Atlaspix3: A high voltage CMOS sensor chip designed for ATLAS Inner Tracker

ATLASpix3 is a 2 x 2 cm$^{2}$ high voltage CMOS sensor chip designed to meet the specifications of outer layers of ATLAS inner tracker. It is compatible with the hybrid pixel sensor ASIC RD53A in terms of electronic interface and geometry. ATLASpix3 is a depleted monolithic CMOS pixel detector which allows the construction of quad modules of the same size as that of hybrid sensors. The readout scheme can be externally configured as triggered or triggerless column drain readout. The hit information is transmitted through a 1.28 Gbit/s serial link. The interface is based on a single command input that is used for providing clock, trigger and configuration commands. This contribution summarizes the detector architecture with focus on the design of its readout circuitry. In addition, simulation results obtained using ReadOut Modelling Environment (ROME), that led to the design of the readout system are discussed

Status of HVCMOS developments for ATLAS

This paper describes the status of the developments made by ATLAS HVCMOS and HVMAPS collaborations. We have proposed two HVCMOS sensor concepts for ATLAS pixels—the capacitive coupled pixel detector (CCPD) and the monolithic detector. The sensors have been implemented in three semiconductor processes AMS H18, AMS H35 and LFoundry LFA15. Efficiency of 99.7% after neutron irradiation to 1015 neq/cm2W has been measured with the small area CCPD prototype in AMS H18 technology. About 84% of the particles are detected with a time resolution better than 25 ns. The sensor was implemented on a low resistivity substrate. The large area demonstrator sensor in AMS H35 process has been designed, produced and successfully tested. The sensor has been produced on different high resistivity substrates ranging from 80 Ωcm to more than 1 kΩ. Monolithic- and hybrid readout are both possible. In August 2016, six different monolithic pixel matrices for ATLAS with a total area of 1 cm2 have been submitted in LFoundry LFA15 process. The matrices implement column drain and triggered readout as well as waveform sampling capability on pixel level. Design details will be presented

MuPix and ATLASPix -- Architectures and Results

High Voltage Monolithic Active Pixel Sensors (HV-MAPS) are based on a commercial High Voltage CMOS process and collect charge by drift inside a reversely biased diode. HV-MAPS represent a promising technology for future pixel tracking detectors. Two recent developments are presented. The MuPix has a continuous readout and is being developed for the Mu3e experiment whereas the ATLASPix is being developed for LHC applications with a triggered readout. Both variants have a fully monolithic design including state machines, clock circuitries and serial drivers. Several prototypes and design variants were characterised in the lab and in testbeam campaigns to measure efficiencies, noise, time resolution and radiation tolerance. Results from recent MuPix and ATLASPix prototypes are presented and prospects for future improvements are discussed.Comment: 10 pages, proceedings, The 28th International Workshop on Vertex Detectors (VERTEX 2019), 13 - 18 Oct 2019, Lopud Island, Croati

Technical design of the phase I Mu3e experiment

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 108 muon decays per second and the low momenta of the decay electrons and 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

Technical design of the phase I Mu3e experiment

The Mu3e experiment aims to find or exclude the lepton flavour violating decay $\mu \rightarrow eee$ 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 $2\cdot 10^{-15}$. 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 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.Comment: 114 pages, 185 figures. Submitted to Nuclear Instruments and Methods A. Edited by Frank Meier Aeschbacher This version has many enhancements for better readability and more detail

Design, upgrade and characterization of the silicon photomultiplier front-end for the AMIGA detector at the Pierre Auger Observatory

AMIGA (Auger Muons and Infill for the Ground Array) is an upgrade of the Pierre Auger Observatory to complement the study of ultra-high-energy cosmic rays (UHECR) by measuring the muon content of extensive air showers (EAS). It consists of an array of 61 water Cherenkov detectors on a denser spacing in combination with underground scintillation detectors used for muon density measurement. Each detector is composed of three scintillation modules, with 10 m$^2$ detection area per module, buried at 2.3 m depth, resulting in a total detection area of 30 m$^2$. Silicon photomultiplier sensors (SiPM) measure the amount of scintillation light generated by charged particles traversing the modules. In this paper, the design of the front-end electronics to process the signals of those SiPMs and test results from the laboratory and from the Pierre Auger Observatory are described. Compared to our previous prototype, the new electronics shows a higher performance, higher efficiency and lower power consumption, and it has a new acquisition system with increased dynamic range that allows measurements closer to the shower core. The new acquisition system is based on the measurement of the total charge signal that the muonic component of the cosmic ray shower generates in the detector.Comment: 40 pages, 33 figure