The QUIJOTE-CMB project has been described in previous publications. Here we present the current status of the
QUIJOTE multi-frequency instrument (MFI) with five separate polarimeters (providing 5 independent sky pixels): two
which operate at 10-14 GHz, two which operate at 16-20 GHz, and a central polarimeter at 30 GHz. The optical
arrangement includes 5 conical corrugated feedhorns staring into a dual reflector crossed-draconian system, which
provides optimal cross-polarization properties (designed to be < −35 dB) and symmetric beams. Each horn feeds a novel
cryogenic on-axis rotating polar modulator which can rotate at a speed of up to 1 Hz. The science driver for this first
instrument is the characterization of the galactic emission. The polarimeters use the polar modulator to derive linear
polar parameters Q, U and I and switch out various systematics. The detection system provides optimum sensitivity
through 2 correlated and 2 total power channels. The system is calibrated using bright polarized celestial sources and
through a secondary calibration source and antenna. The acquisition system, telescope control and housekeeping are all
linked through a real-time gigabit Ethernet network. All communication, power and helium gas are passed through a
central rotary joint. The time stamp is synchronized to a GPS time signal. The acquisition software is based on PLCs
written in Beckhoffs TwinCat and ethercat. The user interface is written in LABVIEW. The status of the QUIJOTE MFI
will be presented including pre-commissioning results and laboratory testing.
The QUIJOTE (Q-U-I JOint Tenerife) CMB Experiment will operate at the Teide Observatory with the aim
of characterizing the polarisation of the CMB and other processes of Galactic and extragalactic emission in the
frequency range of 10-40GHz and at large and medium angular scales. The first of the two QUIJOTE telescopes
and the first multi-frequency (10-30GHz) instrument are already built and have been tested in the laboratory.
QUIJOTE-CMB will be a valuable complement at low frequencies for the Planck mission, and will have the
required sensitivity to detect a primordial gravitational-wave component if the tensor-to-scalar ratio is larger
than r = 0.05.
This article focuses on the study of the statistical properties of the cosmic microwave background (CMB) temperature
fluctuations. This study helps to define a coherent framework for the origin of the Universe, its evolution
and the structure formation. The current standard model is based in the Big-Bang theory, in the context of
the Cosmic Inflation scenario, and predicts that the CMB temperature fluctuations can be understood as the
realization of a statistical isotropic and Gaussian random field. To probe whether these statistical properties are
satisfied or not is capital, since deviations from these hypotheses would indicate that non-standard models might
play an important role in the dynamics of the Universe. But that is not all. There are alternative sources of
anisotropy or non-Gaussianity that could contaminate the CMB signal as well. Hence, sophisticated techniques
must be used to carry out such a probe. Among all the methodologies that one can face in the literature, those
based on wavelets are providing one of the most interesting insights to the problem. Their ability to explore
several scales keeping, at the same time, spatial information of the CMB, is a very useful property to discriminate
among possible sources of anisotropy and/or non-Gaussianity.