Technical design of the phase I Mu3e experiment

K. Arndt, H. Augustin, P. Baesso, N. Berger, F. Berg, C. Betancourt, D. Bortoletto, A. Bravar, K. Briggl, D. vom Bruch, A. Buonaura, F. Cadoux (+93 others)
2021 Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment  
The Mu3e experiment aims to find or exclude the lepton flavour violating decay µ → eee at branching fractions above 10 −16 . A first phase of the experiment using an existing beamline at the Paul Scherrer Institute (PSI) is designed to reach a single event sensitivity of 2 · 10 −15 . We present an overview of all aspects of the technical design and expected performance of the phase I Mu3e detector. The high rate of up to 10 8 muon decays per second and the low momenta of the decay electrons and
more » ... positrons pose a unique set of challenges, which we tackle using an ultra thin tracking detector based on high-voltage monolithic active pixel sensors combined with scintillating fibres and tiles for precise timing measurements. Spokespersons: S. Ritt (, A. Schöning Kirk Arndt was a silicon detector development engineer. He came to Europe in 2014 after an illustrious career in the U.S. where he became known as "the best pair of hands in the silicon business". He built some remarkable silicon digital cameras for particle physics at the University of California Santa Barbara, Purdue University, and Oxford including one that glimpsed the Higgs particle for the first time at the LHC at CERN in 2012. These were the Silicon Micro-Vertex Detector for the CLEO II.V experiment at the Cornell Electron Storage Ring with UCSB, the CLEO III Silicon Vertex Detector and the CMS Phase 0 and Phase 1 Silicon Forward Pixel Detectors for the CMS experiment at the LHC at CERN with Purdue, and he was working on the ATLAS Upgrade Silicon Forward Pixel Detector at Oxford, the Mu3e tracker and detectors for photon science at the time of his death. For over a decade he also played an important role in the design of the 3.2 Gigapixel camera for the Large Synoptic Survey Telescope both at Purdue and Oxford. Kirk was a very highly valued and widely appreciated colleague. He was always ready to help colleagues in the CLEO, CMS, LSST, ATLAS and Mu3e collaborations and many others in the international community who sought him out for advice. His positive can do attitude, exacting professional standards, dedication, willingness to nurture younger colleagues and his kindness are an example to us all. Shortly before his unexpected death at the age of 59, he hosted a Mu3e collaboration meeting in Oxford. It was a privilege to work with Kirk. He will live on in the hearts and minds of all that knew him.
doi:10.1016/j.nima.2021.165679 fatcat:mkogr4bxvvce7ms7obpuhkp4em