38,489 research outputs found
A new functional for charge and mass identification in Delta E-E telescopes
We propose a new functional for the charge and mass identification in Delta
E-E telescopes. This functional is based on Bethe's formula, allowing safe
interpolation or extrapolation in regions with low statistics. When applied to
telescopes involving detectors delivering a linear response, as silicon
detectors or ionization chambers, a good mass and charge identification is
achieved. For other detectors, as caesium-iodide used as a final member of a
telescope, a good accuracy is also obtained except in the low residual energy
region. A good identification is however recovered if a non-linear energy
dependence of the light output is included.Comment: 16 pages, 8 figures, LaTeX2e + EPS figures reduced in size Submitted
to Elsevie
A comprehensive study of rate capability in Multi-Wire Proportional Chambers
Systematic measurements on the rate capability of thin MWPCs operated in
Xenon, Argon and Neon mixtures using CO2 as UV-quencher are presented. A good
agreement between data and existing models has been found, allowing us to
present the rate capability of MWPCs in a comprehensive way and ultimately
connect it with the mobilities of the drifting ions.Comment: 29 pages, 18 figure
A Novel Generic Framework for Track Fitting in Complex Detector Systems
This paper presents a novel framework for track fitting which is usable in a
wide range of experiments, independent of the specific event topology, detector
setup, or magnetic field arrangement. This goal is achieved through a
completely modular design. Fitting algorithms are implemented as
interchangeable modules. At present, the framework contains a validated Kalman
filter. Track parameterizations and the routines required to extrapolate the
track parameters and their covariance matrices through the experiment are also
implemented as interchangeable modules. Different track parameterizations and
extrapolation routines can be used simultaneously for fitting of the same
physical track. Representations of detector hits are the third modular
ingredient to the framework. The hit dimensionality and orientation of planar
tracking detectors are not restricted. Tracking information from detectors
which do not measure the passage of particles in a fixed physical detector
plane, e.g. drift chambers or TPCs, is used without any simplifications. The
concept is implemented in a light-weight C++ library called GENFIT, which is
available as free software
Track Extrapolation and Distribution for the CDF-II Trigger System
The CDF-II experiment is a multipurpose detector designed to study a wide
range of processes observed in the high energy proton-antiproton collisions
produced by the Fermilab Tevatron. With event rates greater than 1MHz, the
CDF-II trigger system is crucial for selecting interesting events for
subsequent analysis. This document provides an overview of the Track
Extrapolation System (XTRP), a component of the CDF-II trigger system. The XTRP
is a fully digital system that is utilized in the track-based selection of high
momentum lepton and heavy flavor signatures. The design of the XTRP system
includes five different custom boards utilizing discrete and FPGA technology
residing in a single VME crate. We describe the design, construction,
commissioning and operation of this system.Comment: 34 pages, 9 figures, submitted to Nucl.Inst.Meth.
Surface and buildup region dose measurements with Markus parallel-plate ionization chamber, Gafchromic EBT3 film and MOSFET detector for high energy photon beams
The aim of the study was to investigate surface and buildup region doses for
6MV and 15MV photon beams using a Markus parallel-plate ionization chamber,
GafChromic EBT3 film, and MOSFET detector for different field sizes and beam
angles. The measurements were made in a water equivalent solid phantom at the
surface and in the buildup region of the 6MV and 15MV photon beams at 100 cm
source-detector distance for 5 x 5, 10 x 10, and 20 x 20 cm2 field sizes and 0,
30, 60, and 80 beam angles. The surface doses using 6MVphoton beams for 10 x 10
cm2 field size were found to be 20.3%, 18.8%, and 25.5% for Markus chamber,
EBT3 film, and MOSFET detector, respectively. The surface doses using 15MV
photon beams for 10 x 10 cm2 field size were found to be 14.9%, 13.4%, and
16.4% for Markus chamber, EBT3 film, and MOSFET detector, respectively. The
surface dose increased with field size for all dosimeters. As the angle of the
incident radiation beam became more oblique, the surface dose increased. The
effective measurement depths of dosimeters vary; thus, the results of the
measurements could be different. This issue can lead to mistakes at surface and
buildup dosimetry and must be taken into account
A 3-D Track-Finding Processor for the CMS Level-1 Muon Trigger
We report on the design and test results of a prototype processor for the CMS
Level-1 trigger that performs 3-D track reconstruction and measurement from
data recorded by the cathode strip chambers of the endcap muon system. The
tracking algorithms are written in C++ using a class library we developed that
facilitates automatic conversion to Verilog. The code is synthesized into
firmware for field-programmable gate-arrays from the Xilinx Virtex-II series. A
second-generation prototype has been developed and is currently under test. It
performs regional track-finding in a 60 degree azimuthal sector and accepts 3
GB/s of input data synchronously with the 40 MHz beam crossing frequency. The
latency of the track-finding algorithms is expected to be 250 ns, including
geometrical alignment correction of incoming track segments and a final
momentum assignment based on the muon trajectory in the non-uniform magnetic
field in the CMS endcaps.Comment: 7 pages, 5 figures, proceedings for the conference on Computing in
High Energy and Nuclear Physics, March 24-28 2003, La Jolla, Californi
Performance of the Muon Identification at LHCb
The performance of the muon identification in LHCb is extracted from data
using muons and hadrons produced in J/\psi->\mu\mu, \Lambda->p\pi and
D^{\star}->\pi D0(K\pi) decays. The muon identification procedure is based on
the pattern of hits in the muon chambers. A momentum dependent binary
requirement is used to reduce the probability of hadrons to be misidentified as
muons to the level of 1%, keeping the muon efficiency in the range of 95-98%.
As further refinement, a likelihood is built for the muon and non-muon
hypotheses. Adding a requirement on this likelihood that provides a total muon
efficiency at the level of 93%, the hadron misidentification rates are below
0.6%.Comment: 17 pages, 10 figure
Position resolution and particle identification with the ATLAS EM calorimeter
In the years between 2000 and 2002 several pre-series and series modules of
the ATLAS EM barrel and end-cap calorimeter were exposed to electron, photon
and pion beams. The performance of the calorimeter with respect to its finely
segmented first sampling has been studied. The polar angle resolution has been
found to be in the range 50-60 mrad/sqrt(E (GeV)). The neutral pion rejection
has been measured to be about 3.5 for 90% photon selection efficiency at pT=50
GeV/c. Electron-pion separation studies have indicated that a pion fake rate of
(0.07-0.5)% can be achieved while maintaining 90% electron identification
efficiency for energies up to 40 GeV.Comment: 32 pages, 22 figures, to be published in NIM
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