Conception et mise au point de l'électronique frontale du détecteur de pied de gerbe (Preshower) de l'expérience CMS

Modern particle physics collider experiments consist of a number of macroscopic modules each consisting of large number of sensors measuring charge deposition from traversing particles. The CMS Preshower detector is designed as a sampling calorimeter producing electromagnetic showers for incident electrons and photons resulting from LHC p-p interactions. The ultimate aim is to provide neutral pion / gamma separation reducing the background to the most promising Higgs channel, SM Higgs to 2 photons. The detector has 4300 silicon sensors each subdivided into 32 channels with a total sensitive area of 16.4 m2. Front-end microelectronics ASICs must measure the charge of each channel accurately with low noise and over a wide dynamic range (4 fC to 1600 fC) at the rate of 40 MHz within a harsh radiation environment. This thesis presents the design and development of the Preshower front-end electronics ASIC development, PACE. The first chapter introduces the Preshower experiment and defines the specification for PACE as derived from the physics. The second chapter examines the radiation environment, its effect on electronic devices, and design techniques / technologies that can resist to LHC radiation levels. Chapters 3 to 5 present the design and results of two PACE developments examining analog memories based on current and voltage sampling techniques. Experimental results from a Preshower electro-mechanical prototype tested in a particle beam are also given

The TOTEM front end driver, its components and applications in the TOTEM experiment

The TOTEM Front End Driver, so-called TOTFED, receives and handles trigger building and tracking data from the TOTEM detectors, and interfaces to the global trigger and data acquisition systems. The TOTFED is based on the VME64x standard and has deliberately been kept modular. It is very flexible and programmable to deal with the different TOTEM sub-detectors and possible evolution of the data treatment and trigger algorithms over the duration of the experiment. The main objectives for each unit are to acquire ondetector data from up to 36 optical links, to perform fast data treatment (reduction, consistency checking, etc.), to transfer it to the next level of the system (via the Slink64 interface), and to store data on request for slow spy readout via VME64x or USB2.0. The TOTFED is fully compatible with CMS and permits TOTEM to run both standalone and together with CMS. The TOTEM Front End Driver, its components and applications in the TOTEM experiment are presented in this paper

VFAT2: A front-end system on chip providing fast trigger information, digitized data storage and formatting for the charge sensitive readout of multi-channel silicon and gas particle detectors

The architecture, key design parameters and results for a highly integrated front-end readout system fabricated as a single ASIC are presented. The chip (VFAT2) comprises complex analog and digital functions traditionally designed as separate components. VFAT2 contains very low noise 128 channel front-end amplification with programmable internal calibration, intelligent “fast OR” trigger building outputs, digital data tagging and storage, data formatting and data packet transmission with error protection. VFAT2 is designed to work in the demanding radiation environments posed by modern H.E.P. experiments and in particular the TOTEM experiment of the LHC. Measured results are presented demonstrating full functionality and excellent analog performance despite intensive digital activity on the same piece of silicon

A low power, large dynamic range, CMOS amplifier and analog memory for capacitive sensors

This paper has been written to announce the design of a CMOS charge to voltage amplifier and it¹s integration within an analog memory. Together they provide the necessary front end electronics for the CMS electromagnetic calorimeter (ECAL) preshower detector systeAspell,Pm in the LHC experiment foreseen at the CERN particle physics laboratory. The design and measurements of the amplifier realised in a 1.5mm bulk CMOS process as a 16 channel prototype chip are presented. Results show the mean gain and peaking time of = 1.74mV/mip, = 18ns with channel to channel variations; s(peak_voltage) = 8% and s(peak_time) = 6.5%. The dynamic range is shown to be linear over 400mips with an integral non linearity (INL)=0.05mV as expressed in terms of sigma from the mean gain over the 400mip range. The measured noise of the amplifier was ENC=1800+41e/pF with a power consumption of 2.4mW/channel. The amplifier can support extreme levels of leakage current. The gain remains constant for up to 200mA of leakage current. The integration of this amplifier within a 32 channel, 128 cell analog memory chip ³DYNLDR² is then demonstrated. The DYNLDR offers sampling at 40MHz with a storage time of up to 3.2ms. It provides continuous Write/Read access with no dead time. Triggered data is protected within the memory until requested for readout which is performed at 2.5MHz. The memory is designed to have a steerable dc level enabling maximum dynamic range performance. Measurements of the DYNLDR are presented confirming the original amplifier performance. The memory itself has a very low pedestal non uniformity (s(ped)) of 0.9mV and a gain of 10mV/mip

First measurement of elastic, inelastic and total cross-section at √s=13 TeV by TOTEM and overview of cross-section data at LHC energies

The TOTEM collaboration has measured the proton-proton total cross section at √ s=13 TeV with a luminosity-independent method. Using dedicated β ∗ = 90 m beam optics, the Roman Pots were inserted very close to the beam. The inelastic scattering rate has been measured by the T1 and T2 telescopes during the same LHC fill. After applying the optical theorem the total proton-proton cross section is σtot = (110.6 ± 3.4) mb, well in agreement with the extrapolation from lower energies. This method also allows one to derive the luminosity-independent elastic and inelastic cross sections: σel = (31.0 ± 1.7) mb and σinel = (79.5 ± 1.8) mb

Construction and Performance of Large-Area Triple-GEM Prototypes for Future Upgrades of the CMS Forward Muon System

At present, part of the forward RPC muon system of the CMS detector at the CERN LHC remains uninstrumented in the high-\eta region. An international collaboration is investigating the possibility of covering the 1.6 < |\eta| < 2.4 region of the muon endcaps with large-area triple-GEM detectors. Given their good spatial resolution, high rate capability, and radiation hardness, these micro-pattern gas detectors are an appealing option for simultaneously enhancing muon tracking and triggering capabilities in a future upgrade of the CMS detector. A general overview of this feasibility study will be presented. The design and construction of small (10\times10 cm2) and full-size trapezoidal (1\times0.5 m2) triple-GEM prototypes will be described. During detector assembly, different techniques for stretching the GEM foils were tested. Results from measurements with x-rays and from test beam campaigns at the CERN SPS will be shown for the small and large prototypes. Preliminary simulation studies on the expected muon reconstruction and trigger performances of this proposed upgraded muon system will be reported.Comment: 7 pages, 25 figures, submitted for publication in conference record of the 2011 IEEE Nuclear Science Symposium, Valencia, Spai