy (MeV) Trappped Protons Solar Event Protons Trapped Electrons Electron & Proton Ground Irradiation Data (Single Junction GaAs/Ge, 1991) Protons 50 kev kev kev Electrons 300 kev kev 0.6 MeV 1 MeV 1 MeV MeV THIS FIGURE IS FOUO MeV 9.5 MeV 12 MeV E E E E E E E E E+17 Particle Fluence 1.0E+09 (#/cm 2 1.0E+10 ) 1.0E E GaAs/Ge 1 Sun, AM0 25 o C

5 mining Maximum Power Remaining Maximum Power Reamining Maximum Power Space Solar Cell Degradation Prediction: The Solution(s) 1. JPL method RDCs equivalent 1 MeV electron fluence & C pe JPL Model Data Collapse GaAs/Ge kev (1 sun, AM kev kev MeV MeV Protons Electrons 9.5 MeV kev 12 MeV kev 2.4 MeV kev 1 MeV MeV 0.6 MeV MeV 1 MeV Equiv. U235 neutrons MeV DDD Fit 0.0 THIS FIGURE IS FOUO MeV 1.E+07 1.E+08 1.E+09 1.E+10 1.E E+13 MeV 1.E+14 1.E+15 1.E+16 1.E Equivalent 1 MeV 1 MeV Electron Fluence (cm -2 ) 0.2 GaAs (1 sun, AM Displacement Damage Dos *The heritage JPL model is well documented ( ): H.Y.Tada and J.R.Carter, Solar Cell Radiation Handbook, JPL Pub (1977) Green Book (Si) B.Anspaugh, GaAs Solar Cell Radiation Handbook, JPL Pub (1996) Blue Book (GaAs) D.C. Marvin, Assessment of Multijunction Solar Cell Performance in Radiation Environments, TOR-00(1210)-1

6 mining Maximum Power Remaining Maximum Power Reamining Maximum Power Reamining Maximum Power Remaining Maximum Power Reamining Maximum Power Space Solar Cell Degradation Prediction: The Solution(s) 1. JPL method RDCs equivalent 1 MeV electron fluence & C pe 2. NRL method NIEL displacement damage dose (DDD) JPL Model Data Collapse GaAs/Ge kev (1 sun, AM kev kev MeV MeV Protons Electrons 9.5 MeV kev 12 MeV kev 2.4 MeV kev 1 MeV MeV 0.6 MeV MeV 1 MeV Equiv. U235 neutrons MeV DDD Fit 0.0 THIS FIGURE IS FOUO MeV 1.E+07 1.E+08 1.E+09 1.E+10 1.E E+13 MeV 1.E+14 1.E+15 1.E+16 1.E Equivalent 1 MeV 1 MeV Electron Fluence (cm -2 ) 0.2 GaAs (1 sun, AM Displacement Damage Dos NRL/DDD Model Data Collapse Protons 200 kev 300 kev 500 kev 1 MeV 3 MeV Electrons 9.5 MeV GaAs/Ge (1 sun, AM keV 12 MeV kev 2.4 MeV kev 1 MeV MeV 0.6 MeV 1 MeV Eq. 235 U MeV 1 MeV Equiv. U235 Neutrons neutrons MeV DDD Fit MeV 1.E+07 1.E+08 THIS 1.E+09 FIGURE 1.E+10 IS FOUO 1.E MeV Displacement Damage Dose (MeV/g) 1 MeV 1.E+07 1.E+08 1.E+09 1.E+10 1.E+11 1.E MeV 0.1 Displacement Damage Dose (MeV/g) 1 MeV Equiv. U235 neutrons GaAs/ (1 sun, AM0 GaAs/Ge (1 sun, AM0 25 o C) *The advanced NRL/DDD model is well documented ( ): S.R. Messenger, et al., "Modeling solar cell degradation in space: A comparison of the NRL displacement damage dose and JPL equivalent fluence approaches", Prog. Photovolt.: Res. Appl. vol. 9, pp , S.R. Messenger, et al., "SCREAM: A new code for solar cell degradation prediction using the displacement damage dose approach," 35th IEEE PVSC, 2010, p

7 Normalized Maximum Power Normalized Maximum Power NRL DDD Method Data needed (*AIAA S-111) Protons E > 1-4 MeV (need uniform DD) (f = to p + /cm 2 ) Electrons E = 1 & >2 MeV (f = to e - /cm 2 ) Advantages ~3-4X cost reduction in qualification Convenient for new tech quals, design tweaks, requals Disadvantages Heritage Heritage Heritage Not applicable to protons on thick silicon Electron and Proton Ground Data Protons 3 MeV THIS FIGURE IS FOUO E E E E E E E+091.0E E+101.0E E+111.0E E Particle Fluence (#/cm 2 ) GaAs/Ge 1 Sun, AM0 25 o C Electrons 0.6 MeV 1 MeV 2.4 MeV 12 MeV Particle F Qualification and Quality Requirements for Space Solar Cells (AIAA S-111A-2014) JPL and/or DDD models acceptable

