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R. Wallny

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DOI: 10.1016/j.nima.2021.165679
2021
Cited 49 times
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.
DOI: 10.1016/j.nima.2015.03.033
2015
Cited 48 times
A 3D diamond detector for particle tracking
A novel device using single-crystal chemical vapour deposited diamond and resistive electrodes in the bulk forming a 3D diamond detector is presented. The electrodes of the device were fabricated with laser assisted phase change of diamond into a combination of diamond-like carbon, amorphous carbon and graphite. The connections to the electrodes of the device were made using a photo-lithographic process. The electrical and particle detection properties of the device were investigated. A prototype detector system consisting of the 3D device connected to a multi-channel readout was successfully tested with 120 GeV protons proving the feasibility of the 3D diamond detector concept for particle tracking applications for the first time.
DOI: 10.1016/j.nima.2012.04.069
2012
Cited 45 times
A visualization of the damage in Lead Tungstate calorimeter crystals after exposure to high-energy hadrons
The anticipated performance of calorimeter crystals in the environment expected after the planned High-Luminosity upgrade of the Large Hadron Collider (HL-LHC) at CERN has to be well understood, before informed decisions can be made on the need for detector upgrades. Throughout the years of running at the HL-LHC, the detectors will be exposed to considerable fluences of fast hadrons that have been shown to cause cumulative transparency losses in Lead Tungstate scintillating crystals. In this study, we present direct evidence of the main underlying damage mechanism. Results are shown from a test that yields a direct insight into the nature of the hadron-specific damage in Lead Tungstate calorimeter crystals exposed to 24 GeV/c protons.
DOI: 10.48550/arxiv.1301.6113
2013
Cited 43 times
Research Proposal for an Experiment to Search for the Decay μ -> eee
We propose an experiment (Mu3e) to search for the lepton flavour violating decay mu+ -> e+e-e+. We aim for an ultimate sensitivity of one in 10^16 mu-decays, four orders of magnitude better than previous searches. This sensitivity is made possible by exploiting modern silicon pixel detectors providing high spatial resolution and hodoscopes using scintillating fibres and tiles providing precise timing information at high particle rates.
DOI: 10.1016/j.nima.2014.02.003
2014
Cited 32 times
Results on damage induced by high-energy protons in LYSO calorimeter crystals
Lutetium-Yttrium Orthosilicate doped with Cerium (LYSO), as a bright scintillating crystal, is a candidate for calorimetry applications in strong ionising-radiation fields and large high-energy hadron fluences are expected at the CERN Large Hadron Collider after the planned High-Luminosity upgrade. There, proton–proton collisions will produce fast hadron fluences up to ~5×1014cm−2 in the large-rapidity regions of the calorimeters. The performance of LYSO has been investigated, after exposure to different fluences of 24 GeV c−1 protons. Measured changes in optical transmission as a function of proton fluence are presented, and the evolution over time due to spontaneous recovery at room temperature is studied. The activation of materials will also be an issue in the described environment. Studies of the ambient dose induced by LYSO and its evolution with time, in comparison with other scintillating crystals, have also been performed through measurements and FLUKA simulations.
DOI: 10.1016/j.nima.2010.04.096
2011
Cited 30 times
Diamond pixel modules
With the commissioning of the LHC in 2010 and upgrades expected in 2015, ATLAS and CMS are planning to upgrade their innermost tracking layers with radiation hard technologies. Chemical Vapor Deposition diamond has been used extensively in beam conditions monitors as the innermost detectors in the highest radiation areas of BaBar, Belle, CDF and all LHC experiments. This material is now being considered as a sensor material for use very close to the interaction region where the most extreme radiation conditions exist. Recently the RD42 collaboration constructed, irradiated and tested polycrystalline and single-crystal chemical vapor deposition diamond sensors to the highest fluences expected at the super-LHC. We present beam test results of chemical vapor deposition diamond up to fluences of 1.8×1016 protons/cm2 illustrating that both polycrystalline and single-crystal chemical vapor deposition diamonds follow a single damage curve. We also present beam test results of irradiated complete diamond pixel modules.
DOI: 10.1016/j.nima.2004.08.133
2005
Cited 41 times
Beam tests of ATLAS SCT silicon strip detector modules
The design and technology of the silicon strip detector modules for the Semiconductor Tracker (SCT) of the ATLAS experiment have been finalised in the last several years. Integral to this process has been the measurement and verification of the tracking performance of the different module types in test beams at the CERN SPS and the KEK PS. Tests have been performed to explore the module performance under various operating conditions including detector bias voltage, magnetic field, incidence angle, and state of irradiation up to 3×1014 protons per square centimetre. A particular emphasis has been the understanding of the operational consequences of the binary readout scheme.
