79 research outputs found
The COMPASS experiment and the RICH-1 detector
No full textFauland P. The COMPASS experiment and the RICH-1 detector. Bielefeld (Germany): Bielefeld University; 2004.The Common Muon and Proton Apparatus for Structure and Spectroscopy (COMPASS) is a new fixed target experiment at the CERN (Conseil Européen pour la Recherche Nucléaire) Super Proton Synchrotron (SPS) with the aim to study hadron structure with polarized muon beams and hadron spectroscopy with hadron beams.
The main physics objective of the muon beam physics program is the measurement of the gluon polarization in a longitudinally polarized nucleon. The hadronic program comprises a search for glue balls in the high mass region in exclusive diffractive pion proton scattering, a study of leptonic and semi leptonic decays of charmed hadrons with high statistics and precision and Primakoff scattering with various probes. A detailed investigation of charmed and doubly charmed baryons is performed in a second stage of the experiment.
The setup consists of two spectrometers, one for small angle and one for large angle particles, giving a wide angular acceptance for all measurements. Each spectrometer performs full particle identification using one Ring Imaging Cherenkov Counter (RICH), electromagnetic and hadronic calorimetry and muon detection. A high momentum resolution is obtained by using highly precise tracking with silicon detectors, gaseous strip detectors and drift tubes. The measurements are performed with high intensity beams allowing to collect the needed statistics.
The key-detector for particle identification is the RICH-1, which is a technological challenge in terms of photon detection and radiator gas supply. The COMPASS setup is presented with special focus on the radiator gas preparation and operational aspects of the gas system. Some first results on D meson analysis are presented
Crystal structure determination of the fungal allergen Alt a 1 and biophysical characterization of mutants from the grass pollen allergen Phl p 3
No full textÜber 25% der Menschen aus industrialisierten Ländern leiden unter sogenannten Immunglobulane E (IgE) vermittelten Allergien, deren Symptome von milden Formen wie Heuschnupfen bis zu starken Formen wie Asthma reichen. Die einzige erfolgreiche Behandlung, die zum zeitweiligen Verlust der Immunantwort führt ist die Immuntherapie. Um modifizierte rekombinante Allergene für die Immuntherapie zu generieren sind genauere Informationen über die IgE bindenden Oberflächen (Epitope) notwendig. Bei den Epitopen kann zwischen linearen Epitopen und Konformationsepitopen unterschieden werden. Erstere können relative leicht mittels der Pepscan Methode detektiert werden. Letztere werden durch die 3D Anordnung der Aminosäuren ausgebildet und können daher durch hoch aufgelöste Allergen Strukturen ermittelt werden.Der erste Teil der Arbeit befasst sich mit der Bestimmung der 3D Struktur des Allergens Alt a 1. Da das Hauptallergen des Schimmelpilzes Alternaria alternata ein Disulfid-überbrücktes Homodimer bildet wurde sowohl die oxidierte als auch die reduzierte Form des Allergens untersucht. Die 3D Strukturen wurden in dieser Arbeit verwendet, um die Oberflächenzugänglichkeit der einzelnen Aminosäuren zu bestimmen. Diese Information wurde genutzt, um Peptide für IgE Inhibitionsversuche zu entwickeln. Der zweite Teil der Arbeit befasst sich mit dem Graspollenallergen von Phleum pratense, Phl p 3. Die 3D Struktur des Allergens wurde mittels Röntgenkristallographie gelöst. Da Phl p 3 zur Gruppe 2/3 Allergen-Familie gehört, konnte die 3D Struktur von Phl p 3 zusammen mit 3D Strukturen weiteren Familienmitgliedern verwendet werden, um Epitope vorherzusagen. Dazu wurde das Vorhersageprogramm SPADE verwendet. Die vorhergesagten Aminosäuren wurden im Zuge dieser Arbeit zu Alanine mutiert. Biophysikalische und immunologische Untersuchungen wurden durchgeführt, um bessere Erkenntnisse über die Allergen-Antikörper Bindung und den Beitrag der einzelnen Aminosäure zu gewinnen.More than 25% of the population in industrialized countries suffers from Immunoglobulin E (IgE)-mediated pollen allergies. The symptoms vary from mild ones like hay fever to heavy one like asthma. The only treatment leading to a temporary loss of the responsiveness and/or permanent non-response is the immunotherapy. For the design of modified recombinant proteins for vaccine generation better knowledge about the IgE binding epitope on the allergen surface is necessary. Epitopes can be divided into continuous (lanear) and discontinuous (conformational) epitopes. Lanear epitopes are quite easy to detect using the pepscan method. The conformational epitopes are built up by the three-dimensional arrangement of the amino acids, so it is necessary to know the three-dimensional structure of