Speaker
Description
The Mu3e Experiment searches for the charged-lepton-flavour-violating decay,
𝜇⁺ → e⁺e⁻e⁺ with an aimed single-event sensitivity on the branching ratio of 10⁻¹⁵, imposing stringent requirements on the noise performance of its ultra-low-mass vertex detector. The MuPix11 sensor, a high-voltage monolithic active pixel sensor (HV-MAPS), has been observed to exhibit spatially fixed noise features, necessitating a detailed characterisation of its noise behaviour.
In this contribution, a systematic noise study of MuPix11 is presented, based on cosmic data from the Mu3e vertex detector and quad-module measurements conducted at the Physics Institute in Heidelberg and the Paul Scherrer Institute. Noise characterisation is performed using a frequency-domain analysis based on Fast Fourier Transform (FFT) techniques to identify spectral features and coherent noise sources. A dedicated reconstruction framework is used to extract per-pixel noise rates, temporal correlations, and spatial noise maps.
First results reveal the dominant noise contributions under varying operating conditions and demonstrate the suitability of the developed FFT-based methods for supporting sensor optimisation and the qualification of MuPix11 for integration into the Mu3e detector.