LHCb is one of the four main experiments running at the Large Hadron Collider (LHC) of the European Organization for Nuclear Research. Since 2010, it has been collecting data to study the Physics of ...b and c quarks. For the past three years, the experimental apparatus underwent significant upgrades to be ready for a new round of data collection, expected to start in June 2022. The new apparatus is designed to be able to run at an instantaneous luminosity five times larger than the previous one, which was 2.0×1032 cm−2s−1, and the whole detector readout will be at a 40 MHz rate. It is worth noticing that the luminosity at the LHCb interaction point, for the characteristics of the detector, needs to be reduced with respect to the luminosity provided by LHC. Major changes in the different subdetectors were required, along with complete modifications of the trigger schemes. The LHCb collaboration is developing and studying different methods for the on-line measurement of luminosity at the LHCb impact point, crucial for the monitoring of correct machine operation and for most experimental physics studies. The present work describes a procedure based on hit counting in the muon detector for an on-line luminosity monitor. The performance and the precision achieved with this method in tests carried out on past data collected are presented, together with proposals for future upgrades.
The Mu2e experiment at Fermi National Accelerator Laboratory will search for the charged-lepton flavour-violating neutrinoless conversion of negative muons into electrons in the Coulomb field of an ...Al nucleus. The conversion electron with a monoenergetic 104.967 MeV signature will be identified by a complementary measurement carried out by a high-resolution tracker and an electromagnetic calorimeter, improving by four orders of magnitude the current single-event sensitivity. The calorimeter—composed of 1348 pure CsI crystals arranged in two annular disks—has a high granularity, 10% energy resolution and 500 ps timing resolution for 100 MeV electrons. The readout, based on large-area UV-extended SiPMs, features a fully custom readout chain, from the analogue front-end electronics to the digitisation boards. The readout electronics design was validated for operation in vacuum and under magnetic fields. An extensive radiation hardness certification campaign certified the FEE design for doses up to 100 krad and 1012 n1MeVeq/cm2 and for single-event effects. A final vertical slice test on the final readout chain was carried out with cosmic rays on a large-scale calorimeter prototype.
The Mu2e experiment at Fermilab will search for the standard model-forbidden, charged lepton flavour-violating conversion of a negative muon into an electron in the field of an aluminium nucleus. The ...distinctive signal signature is represented by a mono-energetic electron with an energy near the muon’s rest mass. The experiment aims to improve the current single-event sensitivity by four orders of magnitude by means of a high-intensity pulsed muon beam and a high-precision tracking system. The electromagnetic calorimeter complements the tracker by providing high rejection power in muon to electron identification and a seed for track reconstruction while working in vacuum in presence of a 1 T axial magnetic field and in a harsh radiation environment. For 100 MeV electrons, the calorimeter should achieve: (a) a time resolution better than 0.5 ns, (b) an energy resolution <10%, and (c) a position resolution of 1 cm. The calorimeter design consists of two disks, each loaded with 674 undoped CsI crystals read out by two large-area arrays of UV-extended SiPMs and custom analogue and digital electronics. We describe here the status of construction for all calorimeter components and the performance measurements conducted on the large-sized prototype with electron beams and minimum ionizing particles at a cosmic ray test stand. A discussion of the calorimeter’s engineering aspects and the on-going assembly is also reported.
Los objetivos del presente trabajo fueron: 1.- Evaluar la cualidad de los roles sociales (recompensas y estresores) en mujeres trabajadoras y su relación con la salud mental y, 2.- Evaluar los ...efectos moderadores del apoyo social sobre los estresores asociados a los roles familiares y el rol laboral y la salud mental. Las participantes fueron 122 mujeres secretarias u oficinistas con un promedio de edad de 38.9 años. Para medir la Cualidad del Rol se utilizo la versión modificada por Feldman et al. (1995) del cuestionario original de Barnett y Marshall (1989). El apoyo social se midió con la escala de Dunn et al. (1987) y como indicador de salud mental se utilizó la versión de 28- ítemes del Cuestionario de Salud General de Goldberg (1972). Los resultados indicaron que el apoyo social estuvo positivamente relacionado con menores niveles de ansiedad y problemas de salud mental. El apoyo religioso y de la pareja constituyeron las fuentes más importantes de apoyo vinculadas a la salud mental y el bienestar en este grupo. Se encontraron interacciones significativas entre los estresores laborales y de pareja el apoyo de grupos y religioso y la depresión. Los hallazgos indican la importancia del apoyo social y en especial el apoyo de grupos y religioso como factor protector en mujeres con roles múltiples.
The timing performance of the Timepix4 application-specific integrated circuit (ASIC) bump-bonded to a \(100\;\mu\textrm{m}\) thick n-on-p silicon sensor is presented. A picosecond pulsed infrared ...laser was used to generate electron-hole pairs in the silicon bulk in a repeatable fashion, controlling the amount, position and time of the stimulated charge signal. The timing resolution for a single pixel has been measured to \(107\;\textrm{ps}\) r.m.s. for laser-stimulated signals in the silicon sensor bulk. Considering multi-pixel clusters, the measured timing resolution reached \(33\;\textrm{ps}\) r.m.s. exploiting oversampling of the timing information over several pixels.
The Mu2e experiment at Fermilab searches for the neutrino-less conversion of a negative muon into an electron, with a distinctive signature of a mono-energetic electron with energy of 104.967 MeV. ...The calorimeter is made of two disks of pure CsI crystals, each read out by two custom large area UV-extended SiPMs. It plays a fundamental role in providing excellent particle identification capabilities and an online trigger filter while improving the track reconstruction, requiring better than 10% energy and 500 ps timing resolutions for 100 MeV electrons. In this paper, we present the status of construction and the Quality Control (QC) performed on the produced crystals and photosensors, the development of the rad-hard electronics, and the most important results of the irradiation tests. Construction of the mechanics is also reported. Status and plans for the calorimeter assembly and its first commissioning are described.
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