# Assessing the Aging Effect on Ti/Au Bilayers for Transition-Edge Sensor (TES) Detectors

## TL;DR

This paper explores how aging affects Ti/Au bilayer sensors used in cryogenic detectors and proposes a solution to maintain their performance.

## Contribution

The study introduces a new production line for TES detectors and investigates aging effects with a potential annealing remedy.

## Key findings

- Repeated R–T measurements showed sensor degradation over time due to aging effects.
- An easy annealing procedure was tested as a potential remedy for sensor degradation.
- The work provides groundwork for a new TES detector production line.

## Abstract

Transition-edge sensor (TES) microcalorimeters are advanced cryogenic detectors that use a superconducting film for particle or photon detection. We are establishing a new production line for TES detectors to serve as cryogenic anticoincidence (i.e., veto) devices. These detectors are made with a superconducting bilayer of titanium (Ti) and gold (Au) thin films deposited via electron beam evaporation in a high vacuum condition on a monocrystalline silicon substrate. In this work, we report on the development of such sensors, aiming to achieve stable sensing performance despite the effects of aging. For this purpose, patterned and non-patterned Ti/Au bilayer samples with varying geometries and thicknesses were fabricated using microfabrication technology. To characterize the detectors, we present and discuss initial results from repeated resistance–temperature (R–T) measurements over time, conducted on different samples, thereby augmenting existing literature data. Additionally, we present a discussion of the sensor’s degradation over time due to aging effects and test a potential remedy based on an easy annealing procedure. In our opinion, this work establishes the groundwork for our new TES detector production line.