954 research outputs found
Irradiation study of a fully monolithic HV-CMOS pixel sensor design in AMS 180 nm
High-Voltage Monolithic Active Pixel Sensors (HV-MAPS) based on the 180 nm
HV-CMOS process have been proposed to realize thin, fast and highly integrated
pixel sensors. The MuPix7 prototype, fabricated in the commercial AMS H18
process, features a fully integrated on-chip readout, i.e. hit-digitization,
zero suppression and data serialization. It is the first fully monolithic
HV-CMOS pixel sensor that has been tested for the use in high irradiation
environments like HL-LHC. We present results from laboratory and test beam
measurements of MuPix7 prototypes irradiated with neutrons (up to
) and protons (up to ) and compare the performance with non-irradiated
sensors. Efficiencies well above 90 % at noise rates below 200 Hz per pixel are
measured. A time resolution better than 22 ns is measured for all tested
settings and sensors, even at the highest irradiation fluences. The data
transmission at 1.25 Gbit/s and the on-chip PLL remain fully functional
The MuPix Telescope: A Thin, high Rate Tracking Telescope
The MuPix Telescope is a particle tracking telescope, optimized for tracking
low momentum particles and 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 data self-triggered 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.Comment: Proceedings TWEPP 2016, 8 pages, 7 figure
MuPix7 - A fast monolithic HV-CMOS pixel chip for Mu3e
The MuPix7 chip is a monolithic HV-CMOS pixel chip, thinned down to 50 \mu m.
It provides continuous self-triggered, non-shuttered readout at rates up to 30
Mhits/chip of 3x3 mm^2 active area and a pixel size of 103x80 \mu m^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.Comment: Proceedingsfor the PIXEL2016 conference, submitted to JINST A
dangling reference has been removed from this version, no other change
The Mu3e Data Acquisition
The Mu3e experiment aims to find or exclude the lepton flavor violating decay μ+→e+e−e+ with a sensitivity of one in 10 16 muon decays. The first phase of the experiment is currently under construction at the Paul Scherrer Institute (PSI, Switzerland), where beams with up to 10 8 muons per second are available. The detector will consist of an ultra-thin pixel tracker made from High-Voltage Monolithic Active Pixel Sensors (HV-MAPS) , complemented by scintillating tiles and fibers for precise timing measurements. The experiment produces about 100Gbit/s of zero-suppressed data, which are transported to a filter farm using a network of field programmable gate arrays (FPGAs) and fast optical links. On the filter farm, tracks and three-particle vertices are reconstructed using highly parallel algorithms running on graphics processing units, leading to a reduction of the data to 100 Mbyte/s for mass storage and offline analysis. This article introduces the system design and hardware implementation of the Mu3e data acquisition and filter farm
Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector
Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente
Technical design of the phase I Mu3e experiment
The Mu3e experiment aims to find or exclude the lepton flavour violating
decay at branching fractions above . 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 . 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
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
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
Combination of the W boson polarization measurements in top quark decays using ATLAS and CMS data at root s=8 TeV
The combination of measurements of the W boson polarization in top quark decays performed by the ATLAS and CMS collaborations is presented. The measurements are based on proton-proton collision data produced at the LHC at a centre-of-mass energy of 8 TeV, and corresponding to an integrated luminosity of about 20 fb(-1)for each experiment. The measurements used events containing one lepton and having different jet multiplicities in the final state. The results are quoted as fractions of W bosons with longitudinal (F-0), left-handed (F-L), or right-handed (F-R) polarizations. The resulting combined measurements of the polarization fractions are F-0= 0.693 +/- 0.014 and F-L= 0.315 +/- 0.011. The fractionF(R)is calculated from the unitarity constraint to be F-R=-0.008 +/- 0.007. These results are in agreement with the standard model predictions at next-to-next-to-leading order in perturbative quantum chromodynamics and represent an improvement in precision of 25 (29)% for F-0(F-L) with respect to the most precise single measurement. A limit on anomalous right-handed vector (V-R), and left- and right-handed tensor (g(L), g(R)) tWb couplings is set while fixing all others to their standard model values. The allowed regions are [-0.11,0.16] for V-R, [-0.08,0.05] for g(L), and [-0.04,0.02] for g(R), at 95% confidence level. Limits on the corresponding Wilson coefficients are also derived.Peer reviewe
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