Different Number Of Beams Research Articles

Control of a 10 m delay-line laser interferometer using the pre-modulation method

We have successfully verified a phase detection scheme using the pre-modulation method in the ISAS 10 m delay-line interferometer, by choosing different numbers of beams in the two delay-lines. With the pre-modulation and a feedback control only to the mirror position, a phase detection without phase modulators inside the interferometer was realized.

Inclusion of the weak beam effects in the bloch-wave simulation of dynamical diffraction by using the bethe potential

The Bloch wave method of high energy transmission electron diffraction involves diagonalization of an nxn matrix, where n is the number of beams included in the simulation. This method is used widely in quantitative electron diffraction as the simulation method because of its flexibility in treating electron diffraction of arbitrary incident beam directions, while the multislice method of simulation is mostly used for low index zone axes of large unit cell crystals. The number of beams included in the simulation is limited by the computing time and the memory size of the computer. The computing time of the Bloch wave method is proportional to the n2. Thus only a limited number of beams can be included in the simulation. The truncation of beams may introduce a systematic error, if the number of beams included fails to converge. This is illustrated by fig. 1, in which the thickness pendelösung for MgO crystal along [001] zone axis is calculated with different number of beams in ZOLZ only, with no absorption, no Debye-Waller factor, atomic scattering factors for neutral spherical Mg and O atoms, and a = 4.2112 Å.

Estimations of model parameters for gravity wave spectra observed by MST radar

The general theory of MST radar observations of gravity wave spectra is developed in this paper. This effort extends the previous results to include anisotropy and Doppler effects for the spectra, as well as the consequences for the multibeam configuration. The relationships between the observed one- or two-dimensional spectra for the line-of-sight velocity in the gravity wave spectra are derived. Expressions for cross spectra, as well as covariances between velocities observed on different beams, are computed. Using these results, studies are carried out to show how model parameters for gravity wave spectra can be estimated from the observed quantities. Model parameters include the variance, power-law indices, anisotropy parameters, Doppler parameters, mean scale sizes, etc. Cases with different numbers of beams will be investigated.