DOI: 10.1016/j.nima.2013.07.015
2013
Cited 25 times
Operational experience, improvements, and performance of the CDF Run II silicon vertex detector
The Collider Detector at Fermilab (CDF) pursues a broad physics program at Fermilab's Tevatron collider. Between Run II commissioning in early 2001 and the end of operations in September 2011, the Tevatron delivered 12 fb-1 of integrated luminosity of p-pbar collisions at sqrt(s)=1.96 TeV. Many physics analyses undertaken by CDF require heavy flavor tagging with large charged particle tracking acceptance. To realize these goals, in 2001 CDF installed eight layers of silicon microstrip detectors around its interaction region. These detectors were designed for 2--5 years of operation, radiation doses up to 2 Mrad (0.02 Gy), and were expected to be replaced in 2004. The sensors were not replaced, and the Tevatron run was extended for several years beyond its design, exposing the sensors and electronics to much higher radiation doses than anticipated. In this paper we describe the operational challenges encountered over the past 10 years of running the CDF silicon detectors, the preventive measures undertaken, and the improvements made along the way to ensure their optimal performance for collecting high quality physics data. In addition, we describe the quantities and methods used to monitor radiation damage in the sensors for optimal performance and summarize the detector performance quantities important to CDF's physics program, including vertex resolution, heavy flavor tagging, and silicon vertex trigger performance.
DOI: 10.22323/1.448.0044
2024
MoTiC: Prototype of a Depleted Monolithic Pixel Detector with Timing
DOI: 10.3929/ethz-b-000271889
2018
Cited 16 times
Observation of ttH Production
The observation of Higgs boson production in association with a top quark-antiquark pair is reported, based on a combined analysis of proton-proton collision data at center-of-mass energies of √s = 7, 8, and 13 TeV, corresponding to integrated luminosities of up to 5.1, 19.7, and 35.9  fb^(-1), respectively. The data were collected with the CMS detector at the CERN LHC. The results of statistically independent searches for Higgs bosons produced in conjunction with a top quark-antiquark pair and decaying to pairs of W bosons, Z bosons, photons, τ leptons, or bottom quark jets are combined to maximize sensitivity. An excess of events is observed, with a significance of 5.2 standard deviations, over the expectation from the background-only hypothesis. The corresponding expected significance from the standard model for a Higgs boson mass of 125.09 GeV is 4.2 standard deviations. The combined best fit signal strength normalized to the standard model prediction is 1.26^(+0.31)_(−0.26).
DOI: 10.1016/j.nima.2007.07.104
2007
Cited 21 times
Status of diamond detectors and their high energy physics application
Particle physics collider experiments at the high energy frontier are being performed today and in the next decade in increasingly harsh radiation environments. New radiation hard technologies, such as particle detectors based on diamond, must be developed. This paper discusses the use of diamond detectors in tracking and beam condition monitoring applications and their survivability in the highest radiation environments. This paper presents recent results of devices based on polycrystalline and single crystal Chemical Vapor Deposition diamond and their tolerance to radiation.
DOI: 10.1088/1748-0221/9/01/c01011
2014
Cited 11 times
The proposed trigger-less TBit/s readout for the Mu3e experiment
The Mu3e experiment searches for charged lepton flavor violation in the rare decay μ→eee with a projected sensitivity of 10−16. A precise measurement of the decay product momenta, decay vertex and time is necessary for background suppression at rates of 109 muons/s. This can be achieved by combining an ultra-lightweight pixel tracker based on HV-MAPS with two timing systems. The trigger-less readout of the detector with three stages of FPGA-boards over multi GBit/s optical links into a GPU filter farm is presented. In this scheme data from all sub-detectors is merged and distributed in time slices to the filter farm.
DOI: 10.1088/1742-6596/587/1/012039
2015
Cited 9 times
Proof-of-principle of a new geometry for sampling calorimetry using inorganic scintillator plates
A novel geometry for a sampling calorimeter employing inorganic scintillators as an active medium is presented. To overcome the mechanical challenges of construction, an innovative light collection geometry has been pioneered, that minimises the complexity of construction. First test results are presented, demonstrating a successful signal extraction. The geometry consists of a sampling calorimeter with passive absorber layers interleaved with layers of an active medium made of inorganic scintillating crystals. Wavelength-shifting (WLS) fibres run along the four long, chamfered edges of the stack, transporting the light to photodetectors at the rear. To maximise the amount of scintillation light reaching the WLS fibres, the scintillator chamfers are depolished. It is shown herein that this concept is working for cerium fluoride (CeF3) as a scintillator. Coupled to it, several different types of materials have been tested as WLS medium. In particular, materials that might be sufficiently resistant to the High- Luminosity Large Hadron Collider radiation environment, such as cerium-doped Lutetium- Yttrium Orthosilicate (LYSO) and cerium-doped quartz, are compared to conventional plastic WLS fibres. Finally, an outlook is presented on the possible optimisation of the different components, and the construction and commissioning of a full calorimeter cell prototype is presented.
