A coherent polarimeter array for the Large Scale Polarization Explorer balloon experiment

TL;DR

This paper presents the design and expected performance of STRIP, a coherent polarimeter array for the LSPE balloon experiment, aimed at measuring CMB polarization with high sensitivity and multi-frequency capabilities.

Contribution

It introduces a novel array of 56 coherent receivers with cryogenic HEMT amplifiers for the LSPE balloon mission, enhancing large-scale CMB polarization measurements.

Findings

Design specifications of the STRIP array and its components.

Expected angular resolution of approximately 1.5 degrees.

The array's role in separating CMB polarization signals from foregrounds.

Abstract

We discuss the design and expected performance of STRIP (STRatospheric Italian Polarimeter), an array of coherent receivers designed to fly on board the LSPE (Large Scale Polarization Explorer) balloon experiment. The STRIP focal plane array comprises 49 elements in Q band and 7 elements in W-band using cryogenic HEMT low noise amplifiers and high performance waveguide components. In operation, the array will be cooled to 20 K and placed in the focal plane of a $\sim 0.6$ meter telescope providing an angular resolution of $\sim1.5$ degrees. The LSPE experiment aims at large scale, high sensitivity measurements of CMB polarization, with multi-frequency deep measurements to optimize component separation. The STRIP Q-band channel is crucial to accurately measure and remove the synchrotron polarized component, while the W-band channel, together with a bolometric channel at the same frequency, provides a crucial cross-check for systematic effects.