Vacuum turbo molecular pump

The glass coating process requires high gas flows for the sputter processes as well as low hydrocarbon concentration. The only vacuum pump which satisfies these requirements as well as high pumping speed stability over time are turbo-molecular pumps which are used almost exclusively. 

Vacuum technology acceptance specifications for turbo-molecular pumps 11/78... 

The vacuum system of the instrument consists of a four-stage, internally integrated membrane pump with an ultimate pressure of about l-2mbar. The final vacuum is reached with a 70 L/s turbo molecular pump. 

Without the target gas, the vacuum in the chamber is usually maintained at 10 —10 torr by a suitable pump, which is usually either a well trapped diffusion pump or a turbo-molecular pump. When the gas target is introduced the vacuum is generally maintained at about 10 torr. 

The ultimate total pressure that can be attained by means of turbomolecular pumps mainly depends upon the partial pressures of the various gases on the pre-vacuum side of the turbo-molecular pump. The partial pressure p0 of a gas on the high-vacuum side is calculated from the partial pressure ppatt on the fore-vacuum side, divided by the compression for this gas acording to (41). 

For the measurements, about 100 crystals are placed in an optical vacuiun cuvette connected to a vacuum system consisting mainly of a gas reservoir, a pressure sensor, and a turbo-molecular pump. The system allows the sor-bate pressure in the cuvette to be changed rapidly (a step change initiating sorbate uptake or release) or to be maintained constant. The concentration integrals are measured of an individual crystal. 

The vacuum system consists of the vacuum chamber and the pump system. The vacuum is created by a rough pump and a turbo molecular pump. The vacuum prevents interactions of the beam electrons with gas atoms and avoids sparkovers which could destroy the electron source and the detectors. 

A collimated beam of neutral molecules is formed by a skimmer. The skimmer is mounted onto a flange, which separates the desorption from the ionization chamber. By using a turbo molecular pump with 150 Ls l capacity at the desorption chamber, it is possible to run the system with jet pulses of 200 ms and repetition rates of 2 - 10 Hz and keep a vacuum of 10 Torr during measurements in the chamber without any influence in the supersonic beam. 

Example of use Semi-conductor production facilities and vacuum equipment (turbo molecular pump, etc.)... 

XPS analyses were performed using a PHI 5700 spectrophotometer equipped with a concentric hemispherical analyzer in the standard configuration (Physical Electronics, Eden Prairie, MN, USA). The vacuum system consists of a turbo-molecular pump, ion pump, and a titanium sublimation pump. The base pressure before the analysis was better than 10 Pa. The X-ray source was A1K0 (1486.6 eV), run at 300 watts. The incident angle was 54.7° and the emission angle was 45° with respect to the sample surface normal. All the spectra were obtained in digital mode. A constant energy of 23.50 eV was set across the hemispheres of the electron analyzer operated in the Fixed Analyzer Transmission (FAT) mode for the detailed spectra the survey spectra have been acquired with 187.85 eV pass... 

In all mass spectrometers a vacuum of 10 Pa or better is maintained to avoid further ion formation from residual gas species or collisions of analyte ions with these species. Nowadays, turbo-molecular pumps are preferred over diffusion pumps as their maintenance is easier and oil back-flow does not occur. 

Figure 8.49. Schematic diagram of the ultra-high vacuum (UHV) equipment. The equipment comprises a sample chamber and a main chamber (for the deposition). In the former chamber, the substrate can be baked, if necessary, under a moderately reduced pressure (approximately 10 Torr) the material deposition is carried out in the latter chamber at high vacuum (approximately 10 Torr). TMP denotes a turbo-molecular pump.

The reaction cell is evacuated by a 300 L/s turbo molecular pump and equipped with a sample manipulator with a cryostat, variable leak valves for gas introduction, and a vacuum gauge. The incident X-ray beam is introduced through a 100 nm thick silicon nitride film which separates the beam line and the reaction cell. The sample is irradiated by the X-ray beam with a grazing incidence angle of 15° and emitted photoelectrons travel approximately 1 mm to the entrance of an aperture under near ambient pressure gas and enter the first stage of the differential pumping system via a hole of 1 mm in diameter as illustrated in Fig. 9.9. The electrons further travel... 

The ion optics, shown in Figure 6.1, are positioned between the skimmer cone and mass separation device and consist of one or more electrostatically controlled lens components, maintained at a vacuum of approximately 10 torr with a turbo-molecular pump. They are not traditional optics that we associate with ICP emission or atomic absorption, but are made up of a series of metallic plates, barrels, or cylinders, which have a voltage placed on them. The function of the ion optic system is to take ions from the hostile environment of the plasma at atmospheric pressure via the interface cones and steer them into the mass analyzer, which is under high vacuum. The nonionic species such as particulates, neutral species, and photons are prevented from reaching the detector by using some kind of physical barrier, positioning the mass analyzer off axis relative to the ion beam, or electrostatically bending the ions by 90° into the mass analyzer. 

The ion beam containing all the analyte and matrix ions exits the ion optics and now passes into the heart of the mass spectrometer—the mass separation device, which is kept at an operating vacuum of approximately 10" torr with a second turbo-molecular pump. There are many different mass separation devices, all with their strengths and weaknesses. Three of the most common types are discussed in this... 

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