The new Multi-Frequency Instrument (MFI2) for the QUIJOTE facility in Tenerife

The QUIJOTE (Q-U-I JOint TEnerife) Experiment combines the operation of two radio-telescopes and three instruments working in the microwave bands 10-20 GHz, 26-36 GHz and 35-47 GHz at the Teide observatory, Tenerife, and has already been presented in previous SPIE meetings (1; 2). The Cosmology group at the IAC have designed a new upgrade to the MFI instrument in the band 10-20 GHz. The aim of the QUIJOTE telescopes is to characterise the polarised emission of the Cosmic Microwave Background (CMB), as well as Galactic and extra-Galactic sources, at medium and large angular scales.This MFI2 will continue the survey at even higher sensitivity levels. The MFI2 project led by the Instituto de Astrofisica de Canarias (IAC) consists of 5 polarimeters, three of them operating in the subband 10-15 GHz, and two in the subband 15-20 GHz. The MFI2 instrument is expected to be a full 2-3 times more sensitive than the former MFI. The microwave complex correlator design has been replaced by a simple correlator design with a digital back-end based on the latest Xilinx FPGAs (ZCU111). During the first half of 2019 the manufacture of the new cryostat was completed and since then the opto-mechanical components have been designed and manufactured. It is expected that the cryogenic front-end will be completed by the end of 2022 along with the FPGA acquisition and observing system. This digital system has been employed to be more robust against stray ground-based and satellite interference, having a frequency resolution of 1 MIIz.