Parallel beam configuration

Figure 6.1 Comparison of 26 — 6 scan profiles obtained by a monochromatized (pure Cu kal) parallel beam configuration (hybrid x-ray mirror) and a conventional parallel beam configuration achieved by divergence slit (ds) module measured at 001/100 (a), 002/200 (b), 003/300 (c), 004/400 (d) of 500nm-thick Pb(Zro.B4Tio.46)03 thin film. Dotted lines represent the second derivative of the profiles, indicating the peak positions. Note that the profiles are simulated fitted profiles for obtained spectrum using pseudo-Voight function (mixed Lorentz and Gauss function).

An alternate configuration, shown in Fig. 1.4, is the parallel beam configuration (typically under line focus) [5,6]. Contrary to the focusing configuration, in this set up the X-ray beam is made parallel either by using appropriate primary optics (X-ray mirrors) and/or at the secondary optics (using parallel plate collimators). Diffiraction peak shapes under this configuration tend to be broader than under... 

The parallel beam configuration is often used in sample stages with four circle capabilities (see Fig. 1.5). In this case, in addition to (o and 20 rotations, the sample can be rotated around the surface normal direction (defined by the z axis in Fig. 1.4) by an azimuthal angle ( ), in addition to a tilt angle / around the x axis parallel to the sample surface ( / tilts the sample back and forth relative to the difltacti(Mi plane defined by the axis x and z). The usefulness of this set up wDl become clear later in this chapter. 

Block the laser beam or spectrometer entrance slit and adjust the spectrometer to an anti-Stokes shift of 1000 cm Caution Exposure of the sensitive phototube to the intense Rayleigh scattering line can seriously damage the detector. Scan the anti-Stokes spectrum from 1000 to 150 cm in the parallel polarization configuration and, using appropriate sensitivity expansion, j measure the ratio of anti-Stokes to Stokes peak heights for each band. 

The results of these measurements are shown in Figure 2.37. Note how the use of a strictly parallel beam can greatly improve the diffractometer s angular resolution. As we will see later on, the resolution of this diffractometer is equivalent to that obtained with Bragg-Brentano diffractometers in the high resolution configuration. 

In another beam configuration (folded BOX CARS), the pump beam with co is split into two parallel beams, which are directed by the focusing lens in such a way that the wave vectors k2 and = ka are contained in a plane orthogonal to that of the two ki vectors (Fig. 3.22d). This has the advantage that neither of the two pump beams overlaps the signal beam at the detector [355]. If the Raman shifts are small, spectral filtering becomes difficult and the advantage of this folded BOX CAR technique is obvious. 

As an example, we consider a parallel plate actuator that is fabricated in the Poly MUMPS process using the first released polysilicon layer. Poly 1, as the structural layer and the first oxide. Oxide 1, as the sacrificial layer. We consider two configurations for the springs an X-beam configuration, as shown in Figure 3.5, and a Z-beam configuration, as shown in Figure 3.6. 

Apart from using the grating in zero order so that it works like a mirror, maintaining a (compact) round beam at the camera (A = 1) requires that the spectrograph adopt the Littrow configuration for which Tf = 0 and the incident and diffracted rays are parallel. From equations 6 and 9, the resolving power at blaze in the Littrow configuration is... 

If the three light pulses of the pulse sequence are only separated in time, and not separated in space (i.e. if the velocity of the atoms is parallel to the laser beams), the interferometer is in a gravimeter or accelerometer configuration. In a uniformly accelerating frame with the atoms, the frequency of the driving... 

We perform flexural testing on polymer rods or beams in the same basic apparatus that we use for tensile or compressive testing. Figure 8.6 illustrates two of the most common flexural testing configurations. In two-point bending, shown in Fig. 8,6 a), we clamp the sample by one end and apply a flexural load to the other. In three-point bending, shown in Fig. 8.6 b), we place the sample across two parallel supports and apply a flexural load to its center. 

The columns are simply supported at the base and continuous at the beam-column connection. This configuration can be modeled as 3 cantilevered columns acting in parallel with a concentrated load and mass at the tip. 

The light source can be a xenon lamp associated with a monochromator. The optical configuration should be carefully optimized because the electro-optic modulator (usually a Pockel s cell) must work with a parallel light beam. The advantages are the low cost of the system and the wide availability of excitation wavelengths. In terms of light intensity and modulation, it is preferable to use a cw laser, which costs less than mode-locked pulsed lasers. 

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