Cristina Oropeza Barrera

Anisole fuel has gained increased attention, since it is considered a biofuel, and its addition to gasoline increases the octane number, improving the engine performance. This study focuses on the comprehensive characterization of soot maturity and sooting propensity of a well-controlled laminar coflow diffusion flame fueled with anisole and using methane as the carrier gas. Four laminar non-premixed flames were established below the smoke point. The oxidizer composition ranged from a molar fraction of oxygen (oxygen index, OI) of 21% to 35% (doped with pure oxygen), while keeping constant the total volumetric flow rate of oxidizer stream. Multi-wavelength line-of-sight attenuation experiments were performed from visible to infrared wavelengths, and the measurements of the extinction coefficient and flame temperature were used to retrieve two dimensional fields of soot temperature, volume fraction, radiative intensity and degree of soot maturity. In general, the sooting propensity and radiative behavior of the anisole flames follows a similar trend than typical hydrocarbon fuels when increasing the OI. However, the spatial distribution of soot volume fraction is enhanced, particularly near the flame centerline. In contrast, the soot production is promoted by the OI, near the flame wings. The same effect can be observed for the soot temperature. Indeed, temperature increases, promoting formation and oxidation processes, specially at the locations near the maximum soot volume fraction. In general, the maturity of soot particles is affected as the OI is changed. Also, it is observed that the degree of maturity is enhanced by flame temperature. In order to support these local observations, a statistical analysis was carried out. Finally, the results obtained yield a curated database for validating detailed soot production models of oxygenated fuels, and to gain further insights on the evolution of soot maturity and propensity of these particular fuels under different oxidizer conditions.

The Pixel Luminosity Telescope is a silicon pixel detector dedicated to luminosity measurement at the CMS experiment at the LHC. It is located approximately 1.75 m from the interaction point and arranged into 16 "telescopes", with eight telescopes installed around the beam pipe at either end of the detector and each telescope composed of three individual silicon sensor planes. The per-bunch instantaneous luminosity is measured by counting events where all three planes in the telescope register a hit, using a special readout at the full LHC bunch-crossing rate of 40 MHz. The full pixel information is read out at a lower rate and can be used to determine calibrations, corrections, and systematic uncertainties for the online and offline measurements. This paper details the commissioning, operational history, and performance of the detector during Run 2 (2015-18) of the LHC, as well as preparations for Run 3, which will begin in 2022.

The 3D silicon sensors aimed for the ATLAS pixel detector upgrade have been tested with a high energy pion beam at the CERN SPS in 2009. Two types of sensor layouts were tested: full-3D assemblies fabricated in Stanford, where the electrodes penetrate the entire silicon wafer thickness, and modified-3D assemblies fabricated at FBK-irst with partially overlapping electrodes. In both cases three read-out electrodes are ganged together to form pixels of dimension 50×400μm2. Data on the pulse height distribution, tracking efficiency and resolution were collected for various particle incident angles, with and without a 1.6 T magnetic field. Data from a planar sensor of the type presently used in the ATLAS detector were used at the same time to give comparison.

Measurements of inclusive two-particle angular correlations in proton-proton collisions at centre-of-mass energies of 900 GeV and 7 TeV are presented. The events were collected with the ATLAS detector at the LHC, using a single-arm minimum-bias trigger, during 2009 and 2010. Correlations are measured for charged particles in the kinematic range defined by pT > 100 MeV and |eta| = 2 are analysed whereas at 7 TeV, a second phase-space region of n_ch >= 20, with a suppressed contribution from diffractive events, is also explored. Data is corrected using a novel approach in which the detector effects are applied repeatedly to the observable distribution and then extrapolated to a detector effect of zero. A complex structure in pseudorapidity and azimuth is observed for the correlation function at both collision energies. Projections of the two-dimensional correlation distributions are compared to the Monte Carlo generators Pythia 8 and Herwig++ as well as the AMBT2B, DW and Perugia 2011 tunes of Pythia 6. The strength of the correlations seen in the data is not reproduced by any of the models.