8 Space Solar Cell Modeling: NRL Displacement Damage Dose (DDD)

9 NRL Displacement Damage Dose Model for Solar Cell EOL Calculations Determine Incident Particle Spectrum (e.g. AP8, AE8) Input Nonionizing Energy Loss (NIEL) Data (Energy Dependence of Damage Coefficients) Calculate Slowed-Down Spectrum (SDS) (Shielding) Determine Characteristic Degradation Curve vs. DDD (NIEL x Fluence) (2 e - and 1 p + energy) Calculate DDD for Mission (Integrate SDS with NIEL) Read Off EOL Value *RED Measurements *Blue Calculation *Green Data input

10 Differential Fluence (p + /cm 2 /MeV) DDD EOL Prediction Method 1.E+16 1.E+15 1.E+14 1.E+13 1.E+12 1.E+11 1.E+10 Omnidirectional Spectra TrP/2 1 mil 3 mils 6 mils 12 mils 20 mils 30 mils 60 mils 1.E+09 1.E+08 1.E+07 1.E+06 1.E+05 THIS FIGURE IS UNCLASSIFIED 1.E-04 1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 Proton Energy (MeV)

11 Differential Fluence (p + /cm 2 /MeV) Nonionizing Energy Loss (MeVcm 2 /g) DDD EOL Prediction Method 1.E+16 1.E+15 1.E+14 1.E+13 1.E+12 1.E+11 1.E+10 1.E+09 Omnidirectional Spectra TrP/2 1 mil 3 mils 6 mils 12 mils 20 mils 30 mils 60 mils Nonionizing Energy Loss (2006) 1.E+01 1.E+00 1.E-01 GaAs 1.E+08 1.E+07 1.E+06 1.E+05 THIS FIGURE IS UNCLASSIFIED 1.E-04 1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 Proton Energy (MeV) 1.E-02 1.E-03 THIS FIGURE IS UNCLASSIFIED 1.E-04 1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 Proton Energy (MeV)

12 Displacement Damage Dose (MeV/g) Differential Fluence (p + /cm 2 /MeV) Nonionizing Energy Loss (MeVcm 2 /g) DDD EOL Prediction Method 1.E+16 1.E+15 1.E+14 1.E+13 1.E+12 1.E+11 1.E+10 1.E+09 Omnidirectional Spectra TrP/2 1 mil 3 mils 6 mils 12 mils 20 mils 30 mils 60 mils Nonionizing Energy Loss (2006) 1.E+01 1.E+00 1.E-01 GaAs 1.E+08 1.E+07 1.E+06 1.E+05 1.E+13 1.E+12 THIS FIGURE IS UNCLASSIFIED 1.E-04 1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 Proton Energy (MeV) Total Mission DDD THIS FIGURE IS UNCLASSIFIED 1.E-02 1.E-03 THIS FIGURE IS UNCLASSIFIED 1.E-04 1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 Proton Energy (MeV) 1.E+11 1.E+10 1.E+09 1.E+08 1.E SiO2 Coverglass Thickness (mils)

13 Displacement Damage Dose (MeV/g) Remaining Maximum Power Differential Fluence (p + /cm 2 /MeV) Nonionizing Energy Loss (MeVcm 2 /g) DDD EOL Prediction Method 1.E+16 1.E+15 1.E+14 1.E+13 1.E+12 1.E+11 1.E+10 1.E+09 Omnidirectional Spectra TrP/2 1 mil 3 mils 6 mils 12 mils 20 mils 30 mils 60 mils Nonionizing Energy Loss (2006) 1.E+01 1.E+00 1.E-01 GaAs 1.E+08 1.E+07 1.E+06 1.E+05 1.E+13 1.E+12 THIS FIGURE IS UNCLASSIFIED 1.E-04 1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 Proton Energy (MeV) Total Mission DDD THIS FIGURE IS UNCLASSIFIED 1.E-02 1.E THIS FIGURE IS UNCLASSIFIED 1.E-04 1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 Proton Energy (MeV) P max Degradation GaAs/Ge (AM0, 1 sun, 25 o C) 1.E+11 1.E+10 1.E+09 1.E Data Fit (a, C, D x ) P ( D d ) D d A C log 1 P 0 Dx THIS FIGURE IS UNCLASSIFIED protons electrons neutrons 1.E SiO2 Coverglass Thickness (mils) E+07 1.E+08 1.E+09 1.E+10 1.E+11 1.E+12 DDD(protron) and DDD(1 MeV electron) (MeV/g)