DOI: 10.1109/tns.2007.913492
2008
Cited 12 times
Beam Condition Monitoring With Diamonds at CDF
Particle physics collider experiments at the high energy frontier are being performed in increasingly harsh radiation environments. While designing adequate detectors is a challenge in itself, their safe operation relies on fast, radiation-hard beam condition monitoring (BCM) systems to protect these fragile devices from beam accidents. This paper will present a BCM system based on polycrystalline chemical vapor deposition (pCVD) diamond sensors used at the Collider Detector at Fermilab (CDF) experiment operating at Fermilab's Tevatron proton-antiproton synchrotron. We report our operational experience with this system, including the recently commissioned abort system. The system is currently the largest of its kind at a hadron collider. It is similar to designs being pursued at the CERN Large Hadron Collider (LHC) experiments.
DOI: 10.1063/1.5090850
2019
Cited 7 times
Three-dimensional charge transport mapping by two-photon absorption edge transient-current technique in synthetic single-crystalline diamond
We demonstrate the application of two-photon absorption transient current technique to wide bandgap semiconductors. We utilize it to probe charge transport properties of single-crystal Chemical Vapor Deposition (scCVD) diamond. The charge carriers, inside the scCVD diamond sample, are excited by a femtosecond laser through simultaneous absorption of two photons. Due to the nature of two-photon absorption, the generation of charge carriers is confined in space (3-D) around the focal point of the laser. Such localized charge injection allows to probe the charge transport properties of the semiconductor bulk with a fine-grained 3-D resolution. Exploiting spatial confinement of the generated charge, the electrical field of the diamond bulk was mapped at different depths and compared to an X-ray diffraction topograph of the sample. Measurements utilizing this method provide a unique way of exploring spatial variations of charge transport properties in transparent wide-bandgap semiconductors.
DOI: 10.1109/nssmic.2006.355953
2006
Cited 10 times
A Diamond-Based Beam Condition Monitor for the CDF Experiment
We present a Beam Condition Monitor system based on polycrystalline chemical vapor deposition diamond sensors. The system is designed for the Collider Detector at Fermilab (CDF) experiment operating at Fermilab's Tevatron proton-antiproton collider. The system currently represents the largest of its kind to be operated at a hadron collider.
DOI: 10.1109/nssmic.2012.6551112
2012
Cited 5 times
Performance studies of scintillating ceramic samples exposed to ionizing radiation
Scintillating ceramics are a promising, new development for various applications in science and industry. Their application in calorimetry for particle physics experiments is expected to involve an exposure to high levels of ionizing radiation. In this paper, changes in performance have been measured for scintillating ceramic samples of different composition after exposure to penetrating ionizing radiation up to a dose of 38 kGy.
DOI: 10.1088/1748-0221/7/03/p03005
2012
Cited 4 times
The ATLAS SCT grounding and shielding concept and implementation
This paper describes the design and implementation of the grounding and shielding system for the ATLAS SemiConductor Tracker (SCT). The mitigation of electromagnetic interference and noise pickup through power lines is the critical design goal as they have the potential to jeopardize the electrical performance. We accomplish this by adhering to the ATLAS grounding rules, by avoiding ground loops and isolating the different subdetectors. Noise sources are identified and design rules to protect the SCT against them are described. A rigorous implementation of the design was crucial to achieve the required performance. This paper highlights the location, connection and assembly of the different components that affect the grounding and shielding system: cables, filters, cooling pipes, shielding enclosure, power supplies and others. Special care is taken with the electrical properties of materials and joints. The monitoring of the grounding system during the installation period is also discussed. Finally, after connecting more than four thousand SCT modules to all of their services, electrical, mechanical and thermal within the wider ATLAS experimental environment, dedicated tests show that noise pickup is minimised.
DOI: 10.1088/1748-0221/10/07/c07009
2015
Cited 3 times
Beam test results of the dependence of signal size on incident particle flux in diamond pixel and pad detectors
We present results of beam tests of charged particle detectors based on single-crystal and poly-crystalline Chemical Vapor Deposition (CVD) diamond. We measured the signal pulse height dependence on the particle flux. The detectors were tested over a range of particle fluxes from 2 kHz/cm2 to 20 MHz/cm2. The pulse height of the sensors was measured with pad and pixel readout electronics. The pulse height of the non-irradiated single-crystal CVD diamond pad sensors was stable with respect to flux, while the pulse height of irradiated single-crystal CVD diamond pad sensors decreased with increasing particle flux. The pulse height of the non-irradiated single-crystal CVD diamond pixel detectors decreased slightly with increasing particle flux while the pulse height of the irradiated single-crystal CVD diamond pixel detectors decreased significantly with increasing particle flux. The observed sensitivity to flux is similar in both the diamond pad sensors constructed using diamonds from the Pixel Luminosity Telescope (PLT) irradiated during its pilot run in the Compact Muon Solenoid (CMS) detector and in neutron irradiated diamond pad sensors from the same manufacturer irradiated to the same fluence of neutrons. The pulse height for irradiated poly-crystalline CVD diamond pad sensors proved to be stable with respect to particle flux.
