Download Lucio Piccirillo, Introduction: Previous BPol instrumental design

B-Pol
L. Piccirillo
Jodrell Bank Centre for Astrophysics
(University of Manchester)
•A European mission to get a CMB
polarization measurement limited only
by natural foreground sources was
proposed in response to the ESA
Cosmic-Vision call.
•The mission is based on the
availability of large format arrays of
ultra-sensitive bolometric detectors,
cooled at 0.1K, and fed by cold
corrugated feedhorns and low
polarization telecentric telescopes.
•Polarization modulation is obtained by
means of rotating waveplates.
Countries involved:
Canada
Denmark
France
Germany
Ireland
Italy
Netherland
Norway
Portugal
Romania
Spain
Sweden
Switzerland
United Kingdom
United States
PI: P. De Bernardis (Italy)
Instrument Group: L. Piccirillo (UK)
Science Group: M. Bucher (Fr)
Foreground Group: C. Burigana (Italy)
Telescope
V-Grooves
Cryostat
3.3 m
2.7 m
Service Module
Optical system:
• Wide field,
• low cross-pol,
• low emissivity
Possible solution:
modified telecontric
telescope
HWP
Lenses (telecentric telescope)
2K
8K
Sub-K
Dilution
L1
L2
Focal
plane
Array
Spinning
half-wave plate
cooler
of Horns and
Bolometers (0.1K)
Sensitivity and frequency coverage: the focal plane
• Baseline technology: TES bolometers arrays
Corrugated feedhorns
for polarization purity and
beam symmetry
Sub-K, 600 mm
Sensitivity
9
9
9
9
Mesh Half Wave Plate
• Space qualified already
bc identical technology
to mesh filters
• Prototypes built and
tested @ 30 and 90
GHz
• Excellent agreement
with theory
END