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a b s t r a c t High-voltage particle detectors in commercial CMOS technologies are a detector family that allows implementation of low-cost, thin and radiation-tolerant detectors with a high time resolution. In the R/D phase of the development, a radiation tolerance of 10 15 n eq =cm 2 , nearly 100% detection efficiency and a spatial resolution of about 3 μm were demonstrated. Since 2011 the HV detectors have first applications: the technology is presently the main option for the pixel detector of the planned Mu3e experiment at PSI (Switzerland). Several prototype sensors have been designed in a standard 180 nm HV CMOS process and successfully tested. Thanks to its high radiation tolerance, the HV detectors are also seen at CERN as a promising alternative to the standard options for ATLAS upgrade and CLIC. In order to test the concept, within ATLAS upgrade R/D, we are currently exploring an active pixel detector demonstrator HV2FEI4; also implemented in the 180 nm HV process.

Mu3e is a novel experiment searching for charged lepton flavor violation in the rare decay µ + → e + e − e + . Decay vertex position, decay time and particle momenta have to be precisely measured in order to reject both accidental and physics background. A silicon pixel tracker based on 50 µm thin high voltage monolithic active pixel sensors (HV-MAPS) in a 1 T solenoidal magnetic field provides precise vertex and momentum information. The MuPix chip combines pixel sensor cells with integrated analog electronics and a periphery with a complete digital readout. The MuPix7 is the first HV-MAPS prototype implementing all functionalities of the final sensor including a readout state machine and high speed serialization with 1.25 Gbit/s data output, allowing for a streaming readout in parallel to the data taking. The observed efficiency of the MuPix7 chip including the full readout system is ≥ 99% in a high rate test beam.

The MuPix7 chip is a monolithic HV-CMOS pixel chip, thinned down to 50 µm. It provides continuous self-triggered, non-shuttered readout at rates up to 30 Mhits/chip of 3 × 3 mm 2 active area and a pixel size of 103 × 80 µm 2 . The hit efficiency depends on the chosen working point. Settings with a power consumption of 300 mW/ cm 2 allow for a hit efficiency > 99.5%. A time resolution of 14.2 ns (Gaussian sigma) is achieved. Latest results from 2016 test beam campaigns are shown.

The development of EUDAQ started as part of the EU-funded Joint Research Activity of the EUDET project "Test Beam Infrastructure" [3,4] in 2005. The goal of the project was the development of a high-precision pixel beam telescope for investigations of the tracking performance of sensor devices. To make this beam telescope a versatile tool for a broad user base and a wide variety of devices, an easy integration strategy for devices under test (DUT) and its DAQ was a priority from the beginning of the project [5]. The interface that was considered to be the most flexible for the user consisted of two separate layers: on the hardware level, the different DAQ systems were to be synchronised using a simple trigger-busy communication protocol; on the software level, the full integration of the DUT into EUDAQ was foreseen as the preferred approach, yet was kept optional.This approach determined the core architecture of EUDAQ [6] which remains today: centralised but distributed core components that communicate with so-called Producers via a custom TCP/IPbased protocol. In this scheme, the latter are responsible for implementing an interface to the individual hardware components, controlling the devices' states and feeding the data into the central data collection unit. Both the beam telescope detector planes and the DUT use the same interface, thus making the framework flexible and independent of any specific hardware. The framework architecture is described in more detail in Section 2.Historically, the most prominent application of EUDAQ is the DAQ of the EUDET-type pixel beam telescopes [7]. They are based on Mimosa26 sensors [8] as telescope planes and a custom-designed trigger logic unit (TLU), the EUDET TLU [9]. Today, the EUDET-type beam telescopes are accessible as common infrastructure at test beam facilities all over the world. This broad availability of beam telescopes combined with the ease-of-use, extensive documentation and user-focus of EUDAQ outlined in Section 3 has led to a large number of successful EUDAQ-based test beam campaigns in the last decade: in Section 4, eleven applications from a wide range of communities are described in more detail.Since the early days of mostly user-driven development, EUDAQ has been moved to a collaborative development model with several active contributors. New features as well as many behind-the-scenes changes such as continuous integration methods paved the road towards the second major version of EUDAQ as briefly outlined in Section 5.