DOI: 10.1088/1742-6596/2374/1/012174
2022
Characterization of passive CMOS sensors with RD53A pixel modules
Both the current upgrades to accelerator-based HEP detectors (e.g. ATLAS, CMS) and also future projects (e.g. CEPC, FCC) feature large-area silicon-based tracking detectors. We are investigating the feasibility of using CMOS foundries to fabricate silicon radiation detectors, both for pixels and for large-area strip sensors. A successful proof of concept would open the market potential of CMOS foundries to the HEP community, which would be most beneficial in terms of availability, throughput and cost. In addition, the availability of multi-layer routing of signals will provide the freedom to optimize the sensor geometry and the performance, with biasing structures implemented in poly-silicon layers and MIM-capacitors allowing for AC coupling. A prototyping production of strip test structures and RD53A compatible pixel sensors was recently completed at LFoundry in a 150nm CMOS process. This presentation will focus on the characterization of pixel modules, studying the performance in terms of charge collection, position resolution and hit efficiency with measurements performed in the laboratory and with beam tests. We will report on the investigation of RD53A modules with 25x100 μm 2 cell geometry.
DOI: 10.1088/1748-0221/17/09/c09004
2022
Characterization of irradiated RD53A pixel modules with passive CMOS sensors
We are investigating the feasibility of using CMOS foundries to fabricate silicon detectors, both for pixels and for large-area strip sensors. The availability of multi-layer routing will provide the freedom to optimize the sensor geometry and the performance, with biasing structures in poly-silicon layers and MIM-capacitors allowing for AC coupling. A prototyping production of strip test-structures and RD53A compatible pixel sensors was recently completed at LFoundry in a 150$\,$nm CMOS process. This paper will focus on the characterization of irradiated and non-irradiated pixel modules, composed by a CMOS passive sensor interconnected to a RD53A chip. The sensors are designed with a pixel cell of $25\times100\,\mu \mathrm{m}^2$ in case of DC coupled devices and $50\times50\,\mu \mathrm{m}^2$ for the AC coupled ones. Their performance in terms of charge collection, position resolution, and hit efficiency was studied with measurements performed in the laboratory and with beam tests. The RD53A modules with LFoundry silicon sensors were irradiated to fluences up to $1.0\times10^{16}\,\frac{\mathrm{n}_\mathrm{eq}}{\mathrm{cm}^2}$.
DOI: 10.1016/j.nima.2015.06.036
2015
Erratum to ‘‘A 3D diamond detector for particle tracking’’ [Nuclear Instruments Methods A 786 (2015) 97–104]
The publisher regrets p 98,“The electrode yield, i.e. the fraction of electrodes produced with a continuous conducting path over the thickness of the diamondsample, was estimated by optical and electrical inspection and found to be9273%.”(Was“9270.3%”) p101, Figure 8 of the paper misses the legend, corrected figure: p103, Figure 13b) of the paper misses 3 blue bin entries (corner bins) of the four, only one entry is visible.
2003
Cited 5 times
Electrical test results from ATLAS-SCT end-cap modules
The LHC operating conditions present several challenges to the module performance of the ATLAS Semiconductor Tracker (SCT). This detector consists of four cylindrical barrel layers of silicon strip detectors and of 18 disks in the forward and backward direction. Four dieren t module designs exist, one for the barrel and three (inner, middle and outer) for the rings of the disks. A series of several end-cap module pre-production prototypes of inner, middle and outer types have been built and extensively characterized on single module test benches in the institutes of the collaboration. The scope of this document is to summarize the electrical performance measurements made in laboratory on these end-cap module pre-production prototypes, with special emphasis on the result of electrical tests after irradiation. As summarized in the conclusion, the electrical performance specications are met before irradiation, but are exceeded at 1 fC threshold after an irradiation dose of 1:5:10 14 24 GeV-p/cm 2 , that is a uence corresponding to about half the total dose ATLAS-SCT is foreseen to receive during its life time. After the full uence, the noise occupancy limits could be met by increasing the threshold of the discriminator, with a corresponding expected loss of tracking eciency .
