Modeling a Three-Stage SQUID System in Space with the First Micro-X Sounding Rocket Flight

TL;DR

This paper models the response of SQUID sensors in a space-based Micro-X X-ray telescope during its first rocket flight, providing insights into their magnetic behavior and informing future improvements.

Contribution

It introduces a model explaining SQUID baseline response in space, highlighting magnetic effects and guiding future system enhancements.

Findings

SQUIDs exhibited baseline shifts due to Earth's magnetic field.

Some pixels failed to lock during the observation.

The model explains the magnetic susceptibility effects observed.

Abstract

The Micro-X sounding rocket is a NASA funded X-ray telescope payload that completed its first flight on July 22, 2018. This event marked the first operation of Transition Edge Sensors (TESs) and their SQUID-based multiplexing readout system in space. Unfortunately, due to an ACS pointing failure, the rocket was spinning during its five minute observation period and no scientific data was collected. However, data collected from the internal calibration source marked a partial success for the payload and offers a unique opportunity to study the response of TESs and SQUIDs in space. Of particular interest is the magnetic field response of the NIST MUX06a SQUID readout system to tumbling through Earth's magnetic field. We present a model to explain the baseline response of the SQUIDs, which lead to a subset of pixels failing to "lock" for the full observational period. Future flights of the Micro-X rocket will include the NIST MUX18b SQUID system with dramatically reduced magnetic susceptibility.