Results from the GIOVE-A CEDEX Space Radiation Monitor B Taylor 1, C Underwood 1, H Evans 2, E Daly 2, G Mandorlo 2, R Prieto 2, M Falcone 2 1. Surrey Space Centre, University of Surrey, UK 2. ESA/ESTEC/TEC-EDD, NL 3 rd European Space Weather Week Brussels, Belgium, November 2006

Results from the GIOVE-A CEDEX Space Radiation Monitor 3rd European Space Weather Week 2 Outline  The CEDEX instrument  Results and model comparisons  Heavy Ion LET spectrum  Proton Flux  Ionising Dose rate  Conclusions

Results from the GIOVE-A CEDEX Space Radiation Monitor 3rd European Space Weather Week 3 CEDEX  Resources: <2.2 kg (including radiation shielding), <4.5W  Heritage: Surrey ’ s CRE Payloads  KITSAT-1, PoSAT-1, AMSAT-OSCAR-40  Measure Proton flux (45-50 MeV) and ion LET spectra  Combined proton and ion telescope employing large-area (3cm x 3cm) PIN diodes  Ion LET values binned into 512 linearly spaced channels  32 to >10,000 MeV cm 2 g -1.  Measure ionising dose-rate induced photocurrents  Dose-rate-induced photocurrents measured in dome shielded PIN photodiodes (provides electron data)  Four shielding depths: 2mm Al, 4mm Al, 2mm Cu, 4mm Cu  Calibrated at QinetiQ ’ s REEF facility

Results from the GIOVE-A CEDEX Space Radiation Monitor 3rd European Space Weather Week 4 CEDEX

Results from the GIOVE-A CEDEX Space Radiation Monitor 3rd European Space Weather Week 5 Heavy Ion LET Spectrum  Flux is assumed to be over 4  with 1cm uniform shielding.  5mm deviation produces a maximum error of 20% at high LET for the model predictions.  The background flux as measured by CEDEX matches the shape of the CREME86 model spectrum, with the interplanetary weather index set to take into account Galactic cosmic rays and the fully ionised component (i.e.: CREME86 M=2) and the 90% worst case cosmic ray level (i.e.: CREME86 M=3).  The majority of the spectrum lies between the M=2 and M=3 CREME86 models.  Further investigation is required to establish true flux through the telescope.

Results from the GIOVE-A CEDEX Space Radiation Monitor 3rd European Space Weather Week 6 Heavy Ion LET Spectrum CEDEX measured Heavy Ion LET Spectrum for January to September 2006 compared to CREME86

Results from the GIOVE-A CEDEX Space Radiation Monitor 3rd European Space Weather Week 7 Proton Flux  Awaiting full analysis  Contamination from  particles and other heavy Ions  Proton Events  Single event associated with M2 solar flare

Results from the GIOVE-A CEDEX Space Radiation Monitor 3rd European Space Weather Week 8 GRAS modelling  GEANT-4 Radiation Analysis for Space- GRAS  Instruments can be easily modelled using gdml files  Range of analysis packages  Range of energetic particles

Results from the GIOVE-A CEDEX Space Radiation Monitor 3rd European Space Weather Week 9 Dose Rate Photodiodes – Short Term  Belt transits  Sensitive to Electrons  Clearly visible in Aluminium shielded domes  Detected in Copper shielded domes at high activity  Shape due to peak differing in L shell

Results from the GIOVE-A CEDEX Space Radiation Monitor 3rd European Space Weather Week 10 Dose Rate Photodiodes – Short Term  AE-8 Predicted Dose rates  >1 MeV Electrons modelled  Assumes spectrum is constant  Worst day 2mm Al diode saturates  Observed dose rates more confined than model predictions

Results from the GIOVE-A CEDEX Space Radiation Monitor 3rd European Space Weather Week 11 Dose Rate Photodiodes – Long Term  Long Term Dose Rate  Highly variable  Clear 27 day periodicity in early 2006  Fair match to model predictions  2mm Al Shielded diode saturates during large event in April

Results from the GIOVE-A CEDEX Space Radiation Monitor 3rd European Space Weather Week 12 Dose Rate Photodiodes – Long Term  Average Dose Rate  Flight data is a fair match to GRAS modelling  2mm Al diode has lower dose rate than expected  Due to saturation and sub-threshold data  Derived dose rate from linear relationship between 2mm & 4mm Al diodes

Results from the GIOVE-A CEDEX Space Radiation Monitor 3rd European Space Weather Week 13 Dose Rate Photodiodes – Long Term  Geomagnetic activity and Dose rate  Large dose rates observed after Geomagnetic Storms  Geomagnetic Storms triggered by interaction with Coronal Holes

Results from the GIOVE-A CEDEX Space Radiation Monitor 3rd European Space Weather Week 14 Conclusions  The GIOVE-A CEDEX instrument is working well.  The heavy ion LET environment is in reasonable agreement with the LET spectrum produced by CREME86.  The Proton environment is quiet with a single small event occurring  The MEO dose environment is observed to be highly variable, especially due to Geomagnetic storms associated with coronal holes  Initial GRAS modelling using the AE-8MIN model indicates a fair match to flight data in the longer term

Results from the GIOVE-A CEDEX Space Radiation Monitor 3rd European Space Weather Week 15 Thank You Questions?