DOI: 10.22323/1.420.0017
2023
MoTIC: Prototype of a Monolithic Particle Tracking Detector with Timing
MoTiC (Monolithic Timing Chip) is a prototype DMAPS Chip that builds on sensor technology developed in the ARCADIA project.The 50 by 50 µm 2 pixels contain a small charge collecting electrode with a very low capacitance surrounded by radiation-hard in-pixel electronics.The chip contains a matrix of 5120 pixels on an area of 3.2 by 4 mm 2 .Each pixel features a trimmable and maskable comparator with a sample and hold circuit for the analog pulse height.Groups of 4 pixels share a TDC situated also in the readout matrix.This work presents the chip design and preliminary results of the hit efficiencies and spatial resolution measured in a first test beam campaign with 4-5 GeV/c electrons conducted at DESY.
DOI: 10.22323/1.420.0095
2023
Progress in Diamond Detectors
Detectors based on Chemical Vapor Deposition (CVD) diamond have been used successfully in Luminosity and Beam Condition Monitors (BCM) in the highest radiation areas of the LHC. Future experiments at CERN will accumulate an order of magnitude larger fluence. As a result, an enormous effort is underway to identify detector materials that can operate under fluences of 1 · $10^{16}$ n cm$^{−2}$ and 1 · $10^{17}$ n cm$^{−2}$. Diamond is one candidate due to its large displacement energy that enhances its radiation tolerance. Over the last 30 years the RD42 collaboration has constructed diamond detectors in CVD diamond with a planar geometry and with a 3D geometry to extend the material’s radiation tolerance. The 3D cells in these detectors have a size of 50 μm×50 μm with columns of 2.6 μm in diameter and 100 μm×150 μm with columns of 4.6 μm in diameter. Here we present the latest beam test results from planar and 3D diamond pixel detectors.
DOI: 10.22323/1.373.0029
2020
Recent progress in CVD diamond detector R&D
We present an overview of the latest developments from RD42 in diamond detector R&D.They include the radiation hardness coefficients for 800 MeV and 24 GeV protons, the hit detection efficiency for two 3D detector prototypes with two different readout chips and a novel method for investigating charge transport in single crystal diamonds.
DOI: 10.48550/arxiv.2111.07797
2021
Characterization of passive CMOS sensors with RD53A pixel modules
Both the current upgrades to accelerator-based HEP detectors (e.g. ATLAS, CMS) and also future projects (e.g. CEPC, FCC) feature large-area silicon-based tracking detectors. We are investigating the feasibility of using CMOS foundries to fabricate silicon radiation detectors, both for pixels and for large-area strip sensors. A successful proof of concept would open the market potential of CMOS foundries to the HEP community, which would be most beneficial in terms of availability, throughput and cost. In addition, the availability of multi-layer routing of signals will provide the freedom to optimize the sensor geometry and the performance, with biasing structures implemented in poly-silicon layers and MIM-capacitors allowing for AC coupling. A prototyping production of strip test structures and RD53A compatible pixel sensors was recently completed at LFoundry in a 150nm CMOS process. This presentation will focus on the characterization of pixel modules, studying the performance in terms of charge collection, position resolution and hit efficiency with measurements performed in the laboratory and with beam tests. We will report on the investigation of RD53A modules with 25x100 mu^2 cell geometry.
DOI: 10.3204/desy-thesis-2001-058
2001
Cited 3 times
A Measurement of the Gluon Distribution in the Proton and of the Strong Coupling Constant $\alpha_s$ from Inclusive Deep-Inelastic Scattering
DOI: 10.1016/j.nima.2005.03.129
2005
Status and performance of the CDF Run II silicon detector
We report our experience commissioning and operating the CDF Run II silicon detector during the first three years of Run II. The performance of the system and its impact on physics analysis are reviewed. As the luminosity delivered by the Tevatron increases, measurable effects of radiation damage have been observed. Studies of charge collection and noise versus applied bias voltage at several different integrated luminosities are presented. These results and their impact on the expected lifetime of the detector are discussed.
DOI: 10.3204/desy-proc-2012-02/331
2012
The LHeC central detector
DOI: 10.2172/1053059
2012
Development of Single Crystal Chemical Vapor Deposition Diamonds for Detector Applications
Diamond was studied as a possible radiation hard technology for use in future high radiation environments. With the commissioning of the LHC expected in 2010, and the LHC upgrades expected in 2015, all LHC experiments are planning for detector upgrades which require radiation hard technologies. Chemical Vapor Deposition (CVD) diamond has now been used extensively in beam conditions monitors as the innermost detectors in the highest radiation areas of BaBar, Belle and CDF and is installed and operational in all LHC experiments. As a result, this material is now being discussed as an alternative sensor material for tracking very close to the interaction region of the super-LHC where the most extreme radiation conditions will exist. Our work addressed the further development of the new material, single-crystal Chemical Vapor Deposition diamond, towards reliable industrial production of large pieces and new geometries needed for detector applications.
