4,310 research outputs found
Laser Wire Scanner Compton Scattering Techniques for the Measurement of the Transverse Beam Size of Particle Beams at Future Linear Colliders
This archive summarizes a working paper and conference proceedings related to
laser wire scanner development for the Future Linear Collider (FLC) in the
years 2001 to 2006. In particular the design, setup and data taking for the
laser wire experiments at PETRA II and CT2 are described. The material is
focused on the activities undertaken by Royal Holloway University of London
(RHUL).Comment: 61 page
The G0 Experiment: Apparatus for Parity-Violating Electron Scattering Measurements at Forward and Backward Angles
In the G0 experiment, performed at Jefferson Lab, the parity-violating
elastic scattering of electrons from protons and quasi-elastic scattering from
deuterons is measured in order to determine the neutral weak currents of the
nucleon. Asymmetries as small as 1 part per million in the scattering of a
polarized electron beam are determined using a dedicated apparatus. It consists
of specialized beam-monitoring and control systems, a cryogenic hydrogen (or
deuterium) target, and a superconducting, toroidal magnetic spectrometer
equipped with plastic scintillation and aerogel Cerenkov detectors, as well as
fast readout electronics for the measurement of individual events. The overall
design and performance of this experimental system is discussed.Comment: Submitted to Nuclear Instruments and Method
QuASeR -- Quantum Accelerated De Novo DNA Sequence Reconstruction
In this article, we present QuASeR, a reference-free DNA sequence
reconstruction implementation via de novo assembly on both gate-based and
quantum annealing platforms. Each one of the four steps of the implementation
(TSP, QUBO, Hamiltonians and QAOA) is explained with simple proof-of-concept
examples to target both the genomics research community and quantum application
developers in a self-contained manner. The details of the implementation are
discussed for the various layers of the quantum full-stack accelerator design.
We also highlight the limitations of current classical simulation and available
quantum hardware systems. The implementation is open-source and can be found on
https://github.com/prince-ph0en1x/QuASeR.Comment: 24 page
Advanced measurement systems based on digital processing techniques for superconducting LHC magnets
The Large Hadron Collider (LHC), a particle accelerator aimed at exploring deeper into matter than ever before, is currently being constructed at CERN. Beam optics of the LHC, requires stringent control of the field quality of about 8400 superconducting magnets, including 1232 main dipoles and 360 main quadrupoles to assure the correct machine operation. The measurement challenges are various: accuracy on the field strength measurement up to 50 ppm, harmonics in the ppm range, measurement equipment robustness, low measurement times to characterize fast field phenomena.
New magnetic measurement systems, principally based on analog solutions, have been developed at CERN to achieve these goals. This work proposes the introduction of digital technologies to improve measurement performance of three systems, aimed at different measurement target and characterized by different accuracy levels.
The high accuracy measurement systems, based on rotating coils, exhibit high performance in static magnetic field. With varying magnetic field the system accuracy gets worse, independently from coil speed, due to the limited resolution of the digital integrator currently used, and the restrictions of the standard analysis. A new integrator based on ADC conversion and numerical integration is proposed. The experimental concept validation by emulating the proposed approach on a PXI platform is detailed along with the improvements with respect to the old integrators. Two new analysis algorithms to reduce the errors in dynamic measurements are presented. The first combines quadrature detection and short time Fourier transform (STFT) of the acquired magnetic flux samples; the second approach is based on the extrapolation of the magnetic flux samples. Unlike other algorithms presented in the literature, both the proposals do not require the information about the magnet current and are able to work in real time so, can be easily implemented in firmware on DSP. The performance of the new proposals are assessed in simulation.
As far as medium accuracy systems are concerned, at CERN was originally developed a probe to measure the sextupolar and decapolar field harmonics of the superconducting dipoles using a suitable Hall plates arrangement for the bucking of the main dipolar field, which is, 4 orders of magnitude higher than the measurement target. The output signals of each Hall plate belonging to the same measurement ring are mixed using analog cards. The resultant signal is proportional to the field harmonic to measure. A complete metrological characterization of this sensor was carried out, showing the limitation of a fully analog solution. The main problems found were the instability of the analog compensation cards and the impossibility to correct the non linearity effects beyond the first order. An automatic calibration procedure implemented in the new instrument software is presented to guarantee measurement repeatability. In alternative a digital bucking solution, namely the compensation of the main field after the sampling of each hall plate signal by means of numerical sum, is proposed. An implementation of this approach, based on 18 bit ADC converter, over-sampling and dithering techniques as well as compensation of the Hall plates non linearity in real time is analyzed.
