Allectra has supplied components and cables for the Large-Scale Polarization Explorer (LSPE) SWIPE and STRIP instruments.
LSPE aims at measuring the polarization of the Cosmic Microwave Background at large angular scales.
Measuring CMB polarization with high precision at large angular scales is very difficult, due to large signals from the interstellar medium (thermal emission from interstellar dust grains and synchrotron emission from electrons in the Galactic magnetic field).
The only way to separate the cosmological signal from the local one is by exploiting the difference in their spectra, which must be sampled over a wide frequency range.
Large sky coverage and wide frequency coverage call for a space mission. On a shorter time-scale, experimentation is required to qualify specific instrumentation (optical systems, polarization modulators, detectors) and methods (sky scan, mapping procedures, polarized foregrounds separation), and possibly to get detections !
The instruments :
The Large-Scale Polarization Explorer is
– a stratospheric balloon payload, SWIPE flying long-duration in the polar night
– spinning to cover a large fraction of the sky (20-25% per flight)
– aiming at CMB polarization at large angular scales
– using polarization modulators to achieve high stability
– using multi-mode bolometers for extreme sensitivity
– Frequency coverage of SWIPE: 120 – 250 GHz (3 channels)
– Angular resolution: 1.3o FWHM
– a ground based instrument, STRIP operated in Tenerife, using coherent radiometers
– Frequency coverage of STRIP: 40 – 90 GHz (2 channels)
– Angular resolution: 0.5o FWHM
– Combined sensitivity: 20 mK arcmin per survey (1y)
– sky coverage overlapping the SWIPE one.
Source: LSPE, INFN
The supply consisted of 2 sets of 4 flanges with 4x Sub-D 37 way feedthroughs on each custom flange, and 1 set of 4 DN160CF flanges with 8x Sub-D 50 way feedthroughs.
The cabling was made by Copper and Manganin wires alternatively in order to match the different temperature steps inside the instruments.
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