Ageing in the LHCb outer tracker: Aromatic hydrocarbons and wire cleaning Tuning, N.; Bachmann, S.; Bagaturia, Y. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2011, Letnik:
656, Številka:
1
Journal Article
Recenzirano
The LHCb Outer Tracker straw tubes have shown to suffer from gain loss after irradiation in the laboratory at moderate intensities. Under irradiation an insulating layer is formed on the anode wire. ...The ageing is caused by contamination of the counting gas due to outgassing of the plastifier di-isopropyl-naphthalene in araldite AY103-1 used at construction. This paper presents irradiation results with and without the plastifier, together with the mass spectra of the glue samples. In addition, the effects of wire heating and large currents are presented.
High-energy-density physics is the field of physics concerned with studying matter at extremely high temperatures and densities. Such conditions produce highly nonlinear plasmas, in which several ...phenomena that can normally be treated independently of one another become strongly coupled. The study of these plasmas is important for our understanding of astrophysics, nuclear fusion and fundamental physics-however, the nonlinearities and strong couplings present in these extreme physical systems makes them very difficult to understand theoretically or to optimize experimentally. Here we argue that machine learning models and data-driven methods are in the process of reshaping our exploration of these extreme systems that have hitherto proved far too nonlinear for human researchers. From a fundamental perspective, our understanding can be improved by the way in which machine learning models can rapidly discover complex interactions in large datasets. From a practical point of view, the newest generation of extreme physics facilities can perform experiments multiple times a second (as opposed to approximately daily), thus moving away from human-based control towards automatic control based on real-time interpretation of diagnostic data and updates of the physics model. To make the most of these emerging opportunities, we suggest proposals for the community in terms of research design, training, best practice and support for synthetic diagnostics and data analysis.
Abstract
Experimental developments in neutrino telescopes are drastically improving their ability to constrain the annihilation cross-section of dark matter. In this paper, we employ an angular power ...spectrum analysis method to probe the galactic and extra-galactic dark matter signals. First we derive projections for a next generation of neutrino telescope that is inspired by KM3NeT. We emphasise that such analysis is much less sensitive to the choice of dark matter density profile. Remarkably, the projected sensitivity is improved by more than an order of magnitude with respect to the existing limits obtained by assuming the Burkert dark matter density profile describing the galactic halo.
Second, we analyse minimal extensions to the Standard Model that will be maximally probed by the next generation of neutrino telescopes. As benchmark scenarios, we consider Dirac dark matter in s- and t-channel models with vector and scalar mediators. We follow a global approach by examining all relevant complementary experimental constraints.
We find that neutrino telescopes will be able to competitively probe significant portions of parameter space. Interestingly, the anomaly-free L_μ-L_τ model can potentially be explored in regions where the relic abundance is achieved through freeze-out mechanism.
The front end electronics of the LHCb straw tube tracker Berkien, A.; Deppe, H.; Dupree, T. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2010, Letnik:
617, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The LHCb experiment is a single-arm spectrometer, designed to study
B-hadron decays at the Large Hadron Collider (LHC). It is crucial to accurately and efficiently track the charged decay products ...with the Outer Tracker straw tube detector, in the high-density particle environment of the LHC. The Outer Tracker Front End electronics provide the precise (0.5
ns) drift-time measurement, at an average occupancy of 5% and at a 1
MHz trigger rate. The tracking procedure requires high-efficiency, while at the same time putting stringent limits on the noise level. The mass production and installation of 450 fully operational Front End boxes is completed. Quality checks have been performed at several stages, at the level of individual boards and at the global level with dedicated test systems mimicking the real detector and capable of simulating all the readout functionalities. An excellent overall threshold uniformity is achieved with low noise levels.
Abstract
The next generation of neutrino telescopes will feature unprecedented sensitivities in the detection of neutrinos. Here we study the capabilities of a large-scale neutrino telescope, like ...the fully-operating KM3NeT experiment in the near future, for detecting dark matter annihilation signals from the Galactic Centre.
We consider both ORCA and ARCA detectors, covering dark matter masses from a few GeV to 100 TeV. We obtain the sensitivities with a maximum-likelihood analysis method and present them as upper limits in the thermally averaged annihilation cross-section into Standard Model fermions. Our projections show that the sensitivity of such a neutrino telescope can reach the thermal relic line for
m
χ
≳ 1 TeV and for
m
χ
≃ few GeV, for the NFW dark matter density profile. This demonstrates that ORCA- and ARCA-like detectors will be able to perform competitive dark matter searches in a wide range of masses. The implications of these striking projections are investigated in a few selected dark matter particle models, where we show that neutrino telescopes are able to probe new parameter space.
KM3NeT is a research infrastructure located in the Mediterranean Sea, that will consist of two deep-sea Cherenkov neutrino detectors. With one detector (ARCA), the KM3NeT Collaboration aims at ...identifying and studying TeV–PeV astrophysical neutrino sources. With the other detector (ORCA), the neutrino mass ordering will be determined by studying GeV-scale atmospheric neutrino oscillations. The first KM3NeT detection units were deployed at the Italian and French sites between 2015 and 2017. In this paper, a description of the detector is presented, together with a summary of the procedures used to calibrate the detector in-situ. Finally, the measurement of the atmospheric muon flux between 2232–3386 m seawater depth is obtained.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The KM3NeT Collaboration runs a multi-site neutrino observatory in the Mediterranean Sea. Water Cherenkov particle detectors, deep in the sea and far off the coasts of France and Italy, are already ...taking data while incremental construction progresses. Data Acquisition Control software is operating off-shore detectors as well as testing and qualification stations for their components. The software, named Control Unit, is highly modular. It can undergo upgrades and reconfiguration with the acquisition running. Interplay with the central database of the Collaboration is obtained in a way that allows for data taking even if Internet links fail. In order to simplify the management of computing resources in the long term, and to cope with possible hardware failures of one or more computers, the KM3NeT Control Unit software features a custom dynamic resource provisioning and failover technology, which is especially important for ensuring continuity in case of rare transient events in multi-messenger astronomy. The software architecture relies on ubiquitous tools and broadly adopted technologies and has been successfully tested on several operating systems.
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