The LHCb Vertex Locator performance and Vertex Locator upgrade

LHCb is an experiment dedicated to the study of new physics in the decays of beauty and charm hadrons at the Large Hadron Collider (LHC) at CERN. The Vertex Locator (VELO) is the silicon detector surrounding the LHCb interaction point. The detector operates in a severe and highly non-uniform radiation environment. The small pitch and analogue readout result in a best single hit precision of 4 $\rm \mu$m. The upgrade of the LHCb experiment, planned for 2018, will transform the entire readout to a trigger-less system operating at 40 MHz event rate. The vertex detector will have to cope with radiation levels up to 10$^{16}$ 1 MeV$\rm n_{eq}/cm^2$, more than an order of magnitude higher than those expected at the current experiment. A solution is under development with a pixel detector, based on the Timepix/Medipix family of chips with 55 x 55 $\rm \mu m$ pixels. In addition a micro-strip solution is also under development, with finer pitch, higher granularity and lower mass than the current detector. The current status of the VELO will be described together with recent testbeam results.Comment: Proceedings for the "*14th International Workshop on Radiation Imaging Detector IWORID 2012*

Performance of the LHCb vertex locator

The Vertex Locator (VELO) is a silicon microstrip detector that surrounds the proton-proton interaction region in the LHCb experiment. The performance of the detector during the first years of its physics operation is reviewed. The system is operated in vacuum, uses a bi-phase CO2 cooling system, and the sensors are moved to 7 mm from the LHC beam for physics data taking. The performance and stability of these characteristic features of the detector are described, and details of the material budget are given. The calibration of the timing and the data processing algorithms that are implemented in FPGAs are described. The system performance is fully characterised. The sensors have a signal to noise ratio of approximately 20 and a best hit resolution of 4 μm is achieved at the optimal track angle. The typical detector occupancy for minimum bias events in standard operating conditions in 2011 is around 0.5%, and the detector has less than 1% of faulty strips. The proximity of the detector to the beam means that the inner regions of the n+-on-n sensors have undergone space-charge sign inversion due to radiation damage. The VELO performance parameters that drive the experiment's physics sensitivity are also given. The track finding efficiency of the VELO is typically above 98% and the modules have been aligned to a precision of 1 μm for translations in the plane transverse to the beam. A primary vertex resolution of 13 μm in the transverse plane and 71 μm along the beam axis is achieved for vertices with 25 tracks. An impact parameter resolution of less than 35 μm is achieved for particles with transverse momentum greater than 1 GeV/c

Silicon Sensors implemented on p-type substrates for high radiation resistance applications

Silicon based micropattern detectors are essential elements of modern high energy physics experiments. Cost effectiveness and high radiation resistance are two important requirements for technologies to be used in inner tracking devices. Processes based on p-type substrates have very strong appeal for these applications. Recent results and prototype efforts under way are reviewed.Comment: 7 pages, 2 figures; invited paper at Vertex 2006, Perugia, Italy, september 200

Status of the LHCb detector

LHCb is an experiment dedicated to study CP violation and other rare phenomena in B mesons decays with very high precision. It is one of the four experiments that will operate at the 14Tev proton-proton Large Hadron Collider (LHC) at CERN in 2008. Here we briefly describe the current status of the experiment, as well as plans towards a future upgrade.Comment: 5 pages, presented at Lake Louise Winter Institute 200

The LHCb Upgrade

The LHCb detector has been designed to study CP violation and other rare phenomena in B-meson decays up to a luminosity of $\sim 5.10^{32}\rm cm^{-2}s^{-1}$. This paper will describe what is limiting LHCb to exploit the much higher luminosities available at the LHC, and what are the baseline modifications which will remedy these limitations. The aim of SuperLHCb is to increase the yields in hadronic B-decay channels by about a factor twenty compared to LHCb, while for channels with leptons in the final state a factor ten increase in statistics is envisaged.Comment: Flavor Physics & CP Violation Conference, Bled, 200

Hunting magnetic monopoles and more with MoEDAL at the LHC

The MoEDAL experiment at the LHC is optimised to detect highly-ionising particles such as magnetic monopoles, dyons and (multiply) electrically-charged stable massive particles predicted in a number of theoretical scenarios. MoEDAL, deployed in the LHCb cavern, combines passive nuclear track detectors with magnetic monopole trapping volumes, while backgrounds are being monitored with an array of MediPix detectors. The detector concept and its physics reach is presented with emphasis given to recent results on monopoles.Comment: 4 pages, 2 figures; Contributed to the 13th Patras Workshop on Axions, WIMPs and WISPs, Thessaloniki, May 15-19, 2017; based on arXiv:1411.7651, arXiv:1612.07012 and arXiv:1703.0714

Physics Benchmarks with the VELO Pixel Upgrade

The LHCb Experiment at the LHC is successfully performing precision measurements primarily in the area of flavour physics. The collaboration is preparing an upgrade that will start taking data in 2021 with a trigger-less readout at five times the current luminosity. The vertex locator has been crucial in the success of the experiment and will continue to be so for the upgrade. It will be replaced by a hybrid pixel detector and this paper discusses the performance benchmarks of the upgraded detector. Despite the challenging experimental environment, the vertex locator will maintain or improve upon its benchmark figures compared to the current detector. Finally the long term plans for LHCb, beyond those of the upgrade currently in preparation, are discussed

Characterisation of Medipix3 Silicon Detectors in a Charged-Particle Beam

While designed primarily for X-ray imaging applications, the Medipix3 ASIC can also be used for charged-particle tracking. In this work, results from a beam test at the CERN SPS with irradiated and non-irradiated sensors are presented and shown to be in agreement with simulation, demonstrating the suitability of the Medipix3 ASIC as a tool for characterising pixel sensors.Comment: 16 pages, 13 figure

Physics Goals and Experimental Challenges of the Proton-Proton High-Luminosity Operation of the LHC

The completion of Run 1 of the CERN Large Hadron Collider has seen the discovery of the Higgs boson and an unprecedented number of precise measurements of the Standard Model, while Run 2 operation has just started to provide first data at higher energy. Upgrades of the LHC to high luminosity (HL-LHC) and the experiments (ATLAS, CMS, ALICE and LHCb) will exploit the full potential of the collider to discover and explore new physics beyond the Standard Model. In this article, the experimental challenges and the physics opportunities in proton-proton collisions at the HL-LHC are reviewed