The Mu3e experiment is searching for the charged lepton flavour violating decay\break μ+→e+e−e+, aiming for an ultimate sensitivity of one in 1016 decays. In an environment of up to 109 muon decays ...per second the detector needs to provide precise vertex, time and momentum information to suppress accidental and physics background. The detector consists of cylindrical layers of 50μm thin High Voltage Monolithic Active Pixel Sensors (HV-MAPS) placed in a 1T magnetic field. The measurement of the trajectories of the decay particles allows for a precise vertex and momentum reconstruction. Additional layers of fast scintillating fibre and tile detectors provide sub-nanosecond time resolution. The MuPix8 chip is the first large scale prototype, proving the scalability of the HV-MAPS technology. It is produced in the AMS aH18 180nm HV-CMOS process. It consists of three sub-matrices, each providing an untriggered datastream of more than 10MHits/s. The latest results from laboratory and testbeam characterisation are presented, showing an excellent performance with efficiencies >99.6% and a time resolution better than 10ns achieved with time walk correction.
Charge collection properties of particle detectors made in HV-CMOS technology were investigated before and after irradiation with reactor neutrons. Two different sensor types were designed and ...processed in 180 and 350 nm technology by AMS. Edge-TCT and charge collection measurements with electrons from super(90)Sr source were employed. Diffusion of generated carriers from undepleted substrate contributes significantly to the charge collection before irradiation, while after irradiation the drift contribution prevails as shown by charge measurements at different shaping times. The depleted region at a given bias voltage was found to grow with irradiation in the fluence range of interest for strip detectors at the HL-LHC. This leads to large gains in the measured charge with respect to the one before irradiation. The increase of the depleted region was attributed to removal of effective acceptors. The evolution of depleted region with fluence was investigated and modeled. Initial studies show a small effect of short term annealing on charge collection.
The MuPix Telescope is a particle tracking telescope, optimized for tracking low momentum particles at high rates. It is based on the novel High-Voltage Monolithic Active Pixel Sensors (HV-MAPS), ...designed for the Mu3e tracking detector. The telescope represents a first application of the HV-MAPS technology and also serves as test bed of the Mu3e readout chain. The telescope consists of up to eight layers of the newest prototypes, the MuPix7 sensors, which send self-triggered data via fast serial links to FPGAs, where the data is time-ordered and sent to the PC. A particle hit rate of 1 MHz per layer could be processed. Online tracking is performed with a subset of the incoming data. The general concept of the telescope, chip architecture, readout concept and online reconstruction are described. The performance of the sensor and of the telescope during test beam measurements are presented.
Characterization results of a HVCMOS sensor for ATLAS Ehrler, F.; Benoit, M.; Dannheim, D. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
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High-voltage CMOS (HVCMOS) pixel sensors are depleted monolithic active n-in-p diode pixel sensors implemented in standard commercial CMOS processes. A substantial part of the readout electronics is ...placed inside each pixel. Due to high radiation tolerance and fast signal generation (Perić, 2017) 1, HVCMOS sensors are going to be used (Mu3e, PSI) or are suggested for usage (ATLAS and CLIC, CERN) in High Energy Physics experiments. In this article characterization results of the ATLASpix_Simple sensor are presented. Special attention was paid to the novel time-over-threshold (ToT) measurement with adaptive sampling rate.
•The ATLASpix_Simple monolithic sensor works as expected with an efficiency of >99%.•Time-over-Threshold was measured with a novel adaptive sampling method.•It has been shown that Time-over-Threshold can be used to compensate for time walk.
Let −∞<a<b<∞. If f is concave on a,b and ψ′ is convex on the interval of integration, then Wulbert proved that 1δ+−δ−∫δ−δ+ψ(u)du≥1b−a∫abψ(f(x))dx, where δ−=f̄−3(‖f‖22−(f̄)2)1/2, ...δ+=f̄+3(‖f‖22−(f̄)2)1/2, f̄=1b−a∫abf(x)dx and ‖f‖p=(1b−a∫ab|f(x)|pdx)1/p. We define new Cauchy type means using a functional defined via above inequality and give some related results as applications.
