Goniometer vertical

All the solid phases were identified and characterized for crystallinity by X-ray powder diffraction (Philips PW 1730/10 diffractometer, Cu Kq radiation equipped with a PW 1030/70 vertical goniometer and connected to a P.C. computer for quantitative analyses). Crystallinities for Nu-10 and cristobalite were computed by comparing the intensity of the most characteristic diffraction peaks of each sample to that of the corresponding pure 100% crystalline phases used as standards. In some cases calibration curves derived from Nu-10/cristobalite mechanical mixtures were used. Si, Al, and alkali contents were determined either on precursors or calcined samples (900 C, air flow, 4h) by atomic absorption, using a Perkin-Elmer 380 AA instrument after digestion and dissolution of the samples in H,S04/HF solutions and further elimination of HF by gentle heating at 60 C for 12 n. 

The synthesized samples were analyzed by X-ray powder diffraction for qualitative and quantitative phase identification. The unit used was a Philips Model with a vertical goniometer and a scintillation counter, utilizing Ni-filtered CuK radiation. For quantitative phase identification an external standard sample of ot-A O, was used. The percentage crystallization was calculated using thez "averaged peak intensities at 20 =35.2° and 20=47.3° of the reference sample and the peak intensity at 20=23.2° for the sample under study (31). 

X-ray diffraction. XRD patterns were acquired on a Philips PW1710 vertical goniometer using CuKa radiation selected by a graphite monochromator in the diffracted beam. All the samples were fully hydrated before XRD diffractograms were measured. Silicon powder was used as an internal standard. 

Powder diffraction data were taken on a Philips PW 1710 X-ray powder diffractometer (XRPD) with Bragg Brentano geometry (vertical goniometer) in 0.025 ° step from 5 to 90 29 with 20 s per step. 

The orientation of both the goniometer axis and specimen surface (or specimen axis) with respect to the horizon, i.e. they may be located in a vertical or horizontal plane. 

Figure 3.7. Horizontal (left) and vertical (right) orientations of a flat sample. The location of the goniometer axis is shown using a dash-double dotted line with small filled circles at the ends. The dashed line indicates the location of the optical axis, which is the line connecting the focus of the x-ray tube, the receiving slit and the sample surface in the reflection geometry, or the sample center in the transmission geometry at 0 = 20 = 0°.

On the other hand, the simplicity of the goniometer arms motion in a horizontal plane, when the sample is located in a vertical plane (Figure 3.7, right), is offset by the need of more complicated sample preparation to ensure that it stays in place and does not fall of This is usually achieved by side packing the sample holder or by mixing a powder with a binder (e.g., x-ray amorphous and chemically inert petroleum jelly, oil, grease or varnish), which typically increase preferred orientation or background, respectively (see section 3.5 for more details on sample preparation). 

The orientation of the sample usually establishes the orientation of the goniometer axis, i.e. the axis around which both the detector and sample (or both the detector and x-ray source) rotate in a synchronized fashion during 0-20 or 0-0 data collection. A horizontal sample orientation implies that the goniometer axis is located in the horizontal plane, and a vertical sample orientation makes the goniometer axis vertical, as depicted in Figure 3.7. 

Figure 3.14. The schematic of a powder diffractometer with the vertical goniometer axis, cylindrical sample in the transmission mode and a curved position sensitive detector (PSD). Solid arrows indicate the incident beam and broken arrows indicate the diffracted beams pathways. F - focal point of the x-ray source, M - monochromator, DS - divergence slit, T -incident beam trap.

The X-ray powder diffraction pattern obtained for lomefloxacin hydrochloride on a Philips model APD 3720 system, equipped with a vertical goniometer in the 0/20 geometry and a theta compensating slit, is shown in Figure 20. The copper Ka line at 1.544056 A was used as the radiation source, and the sample was scanned between 2 and 32 degrees 2-0, in the step sizes of... 

There is a large variety of specimen holders in use, each suited to some particular purpose. The simplest consists of a fixed post to which the specimen is attached with wax or plasticine. A more elaborate holder is required when it is necessary to set a crystal in some particular orientation relative to the x-ray beam. In this case, a three-circle goniometer is used (Fig. 5-7) it has three mutually perpendicular axes of rotation, two horizontal and one vertical, and is so constructed that the crystal, cemented to the tip of the short metal rod at the top, is not displaced in space by any of the three possible rotations. 

Fig. 8-22 Back-reflection Laue pattern of an aluminum crystal. The incident beam is parallel to [Oil], [Oil] points vertically upward, and [100] points horizontally to the left. Tungsten radiation, 30 kV, 19 mA, 40 min exposure, 5 cm specimen-to-film distance. (The light shadow at the bottom is that of the goniometer which holds the specimen.)...

Powder X-ray dififiaction patterns were recorded using Cu Ka (1.5418 A) radiation on a Philips 1050/81 vertical goniometer, fitted with a diffracted beam graphite monochromator. X-ray photoelectron experiments were carried out in a Escalab 200R (Fisons Instrumrats) using monochromatic A1 Ka radiation and operating at 10" Torr base pressure. Transmission electron microscopy analysis was performed in a JEOL lOOCX either by direct observation or after extractive replication of samples (support dissolution). 

Vertical goniometer, 90° rotation, equipped with an optical rail containing a video-camera mount and a rotating stage mounted on an x->r-z translation (Fig. 3,50)... 

An alternative method is to mount the crystal in a precise orientation and to use the 0-axis to explore the blind region of the single rotation axis. It is feasible to place the capillary containing the sample in a vertically upright position via a 135° bracket mounted on the goniometer... 

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