Tuning of Kilopixel Transition Edge Sensor Bolometer Arrays with a Digital Frequency Multiplexed Readout System

TL;DR

This paper presents a digital frequency multiplexing system for tuning large arrays of TES bolometers, improving setup efficiency and reducing heat load in mm-wavelength cosmology telescopes.

Contribution

Introduction of a fully parallelized digital frequency multiplexing system with embedded algorithms for efficient tuning of large TES bolometer arrays.

Findings

Reduces heat load on cryogenic detector stage.

Setup time is independent of array size.

Enables efficient tuning of large bolometer arrays.

Abstract

A digital frequency multiplexing (DfMUX) system has been developed and used to tune large arrays of transition edge sensor (TES) bolometers read out with SQUID arrays for mm-wavelength cosmology telescopes. The DfMUX system multiplexes the input bias voltages and output currents for several bolometers on a single set of cryogenic wires. Multiplexing reduces the heat load on the camera's sub-Kelvin cryogenic detector stage. In this paper we describe the algorithms and software used to set up and optimize the operation of the bolometric camera. The algorithms are implemented on soft processors embedded within FPGA devices operating on each backend readout board. The result is a fully parallelized implementation for which the setup time is independent of the array size.