Sample-Holder

Capillaries are unpopular for several reasons firstly, diffuse X-ray scattering from the glass walls, which are approximately 10 pm thick, adds significantly to the background count. Secondly, they take considerably longer to All than the equivalent flat-plate sample holder. Thirdly, capillaries may require careful alignment on the diffractometer to ensure that the axis of the capillary is 

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Some elements (S, Se, Te, P, As, Sb, Bi, Ge, Sn, Pb) in liquid samples arc conveniently converted into their volatile hydrides before being passed into the plasma, as discussed in Part A (Chapter 15). For some samples, any volatile solvent is first evaporated in a sample holder, which is then heated strongly to vaporize the resulting solid residue, as discussed in Part C (Chapter 17). 

The major methods used for vaporization (ablation) include lasers, electrically heated wires, or sample holders and electrical discharges (arcs, sparks). 

Direct-inlet probe. A shaft or tube having a sample holder at one end that is inserted into the vacuum system of a mass spectrometer through a vacuum lock to place the sample near to, at the entrance of, or within the ion source. The sample is vaporized by heat from the ion source, by heat applied from an external source, or by exposure to ion or atom bombardment. Direct-inlet probe, direct-introduction probe, and direct-insertion probe are synonymous terms. The use of DIP as an abbreviation for these terms is not recommended. 

Ion Implantation Systems. An ion implantation system is used to accelerate ionized atomic or molecular species toward a target sample. The ionized species penetrates the surface of the sample with the resulting depth profile dependent on the implanted species mass, energy, and the sample target s tilt and rotation. An implanter s main components include an ionizer, mass separator, acceleration region, scanning system, and sample holder (168). 

SPMs are simpler to operate than electron microscopes. Because the instruments can operate under ambient conditions, the set-up time can be a matter of minutes. Sample preparation is minimal. SFM does not require a conducting path, so samples can be mounted with double-stick tape. STM can use a sample holder with conducting clips, similar to that used for SEM. An image can be acquired in less than a minute in fact, movies of ten fiames per second have been demonstrated. ... 

A sample holder, including optics for focusing the incident light and collecting the luminescence. Efficient light collection is important, and the sample holder may need to allow for a cryostat, pressure cell, magnet, or electrical contacts. 

VPD-TXRF is also a facile technique for interface analysis [4.78, 4.79]. Automated VPD equipment (Fig. 4.16) improves both the detection limit (upper range 10 atoms cm ) and the reliability (by > 50%) of the VPD-TXRF measurement [4.14]. Current research focuses on sample holders [4.80, 4.81] and light-element detection capability [4.82-4.84]. 

Pyrolyzer CDS Model Pyroprobe 2000 with coil sample probe and quartz boat sample holder Pyrolysis temperature about 650°C for 20 sec Pyrolysis sample size 0.2-0.3 mg GC Hewlett Packard Model 5890... 

Sample cells include Lindemann/capillary tubes (normally < 1 mm in diameter) and aluminium holders. In the latter, thin aluminium windows sandwich the sample in a cylindrical aluminium sample holder. The diffraction from the aluminium is observed in this case, and may be used as a calibration standard. For low-temperature materials, the aluminium window can be replaced by the polymer Kapton. Beryllium may also be used [14]. Sample volumes of between 50 and 100 pL are typically required. 

F Cu-30Ni-2Fe 2Mn 0-014 <1 Very slight pitting attack beneath brown tubercles of corrosion products. Also pitting in areas next to sample holder. No measurable attack opposite jet... 

The conditioned specimens are cantilevered from the sample holder in the test apparatus, which has been brought to a low temperature (that at which the specimens would be expected to fail). When the... 

Fig. 4-3. Lines from copper, nickel, and iron impurities which appeared in the spectrum of an x-ray tube after the tube had been operated for several hundred hpurs. X-rays from the tube were scattered by filter paper in the sample holder.

The following experimental details apply both to the determination of tungsten with bromine as internal standard, and to the experiments of Table 7-2. The solutions filled a 3-ml container made by sectioning a 10-ml beaker. To prevent" evaporation and to maintain a fixed distance between x-ray tube window and sample surface, the beaker-section was covered with Mylar film, 0.0025 cm thick, placed in a plastic sample holder and pressed firmly against the sample drawer. The Mylar film attenuated the x-rays uniformly enough so as not to affect the precision of the results. 

Sample loading is done by loosely placing the ground sample into the sample holders of the Norelco Inverted-Sample Three-Position Spectrograph. 

Fig. 8-10. Contour maps showing spectrograph sensitivities for the iron Ka line for various positions of the sample, (a) At surface of sample holder, (b) 0.16 inch below surface of sample holder, (c) 0.32 inch below surface of sample holder. The sensitivity changes with the x-ray optical system, with the goniometer setting, and with the distance of the sample below the surface of the sample holder. The contour interval is 20 counts per second. (Authors unpublished results.)...

Infrared (IR) investigations can be made on a sample of reactant previously heated to a known extent of reaction (a) and studied in the form of a mull or in an alkali halide disc. An alternative approach is to incorporate the reactant substance in a compact alkali halide disc [287] which is intermittently withdrawn from the reaction vessel for infrared measurements at appropriate intervals. Heated sample holders [288,289] permit repetitive scanning of the spectrum or continuous monitoring of a peak of interest during decomposition. 

As carrier gases dry nitrogen and super-heated steam, both at a pressure of 1 bar, were used. The gas velocity was 4,0 cm. sec for both gases. The samples were flushed from the sample-holder into the pre-heated reactor and reached temperature within a minute. The reactions were stopped by removing the reactor from the oven. 

The direct insertion probe consists of a metal sample holder drilled to accept standard melting point capillaries up to 1 inch in length. This is inserted into the ion source through a vacuum lock and may be heated to 250°C at varying rates. 

The first thing to note is that the furnace surrounds the sample-holder containing the differential thermocouples. A separate control thermocouple controls the furnace temperature and should be placed as close as possible to the position of the sample holder. Some commercial manufacturers use the Reference leg of the differential thermocouple to control the temperature. However, if you were to build a DTA using the components as shown in 7.1.14,... 

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