Antenna-coupled TES Bolometer Arrays for BICEP2/Keck and SPIDER

TL;DR

This paper discusses the development and optimization of antenna-coupled TES bolometer arrays for CMB polarization measurements in BICEP2/Keck and SPIDER, focusing on improving detector uniformity, yield, and sensitivity.

Contribution

It introduces design improvements and characterization of detector arrays to achieve science-grade focal planes with enhanced optical and noise performance.

Findings

Achieved uniform detector parameters across arrays.

Improved fabrication yield of detector arrays.

Deployed a science-grade focal plane at the South Pole.

Abstract

BICEP2/Keck and SPIDER are cosmic microwave background (CMB) polarimeters targeting the B-mode polarization induced by primordial gravitational waves from inflation. They will be using planar arrays of polarization sensitive antenna-coupled TES bolometers, operating at frequencies between 90 GHz and 220 GHz. At 150 GHz each array consists of 64 polarimeters and four of these arrays are assembled together to make a focal plane, for a total of 256 dual-polarization elements (512 TES sensors). The detector arrays are integrated with a time-domain SQUID multiplexer developed at NIST and read out using the multi-channels electronics (MCE) developed at the University of British Columbia. Following our progress in improving detector parameters uniformity across the arrays and fabrication yield, our main effort has focused on improving detector arrays optical and noise performances, in order to produce science grade focal planes achieving target sensitivities. We report on changes in detector design implemented to optimize such performances and following focal plane arrays characterization. BICEP2 has deployed a first 150 GHz science grade focal plane to the South Pole in December 2009.