Towards a Radiation Monitor for the Jovian System

Patrícia Gonçalves

New Worlds in Particle, Astroparticle & CosmologyBraga, January 2014

JUICEThe Jupiter Icy Moons Explorer

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Jun2022

Jan2030

Sep2032

Jun2033

11 months

1 month

9 months

11months

9 months

Launch

Ariane-5

Jupiter

orbit insertion

Transfer to Callisto

Europa phase: 2 Europa +2 Callisto flybys

Jupiter High Latitude Phase

Transfer to Callisto

Ganymede Orbit

insertion

Ganymede tour:Orbits at several altitudes: High altitude500 km200km

End of nomin

al missio

n

Next Class-L (Large) ESA Mission

Current JUICE mission plan

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Study the emergence of habitable worlds around gas giants

• Characterise the Jupiter Icy Moons: Ganymede, Europa and Callisto as planetary objects and potential habitats •Explore the Jovian system as an archetype for gas giants

EuropaGanymedeCallisto

Juice Mission Objectives

Juice mission

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Implications for Astrophysics & Planetary Physics

Extra Solar Planetary Systems

The Plasma UniversePlanetaryAtmospheres

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Juice Scientific Payload11 instruments with total mass of ~100 kg

Narrow Angle CameraWide Angle CameraVisible and Infrared Hyperspectral Imaging SpectrometerUltraviolet Imaging SpectrometerSubmillimetre Wave InstrumentLaser AltimeterIce penetrating radarMagnetometerParticle PackageRadio and Plasma Wave instrumentRadio Science Instrument and Ultrastable Oscillator

Possible configuration

for Scientific Payload

accomodation

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Jovian System Energetic Particle Environment

Severe environment in terms of ionizing particles

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Courtesy of H.B.Garret, Jet Prop.Lab

Data and models Limited data from

Missions- Pioneer 10-11 (1973, 1974) - Voyager 1-2 (1979)- Galileo (1989)- Ulysses and Cassini (2000)

Synchrotron emission observations

Synchrotron emission predictions from Divine model

Models-Divine e- and proton models- GIRE (Galileo Interim Radiation Environment Model)- Salammbô(e-belt model from Jupiter surface to Europa)- JOSE (based on Divine+GIRE+Salammbô+data)

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Very Hard Electron Spectrum

40 MeV300 keV

What is a radiation monitor?

1Radiation

Housekeeping

2Alert and

safeguarding

3Support to

platform and payload

4Future mission preparation & provision of science data

Particle detector Mass ~ 1 kg

Power ~ 1 WattVolume - 1 lt

RADEM Radiation Hard Electron Monitor

RADEM requirements:

Electron detectorSpectral range 300 keV – 40 MeVPeak flux 109 e/cm2/s

Proton and heavy ion detectorSpectral range 5 MeV – 250 MeVpeak flux 108 p/cm2/s

Radiation harddose determination and alarm function

Particle separation from Helium to Oxygen; LET spectra

Phase A RADEM Model (PSI)

A radiation monitor is a key piece in keeping the mission safe but it can also provide valuable scientific data!

ESA RADEM PROTO-FLIGHT model

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LIP is in a consortium with european institutes and industry

for phases B2, C and D, to develop, qualify and build

RADEM PROTO-FLIGHT MODEL

2.5 year project - February 2014 to July 2016

RADEM Phase A and B1 Preliminary Analysis and Definition ( PSI & RUAG) Complete

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Proton Telescope 8 Si layers, 8mm Copper shielding) Electron Spectrometer

permanent magnet

Credits to Wojtek Hadjas & Laurent Desorgher (PSI) @ ESA Space Radiation Workshop, May 2012

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Electron directionality

Ganymede Flyby

304–527 keV electrons

DATA: EPD measurementsGalileo G29 encounter with GanymedeDecember 2000

Electron Directionality Detector

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An additional detector module for RADEM

31 Si sensors (300 μm) = 22.5o , φ = 36o & FOV= 7.2o

Shielding:8 mm Copper to stop electrons with E < 10 MeV

300 μm Al absorber stops e- with E < 300 keV & protons with E< 6 MeV

Collimators

y

z

x

y

Electrons 300 keV < E < 10 MeV

Preliminary Assessment with GEANT4

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Electron Directionality DetectorPreliminary assessment

Geant4 models of the detectors interfaced with electron, proton and ion source spectra predicted by the JOSE model at different locations in the Jovian System.

WORK IN PROGRESS

θ

e-

Primary Electron Incident angle θ (deg)

300keV- 10 MeVElectrons> 10 MeV

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Electron Directionality DetectorPreliminary assessment

300keV- 10 MeV electrons

WORK IN PROGRESS

Primary Electron Incident angle θ vs ϕ (deg)

300keV- 10 MeVElectrons

Primary Electron Incident angle θ (deg) vs Kinetic Energy (MeV))

Electron Directionality Detector

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Ongoing DD Concept Optimization Studies

- trade-off in the number of sensors : 31 vs 24 vs 16 … ( 32 channel ASIC ) - include extra sensors below shielding to veto background- …

Detector configurations and readout to be optimized during design, development and calibration of RADEM .

Improved design

WORK IN PROGRESS !

RADEM

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DD integration in RADEM

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It is not every year “we” travel to Jupiter!

The exploration of the Jovian System is an engineering & scientific challenge

RADEM will be ESA “small” tool to study the Energetic Particle Environment of a giant and complex magnetosphere

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Outlook

LIP participates in a consortium with scientific institutes (PSI & LIP) and with the industry (RUAG,

IDEAS, EFACEC) for the development of a proto-flight model of

RADEM

due to the complex and radiation hard environment, there are strong limitations for thr JUICE mission

a radiation monitor is a key piece in keeping the mission safe but it will also provide valuable scientific data.

The exploration of the Jovian System is an engineering & scientific challenge!

WORK IN PROGRESS

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It is not every year “we” travel to Jupiter!

Electron Directionality DetectorAn additional detector module

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Cumulative dose for the Juice mission

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Electron Directionality DetectorPreliminary assessment

Deposited Energy vs. Primary Electron Kinetic Energy (MeV)

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Europa

Ganymede

Callisto

Io

Jupiter

The Jovian Icy Moons

Ice layer. Thickness?

Liquid water?

Surface and Subsurface

composition Geology

Loc environmentInteraction with

JM

Ice layer. Thickness?

Liquid water?

a cold rigid ice crust, an outer warm ice mantle, an inner silicate mantle, and a metallic core

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Model of Callisto's internal structure showing a surface ice layer, a possible liquid water layer, and an ice-rock interior

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Model of Europa's interior showing a solid ice crust over a layer of liquid water or soft ice, a silicate mantle and a metallic core.

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Very Hard Electron Spectrum

Worst case integral electron flux spectra for worst averaged over 24 h and 20 min.

Earth - GEO

Jupiter - JUICE

Electron Flux #/(cm2.sr.s)

0.2 MeV 5 MeV

Jupiter -JUICE ~5 x E+7 ~5 x E+5

Earth - GEO 1 x E+7 /4π 1 x E+1 /4π

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Particles in the magnetosphere

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