QUBIC : the Q and U bolometric interferometer for cosmology

M. Piat ... [et al.].

Serie: Trabajos publicados del IAR ; no. 1711aSPIE Digital Library

Resumen: QUBIC (Q and U bolometric interferometer for cosmology) is an international ground-based experiment dedicated to the measurement of the polarized fluctuations of the cosmic microwave background (CMB). It is based on bolometric interferometry, an original detection technique which combines the immunity to systematic effects of an interferometer with the sensitivity of low temperature incoherent detectors. QUBIC will be deployed in Argentina, at the Alto Chorrillos mountain site near San Antonio de los Cobres, in the Salta province. The QUBIC detection chain consists of 2048 NbSi transition edge sensors (TESs) cooled to 320 mK. The voltage-biased TESs are read out with time domain multiplexing based on superconducting quantum interference devices (SQUIDs) at 1 K and a novel SiGe application-specific integrated circuit (ASIC) at 60 K allowing an unprecedented multiplexing (MUX) factor equal to 128 to be reached. The current QUBIC version is based on a reduced number of detectors (1/4) in order to validate the detection technique. The QUBIC experiment is currently being validated in the lab in Salta (Argentina) before going to the site for observations. This paper presents the main results of the characterization phase with a focus on the detectors and readout system