2003
Thermal performance of the Atlas SCT forward modules
We describe the thermal design of the Atlas SCT forward modules and their cooling blocks. We report on the performance of the $C_3 F_8$ evaporative cooling system and the blocks alone, then on the performance of an irradiated inner module mounted on two alternative prototype cooling blocks (baseline and PEEK split). Runs are presented at different cooling conditions, representative of those expected to be used in the final experiment. We have also measured thermal runaway, with the module mounted on the PEEK split block and cooled with liquid cooling.
DOI: 10.1016/j.nima.2004.09.001
2005
Design and test of a prototype silicon detector module for ATLAS Semiconductor Tracker endcaps
The ATLAS Semiconductor Tracker (SCT) will be a central part of the tracking system of the ATLAS experiment. The SCT consists of four concentric barrels of silicon detectors as well as two silicon endcap detectors formed by nine disks each. The layout of the forward silicon detector module presented in this paper is based on the approved layout of the silicon detectors of the SCT, their geometry and arrangement in disks, but uses otherwise components identical to the barrel modules of the SCT. The module layout is optimized for excellent thermal management and electrical performance, while keeping the assembly simple and adequate for a large scale module production. This paper summarizes the design and layout of the module and present results of a limited prototype production, which has been extensively tested in the laboratory and testbeam. The module design was not finally adopted for series production because a dedicated forward hybrid layout was pursued.
DOI: 10.1109/nssmic.2014.7431162
2014
Proof-of-principle of a new geometry for sampling calorimetry
A novel geometry for a sampling calorimeter employing inorganic scintillators as an active medium is presented. To overcome the mechanical challenges of construction, an innovative light collection geometry has been pioneered, that minimises the complexity of construction. First test results are presented, demonstrating a successful signal extraction. The geometry consists of a sampling calorimeter with passive absorber layers interleaved with layers of an active medium made of inorganic scintillating crystals. Wavelength-shifting (WLS) fibres run along the four long, chamfered edges of the stack, transporting the light to photodetectors at the rear. To maximise the amount of scintillation light reaching the WLS fibres, the scintillator chamfers are depolished. It is shown herein that this concept is working for cerium fluoride (CeF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ) as a scintillator. Coupled to it, several different types of materials have been tested as WLS medium. In particular, materials that might be sufficiently resistant to the High-Luminosity Large Hadron Collider radiation environment, such as cerium-doped Lutetium-Yttrium Orthosilicate (LYSO) and cerium-doped quartz, are compared to conventional plastic WLS fibres. Finally, an outlook is presented on the possible optimisation of the different components, and the construction and commissioning of a full calorimeter cell prototype is presented.
2015
Was Physik-Studierende von Philosophen lernen
2015
Warum lernen wir das eigentlich
2016
Recent Results from Beam Tests of 3D and Pad pCVD Diamond Detectors
Results from prototypes of a detector using chemical vapor deposited (CVD) diamond with embedded resistive electrodes in the bulk forming a 3D diamond device are presented. A detector system consisting of 3D devices based on poly-crystalline CVD (pCVD) diamond was connected to a multi-channel readout and successfully tested in a 120 GeV/c proton beam at CERN proving for the first time the feasibility of the 3D detector concept in pCVD for particle tracking applications. We also present beam test results on the dependence of signal size on incident particle rate in charged particle detectors based on poly-crystalline CVD diamond. The detectors were tested in a 260 MeV/c pion beam over a range of particle fluxes from 2 kHz/cm$^2$ to 10 MHz/cm$^2$. The pulse height of the sensors was measured with pad readout electronics at a peaking time of 7 ns. Our data from the 2015 beam tests at PSI indicate that the pulse height of poly-crystalline CVD diamond sensor irradiated to $5\times 10^{14}$ $n_{eq}$/cm$^2$ is independent of particle flux at 3% level.
2013
Diamond Sensors in HEP
DOI: 10.3929/ethz-b-000039054
2011
Measurement of Wγ and Zγ production in pp collisions at root s=7 TeV
DOI: 10.1142/9789812778345_0043
2002
THE GLUON DISTRIBUTION AND THE STRONG COUPLING CONSTANT α<sub>S</sub> FROM INCLUSIVE DEEP INELASTIC SCATTERING DATA BY H1
2010
Recent Results from the Tevatron Experiments
DOI: 10.22323/1.282.0276
2017
Recent Results from Beam Tests of 3D and Pad pCVD Diamond Detectors
Results from prototypes of a detector using chemical vapor deposited (CVD) diamond with embedded resistive electrodes in the bulk forming a 3D diamond device are presented.A detector system consisting of 3D devices based on poly-crystalline CVD (pCVD) diamond was connected to a multi-channel readout and successfully tested in a 120 GeV/c proton beam at CERN proving for the first time the feasibility of the 3D detector concept in pCVD for particle tracking applications.We also present beam test results on the dependence of signal size on incident particle rate in charged particle detectors based on poly-crystalline CVD diamond.The detectors were tested in a 260 MeV/c pion beam over a range of particle fluxes from 2 kHz/cm 2 to 10 MHz/cm 2 .The pulse height of the sensors was measured with pad readout electronics at a peaking time of 7 ns.Our data from the 2015 beam tests at PSI indicate that the pulse height of poly-crystalline CVD diamond sensor irradiated to 5 × 10 14 n eq /cm 2 is independent of particle flux at 3% level.
