POLARISED PHOTON BEAMS AT ELSA AND RECENT RESULTS OF DOUBLE POLARISATION MEASURMENTS

2010 ◽  
Vol 19 (05n06) ◽  
pp. 869-881 ◽  
Author(s):  
◽  
DANIEL ELSNER
Keyword(s):  
Excitation Spectrum ◽  
Electron Accelerator ◽  
Solid Angle ◽  
Neutral Meson ◽  
Experimental Setup ◽  
Final States ◽  
Photon Beams ◽  
Beam Asymmetries ◽  
Target Asymmetry ◽  
The University

The puzzle of the excitation spectrum of the nucleon, composed of broad and overlapping resonances, is still unresolved. For a complete experiment at least 8 well chosen single and double polarisation observables are needed. At the electron accelerator ELSA of the University of Bonn single- and double polarisation experiments are currently performed with the Crystal Barrel/TAPS experiment. The experimental setup includes a ɸ-symmetric calorimeter system covering almost the complete solid angle and it is ideally suited to detect single and multiple neutral meson final states. Circularly or linearly polarised photon beams impinge on a longitudinal polarised butanol target in the center of the setup. The linearly polarised photon beams provide the basis for the measurement of azimuthal beam asymmetries, such as Σ and, in combination with the polarised target, G . Circularly polarised photon beams allow the extraction of the beam-target asymmetry E . Preliminary results for the polarisation observables Σ, G and E will be presented.

scholarly journals THE BGO-OD EXPERIMENT AT ELSA

2014 ◽  
Vol 26 ◽  
pp. 1460093 ◽  
Author(s):  
◽  
B. BANTES ◽  
D. BAYADILOV ◽  
R. BECK ◽  
M. BECKER ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Excitation Spectrum ◽  
Final States ◽  
Vector Mesons ◽  
Meson Photoproduction ◽  
Neutral Particles ◽  
Pseudoscalar Mesons ◽  
Initial Program ◽  
The University

Meson photoproduction is a key tool for the experimental investigation of the nucleon excitation spectrum. To disentangle the specific couplings of resonances, in addition to the rather well measured pion and eta photoproduction channels it is mandatory to obtain information on channels involving strange and vector mesons and higher mass pseudoscalar mesons, and the associated multi-particle final states with both charged and neutral particles. In this respect, the new BGO-OD experiment at the ELSA accelerator of the University of Bonn's Physikalisches Institut provides unique instrumentation. We describe the experiment, present its status and the initial program of measurements.

THE BGO-OPENDIPOLE SETUP AT ELSA

2010 ◽  
Vol 19 (05n06) ◽  
pp. 1043-1054 ◽  
Author(s):  
HARTMUT SCHMIEDEN
Keyword(s):  
Excited State ◽  
High Resolution ◽  
Electron Accelerator ◽  
Charged Particles ◽  
Ground States ◽  
Final States ◽  
Meson Photoproduction ◽  
Accelerator Facility ◽  
Photon Detection ◽  
The University

At the electron accelerator facility ELSA of the University of Bonn presently the new BGO-OpenDipole experiment is being setup. It is optimized for meson photoproduction final states of mixed charges. The detector combines hermetic coverage for photon detection through the BGO ball of the former GRAAL experiment with high resolution detection of forward going charged particles in the Open Dipole spectrometer. This setup is well suited for many different channels, including pseudoscalar, vectormeson and associated strangeness photoproduction. This contribution highlights the strangeness channels associated with the Λ and Σ ground states and the Λ(1405) excited state.

scholarly journals Technical Note: Noble gas extraction procedure and performance of the Cologne Helix MC Plus multi-collector noble gas mass spectrometer for cosmogenic neon isotope analysis

2021 ◽  
Author(s):  
Benedikt Ritter ◽  
Andreas Vogt ◽  
Tibor J. Dunai
Keyword(s):  
Mass Spectrometer ◽  
Noble Gas ◽  
Primary Standard ◽  
Isotope Analysis ◽  
Extraction Procedure ◽  
Technical Note ◽  
High Mass ◽  
Experimental Setup ◽  
And Performance ◽  
The University

Abstract. We established a new laboratory for noble gas mass spectrometry that is dedicated for the development and application to cosmogenic nuclides at the University of Cologne (Germany). At the core of the laboratory are a state-of-the-art high mass resolution multicollector Helix MCPlus (Thermo-Fisher) noble gas mass spectrometer and a novel custom-designed automated extraction line. The Mass-spectrometer is equipped with five combined Faraday Multiplier collectors, with 1012 Ω and 1013 Ω pre-amplifiers for faraday collectors. We describe the extraction line and the automized operation procedure for cosmogenic neon and the current performance of the experimental setup. Performance tests were conducted using gas of atmospheric isotopic composition (our primary standard gas); as well as CREU-1 intercomparison material, containing a mixture of neon of atmospheric and cosmogenic composition. We use the results from repeated analysis of CREU-1 to assess the performance of the current experimental setup at Cologne. The precision in determining the abundance of cosmogenic 21Ne is equal or better than those reported for other laboratories. The absolute value we obtain for the concentration of cosmogenic 21Ne in CREU is indistinguishable from the published value.