14 SCREAM (Solar Cell Radiation Environment Analysis Models) Excel file driven menus as inputs Input integral radiation spectra Single & multi-spectra, electron and proton Shielding material Nonionizing energy loss (NIEL) Multilayer shielding Parametric degradation coefficients (GaAs, ITJ, UTJ, ATJ, Si-electrons, user) Output Slowed-down radiation spectra End-of-life (EOL) predictions DDD only options ( ShielDDDose ) Trajectory capability through Time Series Spectra input option SCREAM is available by request in CD format *Contact: Dr. Scott R. Messenger (NGC)

15 SCREAM Success Stories TacSat4 (HEO: 700 km x 12,050 km, 63.4 o ) Used onboard dosimetry (CEASE-II) and solar cell experiment to explain anomalously large solar array degradation rates SCREAM used CEASE-II data to corroborate solar cell experiment (full IV) data and re-project mission lifetime GPS-IIR SV41 (MEO: 20,200 km, 55 o ) GPS has been plagued with anomalous solar array degradation since onset (many mitigation paths successful, but anomaly continues) SCREAM used LANL BDD Detector data to help understand damage mechanisms and eliminate displacement damage as the anomaly Low-Thrust Trajectory Orbit to GEO (LT2GEO) Low-thrust trajectories are extreme mass & cost cutting measures Spacecraft subjected to extreme proton belts SCREAM can simply analyze accumulated DDD to optimize LT trajectory

16 TacSat4 (HEO: 700 km x 12,050 km, 63.4 o ) NRL satellite launched 27 Sept (Kodiak, AK) >1 MeV electrons >10 MeV protons * Graphic created using AFGEOSPACE (V2.5)

17 Remaining Maximum Power TacSat4 (HEO: 700 km x 12,050 km, 63.4 o ) Trapped Protons Dominant Maximum Power Degradation on Emcore ATJ Solar Cell AP9Mean Shielding 6 mils CMG 2 mils DC Emcore BTJM 3J AP8MIN AP9-MC-95 th 1 year spec 0.70 Measured power exceeds predictions using AP9 95 th worst case environment! /27/ /27/ /26/ /26/2011 1/25/2012 2/24/2012 3/25/2012 Date of Mission

18 TacSat4 (HEO: 700 km x 12,050 km, 63.4 o ) Trapped Protons Dominant Two additional payloads on-board AFRL: CEASE-II dosimeter package Several dosimeters (particle fluence, TID, SEE, SC) MeV protons & MeV electrons NRL: Two solar cell experiments yielding full IV curves SCE#1: SolAero BTJM (3J w/ 6 mil CMG coverglass) CEASE-II SCE #1

19 CEASE Proton Energy Comparisons

20 CEASE Proton Energy Comparisons

21 CEASE Proton Energy Comparisons *For 6 mil coverglass, omnidirectionally incident protons having energy from 1-10 MeV are the most important in causing damage to the underlying cell. For mil covers -- NO ANOMALY --- but definitely NO FUN.

22 Displacement Damage Dose (MeV/g) TacSat4 (HEO: 700 km x 12,050 km, 63.4 o ) Trapped Protons Dominant SCREAM: Environment data through 6 mil CMG & 2 mil adhesive 9.0E E E+07 CEASE SCREAM CEASE Shielding 6 mils AP8MIN CMG 2 mils DC AP9Mean Emcore AP9-MC-95th BTJM 3J 6.0E E E+07 AP9-95 th 3.0E E+07 AP8MIN 1.0E+07 AP9Mean 0.0E+00 9/14/ /23/2011 4/1/2012 7/10/ /18/2012 1/26/2013 5/6/2013 Date of Mission

23 Remaining Parameter TacSat4 (HEO: 700 km x 12,050 km, 63.4 o ) Trapped Protons Dominant SCREAM: DDD results applied to SolAero ATJ solar cell technology Isc (Equiv. 1 MeV electron fluence) 2x Voc Pmax Shielding 6 mils CMG 2 mils DC Emcore ATJ 0.60 SOLID: SCREAM calculations using CEASE environment data DOTTED: Onboard data collected from solar cell experiment 0.55 Sep-11 Nov-11 Jan-12 Mar-12 May-12 Jul-12 Sep-12 Nov-12 Jan-13 Mar-13 Date of Mission