DOI: 10.22323/1.092.0001
2010
Recent Results from Tevatron
DOI: 10.1088/1742-6596/110/4/042032
2008
Single top production at CDF
The CDF Collaboration has analyzed 955 pb-1 of CDF II data collected between March 2002 and February 2006 to search for electroweak single top quark production at the Tevatron. We employ three different analysis techniques to search for a single top signal: multivariate likelihood functions; neural networks; the matrix element analysis technique. The sensitivities to a single top signal at the rate predicted by the Standard Model are 2.1 σ, 2.6 σ and 2.5 σ, respectively. The first two analyses observe a deficit of single top-like events and set upper limits on the production cross section. The matrix element analysis observes a 2.3 σ single top excess and measures a combined t-channel and s-channel cross section of 2.7-1.3+1.5pb.
DOI: 10.3360/dis.2009.224
2009
Detector Design Considerations for the LHeC
DOI: 10.1109/rtc.2007.4382739
2007
Beam Condition Monitoring with Diamonds at CDF
Particle physics collider experiments at the high energy frontier are being performed today and in the next decade in increasingly harsh radiation environments. While designing detector systems adequate for these conditions represents a challenge in itself, their safe operation relies heavily on fast, radiation-hard beam condition monitoring (BCM) systems to protect these expensive devices from beam accidents. The talk will present such a BCM system based on polycrystalline chemical vapor deposition (pCVD) diamond sensors designed for the Collider Detector at Fermilab (CDF) experiment operating at Fermilab's Tevatron proton-antiproton synchrotron. We report our operational experience with this system, which was commissioned in the spring of last year. The system currently represents the largest of its kind to be operated at a hadron collider. It is similar to designs being pursued by the next generation of hadron collider experiments at the Large Hadron Collider (LHC).
2007
Beam Condition Monitoring with Diamonds at CDF
Particle physics collider experiments at the high energy frontier are being performed in increasingly harsh radiation environments. While designing adequate detectors is a challenge in itself, their safe operation relies on fast, radiation-hard beam condition monitoring (BCM) systems to protect these fragile devices from beam accidents. This paper will present a BCM system based on polycrystalline chemical vapor deposition (pCVD) diamond sensors used at the Collider Detector at Fermilab (CDF) experiment operating at Fermilab's Tevatron proton-antiproton synchrotron. We report our operational experience with this system, including the recently commissioned abort system. The system is currently the largest of its kind at a hadron collider. It is similar to designs being pursued at the CERN Large Hadron Collider (LHC) experiments.
DOI: 10.3929/ethz-b-000235748
2018
Search for resonant and nonresonant Higgs boson pair production in the bbℓνℓν final state in proton-proton collisions at s√=13 TeV
DOI: 10.3929/ethz-b-000345484
2018
Search for new long-lived particles at s=13 TeV
DOI: 10.3929/ethz-b-000304146
2018
Performance of reconstruction and identification of leptons decaying to hadrons and in pp collisions at √s=13 TeV
DOI: 10.3929/ethz-b-000242166
2018
Search for Higgsino pair production in collisions at √s=13 TeV in final states with large missing transverse momentum and two Higgs bosons decaying via H→bb̄
DOI: 10.1016/j.nima.2020.164594
2020
Study and parameter optimization of a tuning method for the online calibration of the RD53A readout chip
The RD53A is a prototype of the readout chip that will be used in the Compact Muon Solenoid (CMS) pixel detector after the High-Lumi LHC (HL-LHC) upgrade is complete beyond 2025. A new feature of the chip enables the writing of configuration commands between triggers during operation. This feature can be used to compensate for a detuning of the pixels due to radiation damage or temperature fluctuations over time. This paper studies the efficiency of such a method as well as its side-effects and the dependency on its parameters using an equivalent software implementation.
DOI: 10.3929/ethz-b-000460144
2020
Observation of electroweak production of Wγ with two jets in proton-proton collisions at √s = 13 TeV
DOI: 10.3929/ethz-b-000411794
2020
Search for supersymmetry in pp collisions at root s=13 TeV with 137 fb(-1) in final states with a single lepton using the sum of masses of large-radius jets
DOI: 10.1364/dp.2019.29
2019
Three-dimensional mapping of charge transport by two-photon absorption edge transient-current technique in synthetic single-crystalline diamond
A laser-based two-photon absorption transient-current technique is discussed. In this method free charge carriers are excited in the focal point inside the material. We record the current response of electron and hole drift in an externally applied electric field. Charge collection efficiency, electric field distribution and trapping rates are extracted.
