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The most diffused leak detection method for the leak rates lower than 10 −2 mbarL/s that is based on the application of mass spectrometry with tracer gas (generally helium) is considered. A description is given of the metrological characterization of the mass spectrometer leak detectors (MSLD) for industrial applications since they represent the best choice for tightening tests having good...
Gas leaks supplied through metal capillaries are nowadays largely used in industry to calibrate “in situ” leak detectors (necessary in tightness tests, versus both vacuum and atmospheric pressure) or in whatever applications in which well-known (and very low) gas flows are necessary. If the capillaries are calibrated with a primary device or a reference one, the traceability of flow measurements to...
Metoda Monte-Carlo jest często stosowana do wyznaczania parametrów stanu gazu w systemach wzorców próżni. W pracy podjęto próbę weryfikacji założeń modelu symulacyjnego przy wykorzystaniu zestawienia wyników otrzymanych na drodze symulacji i pomiaru. Wyniki różnią się od siebie na poziomie 2x10⁻³, co potwierdza tezę o poprawności przyjętego modelu rozpraszania cząsteczek gazu na powierzchni ścian...
The IMGC-CNR constant pressure and variable volume gas flowmeter is described together with its automatic electronic control and data acquisition system. It is used to produce low pure-gas throughputs in the 10 -3 -10 -8 Pa m 3 s -1 range, at the reference temperature of 294.15 K. This flowmeter may be used for both the pressure generation in the continuous-expansion...
For the pressure lower than the atmosphere, several systems are available based on different principles from the classic U-tubes or piston gauges equipped with more or less sophisticated measuring devices to the gas expansion systems. Some of these systems are easily traced to SI units while others must be well defined to be considered as primary and their chain of traceability has to be clearly indicated...
The effectiveness of some different kinds of surface coatings on austenitic stainless-steel samples is discussed on the basis of their effects on the outgassing flowrates in vacuum and at high temperature. Special attention is given to the reduction of molecular hydrogen diffusion from the bulk. The effects of TiN thin films and oxide layer were studied through total and partial pressure measurements...
The main causes of the instability of the mass of kilogram prototypes are considered and the effects of some surface and bulk phenomena, such as outgassing and surface decontamination by different cleaning procedures, have been studied by means of different techniques on specimens of Pt-Ir alloy of the same composition as the prototypes.
Several rotors were calibrated both at ETL and IMGC in the pressure range from 10 -4 to 100 Pa. The calibrations were performed in argon atmosphere by using a static multi-stage system at the ETL and dynamic and static apparatus at IMGC. With stable rotors, the comparison showed that the two laboratories agree within 1%. Two rotors were calibrated also at higher pressures, with the aim...
The paper discusses the results of a study performed on the materials used for the fabrication of sputter-ion pumps, namely, stainless steel for the anode and body, and titanium for the cathodes. The TDS technique has been applied to study the efficacy of different cleaning procedures (acid and basic baths and vacuum firing) normally adopted by the vacuum industry to minimize the amount of gases absorbed...
Results concerning the calibration of metal capillary tubes of the linear and crimped types with different inert testing gases from 3 10 -8 Pa m 3 s -1 to 3 10 -5 Pa m 3 s -1 (1 10 -11 mol s -1 -1 10 -8 mol s -1 ) are presented. A primary flowmeter connected to a...
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