17 research outputs found
Inclusive and Semi-Inclusive Double Spin Asymmetries at COMPASS
No full textIn 2002 the fixed target experiment COMPASS at CERN has taken data for the first time. Based on this data first results have been presented at this workshop. In this paper a measurement of the inclusive spin asymmetry is shown
Kinetics of 5-aminolevulinic acid-induced fluorescence in organ cultures of bronchial epithelium and tumor
No full textBackground: 5-Aminolevulinic acid (5-ALA)-induced protoporphyrin IX (PPIX) fluorescence improves the differentiation of tumor and normal tissue in the bladder, skin and brain. Objective: The kinetics of 5-ALA-induced protoporphyrin IX (PPIX) fluorescence in organ cultures of normal human bronchial epithelium and cocultures of bronchial epithelium and tumor have been studied. Methods: Cultured biopsies of bronchial epithelium were exposed for 5 or 15 min, or continuously to 5-ALA. PPIX fluorescence was quantified for up to 300 min by spectroscopy. Cocultures of normal bronchial epithelium and a non-small-cell lung cancer cell line (EPLC-32M1) were incubated with 5-ALA. Space-resolved fluorescence microscopy was used to quantify PPIX fluorescence kinetics in the tumor and normal epithelium. Results: In cultures of normal epithelium, PPIX fluorescence kinetics were shown to depend on the duration of exposure to 5-ALA. There was a trend to higher fluorescence intensities with longer exposure times. In cocultures of bronchial epithelium and tumor, increases of fluorescence intensity were significantly greater in the tumor. Best tumor/normal tissue fluorescence ratios were found between 110 and 160 min after exposure to 5-ALA. Conclusion: Data obtained in this coculture system of bronchial epithelium and tumor is valuable to optimize modalities of fluorescence bronchoscopy for the diagnosis of early bronchial carcinoma. Copyright (C) 2002 S. Karger AG, Basel
<title>5-aminolaevulinic acid for fluorescence diagnosis and photodynamic therapy of bronchial cancer: a case report</title>
No full textThe trigger system of the COMPASS experiment
No full textIn the following article the trigger system of the CERN COMPASS experiment is presented. Special emphasis is put on the so called Quasi Real Photon Trigger which was designed to select muon scattering events with a relative energy loss in excess of a certain threshold y/sub min/ over the full range of momentum transfers (Q/sup 2/) down to the quasi real limit (Q/sup 2/ approximately= 0). This trigger system consists of two stages to achieve high selectivity. The first stage is composed of pairs of plastic scintillator hodoscopes which select the scattered muons by measuring their energy. The second stage comprises a hadron trigger based on the two hadron calorimeters of COMPASS. This system detects hadrons in coincidence with the scattered muon to reduce background stemming from radiative and mu -e-scattering events. The Quasi Real Photon Trigger which can be considered as a tagger for quasi real photon events is complemented by larger standard trigger hodoscope systems covering the region of (Q/sup 2/ > 1 GeV/sup 2/). (4 refs)
A new measurement of the Collins and Sivers asymmetries on a transversely polarised deuteron target
No full textAgeev ES, Alexakhin VY, Alexandrov Y, et al. A new measurement of the Collins and Sivers asymmetries on a transversely polarised deuteron target. Nucl.Phys. B. 2007;765(1-2):31-70.New high precision measurements of the Collins and Sivers, asymmetries of charged hadrons produced in deep-inelastic scattering of muons on a transversely polarised (LiD)-Li-6 target are presented. The data were taken in 2003 and 2004 with the COMPASS spectrometer using the muon beam of the CERN SPS at 160 GeV/c. Both the Collins and Sivers asymmetries turn out to be compatible with zero, within the present statistical errors, which are more than a factor of 2 smaller than those of the published COMPASS results from the 2002 data. The final results from the 2002, 2003 and 2004 runs are compared with naive expectations and with existing model calculations. (c) 2006 Elsevier B.V. All rights reserved
Gluon polarization in the nucleon from quasi-real photoproduction of high-p hadron pairs
No full textWe present a determination of the gluon polarization DeltaG/G in the nucleon, based on the helicity asymmetry of quasi-real photoproduction events, Q2 < 1 (GeV/c)2, with a pair of large transverse-momentum hadrons in the final state. The data were obtained by the COMPASS experiment at CERN using a 160 GeV polarized muon beam scattered on a polarized 6LiD target. The helicity asymmetry for the selected events is A/D = 0.002 ± 0.019(stat) ± 0.003(syst). From this value, we obtain in a leading-order QCD analysis DeltaG/G = 0.024 ± 0.089(stat) ± 0.057(syst) at xg = 0.095 and μ2 ~ 3 (GeV/c)2
