Search results for "FLE"
showing 10 items of 3517 documents
Influence of possible reflections on the operation of European ITER gyrotrons
2010
The theory describing the influence of reflection s on operation of gyrotrons with radial output is used for evaluating the effect of reflections on the operation of the ITER 170 GHz 2 MW coaxial cavity gyrotron, which is under development, and the 170 GHz 1 MW cylindrical cavity gyrotron as a fall back solution.
Echographic patterns of an orbital myxoma and schwannoma
1988
A case of intramuscular orbital myxoma and of a schwannoma of the orbit were studied with B-scan and standardized A-scan echography as described by Ossoinig. The myxoma appeared as a well outlined process with medium internal reflectivity and areas of low internal reflectivity. Postoperatively the incompletely excised tumour was followed with echography as well as CT and MRI. The second tumour, a schwannoma had a very sharply defined shape, with a thick low to medium reflective outer wall and low internal reflectivity. This corresponds to the Antoni A and Antoni B patterns of the excised tumour.
Status of the PANDA Barrel DIRC
2014
The PANDA experiment at the future Facility for Antiproton and Ion Research in Europe GmbH (FAIR) at GSI, Darmstadt will study fundamental questions of hadron physics and QCD using high-intensity cooled antiproton beams with momenta between 1.5 and 15 GeV/c. Hadronic PID in the barrel region of the PANDA detector will be provided by a DIRC (Detection of Internally Reflected Cherenkov light) counter. The design is based on the successful BABAR DIRC with several key improvements, such as fast photon timing and a compact imaging region. Detailed Monte Carlo simulation studies were performed for DIRC designs based on narrow bars or wide plates with a variety of focusing solutions. The performan…
Diffusion of neutrons by a slab of moderating material: an application of the Monte Carlo Method
2004
An application of the Monte Carlo method to the diffusion of neutrons passing through a slab of a moderating material is presented. This method can be used as a tool to improve the student's comprehension of the statistical properties of many particle systems, showing the necessity of simulation procedures to obtain information on the expected results of real experiments. We have chosen a very simple example to illustrate it: the evaluation of the transmission, reflection and absorption probabilities of a monochromatic beam of neutrons diffusing through a slab of a moderator material. After a collision with a nucleus of the moderator the neutron may be either elastically scattered or captur…
Detection system for forward emitted photons at the Experimental Storage Ring at GSI
2013
A single photon counting system has been developed for efficient detection of forward emitted fluorescence photons at the Experimental Storage Ring (ESR) at GSI. The system employs a movable parabolic mirror with a central slit that can be positioned around the ion beam and a selected low noise photomultiplier for detection of the collected photons. Compared to the previously used system of mirror segments installed inside the ESR the collection efficiency for forward-emitted photons is improved by more than a factor of 5. No adverse effects on the stored ion beam have been observed during operation besides a small drop in the ion current of about 5% during movement of the mirror into the b…
The PANDA Barrel DIRC
2016
The PANDA detector at the international accelerator Facility for Antiproton and Ion Research in Europe (FAIR) addresses fundamental questions of hadron physics. Experiments concerning charmonium spectroscopy, the search for hybrids and glueballs and the interaction of hidden and open charm particles with nucleons and nuclei will be performed with antiproton beams impinging on hydrogen or nuclear targets. Cooled beams allow the precision scan of resonances in formation experiments. The momentum range of the antiproton beam between 1.5 GeV/c and 15 GeV/c tests predictions by perturbation theory and will reveal deviations originating from strong QCD . An excellent hadronic particle identificat…
Bloch analysis of finite periodic microring chains
2005
We apply Bloch analysis to the study of finite periodic cascading of microring resonators. Diagonalization of the standard transfer matrix approach not only allows to find an exact analytic expression for transmission and reflection, but also to derive a closed form solution for the field in every point of the structure. To give more physical insight we analyze the main features of the transmission resonances in a finite chain and we give some hints for their experimental verification
A new method to measure the wavelength of single-mode pulsed lasers with a scanning Michelson interferometer
1994
We report on the possibility to measure the wave-lengths of pulsed single-mode lasers by means of a two-beam Michelson interferometer in motion [1,2]. The corner reflector moves with a nearly constant speed creating a path differenceL so thatL/C ≪ 1/Δν, Δν being the spectral width of the laser to be measured. The reference laser is a stabilized He-Ne (Spectra-Physics, model 117 A) to a precision of the order of two parts in 109. The fringe pattern of the two beams (reference beam and measured beam) is sampled simultaneously with a repetition rate of 40 ms. With this new method, the frequency doubled injection-seeded Nd: YAG laser wavelength has been measured with an accuracy of the order of…
Magnetic dipole with a flexible tail as a self-propelling microdevice.
2012
By numerical simulations, it is illustrated that a magnetic dipole with a flexible tail behaves as a swimmer in AC magnetic fields. The behavior of the swimmer on long time scales is analyzed and it is shown that due to the flexibility of the tail two kinds of torques arise, the first is responsible for the orientation of the swimmer perpendicularly to the AC field and the second drags the filament in the direction of the rotating field. Due to this, circular trajectories of the swimmer are possible; however, these are unstable. The self-propulsion velocity of this swimmer is higher than the velocities of other magnetic microdevices for comparable values of the magnetoelastic number.
Development of a PbWO 4 detector for single-shot positron annihilation lifetime spectroscopy at the GBAR experiment
2020
International audience; We have developed a PbWO 4 (PWO) detector with a large dynamic range to measure the intensity of a positron beam and the absolute density of the ortho-positronium (o-Ps) cloud it creates. A simulation study shows that a setup based on such detectors may be used to determine the angular distribution of the emission and reflection of o-Ps to reduce part of the uncertainties of the measurement. These will allow to improve the precision in the measurement of the cross section for the (anti) hydrogen formation by (anti) proton-positronium charge exchange and to optimize the yield of antihydrogen ion which is an essential parameter in the GBAR experiment.