space environment and detection : lessons learned from planck/hfi françois pajot institut...
TRANSCRIPT
Space environment and detection : lessons learned
from PLANCK/HFI
François PAJOT Institut d'Astrophysique SpatialeBeyond CoRE, June 26th 2012
F. Pajot – CoRE 2012
Introduction
Planck/HFI first mission with NEP ~10-17 WHz-1/2 bolometers 100 mK uninterrupted operation for nearly 30 months 0.01 Hz- 100 Hz flat noise requirement polarization sensitive bolometers high precision calibration at SE Lagrangian L2
Outline cosmic rays interactions impact on design and tests EMI/EMC note on ground calibrations (spectral, ADC,...)
F. Pajot – CoRE 2012
Glitches
F. Pajot – CoRE 2012
Planck/HFI data processing
glitches templates
1 sglitches removal
F. Pajot – CoRE 2012
High glitch rate on bolo and thermo
100/mn
F. Pajot – CoRE 2012
Cosmic ray impact on HFI
CR on detectors thermometer grid wafer
CR on 100 mK plate CR secondary and showers
higher energy CR interacting with HFI or satellite then with bolometers or 100 mK plate
correlated events on many bolometers, big events on the 100 mK plate (elephants: still lacking an interpretation)
F. Pajot – CoRE 2012
CR on bolometers
Cosmic Rays primary and secondary, hits thermometer, grid and wafer NEP ~10-17 WHz-1/2 means sensitivity down to a few 10 eV on grid or
thermometer, but tens of keV on the wafer
F. Pajot – CoRE 2012
CR on bolometers
total
longvery long
short
F. Pajot – CoRE 2012
CR hits impact on 100 mK stage
Low frequency thermal fluctuations CR hits on bolometer housing (many s) CR hits and showers on bolometer cold plate (10 s and more)
CR hits on thermometers used by the PIDs (depends on PID)
F. Pajot – CoRE 2012
Cosmic ray hits on 100 mK stage:long term trend
bolometer plate PID
bolometer plate
dilution plate PID
SREM count (AU)
Solar activity minimum means higher CR rate below ~500 MeV
F. Pajot – CoRE 2012
Cryochain stability: long term trend
About 4 nW power change on 100mK bolometer plate / 2 years
PID bolo
PID dilution
PID 1.6K PID 4K
EOL
EOL EOL
EOL
The power follows the Helium pressures at the pressure regulators30
nW
correlated with SREM data (ie: sun waking up)
SCS switch over
F. Pajot – CoRE 2012
Cosmic ray energy distribution
-> solar maximum
-> solar minimum est.
F. Pajot – CoRE 2012
Planck/HFI noise PSD
F. Pajot – CoRE 2012
Impact on design and tests
Minimize detector sensitivity to CR minimize cross section to CR for absorber (grid,..) and
thermometer
minimize beams / frame thermal coupling to thermometer
fast time response
differential measurements
model and test under representative environment (instrument + high energy particles : proton accelerators up to few 100 MeV – on going work in Orsay IAS and Grenoble LPSC & INéel)
Cryochain design passive / active thermal regulation
need design sub-K stages more immune to cosmic rays showers.
F. Pajot – CoRE 2012
EMI/EMC
Strict EMI/EMC design of Planck no pertubation from transmitters
no perturbation from other subsystems
except from known 4K cooler drive electronics
synchronization with modulation of bolometer readout gives very narrow lines
requires design at system level (ex SPICA/SAFARI)
F. Pajot – CoRE 2012
Thoughts on ground calibrations
Temporal response direct impact on C(l)
more characterisations
ADC calibration large dynamics, but usefull range on a few bits
Spectral transmission calibration the best achievable on ground may not be enough
check with multiband sky measurement
Polarization calibration...
F. Pajot – CoRE 2012
Thank You !
F. Pajot – CoRE 2012
The results presented here are a product of the Planck Collaboration, including individuals from more than 50 scientific institutes in Europe, the USA and Canada
Planck is a project of the European Space Agency -- ESA -- with instruments provided by two scientific Consortia funded by ESA member states (in particular the lead countries: France and Italy) with contributions from NASA (USA), and telescope reflectors provided in a collaboration between ESA and a scientific Consortium led and funded by Denmark.