14,704 research outputs found
G Electronics and Data Acquisition (Forward-Angle Measurements)
The G parity-violation experiment at Jefferson Lab (Newport News, VA) is
designed to determine the contribution of strange/anti-strange quark pairs to
the intrinsic properties of the proton. In the forward-angle part of the
experiment, the asymmetry in the cross section was measured for
elastic scattering by counting the recoil protons corresponding to the two
beam-helicity states. Due to the high accuracy required on the asymmetry, the
G experiment was based on a custom experimental setup with its own
associated electronics and data acquisition (DAQ) system. Highly specialized
time-encoding electronics provided time-of-flight spectra for each detector for
each helicity state. More conventional electronics was used for monitoring
(mainly FastBus). The time-encoding electronics and the DAQ system have been
designed to handle events at a mean rate of 2 MHz per detector with low
deadtime and to minimize helicity-correlated systematic errors. In this paper,
we outline the general architecture and the main features of the electronics
and the DAQ system dedicated to G forward-angle measurements.Comment: 35 pages. 17 figures. This article is to be submitted to NIM section
A. It has been written with Latex using \documentclass{elsart}. Nuclear
Instruments and Methods in Physics Research Section A: Accelerators,
Spectrometers, Detectors and Associated Equipment In Press (2007
The ARGUS Vertex Trigger
A fast second level trigger has been developed for the ARGUS experiment which
recognizes tracks originating from the interaction region. The processor
compares the hits in the ARGUS Micro Vertex Drift Chamber to 245760 masks
stored in random access memories. The masks which are fully defined in three
dimensions are able to reject tracks originating in the wall of the narrow
beampipe of 10.5\,mm radius.Comment: gzipped Postscript, 27 page
Residue analyses and exposure assessment of the Irish population to nitrofuran metabolites from different food commodities in 2009–2010
peer-reviewedAn exposure assessment to nitrofuran residues was performed for three human populations (adults, teenagers and children),
based on residue analyses of foods of animal origin (liver, honey, eggs and aquaculture) covering the 2-year period 2009–
2010. The occurrence of nitrofuran metabolites in food on the Irish market was determined for the selected period using the
data from Ireland’s National Food Residue Database (NFRD) and from results obtained from the analysis of retail samples
(aquaculture and honey). Laboratory analyses of residues were performed by methods validated in accordance with
Commission Decision 2002/657/EC regarding performance of the analytical method and interpretation of results.
Semicarbazide (SEM) was the contaminant most frequently identified and its content ranged from 0.09 to 1.27 μg kg−1.
SEM is currently used as a marker of nitrofuran abuse, but it may also occur from other sources. The presence of nitrofuran
metabolite 3-amino-2-oxazolidinone (AOZ) was detected in two aquaculture samples (prawns) at 1.63 and 1.14 μg kg−1, but
such a low number of positive cases did not present sufficient data for a full AOZ exposure assessment. Therefore, the
evaluation of exposure was focused on SEM-containing food groups only. Exposure assessments were completed using a
probabilistic approach that generated 10 iterations. The results of both the upper- and lower-bound exposure assessments
demonstrate that SEM exposure for Irish adults, teenagers and children from selected food commodities are well below
EFSA-estimated safe levels.This research was funded by the Food for Health Research Initiative (FHRI) administered by the Irish Department of Agriculture, Food and the Marine and the Health Research Board (Contract 07FHRIAFRC5
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