PICAM Status
Klaus Torkar (IWF Graz)for the PICAM Team
SERENA-HEWG Meeting, Key Largo, FL, 17 May 2013
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Contents
PICAM basics
QM status and test results
Front-end ASIC (TIMPO32) status
FM status and schedule
• 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
Planetary Ion CAMera
Main contributions:
IWF/OAW (Austria)LATMOS, LPP (France)MPS (Germany)WIGNER (Hungary)STIL (Ireland)ESTEC
Responsibilities
IWF
Controller unit (DPU)
Integration at PICAM level
Environmental tests
On-board software
Thermal and mechanical analysis
Partial manufacture of ion optics (OPT)
Harness
LPP/ LATMOS
Detector with its electronics (DET)
ASIC development support
Design of ion optics (OPT), partial manufacture of OPT
Ground and in-flight calibration
ESTEC ASIC contract management, MCPs
WIGNERDC/DC converter board (DCC)
Experiment ground support equipment
MPS
Gate encoder and driver board (GED)
High voltage board (HVC)
Ground calibration
STILElectronics box housing
Mechanical design
Ions in the Hermean Environment
Scientific Topic Energy Major Components
Observable region
Exo-ionosphere density and composition
>1 eV H+, He+, Na+, O+, K+, others … Whole planet
Ion component of the Surface release
Solar wind sputtering
1- hundreds eV
Mg+, Si+, Na+, Ca+, O+, K+, others…
Mainly dayside middle- latitude
Ion component of the Surface release
heavy ion sputtering
1- hundreds eV
Mg+, Si+, Na+, Ca+, O+, K+, others…
Mainly night side middle-
latitude
Solar wind circulation and precipitation 1-10 keV Mainly H+ Dayside
Heavy ions circulation and precipitation
500 eV-10 keV Mainly Na+, O+ Mainly middle-
latitude
Unperturbed Solar wind 1 keV Mainly H+ Specific MPO
positions
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Science Performance Requirements
PICAM-related requirements from the Science Performance Report
Scientific TopicEnergyEnergy
resolution
Mass resolution
FOVAngular
resolution
Time resolution
Synergies with other BC
instruments#
3. Exo-ionosphere composition
>10 eV ~ 40 NA NAMMO/MPPE
MPO/PHEBUS
4. Exo-ionosphere spatial and energy
distribution
>10 eVE/E < 30%
~ 40 < 60o T < 3 mn
MPO/MAG
MMO/MPPE
MMO/MGF
5b. Plasma precipitation rate and distribution
> 10 eVE/E <30%
~105ox180o FOV in the orbit plane
< 25o T< 1 mn
MPO/MAGMMO/MPPEMMO/MGF
7c. Loss of planetary
ions and distribution
> 10 eVE/E < 30%
~ 40Hemispheric
FOV < 25o
T< 5 mnMPO/MAG
MMO/MPPEMMO/MGF
Ion Optics PrincipleAnnular input slit
Mirror M1
Start gate
Mirror M2 Toroidal analyzer
Detector
Ion Optics Layout
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)
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).
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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
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QM Detector
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QM Gate, Mirror 1, 2, Partial Assy
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QM Electronics
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
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
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Power versus Performance
100 10000
2,000
4,000
6,000
8,000
10,000
12,000
14,000
16,000
18,000
20,000
22,000
PICAM Power (BOL) in Hadamard Mode
12.5 ns Code
Energy [eV]
Pri
ma
ry P
ow
er
[m
W]
Hadamard mode may be used below several 100 eV depending on code frequency
For higher ion energies, single pulses will be used
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)
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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
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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
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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
315°
0°
45°
90°
270°
135°
225°
180°
0.3707AU9960W/m²
0.3075AU14470W/m²
0.3237AU13100W/m²0.4338AU
7270W/m²
0.4667AU6280W/m²
Orbit phaseA B C D
p a p a p a p a
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
pixel A pixel B pixel C pixel D pixel E pixel F
0°-10°
10°-20°
20°-30°
30°-40°
40°-50°
50°-60°
60°-70°
70°-80°
Numerical model, 1 keV ions
QM measurement, ions N2+, 1 keV
2N
Angular distribution
Numerical model, 1 keV ions
Energy resolution
QM measurement, ions N2+, 1 keV
ΔE1/2 ~ 110 eV
E = 1 keVΔE1/2/E ~ 11%
E ~ 1.015 keV
ΔE1/2 ~ 40 eV
ΔE1/2/E ~ 4%
Pre-Calibration Examples
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Simulation of the time of flight for masses 23 (Na) and 24 (Mg)
Measured TOF with QM, ions N2+ , 300 eV
Resolution in this case was driven by gate pulse duration, not by geometry
T ~ 2.81 µs
ΔT1/10 ~ 0.1 µs
T/ΔT1/10 ~ 28
T ~ 5.72 µs
ΔT1/10 ~ 0.28 µs
T/ΔT1/10 ~ 21
Pre-Calibration Examples
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Measured TOF with QM, ions N+ and N2+ , 1000 eV
T ~ 2.81 µs
ΔT1/10 ~ 0.1 µs
T/ΔT1/10 ~ 28
T ~ 3.15 µs
ΔT1/10 ~ 0.08 µs
T/ΔT1/10 ~ 39
Pre-Calibration Examples
Mass resolution may exceed values of the numerical model, provided that gate pulse duration is properly set
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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
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TVAC Sequence
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QM in TV Chamber
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QM in Shock Test
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QM in Vibration Test
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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
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Heavy Ion Test Summary
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
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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