Measurements of two-particle angular correlations in proton-proton collisions at a centre-of-mass energy of 7 TeV, produced by the Large Hadron Collider, are presented. Correla- tions are measured for charged particles in the kinematic region pT > 100 MeV andjhj < 2.5. Collision events were recorded using a minimum bias trigger with the ATLAS Detector at the LHC during 2010. A complex correlation structure in Dh and Df is observed. Results are compared to Pythia 8 and Phojet as well as the ATLAS MC09, DW and Perugia0 tunes of Pythia 6.

The design and expected performance for precision luminosity measurement of the Tracker Endcap Pixel (TEPX) detector for the CMS experiment at the upcoming High-Luminosity LHC (HL-LHC) is described. The TEPX detector is composed of 4 double-sided double disks at each end of CMS covering the range of | z | from 175 to 265 cm, each disk made of 5 rings composed of silicon sensors, with a total of 800 million pixels distributed across the 8 disks. Disk 4 Ring 1 (TEPXD4R1) will be dedicated to luminosity and beam-induced background measurements, utilising the same method as that of the rest of TEPX, namely pixel cluster counting. For the HL-LHC, the goal is to achieve a final uncertainty of 1% for offline luminosity measurements. The expected performance of the TEPX and TEPXD4R1 luminometers in terms of statistical precision for van der Meer scan calibration and for physics conditions, as well as the linearity performance of each disk are presented.&#x0D;

The Resistive Plate Chamber (RPC) system at the CMS Detector has been operating successfully since the beginning of data taking.The high Large Hadron Collider (LHC) instantaneous luminosity provides an extremely high flux of ionizing particles.The long period of operation (Run-I and Run-II) in a large radiation background conditions, gives the opportunity to study the operational capability of the RPCs and also to predict a data-driven extrapolation of measured parameters like currents and integrated charged.[1]Those results will be compared to the relevant results obtained from the dedicated R&D study, where a set of test chambers have been irradiated at GIF++ laboratory setup.[2]

The High Luminosity upgrade of the LHC (HL-LHC) is foreseen to increase the instantaneous luminosity by a factor of five over the present LHC nominal value.The resulting, unprecedented requirements for background monitoring and luminosity measurements create the need for new high-precision instrumentation at CMS, using radiation hard detector technologies.This contribution discusses the implications of using the Tracker Endcap Pixel Detector for online measurements of luminosity and beam-induced background.The suitability of the TEPX detector for these tasks is explored and implementations for separate triggering and readout systems are explained.

La física experimental de partículas se encuentra en una era dorada llena de retos tecnológicos. Para superarlos, las grandes colaboraciones del LHC (Large Hadron Collider) han implementado técnicas de Machine Learning en sus operaciones con resultados impresionantes. En este documento se resumen algunas de las aplicaciones principales del aprendizaje automatizado, en particular de las redes neuronales artificiales, en el experimento CMS (Compact Muon Solenoid). Además, se resalta la importancia del trabajo colaborativo e interdisciplinario para la correcta implementación e interpretación de estas técnicas de análisis. El objetivo del presente trabajo consiste en despertar el interés por estos temas entre los miembros de las comunidades de física de partículas y ciencias de la computación, con el fin de ampliar las posibilidades de trabajos de investigación conjuntos.

The high-luminosity upgrade of the LHC (HL-LHC) is expected to reach an instantaneous luminosity of roughly a factor five of the current value.The resulting requirements for background monitoring and luminosity measurement create the need for new high-precision instrumentation at CMS, using radiation-hard detector technologies.This contribution presents the strategy for bunch-by-bunch online luminosity measurements based on various detector technologies.A main component of the system is the Tracker Endcap Pixel Detector with dedicated triggers for the online measurement of the luminosity and the beam-induced background using the pixel cluster counting method as implemented in FPGAs.The potential of exploiting the outer tracker, the forward hadron calorimeter, and muon trigger objects is discussed, as well as the concept of a standalone luminosity and beam-induced background monitor using silicon-pad sensors.