DOI: 10.1109/nssmic.2005.1596446
2006
Single Event Effects and Their Mitigation for the Collider Detector at Fermilab
We present an overview of radiation induced failures and operational experiences from the Collider Detector at Fermilab (CDF). In our summary, we examine single event effects (SEE) in electronics located in and around the detector. We present results of experiments to identify the sources and composition of the radiation and steps to reduce the rate of SEEs in our electronics. Our studies have led to a better, more complete understanding of the radiation environment in a modern hadron collider experiment
2005
Measurement of W and Z production in pp̄ collisions at √s = 1.96 TeV
The standard model predictions for W and Z production are tested using an integrated luminosity of 200 pb of pp collision data collected at the Collider Detector at Fermilab. The cross sections are measured by selecting leptonic decays of the W and Z bosons, and photons with transverse energy E > 7 GeV that are well separated from leptons. The production cross sections and kinematic distributions for the W and Z data are compared to SM predictions. © 2005 The American Physical Society.
DOI: 10.1142/9789812702227_0186
2005
STATUS AND PERFORMANCE OF THE CDF RUN II SILICON DETECTOR
We report our experience commissioning and operating the CDF Run II silicon detector during the first three years of Run II. The performance of the system and its impact on physics analysis are reviewed. As the luminosity delivered by the Tevatron increases, measurable effects of radiation damage have been observed. Studies of charge collection and noise versus applied bias voltage at several different integrated luminosities are presented. These results and their impact on the expected lifetime of the detector are discussed.
2005
Single event effects and their mitigation for the Collider Detector at Fermilab
DOI: 10.1109/nssmic.2003.1351866
2003
The radiation environment and damage in the CDF tracking volume
We present direct measurements of the spatial distribution of ionizing radiation and low energy neutrons (E/sub n/ < 200 keV) inside the tracking volume of the collider detector at Fermilab (CDF). Using data from multiple exposures, the radiation field can be separated into components from beam losses and collisions and can he checked for consistency between the measurements. We compare the radiation measurements with an increase in the leakage currents of the CDF silicon detectors and find reasonable agreement.
2003
Thermal performance measurements on ATLAS-SCT KB forward modules
The thermal design of the KB module is presented. A Finite Elements Analysis (FEA) has been used to finalize the module design. The thermal performance of an outer irradiated KB module has been measured at different cooling conditions. The thermal runaway of the module has been measured. The FEA model has been compared with the measurements and has been used to predict the thermal performance in a realistic SCT scenario.
DOI: 10.5281/zenodo.4637623
2021
CHIPP Roadmap for Research and Infrastructure 2025–2028 and beyond by the Swiss Particle Physics Community
2021
Characterization of passive CMOS sensors with RD53A pixel modules
Both the current upgrades to accelerator-based HEP detectors (e.g. ATLAS, CMS) and also future projects (e.g. CEPC, FCC) feature large-area silicon-based tracking detectors. We are investigating the feasibility of using CMOS foundries to fabricate silicon radiation detectors, both for pixels and for large-area strip sensors. A successful proof of concept would open the market potential of CMOS foundries to the HEP community, which would be most beneficial in terms of availability, throughput and cost. In addition, the availability of multi-layer routing of signals will provide the freedom to optimize the sensor geometry and the performance, with biasing structures implemented in poly-silicon layers and MIM-capacitors allowing for AC coupling. A prototyping production of strip test structures and RD53A compatible pixel sensors was recently completed at LFoundry in a 150nm CMOS process. This presentation will focus on the characterization of pixel modules, studying the performance in terms of charge collection, position resolution and hit efficiency with measurements performed in the laboratory and with beam tests. We will report on the investigation of RD53A modules with 25x100 mu^2 cell geometry.
DOI: 10.22323/1.007.0008
2001
Measurement and QCD interpretation of the deep inelastic ep scattering cross section by H1
RecentH1crosssectionmeasurementsatlowxandQ 2 arereportedaswellas analysisresultsregardingthe behaviourofthe protonstructurefunctionF2(x;Q 2 )andof the longitudinalprotonstructure functionFL(x;Q 2 )atlowxas wellas the measurement of the gluon distribution and of the strong coupling constants.
2001
TESLA: The superconducting electron positron linear collider with an integrated X-ray laser laboratory. Technical design report. Pt. 6: Appendices. Chapter 2: THERA: Electron proton scattering at s**(1/2) approximately 1-TeV