[séminaire] QUBIC — the Q and U Bolometric Interferometer for Cosmology

by Misha Stolpovskiy

Tuesday 23 May 2017, 11:00 → 12:00 Europe/Paris

Grand Amphi

One of the major challenges in the modern CMB physics is the measurement of the primordial B-modes of polarisation of CMB, which would be the smoking gun detection of the inflation epoch of the early Universe. Usually the imager instruments are used for this purpose. Another possible approach is interferometry. Both approaches have their pros and cons: interferometers are good in the sense of systematics control, but not as good in the sense of sensitivity, while for imagers it is the other way round — great sensitivity and poor systematics control. The bolometric interferometry offers a fusion between the two approaches, inheriting pros from the both: high sensitivity thanks to the use of bolometric detectors and instrumental systematics control thanks to the use of the technique called self-calibration. Moreover, modern instruments suffer from the poor frequency resolution, which is crucially important for the primordial B-modes observation. Bolometric interferometry solves this issue by the possibility to reconstruct multiple frequency bands per focal plane. QUBIC is the first bolometric interferometer. It is a ground-based experiment, which is going to be installed in Puna desert, Argentina, in 2018. The sensitivity of QUBIC on the tensor-to-scalar ratio parameter r is predicted to be 0.012 at 68% CL after 2 years of observations.