The vertex detector at the proposed CLIC multi-TeV linear e+e− collider must have minimal material content and high spatial resolution, combined with accurate time-stamping to cope with the expected ...high rate of beam-induced backgrounds. One of the options being considered is the use of active sensors implemented in a commercial high-voltage CMOS process, capacitively coupled to hybrid pixel ASICs. A prototype of such an assembly, using two custom designed chips (CCPDv3 as active sensor glued to a CLICpix readout chip), has been characterised both in the lab and in beam tests at the CERN SPS using 120GeV/c positively charged hadrons. Results of these characterisation studies are presented both for single and dual amplification stages in the active sensor, where efficiencies of greater than 99% have been achieved at −60V substrate bias, with a single hit resolution of 6.1μm. Pixel cross-coupling results are also presented, showing the sensitivity to placement precision and planarity of the glue layer.
This paper reports on the characterisation with Transient Current Technique measurements of the charge collection and depletion depth of a radiation-hard high-voltage CMOS pixel sensor produced at ...ams AG. Several substrate resistivities were tested before and after proton irradiation with two different sources: the 24 GeV Proton Synchrotron at CERN and the 16.7 MeV Cyclotron at Bern Inselspital.
Mu3e is a novel experiment searching for charged lepton flavor violation in the rare decay mu arrowright eee. In order to reduce background by up to 16 orders of magnitude, decay vertex position, ...decay time and particle momenta have to be measured precisely. A pixel tracker based on 50 mum thin high voltage monolithic active pixel sensors (HV-MAPS) in a magnetic field will deliver precise vertex and momentum information. Test beam results like an excellent efficiency of >99.5% and a time resolution of better than 16.6 ns obtained with the MuPix HV-MAPS chip developed for the Mu3e pixel tracker are presented.
Monolithic Active Pixel Sensors (MAPS) produced in High Voltage CMOS (HV-CMOS) technology are being considered for High Energy Physics applications due to the ease of production and the reduced ...costs. Such technology is especially appealing when large areas to be covered and material budget are concerned. This is the case of the outermost pixel layers of the future ATLAS tracking detector for the High Luminosity LHC. For experiments at hadron colliders, radiation hardness is a key requirement which is not fulfilled by standard CMOS sensor designs that collect charge by diffusion. This issue has been addressed by depleted active pixel sensors in which electronics are embedded into a large deep implantation ensuring uniform charge collection by drift. Very first small prototypes of hybrid depleted active pixel sensors have already shown a radiation hardness compatible with the ATLAS requirements. Nevertheless, to compete with the present hybrid solutions a further reduction in costs achievable by a fully monolithic design is desirable. The H35DEMO is a large electrode full reticle demonstrator chip produced in AMS 350 nm HV-CMOS technology by the collaboration of Karlsruher Institut für Technologie (KIT), Institut de F'isica d'Altes Energies (IFAE), University of Liverpool and University of Geneva. It includes two large monolithic pixel matrices which can be operated standalone. One of these two matrices was characterised at beam test before and after irradiation with protons and neutrons. Results demonstrated the feasibility of producing radiation hard large area fully monolithic pixel sensors in HV-CMOS technology. H35DEMO chips with a substrate resistivity of 200 Ωcm} irradiated with neutrons showed a radiation hardness up to a fluence of 1×1015 neq/cm2 with a hit efficiency of about 99% and a noise occupancy lower than 10-6 hits in a LHC bunch crossing of 25 ns at 150 V.
This paper describes several monolithic pixel detector designs implemented in a high-voltage CMOS technology. The total size of all chips is 1cm×1cm. The pixel matrices are distinguished by the ...readout cell type, the pixel type and the pixel address multiplexing. Design details and first measurement results are described.
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