812 research outputs found
Laser-driven electron source suitable for single-shot Gy-scale irradiation of biological cells at dose-rates exceeding Gy/s
We report on the first systematic characterisation of a tuneable laser-driven
electron source capable of delivering Gy-scale doses in a duration of 10 - 20
ps, thus reaching unprecedented dose rates in the range of
Gy/s. Detailed characterisation of the source indicates, in agreement with
Monte-Carlo simulations, single-shot delivery of multi-Gy doses per pulse over
cm-scale areas, with a high degree of spatial uniformity. The results reported
here confirm that a laser-driven source of this kind can be used for systematic
studies of the response of biological cells to picosecond-scale radiation at
ultra-high dose rates.Comment: submitted for publicatio
Development of an algorithm for assessing canopy volumes with terrestrial LiDAR to implement precision spraying in vineyards
Received: February 13th, 2021 ; Accepted: November 28th, 2021 ; Published: December 3rd, 2021 ; Correspondence: [email protected] spraying is one of the techniques for the reduction of pesticides use and it
can help achieve the new European Green Deal standards. The aim of such technique is to apply
the right amount of pesticides according to the target characteristics. The precision spraying
implementation requires target volume assessment, which can be carried out by LiDAR sensors.
Such technique requires complex and time-consuming procedures of canopy characteristics
computing through post-processing points cloud reconstruction. The present work aimed to
develop and test an algorithm through the use of a tractor-coupled with terrestrial LiDAR and
GNSS technology in order to simplify the process. With the aim to evaluate the algorithm the
LiDAR-based volume was correlated with two manual measurements of canopy volume (Tree
Row Volume and Point Net Cloud). The results showed good correlations between manual and
LiDAR measures both for total canopy volumes (R
2 = 0.67 and 0.56) and for partial canopy
volume (R
2 = 0.74). In conclusion, although the LiDAR-based algorithm works in automatic
mode, the canopy volumes approximation seems acceptable to estimate the canopy volumes, with
the advantages of a swifter procedure and less laborious post-processing computations
A PMT-Block test bench
The front-end electronics of the ATLAS hadronic calorimeter (Tile Cal) is
housed in a unit, called {\it PMT-Block}. The PMT-Block is a compact instrument
comprising a light mixer, a PMT together with its divider and a {\it 3-in-1}
card, which provides shaping, amplification and integration for the signals.
This instrument needs to be qualified before being assembled on the detector. A
PMT-Block test bench has been developed for this purpose. This test bench is a
system which allows fast, albeit accurate enough, measurements of the main
properties of a complete PMT-Block. The system, both hardware and software, and
the protocol used for the PMT-Blocks characterisation are described in detail
in this report. The results obtained in the test of about 10000 PMT-Blocks
needed for the instrumentation of the ATLAS (LHC-CERN) hadronic Tile
Calorimeter are also reported.Comment: 23 pages, 10 figure
Development of FTK architecture: a fast hardware track trigger for the ATLAS detector
The Fast Tracker (FTK) is a proposed upgrade to the ATLAS trigger system that
will operate at full Level-1 output rates and provide high quality tracks
reconstructed over the entire detector by the start of processing in Level-2.
FTK solves the combinatorial challenge inherent to tracking by exploiting the
massive parallelism of Associative Memories (AM) that can compare inner
detector hits to millions of pre-calculated patterns simultaneously. The
tracking problem within matched patterns is further simplified by using
pre-computed linearized fitting constants and leveraging fast DSP's in modern
commercial FPGA's. Overall, FTK is able to compute the helix parameters for all
tracks in an event and apply quality cuts in approximately one millisecond. By
employing a pipelined architecture, FTK is able to continuously operate at
Level-1 rates without deadtime. The system design is defined and studied using
ATLAS full simulation. Reconstruction quality is evaluated for single muon
events with zero pileup, as well as WH events at the LHC design luminosity. FTK
results are compared with the tracking capability of an offline algorithm.Comment: To be published in the proceedings of DPF-2009, Detroit, MI, July
2009, eConf C09072
The Evolution of FTK, a Real-Time Tracker for Hadron Collider Experiments
We describe the architecture evolution of the highly-parallel dedicated
processor FTK, which is driven by the simulation of LHC events at high
luminosity (1034 cm-2 s-1). FTK is able to provide precise on-line track
reconstruction for future hadronic collider experiments. The processor,
organized in a two-tiered pipelined architecture, execute very fast algorithms
based on the use of a large bank of pre-stored patterns of trajectory points
(first tier) in combination with full resolution track fitting to refine
pattern recognition and to determine off-line quality track parameters. We
describe here how the high luminosity simulation results have produced a new
organization of the hardware inside the FTK processor core.Comment: 11th ICATPP conferenc
Observation of plasma density dependence of electromagnetic soliton excitation by an intense laser pulse
The experimental evidence of the correlation between the initial electron density of the plasma and electromagnetic soliton excitation at the wake of an intense (1019 Wcm2) and short (1 ps) laser pulse is presented. The spatial distribution of the solitons, together with their late time evolution into post-solitons, is found to be dependent upon the background plasma parameters, in agreement with published analytical and numerical findings. The measured temporal evolution and electrostatic field distribution of the structures are consistent with their late time evolution and the occurrence of multiple merging of neighboring post-solitons. © 2011 American Institute of Physics
Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC
The uncertainty on the calorimeter energy response to jets of particles is
derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the
calorimeter response to single isolated charged hadrons is measured and
compared to the Monte Carlo simulation using proton-proton collisions at
centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009
and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter
response to specific types of particles (positively and negatively charged
pions, protons, and anti-protons) is measured and compared to the Monte Carlo
predictions. Finally, the jet energy scale uncertainty is determined by
propagating the response uncertainty for single charged and neutral particles
to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3%
for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table,
submitted to European Physical Journal
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