FIRPO , Giuseppe

Commercial He mass spectrometer leak detectors usually do not provide sufficient sensitivity to perform accurate measurements of the permeation rate of He through glass. Ultrasensitive dedicated systems have adeguate sensitivity but involve high costs and complex procedures. However, both cryogenics and photomultiplier technology routinely...

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Reference leakage device (1) for use in leakage detection of gas, comprises a membrane (5) adapted to be interposed between two environments having respective pressures pu and pa, where (I). The membrane has an orifice (6) adapted to determine a controlled gas flow depending on the pressure pu. The orifice has a preset diameter D and length L...

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The paper describes a reliable technique to prepare PDMS membrane used to determine the permeability to CO2 and He. SEM controls morphology of surface membrane and SEM/FIB measures the membrane thickness. The data show that permeability becomes thickness dependent below some tens of micrometers. The Islam׳s model, based on the non-equilibrium...

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The leak devices most frequently used to calibrate leak-detection instruments are permeation leaks. These devices are very sensitive to temperature and can only be used with helium. The physical-leak types that could overcome this limits are prone to clog and their minimum size (about 1 μm) limits their applicability in the lowest flow range....

Nowadays helium permeation leaks are the most diffused leaks in the lowest flow range, but its flow rate is temperature dependent. On the contrary, orifice leaks has a low coefficient temperature, but they have a size (about 1 µm) that limits their applicability in the lowest flow range. The Focused Ion Beam is used in widespread fields, both...

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We demonstrate the possibility of using a simple functionalization procedure, based on an initial vapour-phase silanization, to control the size and functionality of solid state nanopores. The presented results show that, by varying the silanization time, it is possible to modify the efficiency of probe molecule attachment, thus shrinking the...