Finally, as far as the low accuracy measurement systems are concerned, the design of an instrument based on a rotating Hall plate to check the polarity of all LHC magnets is presented. Even if this architecture is characterized by low accuracy in the measurement of field strength and phase, the results are sufficient to identify main harmonic order, type and polarity with practically no errors, thanks to an accurate definition of the measurement algorithm. A complete metrological characterization of the prototype developed and a correction of all the systematic measurement errors was carried out. This instrument, integrated in a test bench developed ad hoc, is become the standard at CERN for the polarity test of all the magnets will compose the machine
LUNASKA experiments using the Australia Telescope Compact Array to search for ultra-high energy neutrinos and develop technology for the lunar Cherenkov technique
We describe the design, performance, sensitivity and results of our recent
experiments using the Australia Telescope Compact Array (ATCA) for lunar
Cherenkov observations with a very wide (600 MHz) bandwidth and nanosecond
timing, including a limit on an isotropic neutrino flux. We also make a first
estimate of the effects of small-scale surface roughness on the effective
experimental aperture, finding that contrary to expectations, such roughness
will act to increase the detectability of near-surface events over the neutrino
energy-range at which our experiment is most sensitive (though distortions to
the time-domain pulse profile may make identification more difficult). The aim
of our "Lunar UHE Neutrino Astrophysics using the Square Kilometer Array"
(LUNASKA) project is to develop the lunar Cherenkov technique of using
terrestrial radio telescope arrays for ultra-high energy (UHE) cosmic ray (CR)
and neutrino detection, and in particular to prepare for using the Square
Kilometer Array (SKA) and its path-finders such as the Australian SKA
Pathfinder (ASKAP) and the Low Frequency Array (LOFAR) for lunar Cherenkov
experiments.Comment: 27 pages, 18 figures, 4 tables
The CLIC Programme: Towards a Staged e+e- Linear Collider Exploring the Terascale : CLIC Conceptual Design Report
This report describes the exploration of fundamental questions in particle
physics at the energy frontier with a future TeV-scale e+e- linear collider
based on the Compact Linear Collider (CLIC) two-beam acceleration technology. A
high-luminosity high-energy e+e- collider allows for the exploration of
Standard Model physics, such as precise measurements of the Higgs, top and
gauge sectors, as well as for a multitude of searches for New Physics, either
through direct discovery or indirectly, via high-precision observables. Given
the current state of knowledge, following the observation of a 125 GeV
Higgs-like particle at the LHC, and pending further LHC results at 8 TeV and 14
TeV, a linear e+e- collider built and operated in centre-of-mass energy stages
from a few-hundred GeV up to a few TeV will be an ideal physics exploration
tool, complementing the LHC. In this document, an overview of the physics
potential of CLIC is given. Two example scenarios are presented for a CLIC
accelerator built in three main stages of 500 GeV, 1.4 (1.5) TeV, and 3 TeV,
together with operating schemes that will make full use of the machine capacity
to explore the physics. The accelerator design, construction, and performance
are presented, as well as the layout and performance of the experiments. The
proposed staging example is accompanied by cost estimates of the accelerator
and detectors and by estimates of operating parameters, such as power
consumption. The resulting physics potential and measurement precisions are
illustrated through detector simulations under realistic beam conditions.Comment: 84 pages, published as CERN Yellow Report
https://cdsweb.cern.ch/record/147522
Technical Design Report for the PANDA Micro Vertex Detector
This document illustrates the technical layout and the expected performance of the Micro Vertex Detector (MVD) of the PANDA experiment. The MVD will detect charged particles as close as possible to the interaction zone. Design criteria and the optimisation process as well as the technical solutions chosen are discussed and the results of this process are subjected to extensive Monte Carlo physics studies. The route towards realisation of the detector is
outlined
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