Paper PC13102-90
Paper PC13102-90
Calibration measurements of the BICEP3 and BICEP array CMB polarimeters from 2017 to 2024
On demand | Presented live 18 June 2024 
Abstract
The BICEP3 and BICEP Array polarimeters are small-aperture refracting telescopes located at the South Pole designed to measure primordial gravitational wave signatures in the Cosmic Microwave Background (CMB) polarization, predicted by inflation. Constraining the inflationary signal requires not only excellent sensitivity, but also careful control of instrumental systematics. Both instruments use antenna-coupled orthogonally polarized detector pairs, and the polarized sky signal is reconstructed by taking the difference in each detector pair. As a result, the differential response between detectors within a pair becomes an important systematic effect we must control. Additionally, mapping the intensity and polarization response in regions away from the main beam can inform how sidelobe levels affect CMB measurements. Extensive calibration measurements are taken in situ every austral summer for control of instrumental systematics and instrument characterisation. In this work, we detail the set of beam calibration measurements that we conduct on the BICEP receivers, from deep measurements of main beam response to polarized beam response and sidelobe mapping. We discuss the impact of these measurements for instrumental systematics studies and design choices for future CMB receivers.
Presenter
Christos Giannakopoulos
BICEP/Keck Collaboration (United States)
My name is Christos Giannakopoulos, I am a 5th year graduate student at the University of Cincinnati and part of the BICEP/Keck Collaboration working with my supervisor Colin Bischoff. I was born and raised in Greece and moved to the United States when I was 18 years old. I focus on instrumental systematics analysis with the BICEP3 and BICEP Array polarimeters at the South Pole and how sidelobe pickup impact our CMB measurements. I work with people on site to perform calibration measurements that help us probe detector response in both intensity and polarization.
Fun fact: I am passionate about automotive systems and am familiar with the function and physics of the majority of them!