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PICAM Status

PICAM Status. Klaus Torkar (IWF Graz) for the PICAM Team SERENA-HEWG Meeting, Key Largo, FL, 17 May 2013. Contents. PICAM basics QM status and test results Front-end ASIC (TIMPO32) status FM status and schedule. P lanetary I on CAM era.

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PICAM Status

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  1. PICAM Status Klaus Torkar (IWF Graz) for the PICAM Team SERENA-HEWG Meeting, Key Largo, FL, 17 May 2013

  2. Contents • PICAM basics • QM status and test results • Front-end ASIC (TIMPO32) status • FM status and schedule

  3. PlanetaryIonCAMera • All-sky camera for charged particles to investigate the exo-ionosphere composition and distribution • Hemispherical instantaneous field of view to measure the 3-D velocity distribution and mass composition of ions at high resolution Main contributions: IWF/OAW (Austria)LATMOS, LPP (France)MPS (Germany)WIGNER (Hungary)STIL (Ireland)ESTEC

  4. Responsibilities

  5. Ions in the Hermean Environment

  6. Science Performance Requirements • PICAM-related requirements from the Science Performance Report

  7. Ion Optics Principle Annular input slit Start gate Mirror M1 Mirror M2 Toroidal analyzer Detector

  8. Ion Optics Layout • Ions enter through an annular slit (1) • After reflection on an ellipsoidal mirror (2) the ions pass through a gate (3), and the 90° polar angle distribution is folded to a narrow range. • Through a slit (4) the ions enter a toroidal analyzer (5) for energy selection. • Through exit slit (6) the ions enter the mass analysis section consisting of a plane mirror (7) whose geometry and potentials are set to optimize the resolution of the TOF measurements, and finally hit the MCP (8). 2 1 – entrance window, 2 – primary mirror, 3 – gate, 4 – secondary slit, 5 – toroidal analyzer, 6 – exit slit, 7 – secondary mirror, 8 – MCP detector Ion beams with entrance polar angles 0° (green), 45° (red), and 90° (blue)

  9. Ion Optics Design Update • Deflecting electrodes (6) allow for the correction of any misalignment between first mirror and electrostatic analyser • Converging lens (4) improves polar angle resolution • Retarding grid (5) - if activated - may improve the mass resolution

  10. QM Detector

  11. QM Gate, Mirror 1, 2, Partial Assy

  12. QM Electronics

  13. Anode Group Arrangement • Grouping of anodes is necessary to reduce data volume • Modes will be selected to support the various scientific objectives No image (TOF only) Full image 4 groups 7 groups

  14. Time-of-Flight Measurement • Standard method: gate opens briefly and remains closed until the slowest ions in the passing packet have hit the MCP  low efficiency • Random sequence (Hadamard code) at gate & deconvolution  high efficiency (~50% of the ions pass) TOF spectrum before deconvolution after deconvolution

  15. Power versus Performance • Hadamard mode may be used below several 100 eV depending on code frequency • For higher ion energies, single pulses will be used

  16. Operating Modes • PICAM can simultaneously produce two data products: • Primary science data: • TOF spectra averaged over few or many pixels, for each out of typically 32 energy steps, typical sampling intervals 8 s to 64 s per data set • Secondary (survey) data: • Omnidirectional TOF spectra + full resolution images (31 pixels) without mass discrimination, both at 32 energies, variable sampling intervals up to several minutes • Common to both data sets are the settings for the energy sweep and the gating (single pulses or Hadamard codes)

  17. Imaging Modes • Without mass discrimination • Three different image resolutions • Primary telemetry with 8 or 32 s time resolution • Secondary TM with full image but 64 s time resolution 8 s 32 s

  18. Mass Discrimination and Combined Modes • 4 modes with mass discrimination, without imaging • 4 modes with combination of limited mass resolution and imaging • Primary telemetry with 32 s time resolution, 16 or 32 E-steps • Secondary TM with full mass spectrum integrated over FoV, but only 64s time resolution

  19. Modes Selected as Baseline • 1 imaging mode: mainly used at Apoherm • 1 mass mode: mainly used at Periherm • 1 combined mode: mainly used at Periherm

  20. Pre-Calibration Examples Angular distribution Energy resolution E = 1 keV ΔE1/2/E ~ 11% ΔE1/2 ~ 110 eV Numerical model, 1 keV ions Numerical model, 1 keV ions ΔE1/2/E ~ 4% E ~ 1.015 keV ΔE1/2 ~ 40 eV QM measurement, ions N2+, 1 keV QM measurement, ions N2+, 1 keV

  21. Pre-Calibration Examples Simulation of the time of flight for masses 23 (Na) and 24 (Mg) T ~ 2.81 µs T/ΔT1/10 ~ 28 ΔT1/10 ~ 0.1 µs T/ΔT1/10 ~ 21 T ~ 5.72 µs ΔT1/10 ~ 0.28 µs Measured TOF with QM, ions N2+ , 300 eV Resolution in this case was driven by gate pulse duration, not by geometry

  22. Pre-Calibration Examples Mass resolution may exceed values of the numerical model, provided that gate pulse duration is properly set T ~ 2.81 µs T/ΔT1/10 ~ 28 ΔT1/10 ~ 0.1 µs T ~ 3.15 µs T/ΔT1/10 ~ 39 ΔT1/10 ~ 0.08 µs Measured TOF with QM, ions N+andN2+ , 1000 eV

  23. QM Status • QM has been successfully vibrated and shock tested • Functional testing and calibration has started • Angular, energy, and mass resolution have been characterised • Further future improvement of angular and mass resolution by fine-tuning internal voltages is expected • Calibration will be resumed as soon as possible after the ongoing thermal vacuum test, for as long as possible • Open work includes implementation of compression for PICAM data in the SCU • Thermal vacuum test is ongoing • Challenging set-up to achieve wide temperature range (-90°...+240°C) for outer parts in a single facility • Test is split into cruise phase and Mercury orbit qualification

  24. TVAC Sequence

  25. QM in TV Chamber

  26. QM in Shock Test

  27. QM in Vibration Test

  28. TIMPO Issues • Latch-up and SEU susceptibility of TIMPO ASIC detected during heavy-ion tests in October 2012 • Mainly in analogue part due to wrong choice of decoupling capacitors • Also some sensitivity in digital part • New ASIC will be developed, availability not earlier than Dec 2013 • Use of existing ASIC studied as an alternative, but it will suffer from very frequent latch-ups • Additional electronic protection circuit mandatory for both versions • Circuit requires new detector electronics layout and new layout of DPU • Re-design of ASIC already completed • Funding of delta qualification testing is under negotiation

  29. Heavy Ion Test Summary

  30. FM Status • Some FM components already delivered • Electronics not affected by TIMPO changes is under manufacture • Protection electronics development for the TIMPO and the delta qualification testing of the TIMPO drive the FM schedule • QM has to be temporarily delivered to system as FM substitute

  31. Summary • The QM is under environmental testing and calibration • Key performance parameters have been verified, but calibration is not yet complete and further tuning of the instrument is advisable • Major current issue is the schedule and funding of the front-end ASIC modification and related work • QM has to be delivered temporarily as FM substitute • FM with modified ASIC and additional protection electronics will not be ready before late summer 2014

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