5,491 research outputs found
CERN openlab Whitepaper on Future IT Challenges in Scientific Research
This whitepaper describes the major IT challenges in scientific research at CERN and several other European and international research laboratories and projects. Each challenge is exemplified through a set of concrete use cases drawn from the requirements of large-scale scientific programs. The paper is based on contributions from many researchers and IT experts of the participating laboratories and also input from the existing CERN openlab industrial sponsors. The views expressed in this document are those of the individual contributors and do not necessarily reflect the view of their organisations and/or affiliates
The ArgoNeuT Detector in the NuMI Low-Energy beam line at Fermilab
The ArgoNeuT liquid argon time projection chamber has collected thousands of
neutrino and antineutrino events during an extended run period in the NuMI
beam-line at Fermilab. This paper focuses on the main aspects of the detector
layout and related technical features, including the cryogenic equipment, time
projection chamber, read-out electronics, and off-line data treatment. The
detector commissioning phase, physics run, and first neutrino event displays
are also reported. The characterization of the main working parameters of the
detector during data-taking, the ionization electron drift velocity and
lifetime in liquid argon, as obtained from through-going muon data complete the
present report.Comment: 43 pages, 27 figures, 5 tables - update referenc
Perspectives of Imaging of Single Protein Molecules with the Present Design of the European XFEL. - Part I - X-ray Source, Beamlime Optics and Instrument Simulations
The Single Particles, Clusters and Biomolecules (SPB) instrument at the
European XFEL is located behind the SASE1 undulator, and aims to support
imaging and structure determination of biological specimen between about 0.1
micrometer and 1 micrometer size. The instrument is designed to work at photon
energies from 3 keV up to 16 keV. This wide operation range is a cause for
challenges to the focusing optics. In particular, a long propagation distance
of about 900 m between x-ray source and sample leads to a large lateral photon
beam size at the optics. The beam divergence is the most important parameter
for the optical system, and is largest for the lowest photon energies and for
the shortest pulse duration (corresponding to the lowest charge). Due to the
large divergence of nominal X-ray pulses with duration shorter than 10 fs, one
suffers diffraction from mirror aperture, leading to a 100-fold decrease in
fluence at photon energies around 4 keV, which are ideal for imaging of single
biomolecules. The nominal SASE1 output power is about 50 GW. This is very far
from the level required for single biomolecule imaging, even assuming perfect
beamline and focusing efficiency. Here we demonstrate that the parameters of
the accelerator complex and of the SASE1 undulator offer an opportunity to
optimize the SPB beamline for single biomolecule imaging with minimal
additional costs and time. Start to end simulations from the electron injector
at the beginning of the accelerator complex up to the generation of diffraction
data indicate that one can achieve diffraction without diffraction with about
0.5 photons per Shannon pixel at near-atomic resolution with 1e13 photons in a
4 fs pulse at 4 keV photon energy and in a 100 nm focus, corresponding to a
fluence of 1e23 ph/cm^2. This result is exemplified using the RNA Pol II
molecule as a case study
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
Hardware Acceleration of Neural Graphics
Rendering and inverse-rendering algorithms that drive conventional computer
graphics have recently been superseded by neural representations (NR). NRs have
recently been used to learn the geometric and the material properties of the
scenes and use the information to synthesize photorealistic imagery, thereby
promising a replacement for traditional rendering algorithms with scalable
quality and predictable performance. In this work we ask the question: Does
neural graphics (NG) need hardware support? We studied representative NG
applications showing that, if we want to render 4k res. at 60FPS there is a gap
of 1.5X-55X in the desired performance on current GPUs. For AR/VR applications,
there is an even larger gap of 2-4 OOM between the desired performance and the
required system power. We identify that the input encoding and the MLP kernels
are the performance bottlenecks, consuming 72%,60% and 59% of application time
for multi res. hashgrid, multi res. densegrid and low res. densegrid encodings,
respectively. We propose a NG processing cluster, a scalable and flexible
hardware architecture that directly accelerates the input encoding and MLP
kernels through dedicated engines and supports a wide range of NG applications.
We also accelerate the rest of the kernels by fusing them together in Vulkan,
which leads to 9.94X kernel-level performance improvement compared to un-fused
implementation of the pre-processing and the post-processing kernels. Our
results show that, NGPC gives up to 58X end-to-end application-level
performance improvement, for multi res. hashgrid encoding on average across the
four NG applications, the performance benefits are 12X,20X,33X and 39X for the
scaling factor of 8,16,32 and 64, respectively. Our results show that with
multi res. hashgrid encoding, NGPC enables the rendering of 4k res. at 30FPS
for NeRF and 8k res. at 120FPS for all our other NG applications
Summary: Working Group on QCD and Strong Interactions
In this summary of the considerations of the QCD working group at Snowmass
2001, the roles of quantum chromodynamics in the Standard Model and in the
search for new physics are reviewed, with empahsis on frontier areas in the
field. We discuss the importance of, and prospects for, precision QCD in
perturbative and lattice calculations. We describe new ideas in the analysis of
parton distribution functions and jet structure, and review progress in
small- and in polarization.Comment: Snowmass 2001. Revtex4, 34 pages, 4 figures, revised to include
additional references on jets and lattice QC
Development and Applications of a Real-time Magnetic Electron Energy Spectrometer for Use with Medical Linear Accelerators
Purpose – This work presents a design for a real-time electron energy spectrometer, and provides data analysis methods and characterization of the real-time system. This system is intended for use with medical linear accelerators (linacs). The goal is 1 Hz acquisition of the energy range 4-25 MeV, reconstructed in 0.1 MeV increments.
Methods – Our spectrometer uses a nominal 0.54 T permanent magnet block as the dispersive element and scintillating fibers coupled to a CCD camera as the position sensitive detector. A broad electron beam produced by a linac is collimated by a 6.35 mm dimeter aperture at the entrance to the spectrometer. The collimated beam is dispersed by the magnetic field onto a row of 60 vertical 1 mm x 1 mm square scintillating fibers mounted to a lateral face of the magnet. Detector response functions (DRFs) were created using a simplified physics model of the spectrometer to determine electron trajectories within the magnet block from the entrance aperture to the detector plane. The DRFs were used in an iterative method to transform the fiber signal intensity versus position into an energy spectrum. We made measurements on an Elekta Infinity linac; each available energy (7, 9, 10, 11, 13, 16, 20 MeV) was investigated. Measurements were used to assess setup reproducibility, pinhole mismatch, dose rate effects, temporal stability, and linac detuning.
Results – Our reconstruction method was able to reconstruct energy spectra from idealized simulations to within 0.14 MeV ± 0.28 MeV of the ideal FWHM value, and 0.06 MeV ± 0.12 MeV of the ideal most probable energy, Ep0. The measured spectral stability was consistent with the expected linac operating stability. The system achieved a refresh rate of 0.8 Hz during real-time operation.
Conclusions – We developed a real-time electron energy spectrometer that measures electron energies from 4 to 25 MeV with a continuous readout rate of 0.8 Hz. The device can be used for assessing linac performance as a routine clinical tool, assist in diagnostic maintenance and repair, or potentially provide a more efficient method for beam tuning and matching
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