# Diamond-loaded polyimide aerogel scattering filters and their applications in astrophysical and planetary science observations

## TL;DR

This paper presents conductively-loaded polyimide aerogel scattering filters that meet the mechanical and thermal requirements for astrophysical and planetary science instruments, demonstrating their performance through simulations and cryogenic testing.

## Contribution

It introduces a new type of infrared-blocking aerogel filter suitable for cryogenic applications in astrophysics and planetary science instruments.

## Key findings

- Filters survive cryogenic cycling to 4 K without degradation.
- Simulations predict effective performance in cryogenic receivers.
- Measurements estimate the filters' infrared emissivity for instrument design.

## Abstract

Infrared-blocking, aerogel-based scattering filters have a broad range of potential applications in astrophysics and planetary science instruments in the far-infrared, sub-millimeter, and microwave regimes. This paper demonstrates the ability of conductively-loaded, polyimide aerogel filters to meet the mechanical and science instrument requirements for several experiments, including the Cosmology Large Angular Scale Surveyor (CLASS), the Experiment for Cryogenic Large-Aperture Intensity Mapping (EXCLAIM), and the Sub-millimeter Solar Observation Lunar Volatiles Experiment (SSOLVE). Thermal multi-physics simulations of the filters predict their performance when integrated into a cryogenic receiver. Prototype filters have survived cryogenic cycling to 4\,K with no degradation in mechanical properties. Measurement of total hemispherical reflectance and transmittance, as well as cryogenic tests of the aerogel filters in a full receiver context, allow estimates of the integrated infrared emissivity of the filters. Knowledge of the emissivity will help instrument designers incorporate the filters into future experiments in planetary science, astrophysics, and cosmology.