One step closer to confirm (or not) the inflationary epoch

The IAC has completed the integration and testing of the first pixel for the second QUIJOTE instrument, which will confirm or deny the detection of B-modes in the polarization of the cosmic microwave background

QUIJOTE (Q-U-I JOint Tenerife) CMB Experiment is an installation of two telescopes and three instruments designed to study the polarization of the signal from the cosmic microwave background (CMB) in the frequency range between 10 GHz and 42 GHz. The second QUIJOTE instrument, the TGI (Thirty GHz Instrument), is intended to confirm or deny the recent (and not yet corroborated) detection of B-modes in the polarization of the CMB. This detection would be an important milestone in Cosmology, as it would confirm the presence of gravitational waves in the primordial universe, which would have been created by inflation, an epoch of exponential expansion of the early universe.

The first QUIJOTE telescope and the first instrument are both operating in the band from 10 to 20 GHz since November 2012, at the Teide Observatory, in Tenerife. The second telescope has recently been installed at the Observatory, and the TGI is in the integration stage at the IAC headquarters. Both the second telescope and TGI are planned to be in commissioning by the end of 2014, covering the range from 26 to 36 GHz.

The TGI is a complex instrument that broadly consists of 31 pixels contained in a large cryostat, which will maintain a temperature of only 20K (-253ºC). Each of these pixels is a polarimeter that captures the CMB signal in a given frequency, decomposes it into its different types of polarization, and recombines them conveniently to obtain its Stokes parameters, which are the variables that determine the state of polarization of the detected light.

The first pixel of the TGI has been assembled these days in the IAC laboratories. Each of the component parts: horns, polarizers, ortho mode transducers, wave-guides and low-noise amplifiers have been carefully integrated with fiberglass rods, giblets, screws, inserts, washers, helicoids, and all kinds of tiny parts, manufactured to fit like a perfect puzzle and form, in short, a detector. This is the first of 31 detectors that will constitute, along with the rest of subsystems, the powerful instrument that will reveal the keys of the inflationary era.

The QUIJOTE project is a scientific collaboration between four main institutions: the IAC, the Instituto de Física de Cantabria, the University of Cantabria, the University of Manchester and the University of Cambridge. This experiment, and in particular the TGI, is one of the technology projects supported by the Severo Ochoa Program.