24 GPS-IIR (MEO: 20,200 km, 55 o ) SVN41 Launched 10 Nov 2000 *NIM A 482, 653 (2002)

25 12/10/00 12/10/01 12/10/02 12/10/03 12/10/04 12/10/05 12/10/06 12/10/07 12/10/08 12/10/09 Remaining Current at 28.28V GPS-IIR (MEO: 20,200 km, 55 o ) Trapped Electrons Dominant GPS spacecraft have shown anomalous silicon solar array degradation throughout [>30] year existence (Marvin, 1988) Solar array telemetry data AE8MAX GPS SVN 41 (Block IIR-6) AE8MAX+ESP(50%) ~25% deviation after 9 yrs! Many possibilities posed (coatings, coverglass, contamination, ESD, radiation environment related) but none confirmed GPS III plans on using oversized arrays to maintain necessary EOL levels

26 GPS-IIR (MEO: 20,200 km, 55 o ) Trapped Electrons Dominant LANL Burst Dosimeter Detector (BDD) onboard SVN41 Ion-implanted Si detectors behind varying shielding levels Gives electron fluences for E>0.04 to >10 MeV Gives proton fluences for E>0.05 to >6 MeV Daily fluence and energy spectra supplied by LANL *LA-UR , LA-UR

27 GPS-IIR (MEO: 20,200 km, 55 o ) Trapped Electrons Dominant SCREAM used BDD data to determine expected Si solar cell degradation behind 12 mil CMX coverglass Remaining V /10/ /10/ /10/ /10/2003 On-orbit correction 12/10/2004 Other damage mechanisms Displacement damage eliminated from secondary damage mechanism Other damage mechanism causing anomaly 12/10/ /10/2006 AE8MAX AE8MAX + ESP Total (50%) LANL Electrons (JPL Model) LANL Electrons (NRL Model) Solar Array V AE8 not so bad! 12/10/ /10/ /10/2009

28 12/10/ /10/ /10/ /10/ /10/ /10/ /10/ /10/ /10/ /10/2009 Difference Between Model and Data GPS-IIR (MEO: 20,200km, 55 o ) Trapped Electrons Dominant Analytical determination between expected (SCREAM) and measured showed interesting trends (IEEE Trans. Nucl. Sci. 58, p.3188 (2011)) Fast rate (4%/yr): contamination, UV, photo-fixing --- AR coating/conductive oxide? Slow rate (1.5%/yr): trapped electrons --- coverglass damage, ESD (Ferguson et al. 2015)? ~1.5%/year ~4%/year *Two accumulative mechanisms for anomalous degradation suggested! 0.00

29 Low-Thrust Trajectory to GEO (LT2GEO) >1 MeV electrons >10 MeV protons Graphic created using AFGEOSPACE (V2.5) Reduced Launch Costs Increased Payload Trade Off Delayed GEO operations More Radiation Exposure

30 Altitude (km) Low-Thrust Trajectory to GEO (LT2GEO) Minimum-Time Low-Thrust Trajectory *Initial Orbit - GTO days to GEO 0 12/1/ /31/2017 1/31/2018 3/2/2018 4/2/2018 5/2/2018 Date Along Trajectory

31 Particle Flux (#/cm 2 /s) Low-Thrust Trajectory to GEO (LT2GEO) Electron & Proton Fluxes Along Trajectory (AE8MAX/AP8MAX) 1.0E E E E E E E+01 AE8MAX (>1 MeV electrons) AP8MAX (>10 MeV protons) 1.0E Days in Mission

32 DDD (MeV/g) Low-Thrust Trajectory to GEO (LT2GEO) Trapped Protons Dominant 1.0E E+04 DDD Along Trajectory (AE8MAX/AP8MAX) 4.83 mils CMG (4 mils CMG & 1 mils adhesive) AP8MAX AE8MAX 1.0E E E E E E Days in Mission * Trapped protons dominate the DDD for the LT2GEO transfer

33 Remaining Pmax Low-Thrust Trajectory to GEO (LT2GEO) Trapped Protons Dominant Solar Cell Degradation (AP8MAX/AE8MAX) Triple Junction Single Junction 4.83 mils CMG (4 mils CMG & 1 mil adhesive, infinite back) Days in Mission After further 15 year GEO parked environment *The LT2GEO transfer significantly degrades both 1J and 3J solar cells

34 Summary SCREAM employs the DDD model for solar cell degradation Slab geometry (2p) Bonus Capabilities Multi-layered shielding Time series spectra (on-orbit data, trade studies) ShielDDDose (Depth-DDD curves) Applications Easy interpretation of dosimeter data onboard spacecraft for ORS TacSat4 helped understand extra radiation to project mission lifetime GPS eliminated DDD effects in solar cell to push efforts elsewhere LT2GEO aids in better solar array designs in present low-cost needs Not only for solar cells (LEDs, laser diodes, CCDs, etc.) Any ground data for which a parametric vs. DDD curve can be created

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