This textbook provides an accessible yet comprehensive introduction to detectors in particle physics. It emphasises the core physics principles, enabling a deeper understanding of the subject for ...further and more advanced studies. In addition to the discussion of the underlying detector physics, another aspiration of this book is to introduce the reader to practically important aspects of particle detectors, like electronics, alignment, calibration, and simulation of particle detectors. Case studies of the various applications of detectors in particle physics are provided.
The primary audience is graduate students in particle or nuclear physics, in addition to advanced undergraduate students in physics.
Key Features:
Provides an accessible yet thorough discussion of the basic physics principles needed to understand how particle detectors work.
Presents applications of the basic physics concepts to examples of modern detectors.
Discusses practically important aspects like electronics, alignment, calibration and simulation of particle detectors.
Contains exercises for each chapter to further understanding.
Both authors have a long experience in teaching undergraduate and graduate students at the University of Oxford.
Evaporative cooling in ATLAS—Present and future Viehhauser, Georg
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2011, Letnik:
628, Številka:
1
Journal Article
Recenzirano
The ATLAS Inner Detector cooling system is the largest evaporative cooling system used in High Energy Physics today. During the installation and commissioning of this system many lessons had to be ...learned, but the system is now operating reliably, although it does not achieve all original design specifications in all its circuits.
We have re-evaluated the requirements for the cooling system for the barrel SCT, in particular for the evaporation temperature, over the full ATLAS operational lifetime. We find that the critical requirement is for thermal stability at the end of LHC operation. To predict this we have developed a simple thermal model of the detector modules which yields analytical expressions to evaluate the results of changes in the operating conditions. After a comparison of the revised requirements and the actual present cooling system performance we will discuss various modifications to the system which will be required for future operation.
In parallel we are developing a cooling system for the ATLAS phase II upgrade (sLHC) tracker, for which a set of requirements has been specified. Two technologies, based on different coolants, fluorocarbons or CO
2, are being pursued.
Light-by-light scattering (γγ -> γγ) is a quantum-mechanical process that is forbidden in the classical theory of electrodynamics. This reaction is accessible at the Large Hadron Collider thanks to ...the large electromagnetic field strengths generated by ultra-relativistic colliding lead ions. Using 480 μb-1 of lead-lead collision data recorded at a centre-of-mass energy per nucleon pair of 5.02 TeV by the ATLAS detector, here we report evidence for light-by-light scattering. A total of 13 candidate events were observed with an expected background of 2.6 ± 0.7 events. After background subtraction and analysis corrections, the fiducial cross-section of the process Pb + Pb (γγ) -> Pb(∗) + Pb(∗) γγ, for photon transverse energy ET > 3 GeV, photon absolute pseudorapidity |η| < 2.4, diphoton invariant mass greater than 6 GeV, diphoton transverse momentum lower than 2 GeV and diphoton acoplanarity below 0.01, is measured to be 70 ± 24 (stat.) ± 17 (syst.) nb, which is in agreement with the standard model predictions.
A search for the associated production of the Higgs boson with a top quark pair (tt¯H) is reported. The search is performed in multilepton final states using a data set corresponding to an integrated ...luminosity of 36.1 fb−1 of proton-proton collision data recorded by the ATLAS experiment at a center-of-mass energy s=13 TeV at the Large Hadron Collider. Higgs boson decays to WW*, ττ, and ZZ* are targeted. Seven final states, categorized by the number and flavor of charged-lepton candidates, are examined for the presence of the Standard Model Higgs boson with a mass of 125 GeV and a pair of top quarks. An excess of events over the expected background from Standard Model processes is found with an observed significance of 4.1 standard deviations, compared to an expectation of 2.8 standard deviations. The best fit for the tt¯H production cross section is σ(tt¯H)=790−210+230 fb, in agreement with the Standard Model prediction of 507−50+35 fb. The combination of this result with other tt¯H searches from the ATLAS experiment using the Higgs boson decay modes to bb¯, γγ and ZZ*→4ℓ, has an observed significance of 4.2 standard deviations, compared to an expectation of 3.8 standard deviations. This provides evidence for the tt¯H production mode.
Thermo-electrical modelling of the ATLAS ITk Strip Detector Beck, Graham; Brendlinger, Kurt; Chen, Yu-Heng ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
07/2020, Letnik:
969
Journal Article
Recenzirano
Odprti dostop
In this paper we discuss the use of linked thermal and electrical network models to predict the behaviour of a complex silicon detector system. We use the silicon strip detector for the ATLAS ...Phase-II upgrade to demonstrate the application of such a model and its performance. With this example, a thermo-electrical model is used to test design choices, validate specifications, predict key operational parameters such as cooling system requirements, and optimize operational aspects like the temperature profile over the lifetime of the experiment. The model can reveal insights into the interplay of conditions and components in the silicon module, and it is a valuable tool for estimating the headroom to thermal runaway, all with very moderate computational effort.