Final states with a neutral meson and a π+π− or pair in interactions at 7.2 GeV/c

1978 ◽  
Vol 133 (2) ◽  
pp. 245-265 ◽  
Author(s):  
G.W. Van Apeldoorn ◽  
R.L.F. Gründeman ◽  
D. Harting ◽  
D.J. Holthuizen ◽  
R. Leeuwerink ◽  
...  
Keyword(s):  
Neutral Meson ◽  
Final States

Generation of Intake Distortion due to Angle of Attack for a High Bypass Turbofan Model

2014 ◽  
Author(s):  
Jan-Hendrik Krone ◽  
Jens Friedrichs
Keyword(s):  
Wind Tunnel ◽  
Angle Of Attack ◽  
Experimental Setup ◽  
Jet Engine ◽  
Numerical Investigations ◽  
Fan Performance ◽  
Aerodynamic Interaction ◽  
Inlet Conditions ◽  
The University ◽  
Operating Points

This article presents a new fan testing concept which was developed by the University of Braunschweig. The aim of the concept is to provide an experimental setup for integrated jet engine fan investigations. This integrated setup includes a full bypass model with nacelle geometry in order to obtain all aerodynamic interaction effects. Since these interactions have a strong dependency from fan inlet conditions the facility provides wind tunnel capacities. Generating both uniform and angle of attack inlet conditions it is possible to investigate fan performance during the most critical operating points of a civil flight mission. The main innovation of the wind tunnel is the crosswind concept for generating angle of attack conditions in case of a non-pitchable fan unit. Numerical investigations in this paper are intended to validate this new concept by means of typical angle of attack simulations. The results show that the crosswind concept is able to generate equivalent cp-characteristics as obtained for the reference simulations at the nacelle 6 o‘clock and 12 o‘clock positions.

scholarly journals Photoproduction of mesons and Compton scattering on the proton: Selected results from the A2 Collaboration at MAMI

2020 ◽  
Vol 241 ◽  
pp. 01017
Author(s):  
Vahe Sokhoyan
Keyword(s):  
Compton Scattering ◽  
High Precision ◽  
Cross Sections ◽  
Final States ◽  
Photon Beams ◽  
Accelerator Facility ◽  
Crystal Ball ◽  
Plane Detector ◽  
Baryon Resonances ◽  
Focal Plane Detector

The A2 Collaboration performs a manifold research program using real photons in the Crystal Ball/TAPS experiment at the MAMI accelerator facility in Mainz. The experiments take advantage of high- intensity unpolarized, linearly or circularly polarized photon beams, and unpolarized or polarized targets. The detector setup provides almost complete coverage in solid angle and is well suited for the detection of multi particle final states. In order to probe the internal structure of the nucleon, the spectrum of baryon resonances is studied via measurements of unpolarized cross sections and various polarization observables in single and double meson photoproduction. The program aiming to determine the scalar and spin polarizabilities of the nucleons with high precision is performed with the Compton scattering experiments. In 2017, the focal plane detector used in the tagging system of the Crystal Ball/TAPS experiment was completely renewed, allowing new measurements with unprecedentedly high precision. This paper presents recent selected results from the A2 Collaboration at MAMI.

Experimental Setup for Full-Scale Testing of Pipes Under Combined Loads

2006 ◽  
Author(s):  
Istemi F. Ozkan ◽  
Magdi Mohareb
Keyword(s):  
Internal Pressure ◽  
Tensile Force ◽  
Compressive Force ◽  
Full Scale ◽  
Experimental Setup ◽  
Combined Loads ◽  
Axial Tensile ◽  
Deformational Behavior ◽  
Combined Action ◽  
The University

A versatile experimental setup was recently built at the University of Ottawa Structural Laboratory with the capability of testing full-scale pipes under load combinations involving axial tensile/compressive force, twist, shear, internal pressure, and imposed bending deformations. This paper presents the innovative aspects of the new experimental setup and documents some aspects of the deformational behavior of pipe specimen of X65 material, 20 in. OD with a diameter to thickness ratio of 80, under the combined action of internal pressure, axial tensile force, torsion, and imposed curvature, which was recently conducted under the new setup. The results reported are part of a testing program, which is currently underway.

Studies on the Instrumental Factors Determining Errors in the Measurements of Raman Band Profiles. Part I: Optical Factors—A Comparison of Three Different Methods

1993 ◽  
Vol 47 (8) ◽  
pp. 1227-1233 ◽  
Author(s):  
L. Mariani ◽  
A. Morresi ◽  
M. G. Giorgini ◽  
G. Paliani ◽  
R. S. Cataliotti
Keyword(s):  
Solid Angle ◽  
Raman Band ◽  
Incident Beam ◽  
Suitable Method ◽  
Beam Polarization ◽  
Experimental Setup ◽  
Band Shape ◽  
Error Sources ◽  
Anisotropic Component ◽  
Following Error

A treatment is proposed which takes into account the following error sources in Raman band shape measurements: incident beam polarization, polarization analyzer misorientation, monochromator response, and observation over a finite solid angle. Three methods generally adopted for this type of measurements are compared in terms of the amount of spurious anisotropic component which enters the isotropic profile. The pertinence zones of each method are shown. The percentage of error is expressed by well-defined quantities entering analytical equations; this allows the experimentalist to choose the more suitable method on the basis of the experimental setup.

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