# 18th International Workshop on Low Temperature Detectors (LTD-18)

22-26 July 2019
Milano
Europe/Rome timezone

## High speed microwave rf-SQUID multiplexing read-out for the HOLMES experiment

25 Jul 2019, 17:45
1h 15m
Piazza Città di Lombardia (Milano)

### Piazza Città di Lombardia

#### Milano

Piazza Città di Lombardia, 1, 20124 Milano MI
Poster Detector readout, signal processing, and related technologies

Andrea Giachero

### Description

HOLMES is an experiment with the aim to directly measure the neutrino mass. HOLMES will perform a precise calorimetric measurement of the end point of the Electron Capture (EC) decay spectrum of $^{163}$Ho in order to extract information on neutrino mass with a sensitivity below 2 eV. In its final configuration, HOLMES will deploy 1000 detectors of low temperature microcalorimeters with implanted $^{163}$Ho nuclei.

The baseline sensors for HOLMES are Mo/Cu TESs (Transition Edge Sensors) on SiN$_x$ membrane with gold absorbers. The TES detectors are designed to have an energy resolution of few eV FWHM at the 2.8 keV $^{163}$Ho end-point and to be fast enough to assure a time resolution of 3 $\mu$s, in order contain systematics coming from unresolved pile-ups. Considering the large number of pixels and an event rate of about 300 Hz/pixel, a large multiplexing factor and a large bandwidth are needed.

A promising readout candidate that can fulfill this requirement is the microwave multiplexer, which offers several gigahertz of readout bandwidth per pair of coaxial cables. The TESs are coupled to rf-SQUIDs embedded in superconducting microwave resonators, which are probed via a common microwave feedline and read out at room temperature using GHz signals carried on coaxial cables. This form of multiplexing moves complexity from the cryogenic stages to room temperature hardware and digital signal processing firmware which must synthesize the microwave tones and process the information contained within them. In this contribution we present the basic theory and the considerations of a microwave SQUID multiplexer designed to match HOLMES requirements. Finally the status of the development and the performances currently obtained, in terms of noise, time and energy resolutions, are presented.

Less than 5 years of experience since completion of Ph.D N N

### Co-authors

Daniel Becker (National Institute of Standards and Technology) Doug Bennett (NIST) Michele Biasotti (GE) Matteo Borghesi (Istituto Nazionale di Fisica Nucleare) Matteo De Gerone (GE) Mrs Elena Ferri Joseph Fowler (NIST) Dr Johnathon Gard (NIST) Gene Hilton (NIST-Boulder) John Mates (National Institute of Standards and Technology) Andrei Puiu (MIB) Carl Reintsema (NIST) Dr Daniel Schmidt (NIST) Daniel Swetz (NIST) Joel Ullom (NIST/University of Colorado) Leila Vale (NIST) Flavio Gatti (GE)

### Presentation Materials

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