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

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8,000

10,000

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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

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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