The design and study of a compact bakeable ultra-high vacuum system for calibrating absolutely low pressure gauges

Vacuum ◽  
1977 ◽  
Vol 27 (9) ◽  
pp. 511-517 ◽  
Author(s):  
K.J. Close ◽  
R.S. Vaughan-Watkins ◽  
J Yarwood
2002 ◽  
Vol 2 (4) ◽  
pp. 189-195
Author(s):  
Z.D. Nikitovic

Vacuum system set-up is presented and used for calibration of pressure gauges in the region of rough vacuum, from 103 mbar to 10-1 mbar, with dry air. The capacitance manometer is used for the calibration of piezoresistant manometer, oil, mercury and mercury micrometers U manometers. The applicability of the experimental set-up and obtained results for the low pressure gauges calibration in the medium and high vacuum region is approved. It was shown how calibration of some cheaper pressure gauges might be performed and reliable measurements of the pressure may be made in the region that is of interest for atomic and molecular collision physics and low-pressure gas discharges. It was also shown that mentioned calibration procedure could be used for calibration of different U manometer types in order to renormalize older atomic and molecular collision data.


1993 ◽  
Vol 1 (8) ◽  
pp. 5-6
Author(s):  
Anthony D. Buonaquisti

Pressure scales can be extremely confusing to new operators. This is not surprising. To my mind, there are three primary areas of confusion.Firstly, the pressure of gas inside an instrument changes over many orders of magnitude during pumpdown. The change is about 9 orders of magnitude for a traditional Scanning Electron Microscope and about 13 orders of magnitude for an ultra-high vacuum instrument such as a Scanning Auger Microprobe.To give an idea about the scale of change involved in vacuum, consider that the change in going from ambient pressure to that inside a typical ultra high vacuum system is like comparing one meter with the mean radius of the planet Pluto's orbit. The fact is that we don't often get to play with things on that scale. As a consequence, many of us have to keep reminding ourselves that 1 X 10-3 is one thousand times the value of 1 X 10-6 - not twice the value.


2013 ◽  
Author(s):  
Margot H. Phelps ◽  
Kaitlin E. Gushwa ◽  
Calum I. Torrie

Vacuum ◽  
2004 ◽  
Vol 73 (2) ◽  
pp. 243-248 ◽  
Author(s):  
F. Grangeon ◽  
C. Monnin ◽  
M. Mangeard ◽  
D. Paulin

1993 ◽  
Vol 318 ◽  
Author(s):  
D. Lubben ◽  
F. A. Modine

ABSTRACTThe ionic conductivity of LiI thin films grown on sapphire(0001) substrates has been studied in situ during deposition as a function of film thickness and deposition conditions. LiI films were produced at room temperature by sublimation in an ultra-high-vacuum system. The conductivity of the Lil parallel to the film/substrate interface was determined from frequency-dependent impedance measurements as a function of film thickness using Au interdigital electrodes deposited on the sapphire surface. The measurements show a conduction of ∼5 times the bulk value at the interface which gradually decreases as the film thickness is increased beyond 100 nm. This interfacial enhancement is not stable but anneals out with a characteristic log of time dependence. Fully annealed films have an activation energy for conduction (σT) of ∼0.47 ± .03 eV, consistent with bulk measurements. The observed annealing behavior can be fit with a model based on dislocation motion which implies that the increase in conduction near the interface is not due to the formation of a space-charge layer as previously reported but to defects generated during the growth process. This explanation is consistent with the behavior exhibited by CaF2 films grown under similar conditions.


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