Analytic model of thermal runaway in silicon detectors Beck, Graham; Viehhauser, Georg
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
06/2010, Letnik:
618, Številka:
1
Journal Article
Recenzirano
Usually the thermal behavior of silicon detectors is predicted from numerical methods (FEA or finite difference methods). However, these results are specific to the modelled structure and the input ...parameter set. Here we pursue the complementary, analytic, approach which offers some general (if approximate) results that allow relatively simple extrapolation of the performance of a specific detector design.
We present simple network models to calculate analytically the limit of thermal stability in silicon detectors. In particular we use a minimal model, which ignores the thermal resistance within the sensor in comparison with the off-detector resistance. We further discuss an extension of this model to study the effects of a finite sensor thermal resistance.
A measurement of the production processes of the recently discovered Higgs boson is performed in the two-photon final state using 4.5 fb super(-1) of proton-proton collisions data at radicals = 7 TeV ...and 20.3 fb super(-1) at radicals = 8 TeV collected by the ATLAS detector at the Large Hadron Collider. The number of observed Higgs boson decays to diphotons divided by the corresponding Standard Model prediction, called the signal strength, is found to be mu = 1.17 + or - 0.27 at the value of the Higgs boson mass measured by ATLAS, m sub(H) = 125.4 GeV. The analysis is optimized to measure the signal strengths for individual Higgs boson production processes at this value of m sub(H). They are found to be mu sub(ggF) = 1.32 + or - 0.38, mu sub(VBF) = 0.8 + or - 0.7, mu sub(WH) = 1.0 + or - 1.6, (ProQuest: Formulae and/or non-USASCII text omitted), and (ProQuest: Formulae and/or non-USASCII text omitted), for Higgs boson production through gluon fusion, vector-boson fusion, and in association with a W or Z boson or a top-quark pair, respectively. Compared with the previously published ATLAS analysis, the results reported here also benefit from a new energy calibration procedure for photons and the subsequent reduction of the systematic uncertainty on the diphoton mass resolution. No significant deviations from the predictions of the Standard Model are found.
This paper presents the electron and photon energy calibration achieved with the ATLAS detector using about 25 fb
-
1
of LHC proton–proton collision data taken at centre-of-mass energies of
s
=
7
and ...8 TeV. The reconstruction of electron and photon energies is optimised using multivariate algorithms. The response of the calorimeter layers is equalised in data and simulation, and the longitudinal profile of the electromagnetic showers is exploited to estimate the passive material in front of the calorimeter and reoptimise the detector simulation. After all corrections, the
Z
resonance is used to set the absolute energy scale. For electrons from
Z
decays, the achieved calibration is typically accurate to 0.05 % in most of the detector acceptance, rising to 0.2 % in regions with large amounts of passive material. The remaining inaccuracy is less than 0.2–1 % for electrons with a transverse energy of 10 GeV, and is on average 0.3 % for photons. The detector resolution is determined with a relative inaccuracy of less than 10 % for electrons and photons up to 60 GeV transverse energy, rising to 40 % for transverse energies above 500 GeV.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
(ProQuest: ... denotes formulae and/or non-USASCII text omitted)The final ATLAS Run 1 measurements of Higgs boson production and couplings in the decay channel H arrow right ZZ* arrow right l ...super(+) l super(-) l' super(+) l' super(-), where l, l' = e or mu , are presented. These measurements were performed using pp collision data corresponding to integrated luminosities of 4.5 and 20.3 fb super(-1) at center-of-mass energies of 7 and 8 TeV, respectively, recorded with the ATLAS detector at the LHC. The H arrow right ZZ* arrow right 4l signal is observed with a significance of 8.1 standard deviations, with an expectation of 6.2 standard deviations, at m sub(H) = 125.36 GeV, the combined ATLAS measurement of the Higgs boson mass from the H arrow right gamma gamma and H arrow right ZZ* arrow right 4l channels. The production rate relative to the Standard Model expectation, the signal strength, is measured in four different production categories in the H arrow right ZZ* arrow right 4l channel. The measured signal strength, at this mass, and with all categories combined, is ... The signal strength for Higgs boson production in gluon fusion or in association with tt or bb pairs is found to be ..., while the signal strength for vector-boson fusion combined with WH/ZH associated production is found to be ...
A search for supersymmetric partners of gluons and quarks is presented, involving signatures with jets and either two isolated leptons (electrons or muons) with the same electric charge, or at least ...three isolated leptons. A data sample of proton-proton collisions at root s = 13 TeV recorded with the ATLAS detector at the Large Hadron Collider between 2015 and 2018, corresponding to a total integrated luminosity of 139 fb(-1), is used for the search. No significant excess over the Standard Model expectation is observed. The results are interpreted in simplified supersymmetric models featuring both R-parity conservation and R-parity violation, raising the exclusion limits beyond those of previous ATLAS searches to 1600 GeV for gluino masses and 750 GeV for bottom and top squark masses in these scenarios.
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