In order to cope with the occupancy and radiation doses expected at the High-Luminosity LHC, the ATLAS experiment will replace its Inner Detector with an all-silicon Inner Tracker (ITk), consisting ...of pixel and strip subsystems.
In the last two years, several prototype ITk strip modules have been tested using beams of high energy electrons produced at the DESY-II testbeam facility. Tracking was provided by EUDET telescopes. The modules tested are built from two sensor types: the rectangular ATLAS17LS, which will be used in the outer layers of the central barrel region of the detector, and the annular ATLAS12EC, which will be used in the innermost ring (R0) of the forward region. Additionally, a structure with two R0 modules positioned back-to-back has been measured, demonstrating space point reconstruction using the stereo angle of the strips. Finally, one barrel and one R0 module have been measured after irradiation to 40% beyond the expected end-of-lifetime fluence. The data obtained allow for thorough tests of the module performance, including charge collection, noise occupancy, detection efficiency, and tracking performance. The results give confidence that the ITk strip detector will meet the requirements of the ATLAS experiment.
The production of two prompt Formula: see text mesons, each with transverse momenta Formula: see text GeV and rapidity Formula: see text, is studied using a sample of proton-proton collisions at ...Formula: see text TeV, corresponding to an integrated luminosity of 11.4 fbFormula: see text collected in 2012 with the ATLAS detector at the LHC. The differential cross-section, assuming unpolarised Formula: see text production, is measured as a function of the transverse momentum of the lower-Formula: see text Formula: see text meson, di-Formula: see text Formula: see text and mass, the difference in rapidity between the two Formula: see text mesons, and the azimuthal angle between the two Formula: see text mesons. The fraction of prompt pair events due to double parton scattering is determined by studying kinematic correlations between the two Formula: see text mesons. The total and double parton scattering cross-sections are compared with predictions. The effective cross-section of double parton scattering is measured to be Formula: see text mb.
The ATLAS ITk strip local support structures Diez, Sergio
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2024, Letnik:
1066
Journal Article
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A new silicon tracker for the ATLAS detector is envisioned during the Phase-II upgrade of the Large Hadron Collider experiment (LHC), the so-called High Luminosity LHC (HL-LHC). The new Inner Tracker ...(ITk) consists of a silicon pixel inner tracker and a silicon microstrips outer tracker. This paper focuses on the strips ITk detector, and, in particular, on the high precision, low-mass, high thermo-mechanical performance structures supporting the silicon microstrip modules, so-called “staves” for the barrel region and “petals” for the end-cap regions. A detailed description of these structures is provided, along with the manufacturing procedures employed. This paper covers also the Quality Control (QC) program during pre-production phase, evaluating the mechanical, electrical and thermal performance of twenty support structures of each type, and the validation for their production phase.
The consequence was that hundreds of thousands of non-citizen residents lost their right to health care, except for emergency services and maternal health.1 The reform might be in conflict with the ...Spanish Constitution and the statutes of autonomy of some Spanish regions, with the Constitutional Tribunal having granted leave to appeal to them.2 The reform was based on a report from the Court of Auditors stating that the NHS was bearing the health-care cost of European citizens (so-called health tourism) due to its inability to secure reimbursement.
The technique of evaporative CO2 cooling is one of the standard cooling options for high-energy particle detectors, such as the new ATLAS Inner Tracker (ITk) for the planned high-luminosity upgrade ...of the LHC by 2026. The advantages of CO2 are a high latent heat transfer at reasonable flow parameters, a low viscosity which allows to use small diameter cooling pipes with a low pressure drops, a well-suited temperature range for detector cooling between ＋25 and −40 °C and being an environment friendly alternative to many other currently used coolants. When comparing with a monophase coolant, the operation in the dual-phase regime comes with several parameters influencing the cooling performance.
This paper contains the results of experimental studies performed to understand these influencing factors. For this, prototype structures from the ITk strip detector end-cap were used, like bare local support structures (‘cores’) or fully loaded structures (‘petals’). Here, the design is optimized to guarantee a good heat transfer between the silicon strip modules glued on the surface and the embedded titanium cooling pipe with the CO2 coolant. Systematic investigations on the thermal performance using infrared thermography are used to study the influence of dual-phase CO2 cooling parameters such as the orientation of CO2 flow. Moreover, the dependence of the pressure drop as a key parameter for the cooling performance on the applied heat load or the selected mass flow rate is investigated.
The gastric stomach of humans is a barrier to food-borne pathogens, but Escherichia coli can survive at pH 2.0 if it is grown under mildly acidic conditions. Cattle are a natural reservoir for ...pathogenic E. coli, and cattle fed mostly grain had lower colonic pH and more acid-resistant E. coli than cattle fed only hay. On the basis of numbers and survival after acid shock, cattle that were fed grain had 10(6)-fold more acid-resistant E. coli than cattle fed hay, but a brief period of hay feeding decreased the acid-resistant count substantially
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