Search results for "Computer Science Applications"
showing 10 items of 3993 documents
Far-infrared laser action from parabolic quantum dots matrix
2008
In this paper we present results of calculations for quantum dots matrix acting as an active medium in novelty proposal of far-infrared laser. The proposal is based on the pumping laser by rapid (nonadiabatic) switching on in-plane electric field which allows us to obtain population inversion. The numerical analysis of electron-photon system kinetics was performed for various electric fields and temperatures. These calculation utilises the method of solving the Cauchy problem for infinite chain of linear differential equations. Also the contribution of dynamics of non-radiative transitions mediated by the phonons has been taken account. The obtained results indicate that by the properly cho…
Ionization of atomic hydrogen with up to four excess photons by circularly and linearly polarized light
2012
The above threshold ionization (ATI) is investigated for H in ns states. The total generalized cross sections are calculated for up to 4 excess photons using perturbation theory and modified Coulomb Green's function Sturmian expansion.
Theg-factor of highly charged ions
2015
Highly charged ions provide a unique opportunity to test our understanding of atomic properties under extreme conditions: The electric field strength seen by an electron bound to a nucleus at the distance of the Bohr radius ranges from 1010 V/cm in hydrogen to1016 V/cm in hydrogenlike uranium. The theory of quantum electrodynamics (QED) allows for calculation e.g. of binding energies, transition probabilities or magnetic moments. While at low fields QED is tested to very high precision, new, hypothetical nonlinear effects like photon- photon interaction or a violation of Lorentz symmetry may occur in strong fields which then would lead to an extension of the Standard Model. The ultra-high p…
Photoreactions with tensor-polarized deuterium target at VEPP–3
2011
We give an overview of the activity in studying photoprocesses on a tensor-polarized deuterium target, which is carried out at the VEPP–3 electron storage ring. Recent experimental results on tensor asymmetries in two-body deuteron photodisintegration at the photon energy up to 500 MeV, and in coherent pion photoproduction on deuteron are presented. Plans to upgrade the facility and future experiments are discussed. Further progress is connected with the installation of a tagging system for almost-real photons. This would allow us to extend the measurements of polarization observables in photonuclear reactions on deuteron up to a photon energy of 1.5 GeV and permit to perform double polariz…
Acoustic phonons for coherent photon control in semiconductor structures
2007
We present a novel concept for acousto-optical modulation in waveguide (WG) structures using coherent phonons in the form of surface acoustic waves (SAWs). Here, a SAW impinging perpendicular to a waveguide structure induces a change in phase of the light propagating through it, which is translated into a transmission intensity modulation by using the WG as an arm of a Mach-Zehnder interferometer (MZI). We show that the modulation becomes strongly enhanced if the SAW induces phase changes of opposite sign in the MZI arms. Very compact modulators with an interaction length between the optical and acoustic waves of approx. 15 µm have been fabricated using focusing acoustic transducers to gene…
Vector polarimetry at MaMi – Measurements of tensor correlation coefficients in e−bremsstrahlungs processes
2011
Electron/photon tensor-correlation coefficients may allow to design a polarimeter that can measure all components of beam polarization simultaneously—a so-called vector polarimeter. Besides its purpose as a beam diagnostic device this vector polarimeter would also allow to test theoretical predictions for the electron-photon polarization correlations at energies between 1 MeV and 3.5 MeV. As a first step we have set up a measurement of the helicity transfer to the photon as a function of energy which is based on the Compton absorption method.
Project 8 Phase III Design Concept
2017
We present a working concept for Phase III of the Project 8 experiment, aiming to achieve a neutrino mass sensitivity of $2~\mathrm{eV}$ ($90~\%$ C.L.) using a large volume of molecular tritium and a phased antenna array. The detection system is discussed in detail.
New developments on the recoil distance doppler-shift method
2010
Absolute transition probabilities are fundamental observables for nuclear structure. The recoil-distance-Doppler-shift (RDDS) technique, also called plunger technique, is a well established tool for the determination of these important experimental quantities via the measurement of lifetimes of excited nuclear states. Nowadays nuclear structure investigations are concentrated on exotic nuclei which are often produced with extremely small cross sections or with very low beam intensities. In order to use the RDDS technique also for the investigation of very exotic nuclei this method has to be adapted to the specific needs of these special reactions. This article gives an overview on recent RD…
Studies of astrophysically interesting nucleus23Al
2010
We have studied the β-delayed proton decay of 23Al with a novel detector setup at the focal plane of the MARS separator at the Texas A&M University to resolve existing controversies about the proton branching of the IAS in 23Mg and to determine the absolute proton branchings by combining our results to the latest βγ-decay data. We have made also a high precision mass measurement of the ground state of 23Al to establish more accurate proton separation energy of 23Al. Here the description of the used techniques along with preliminary results of the experiments are given.
Neutron Decay with PERC: a Progress Report
2011
The PERC collaboration will perform high-precision measurements of angular correlations in neutron beta decay at the beam facility MEPHISTO of the Forschungs-Neutronenquelle Heinz Maier-Leibnitz in Munich, Germany. The new beam station PERC, a clean, bright, and versatile source of neutron decay products, is designed to improve the sensitivity of neutron decay studies by one order of magnitude. The charged decay products are collected by a strong longitudinal magnetic field directly from inside a neutron guide. This combination provides the highest phase space density of decay products. A magnetic mirror serves to perform precise cuts in phase space, reducing related systematic errors. The …