the allergen to detect the conformational IgE binding epitope.The first part of the thesis deals with the determination of the high resolution structure of the allergen Alt a 1. Alt a 1 is the major allergen of Alternaria alternata and is associated with asthma. Because it is known to form a disulfide linked homodimer the oxidized as well as the reduced form of the allergen was characterized. The high resolution 3D structures were used to determine the solvent accessible surface of the single amino acids. This information was used to design new peptides for IgE inhibition experiments.The second part of the thesis deals with the grass pollen allergen of Phleum pretense Phl p 3. Because Phl p 3 is a member of the group 2/3 allergen family it was possible to predict epitopes using the high resolution structure of Phl p 3, solved in our group, and high resolution structures of other members of the group 2/3 family. The epitope prediction was done using the program SPADE. The predicted amino acids were mutated to alanines. Biophysical and immunological experiments of the 24 point mutants should lead to information about the binding behavior of the predicted amino acids.Kerstin FaulandAbweichender Titel laut Übersetzung der Verfasserin/des VerfassersGraz, Univ., Diss., 2013Zsfassung in dt. und engl. Sprach
Metabolomics analysis identifies different metabotypes of asthma severity
No full textIn this study, we sought to determine whether asthma has a metabolic profile and whether this profile is related to disease severity.We characterised the serum from 22 healthy individuals and 54 asthmatics (12 mild, 20 moderate, 22 severe) using liquid chromatography–high-resolution mass spectrometry-based metabolomics. Selected metabolites were confirmed by targeted mass spectrometry assays of eicosanoids, sphingolipids and free fatty acids.We conclusively identified 66 metabolites; 15 were significantly altered with asthma (p≤0.05). Levels of dehydroepiandrosterone sulfate, cortisone, cortisol, prolylhydroxyproline, pipecolate and N-palmitoyltaurine correlated significantly (p<0.05) with inhaled corticosteroid dose, and were further shifted in individuals treated with oral corticosteroids. Oleoylethanolamide increased with asthma severity independently of steroid treatment (p<0.001). Multivariate analysis revealed two patterns: 1) a mean difference between controls and patients with mild asthma (p=0.025), and 2) a mean difference between patients with severe asthma and all other groups (p=1.7×10−4). Metabolic shifts in mild asthma, relative to controls, were associated with exogenous metabolites (e.g. dietary lipids), while those in moderate and severe asthma (e.g. oleoylethanolamide, sphingosine-1-phosphate, N-palmitoyltaurine) were postulated to be involved in activating the transient receptor potential vanilloid type 1 (TRPV1) receptor, driving TRPV1-dependent pathogenesis in asthma.Our findings suggest that asthma is characterised by a modest systemic metabolic shift in a disease severity-dependent manner, and that steroid treatment significantly affects metabolism
VUV absorbing vapours in n-perfluorocarbons
No full textAlbrecht E, Baum G, Bellunato T, et al. VUV absorbing vapours in n-perfluorocarbons. Nucl.Instrum.Meth. A. 2003;510(3):262-272.The optical transparency, of perfluorocarbons used as Cherenkov media is of prime importance to many Ring Imaging Cherenkov detectors. We will in this paper show that the main photon absorbers in these fluids are hydrocarbons with double or triple bonds. We will moreover discuss a process which can eliminate these pollutants and restore the intrinsic excellent optical transparency of these fluids in the VUV range. (C) 2003 Elsevier B.V. All rights reserved
Monte Carlo studies of the COMPASS RICH 1 optical properties
No full textBaum G, Birsa R, Bradamante F, et al. Monte Carlo studies of the COMPASS RICH 1 optical properties. In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. Nucl.Instrum.Meth. A. Vol 433. ELSEVIER SCIENCE BV; 1999: 401-405.A dedicated Monte Carlo has been built to study the optical properties of the RICH 1 detector presently under construction for the COMPASS experiment at CERN. In this paper we focus on the optimization of the position of the photon detector with respect to the RICH mirror and on the alignment of the mirror elements forming the mirror surface. (C) 1999 Elsevier Science B.V. All rights reserved
The COMPASS RICH-1 read-out system
