121671017
Recent test results of the ALICE silicon pixel detector
The ALICE SPD (Silicon Pixel Detector) forms the two innermost layers of the Inner Tracking System (ITS) of the ALICE experiment at LHC. After several years of development the production of the modules is starting. The present article provides an overview of the different elements that will be used in the SPD with special emphasis given to testing of wafers and bump-bonded ladders.
109085314
The silicon pixel detector (SPD) for the ALICE experiment
The ALICE silicon pixel detector (SPD) constitutes the two innermost layers of the inner tracking system (ITS). The basic building block of the SPD is the half-stave carrying two detector ladders. The half-stave is equipped with a multi-chip module (MCM) and an optical fibre link for control and readout. A 5-layer aluminium/polyimide bus ensures the distribution of power and signals on each half-stave. The half-staves are mounted on a light-weight carbon-fibre structure with an integrated evaporative cooling system. An overview of the SPD development and the current status of the construction are presented.
53308940
The ALICE silicon pixel detector readout electronics
Abstract The ALICE silicon pixel detector (SPD) constitutes the two innermost layers of the ALICE inner tracking system (ALICE Collaboration, 1999) [1] . The SPD is built with 120 detector modules (half-staves) and contains about 10 million pixels in total. The half-staves are connected to the off-detector electronics, housed in a control room 100 m away, via bidirectional optical links. The stream of data from the front-end electronics is processed in 20 VME readout modules, called routers, based on FPGAs. Three 2-channel link-receiver daughter cards, also based on FPGAs, are plugged in each router. Each link-receiver card receives data via the optical link from two half-staves, applies the zero suppression and passes them to the router to be processed and sent to the ALICE–DAQ system through the detector data link (DDL). The SPD control, configuration and data monitoring are performed using the VME interface embedded in the router.
141117760
Assembly procedure of the ALICE silicon pixel detector module
110392152
LEPIX: MONOLITHIC DETECTORS FOR PARTICLE TRACKING IN STANDARD VERY DEEP SUBMICRON CMOS TECHNOLOGIES
A few silicon foundries offer the possibility of porting standard deep-submicron CMOS processes on wafers with resistivity well above 100 Ω·cm. In this paper we propose to use this option to implement monolithic sensors for particle tracking that combine the low power consumption and material budget offered by monolithic active pixel sensors (MAPS) with the speed and radiation hardness characterizing hybrid pixel detectors. Our simulations suggest that a uniform depletion layer with a thickness of at least 40 μm should be obtained by applying a reverse bias voltage of 100 V. The charge collection is fully dominated by drift, which is a key factor to guarantee adequate resistance against radiation-induced bulk damage. The paper describes the sensor concept and the key issues involved in the design of the associated read-out electronics.
18604142
A new class of solutions of the DMPK equation.
We introduce and discuss a new class of solutions of the DMPK equation in which some of the eigenvalues are grouped into clusters which are conserved in the asymptotic large distance limit (i.e. as the length of the wire increases). We give an explicit expression for the asymptotic expansion of these solutions and suggest some possible applications. In particular these new solution could be useful to avoid the quasi one dimensional constraint in the DMPK equation and to study the crossover between the metallic and insulating phases.
16435704
Finite-size Effects in the Interface of 3 D Ising Model
The interface between domains of opposite magnetization in the 3D Ising model near the critical temperature displays universal finite-size effects which can be described in terms of a gaussian model of capillary waves. It turns out that these finite-size corrections depend rather strongly on the shape of the lattice. This prediction, which has no adjustable parameters, is tested and accurately verified for various lattice shapes by means of numerical simulations with a cluster algorithm. This supports also a long-standing conjecture on the finite-size effects in Wilson loops of Lattice Gauge Theories.
15109838
Short distance behaviour of correlators in the 2d Ising model in a magnetic field
Abstract We study the 〈σσ〉 , 〈σϵ〉 , 〈ϵϵ〉 correlators in the 2d Ising model perturbed by a magnetic field. We compare the results of a set of high precision Monte Carlo simulations with the predictions of two different approximations: the Form Factor approach, based on the exact S-matrix description of the model, and a short distance perturbative expansion around the conformal point. Both methods give very good results, the first one performs better for distances larger than the correlation length, while the second one is more precise for distances smaller than the correlation length. In order to improve this agreement we extend the perturbative analysis to the second order in the derivatives of the OPE constants.
123164438
Bound states in the 3d Ising model and implications for QCD at finite temperature and density
Abstract We study the spectrum of bound states of the three dimensional Ising model in the ( h , β) plane near the critical point. We show the existence of an unbinding line, defined as the boundary of the region where bound states exist. Numerical evidence suggests that this line coincides with the β = β c axis. When the 3 D Ising model is considered as an effective description of hot QCD at finite density, we conjecture the correspondence between the unbinding line and the line that separates the quark-gluon plasma phase from the superconducting phase. The bound states of the Ising model are conjectured to correspond to the diquarks of the latter phase of QCD.