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Goniostat

Crystallography. The crystal was transferred to the goniostat using inert atmosphere techniques. [Pg.44]

Both the MAR345 and the MARCCD are supplied with a MARDTB goniostat (DTB being an... [Pg.85]

Once a crystal has been mounted, it must be placed in the X-ray beam. Most modern goniostats are motorized, permitting this process to be executed remotely or, for high-throughput data collection, automatically. At third-generation s)mchrotron sources, highly focused X-ray beams and small... [Pg.178]

In the diffractometer, the goniometer head and crystal are mounted in a system of movable circles called a goniostat, which allows automated movement of the crystal into almost any orientation with respect to the X-ray beam and the detector (see Figs. 4.21 and 4.22). [Pg.73]

The complete diffractometer consists of a fixed X-ray source, the goniostat, and a movable scintillation-counter detector. The system of circles (Fig. 4.21) allows rotation of the goniometer head (angle ), movement of the head around a circle centered on the X-ray beam (angle x), and rotation of the X circle around an axis perpendicular to the beam (angle o). Furthermore, the detector moves on a circle coplanar with the beam. The axis of this circle coincides with the o-axis. The position of the detector with respect to the beam is denoted by the angle 20. With this arrangement, the crystal can be moved to... [Pg.73]

In this photo, the goniostat (a) and area detector (c) are separated by a drum of helium (b) which transmits X rays with less loss than air. The crystal (d) is barely visible in the tiny glass tube. The two arrows (e) mark the collimator (left) and the beam stop (right), which prevents the direct X-ray beam from reaching the detector. Arrows 1, 2, and 3 on the goniostat indicate the X, < >, and u> circles. [Pg.74]

The common optical features described above may be realized in different ways in the actual hardware design of a powder diffractometer goniostats and thus, goniometers differ from one another by ... [Pg.269]

Powder diffractometer goniostats can be constructed in a way that both the detector and the sample revolve around a common goniometer axis in a synchronized fashion, or the sample is stationary, but both the detector and the x-ray source arms rotations are synchronized, as shown in Figure 3.10. When cylindrical samples are employed, generally there is no need in the synchronization of the goniometer arms, and only the detector arm (if any, e.g. see Figure 3.14, below) should be rotated. [Pg.272]

Figure 3.11. The schematic of the goniostat of a Scintag XDS2000 powder diffractometer with the horizontal axis and synchronized rotations of both the source and detector arms. This goniometer is equipped with a liquid nitrogen-cooled solid-state detector, which enables monochromatization of the diffracted beam by selecting a narrow energy window, thus registering only characteristic energy photons. R - is the radius of the goniometer. Figure 3.11. The schematic of the goniostat of a Scintag XDS2000 powder diffractometer with the horizontal axis and synchronized rotations of both the source and detector arms. This goniometer is equipped with a liquid nitrogen-cooled solid-state detector, which enables monochromatization of the diffracted beam by selecting a narrow energy window, thus registering only characteristic energy photons. R - is the radius of the goniometer.
A different goniostat with the horizontal orientation of the specimen and Bragg-Brentano geometry is shown in Figure 3.13. The x-ray tube housing is mounted on the movable arm, and both the x-ray source and the detector can be rotated in a synchronized fashion about the common horizontal goniometer axis (also see the schematic in Figure 3.10, middle). [Pg.275]

What kind of experimental setup is required to record the diffraction patterns from the macromolecular crystals and what kind of information is usually reported about the experiment Figure 16 shows a typical X-ray setup. The main parts are the X-ray source, including the optics to focus the parallel radiation onto the crystal, a device called a goniostat, and the detector that records the diffracted radiation. X-ray sources fall into two categories conventional generators and synchrotron sources. Most data these days are collected at synchrotrons. [Pg.63]

The X-ray beam from the source is monochromated, focused, and collimated to deliver a parallel beam of defined size and wavelength to the crystal. Because of the intrinsically superior optical qualities of synchrotron beams, the radiation delivered to the crystal is also superior to that from conventional sources. The crystal is mounted on a goniostat, which allows the crystal to be rotated. The crystal is usually flash-cooled to a temperature of 100 K by a cold stream of nitrogen gas to reduce radiation damage. X-rays are ionizing radiation and the free radicals produced as they pass through the protein destroy the crystal. Without flash cooling, protein crystals last only seconds on a synchrotron beamline. [Pg.66]

In order to use the synchrotron X-radiation effectively, the white beam of photons diverging from the source must be collected by beam line optical element (s), and brought to a focus with a size approximately equal to the protein crystal size. The sample must be centred in the beam and oriented on a goniostat of some kind. The diffraction pattern has to be measured accurately and efficiently with a detector. In the case of monochromatic experiments the beam line optical scheme will include a monochromator of which there are several common types. There are some special needs for each experimental class. [Pg.136]

The Biology Department beam line includes a station for protein crystallography (with Supper oscillation camera and FAST TV diffractometer) and a station for small angle diffraction (with a three-circle goniostat and MWPC electronic area detector). The latter station may be available for optimised anomalous dispersion crystallographic studies. The optical design for each consists of a bent pre-mirror, double crystal monochromator and bent post-mirror the mirrors have rhodium coatings (Wise and Schoenborn 1982). [Pg.238]

The purpose of the diffractometer goniostat is to bring a selected reflected beam into the detector aperture (see figure A1.6) or a number of reflected beams onto an area detector of limited aperture (i.e. an aperture which does not intercept all the available diffraction spots at one setting of the area detector. [Pg.480]

The x circle is a relatively bulky object whose thickness can stop the measurement of diffracted beams at high 6. Also, collision of the x circle with the collimator or X-ray tube housing has to be avoided. An alternative is the Kappa goniostat geometry. In the Kappa diffractometer (see figure A1.8) the Kappa axis is inclined at 50° to the tu-axis and can be rotated about the tu-axis the K-axis is an alternative to x> therefore. The... [Pg.482]


See other pages where Goniostat is mentioned: [Pg.78]    [Pg.81]    [Pg.81]    [Pg.83]    [Pg.83]    [Pg.176]    [Pg.179]    [Pg.258]    [Pg.41]    [Pg.351]    [Pg.267]    [Pg.272]    [Pg.273]    [Pg.273]    [Pg.276]    [Pg.276]    [Pg.327]    [Pg.151]    [Pg.159]    [Pg.161]    [Pg.162]    [Pg.481]   
See also in sourсe #XX -- [ Pg.73 , Pg.74 ]




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Goniostats with point detectors

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