No full textBaum G, Birsa R, Bradamante F, et al. The COMPASS RICH-1 read-out system. In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. Nucl.Instrum.Meth. A. Vol 502. Elsevier Science BV; 2003: 246-250.This paper describes the reconfigurable read-out system for the 82944 RICH-1 channels of the COMPASS experiment (NA58) at CERN. The system is based on 192 identical large front-end boards (BORA board). BORA was designed for acquiring, digitizing, threshold subtracting and transmitting event data. The overall operation of the board is controlled and supervised by a DSP tightly interacting with an FPGA that acts as a parallel co-processor. The DSP allows characterizing each analog channel by locally calculating noise and pedestal. Each BORA communicates with the outside world through two optical fibers and through a dedicated DSP network. One optical fiber is used to receive event triggers, and the other one is used to transmit event data to subsequent processing stages of the acquisition system. The DSP network allows reconfiguring and reprogramming the DSPs and FPGAs as well as acquiring sample events to visualize the overall operation of the system. The whole RICH has eight DSP networks working in parallel. These networks are handled by DOLINA. a PC resident multiprocessor board containing eight DSPs. Each network is formed by 24 BORA DSPs and I DOLINA DSP. The read-out system can steadily work up to a trigger rate of 75 kHz with maximum pixel occupancy of 20%, reaching a transmission data rate of 5.13 Gbytes/s. (C) 2003 Elsevier Science B.V. All rights reserved
The COMPASS RICH1 detector
No full textBaum G, Birsa R, Bradamante F, et al. The COMPASS RICH1 detector. In: Nuclear Physics B - Proceedings Supplements. Nucl.Phys.Proc.Suppl. Vol 78. ELSEVIER SCIENCE BV; 1999: 354-359.A large acceptance gas RICH detector is presently under construction for the spectrometer of the COMPASS Experiment. Tts design parameters are presented and the main characteristics of the vessel, the mirrors system, the photon detectors and the front-end electronics are-discussed together with some results from prototyping activities
The COMPASS RICH project
No full textBaum G, Birsa R, Bradamante F, et al. The COMPASS RICH project. In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. Nucl.Instrum.Meth. A. Vol 433. ELSEVIER SCIENCE BV; 1999: 207-211.The set-up of the COMPASS experiment (NA58 at CERN SPS) consists of two spectrometers (a large-angle one followed by a small-angle spectrometer) both equipped with a gas RICH (RICH 1 and RICH 2) for hadron identification. RICH 1 is currently under construction, while RICH 2 will be added at a second stage. RICH 1 design parameters and technological choices are discussed. (C) 1999 Elsevier Science B.V. All rights reserved
RICHONE: a software package for the analysis of COMPASS RICH-1 data
No full textBaum G, Birsa R, Bradamante F, et al. RICHONE: a software package for the analysis of COMPASS RICH-1 data. In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. Nucl.Instrum.Meth. A. Vol 502. Elsevier Science BV; 2003: 315-317.RICHONE is the pattern recognition and PID code for COMPASS RICH-1. RICHONE is part of CORAL, the COMPASS software system, a C++ framework developed within the collaborations using up-to-date techniques and tools. (C) 2003 Elsevier Science B.V. All rights reserved
BORA: a front end board, with local intelligence, for the RICH detector of the Compass Collaboration
No full textBaum G, Birsa R, Bradamante F, et al. BORA: a front end board, with local intelligence, for the RICH detector of the Compass Collaboration. In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. Nucl.Instrum.Meth. A. Vol 433. ELSEVIER SCIENCE BV; 1999: 426-431.In this paper we describe the design of the re-configurable front-end boards (BORA boards) for the 82944 channel RICH-1 (Ring Imaging CHerenkov) of the Compass Collaboration (NA58). The front-end electronics controls the sample-and-hold operation after the arrival of an event trigger, acquires the analog voltages from the pre-amp VLSI and converts them into 10 bits at a rate of 20 Ms/s per analog channel. The digitized analogue values are then written into FIFOs. A subsequent operation compares the readings of each and every channel with corresponding programmable thresholds, and transmits those values larger than the threshold, together with the channel number, through an optical fiber to subsequent processing stages of the acquisition system. The overall operation of the board is controlled and supervised by a fast DSP. The availability of local intelligence allows the board to present innovative features such as: to be part of a computer network that connects several similar boards of the detector with a PC. The presence of the DSP allows testing the operability and linearity of the analog channels; and creating engineering frames containing local temperatures and voltages and transmitting the results through the network. The operator can reconfigure the hardware and software of the board by downloading programs from the PC. (C) 1999 Elsevier Science B.V. All rights reserved
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