624 research outputs found
Characterisation of AMS H35 HV-CMOS monolithic active pixel sensor prototypes for HEP applications
Monolithic active pixel sensors 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 HL-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 f\"ur 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 has been 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 cm irradiated with neutrons showed a radiation
hardness up to a fluence of ncm with a hit efficiency of
about 99% and a noise occupancy lower than hits in a LHC bunch
crossing of 25ns at 150V
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 pixelsâthe 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
An experiment for electron-hadron scattering at the LHC
Novel considerations are presented on the physics, apparatus and accelerator
designs for a future, luminous, energy frontier electron-hadron ()
scattering experiment at the LHC in the thirties for which key physics topics
and their relation to the hadron-hadron HL-LHC physics programme are discussed.
Demands are derived set by these physics topics on the design of the LHeC
detector, a corresponding update of which is described. Optimisations on the
accelerator design, especially the interaction region (IR), are presented.
Initial accelerator considerations indicate that a common IR is possible to be
built which alternately could serve and collisions while other
experiments would stay on in either condition. A forward-backward
symmetrised option of the LHeC detector is sketched which would permit
extending the LHeC physics programme to also include aspects of hadron-hadron
physics. The vision of a joint and physics experiment is shown to
open new prospects for solving fundamental problems of high energy heavy-ion
physics including the partonic structure of nuclei and the emergence of
hydrodynamics in quantum field theory while the genuine TeV scale DIS physics
is of unprecedented rank.Comment: 27 pages, 24 figures, 6 tables; to appear in Eur. Phys. J.
Test beam measurement of ams H35 HV-CMOS capacitively coupled pixel sensor prototypes with high-resistivity substrate
In the context of the studies of the ATLAS High Luminosity LHC programme, radiation tolerant pixel detectors in CMOS technologies are investigated. To evaluate the effects of substrate resistivity on CMOS sensor performance, the H35DEMO demonstrator, containing different diode and amplifier designs, was produced in ams H35 HV-CMOS technology using four different substrate resistivities spanning from 80-1000 ohm cm. A glueing process using a high-precision flip-chip machine was developed in order to capacitively couple the sensors to FE-I4 Readout ASIC using a thin layer of epoxy glue with good uniformity over a large surface. The resulting assemblies were measured in beam test at the Fermilab Test Beam Facilities with 120 GeV protons and CERN SPS H8 beamline using 180 GeV pions. The in-time efficiency and tracking properties measured for the different sensor types are shown to be compatible with the ATLAS ITk requirements for its pixel sensors
Technical design of the phase I Mu3e experiment
The Mu3e experiment aims to find or exclude the lepton flavour violating decay ÎŒâeee at branching fractions above 10â16. 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 2â
10â15. 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 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
Study of charmonium decays to in the channels
A study of the and decays
is performed using proton-proton collisions at center-of-mass energies of 7, 8
and 13 TeV at the LHCb experiment. The invariant mass spectra from
both decay modes reveal a rich content of charmonium resonances. New precise
measurements of the and resonance parameters are
performed and branching fraction measurements are obtained for decays to
, , and resonances. In particular, the
first observation and branching fraction measurement of is reported as well as first measurements of the
and branching fractions. Dalitz plot analyses of
and decays are performed. A
new measurement of the amplitude and phase of the -wave as functions
of the mass is performed, together with measurements of the
, and parameters. Finally, the branching
fractions of decays to resonances are also measured.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-051.html (LHCb
public pages
Studies of and production in and Pb collisions
The production of and mesons is studied in proton-proton and
proton-lead collisions collected with the LHCb detector. Proton-proton
collisions are studied at center-of-mass energies of and ,
and proton-lead collisions are studied at a center-of-mass energy per nucleon
of . The studies are performed in center-of-mass rapidity
regions (forward rapidity) and
(backward rapidity) defined relative to the proton beam direction. The
and production cross sections are measured differentially as a function
of transverse momentum for and , respectively. The differential cross sections are used to
calculate nuclear modification factors. The nuclear modification factors for
and mesons agree at both forward and backward rapidity, showing
no significant evidence of mass dependence. The differential cross sections of
mesons are also used to calculate cross section ratios,
which show evidence of a deviation from the world average. These studies offer
new constraints on mass-dependent nuclear effects in heavy-ion collisions, as
well as and meson fragmentation.Comment: All figures and tables, along with machine-readable versions and any
supplementary material and additional information, are available at
https://lhcbproject.web.cern.ch/Publications/p/LHCb-PAPER-2023-030.html (LHCb
public pages
Measurement of lepton universality parameters in and decays
A simultaneous analysis of the and decays is performed to test muon-electron universality in
two ranges of the square of the dilepton invariant mass, . The measurement
uses a sample of beauty meson decays produced in proton-proton collisions
collected with the LHCb detector between 2011 and 2018, corresponding to an
integrated luminosity of . A sequence of multivariate
selections and strict particle identification requirements produce a higher
signal purity and a better statistical sensitivity per unit luminosity than
previous LHCb lepton universality tests using the same decay modes. Residual
backgrounds due to misidentified hadronic decays are studied using data and
included in the fit model. Each of the four lepton universality measurements
reported is either the first in the given interval or supersedes previous
LHCb measurements. The results are compatible with the predictions of the
Standard Model.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-045.html (LHCb
public pages
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