Search results for "electromagnetic"
showing 10 items of 1595 documents
Status and recent developments at the polarized-electron injector of the superconducting Darmstadt electron linear accelerator S-DALINAC
2011
At the superconducting Darmstadt electron linac a 100 keV source of polarized electrons has been installed. Major components had been tested prior to installation at an offline teststand. Commissioning of the new source at the S-DALINAC will take place early in 2011. We report on the performance of the teststand, simulations, developments on the laser systems, new radio-frequency components for the S-DALINAC injector, and the status of the implementation of the source.
Spectral broadening by spatial effects in X-ray microcalorimeters with superconducting absorber and NTD-Ge thermal sensor
2004
We discuss how the sensitivity to the position of absorption of the photons can affect the spectral resolution of X-ray microcalorimeters with superconducting Sn absorber and NTD-Ge thermal sensor. Data obtained through the computer simulations are reported for microcalorimeters with different geometries and phonon transmission probabilities at the interface between the absorber and thermistor.
Experimental evidence of an incomplete thermalization of the energy in an x-ray microcalorimeter with a TaAu absorber.
2008
We have conducted an experimental test at our XACT facility using an x-ray microcalorimeter with Ta∕Au absorber and neutron transmutation doped germanium thermal sensor. The test was aimed at measuring the percentage of energy effectively thermalized after absorption of x-ray photons in superconducting tantalum. Moreover, in general, possible formation of long living quasiparticles implies that by using a superconducting absorber, a fraction of the deposited energy could not be thermalized on the useful time scale of the thermal sensor. To investigate this scenario, we exploited an absorber made of gold, where no energy trapping is expected, with a small piece of superconducting tantalum at…
Nonlinear electromagnetic response and Higgs-mode excitation in BCS superconductors with impurities
2019
We reveal that due to the presence of disorder oscillations of the order parameter amplitude called the Higgs mode can be effectively excited by the external electromagnetic radiation in usual BCS superconductors. This mechanism works for superconductors with both isotropic s-wave and anisotropic, such as d-wave, pairings. The non-linear response in the presence of impurities is captured by the quasiclassical formalism. We demonstrate that analytical solutions of the Eilenberger equation with impurity collision integral and external field drive coincide with the exact summation of ladder impurity diagrams. Using the developed formalism we show that resonant third-harmonic signal observed in…
Anomalous magnetic hysteresis in the microwave surface resistance of MgB2 superconductor
2007
We report experimental results of the field-induced variations of the microwave surface resistance in samples of MgB2, produced by different methods. By sweeping the DC magnetic field at increasing and decreasing values, we have detected a magnetic hysteresis that can be ascribed to the different magnetic induction, due to the critical state of the fluxon lattice. The hysteresis observed in the bulk samples has an unusual shape, which cannot be justified in the framework of the critical-state models.
Surface area, density and porosity measurements using the magnetic suspension balance
1989
The advantage of gravimetry in the determination of surface area is discussed in comparison with the volumetric method. The magnetic suspension balance is described and new developments are presented. As an example of the application of gravimetric measurements the determination of apparent density and specific surface area before and after oxidation of a Poco graphite are described.
Second-harmonic generation in surface periodically poled lithium niobate waveguides:On the role of multiphoton absorption
2008
Second harmonic generation is investigated in lithium niobate channels realized by proton exchange and quasi-phase-matched by surface periodic-poling. The reduction in conversion efficiency at high powers is interpreted in terms of multi-photon absorption via two-color terms, yielding an estimate of the dominating three-photon process.
Isotopic Effects and Surface Absorption in $^{35-37}$Cl+$^{24}$Mg Interactions
1992
Abstract The few-nucleon transfer is found to play an important role in the isotopic effects observed in absorption. This conclusion is obtained by measuring elastic scattering and quasielastic reactions and by analysing elastic data with both phenomenological and microscopic models. The sensitivity domain is found to be different for imaginary and real potentials. The implication for the validity of the dispersion relation for phenomenological potentials at the real sensitivity radius, when transfers are important, is discussed.
Effects of organic aerosol constituents on extinction and absorption coefficients and liquid water contents of fogs and clouds
1978
We have speculated on the influence of organic material on extinction and absorption coefficients and liquid water content of fogs and of clouds immediately after their condensational stage. It results therefore, that the reduction of the speed of growth from fog to cloud droplets due to the presence of organic films largely reduces the properties mentioned. Compared to that their increase coming from the surface tension reduction due to organic material being dissolved or building up films is expected to be less effective.
MR-guided focused ultrasound application for moving target tumor ablation in abdominal area: Coil selection
2020
PubMed: 32276552