An LHCb Vertex Locator (VELO) for 2030s

LHCb has recently submitted a physics case for an Upgrade II detector to begin operation in 2031. The upcoming upgrade stage is designed to run at instantaneous luminosities of up to $1.5 \times 10^{34}$ $cm^{-2}s^{-1}$, and accumulate a sample of more than $300$ $f$^{-1}$. At this intensity, the mean number of interactions per crossing would be 42, producing around 2000 charged particles within the LHCb acceptance. To meet this challenge, precise timing information will be added to the vertexing and tracking systems. In particular, the LHCb upgrade physics programme is reliant on an efficient and precise vertex detector (VELO). The higher luminosity poses significant challenges which need the construction of a new VELO with enhanced capabilities. Compared to the currently installed detector, the data rate will be 10 times higher with corresponding increases in radiation doses and occupancies. To cope with the large increase in pile-up, new techniques to correctly assign each b hadron to the primary vertex from which it originates, and to perform the real time pattern recognition, are needed. To solve these problems a new 4D hybrid pixel detector with enhanced rate and timing capabilities in the ASIC and sensor will be developed. Improvements in the mechanical design of the Upgrade II VELO will also be needed to allow for periodic module replacement. The design will be further optimised to minimise the material budget before the first measured point on a track (which is dominated by the RF foil) and to achieve a more fully integrated module design with thinned sensors and ASICs combined with a lightweight cooling solution. As well as improving the VELO performance, quantified by the impact parameter resolution, these changes will be beneficial both in improving the momentum resolution of the spectrometer and reducing the impact of secondary interactions on the downstream detectors. This presentation will show the most promising technologies to be used in the future upgrade for the HL-LHC, with emphasis on the timing precision as a tool for vertexing in the next generation detectors. The most recent results from beam tests motivated by time measurements will be presented together with the possible R& D scenarios for the future upgrade

Background studies on the H→ZZ*→4l channel at LHC Run 1. Prospects of the bbH(→γγ) mode and studies for an improved pixel detector system for the ATLAS upgrade towards HL-LHC

The discovery of a scalar boson, known as the Higgs boson, marked the first LHC data period (2010 - 2012). Using mainly di-photon and di-Z decays, with the latest leading to a four lepton final state, the mass of the boson was measured with a precision of < 0.2 %. Relevant couplings were estimated by combining several final states, while corresponding uncertainties would largely benefit from the increased statistics expected during coming LHC data periods (Run 2, Phase II). The H→ZZ*→4l channel, in spite of its suppressed brunching ratio, benefits from a weak background, making it a prime choice for the investigation of the new boson’s properties. In this thesis, the analysis aimed to the observation of this mode with the ALTAS detector is presented, with a focus on the measurement and control of the reducible electron background. In the context of preparation for future high luminosity data periods, foreseen from 2025 onward, two distinct studies are conducted: 1. The first concerns the observability potential of the Higgs associated production mode in conjunction with two b-quarks. A multivariate analysis based on simulated data confirms a very weak expected signal in the H→di-photon channel. 2. The second revolves around the conception and development of an inner silicon detector capable of operating in the hostile environment of high radiation and in-creased occupancy, expected during LHC Phase II. Main studies were concentrated on improving radiation hardness, geometrical and detection efficiency. Through fabrication process simulation and SIMS measurements, doping profiles and electrical characteristics, expected for innovative technologies, are explored. Prototypes were designed and evaluated in test beams and irradiation experiments in order to assess their performances and that of associated read-out electronics

SAMPIC Calibration Procedute

This document provides instructions for voltage and time domain ADC calibration of the 32 channel Sampic desktop device using the included Labwindows software

Design and integration of a SiPM based Timing Reference for ATLAS HGTD test beam

For the upcoming high luminosity upgrade of the LHC, CERN is considering the addition of the High Granularity Timing Detector (HGTD) in front of the end cap and forward calorimeters of ATLAS detector to mitigate pile-up effects. Low Gain Avalanche Diodes (LGADs) are the technology of choice for this timing application. Several test beam campaigns are performed to evaluate sensor performance. A Silicon Photomultiplier (SiPM) coupled to a quartz crystal is used as a timing reference, providing resolutions < 20 ps. A new readout and support board was developed for the upcoming test beam campaigns along with a 3D printed light-tight enclosure and support structure. The design, fabrication and assembly of the new timing reference system are presented

HGTD test beam results

The performance of a CNM Gallium-doped LGAD sensor irradiated to 3e15 neutron is studied with a 5 GeV electron beam. 2D timing map is shown: time resolution as a function of the reconstructed position of electrons for the entire sensor and its central area

HGTD Testbeam results of a CNM Gallium-doped LGAD sensor irradiated to 3e15 neutron

The performance of a CNM Gallium-doped LGAD sensor irradiated to 3e15 neutron is studied with a 5 GeV electron beam. Collected charge and efficiency are shown as a function of bias voltage, time resolution as a function of the collected charge and a 2D efficiency map are shown

Considerations for the VELO detector at the LHCb Upgrade II

The LHCb experiment is planning to operate with a 7.5-fold increase in instantaneous luminosity for LHC Runs 5 and 6. The performance of the Vertex Locator detector is crucial in the event reconstruction at the increased pile-up, providing real-time information to be used in the trigger. This document presents the considerations for a future detector with timing capabilities for each track and minimal amount of material. Simulation studies indicate that a track temporal resolution of 20 ps is required to achieve the physics performance desired in Upgrade II, while keeping the same spatial resolutions as in VELO Upgrade I. Key promising technologies are listed and an R&D plan to achieve the complete set of requirements is laid out

Strategic R&D Programme on Technologies for Future Experiments - Annual Report 2020

This report summarises the activities and achievements of the strategic R&D programme on technologies for future experiments in the year 2020

Strategic R&D Programme on Technologies for Future Experiments - Annual Report 2021

This report summarises the activities and main achievements of the CERN strategic R&D programme on technologies for future experiments during the year 2021