Koji Ishidoshiro, Makoto Nagai, Takeo Higuchi, Masaya Hasegawa, Masashi Hazumi, Masahiro Ikeno, Osamu Tajima, Manobu Tanaka, Tomohisa Uchida
B-modes are special patterns in cosmic microwave background (CMB)
polarization. The detection of them is a smoking-gun signature of primordial
gravitational waves. The generic strategy of the CMB polarization experiments
is to employ a large number of polarimeters for improving the statistics. The
Q/U Imaging ExperimenT-II (QUIET-II) has been proposed to detect the B-modes
using the world's largest coherent polarimeter array (2,000 channels). An
unique detection technique using QUIET's polarimeters, which is a modula-
tion/demodulation scheme, enables us directly extracting the polarization
signal. The extracted signal is free from non- polarized components and
intrinsic 1/f noise. We developed a data readout system with on-board
demodulation functions for the QUIET-II experiment. We employed a "master"
clock strategy. This strategy guarantees phase matching between the modulation
by the polarimeters and the demodulation by ADC modules. The single master
generates all carrier clocks and distributes them to each module. The developed
electronics, clock modules, and the ADC modules fulfill requirements. Tests
with a setup similar to that of the real experiment proved that the system
works properly. The performance of all system components are validated to be
suitable for B-mode measurements.
View original:
http://arxiv.org/abs/1112.0644
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