Multimode bolometer development for the PIXIE instrument

TL;DR

This paper presents the design, fabrication, and testing of advanced multimode bolometers for the PIXIE mission, featuring improved vibrational mode frequencies and robustness suitable for space deployment.

Contribution

It introduces a novel tensioning scheme for silicon-based bolometers that enhances vibrational stability and microphonic resistance in space applications.

Findings

Bolometers achieved high vibrational mode frequencies.

Demonstrated robustness in cryogenic and vibrational environments.

Performance metrics meet PIXIE mission requirements.

Abstract

The Primordial Inflation Explorer (PIXIE) is an Explorer-class mission concept designed to measure the polarization and absolute intensity of the cosmic microwave background. In the following, we report on the design, fabrication, and performance of the multimode polarization-sensitive bolometers for PIXIE, which are based on silicon thermistors. In particular we focus on several recent advances in the detector design, including the implementation of a scheme to greatly raise the frequencies of the internal vibrational modes of the large-area, low-mass optical absorber structure consisting of a grid of micromachined, ion-implanted silicon wires. With $\sim30$ times the absorbing area of the spider-web bolometers used by Planck, the tensioning scheme enables the PIXIE bolometers to be robust in the vibrational and acoustic environment at launch of the space mission. More generally, it could be used to reduce microphonic sensitivity in other types of low temperature detectors. We also report on the performance of the PIXIE bolometers in a dark cryogenic environment.