A double wall ultra-high vacuum system with electron gun and evaporation rate monitor

1970 ◽  
Vol 6 (3) ◽  
pp. 213-216 ◽  
Author(s):  
M. Hinoul ◽  
J. Witters
Keyword(s):  
Evaporation Rate ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Electron Gun ◽  
Vacuum System ◽  
Double Wall

The structure and basic operating modes of a STEM

1984 ◽  
Vol 42 ◽  
pp. 332-335
Author(s):  
John B. Vander Sande
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
High Vacuum ◽  
Scanning Transmission Electron Microscope ◽  
Ultra High Vacuum ◽  
Electron Gun ◽  
Vacuum System ◽  
Major Advance ◽  
Operating Modes ◽  
Transmission Electron

The scanning transmission electron microscope (STEM) represents a major advance in the microanalytical capabilities of instruments available to materials scientists. The STEM concept resulted from the desire to combine features of the transmission electron microscope (TEM), scanning electron microscope (SEM), and the electron microprobe. Several types of STEMs are currently in use; they can be divided into roughly three categories based on origin and philosophy of design. First are the “dedicated” STEMs, pioneered by Crewe and his coworkers, which generally use a field-emission electron gun housed in an ultra-high-vacuum system. A conventional TEM may also be equipped with a scanning attachment and an electron detector and/or spectrometer, yielding what may be referred to as a TEM(S). Finally, in practice an SEM may be fitted with a transmission stage; in this case the designation SEM(T) may be most appropriate. The first two designs are by far the most popular for currently available commercial instruments.

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
Keyword(s):  
High Vacuum ◽  
Low Pressure ◽  
Ultra High Vacuum ◽  
Vacuum System

scholarly journals Why Pressure Scales Cause So Much Confusion

1993 ◽  
Vol 1 (8) ◽  
pp. 5-6
Author(s):  
Anthony D. Buonaquisti
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Ambient Pressure ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Vacuum System ◽  
Scanning Auger Microprobe ◽  
The Mean ◽  
Scanning Electron

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.

scholarly journals Optical contamination control in the Advanced LIGO ultra-high vacuum system

2013 ◽  
Author(s):  
Margot H. Phelps ◽  
Kaitlin E. Gushwa ◽  
Calum I. Torrie
Keyword(s):  
High Vacuum ◽  
Ultra High Vacuum ◽  
Vacuum System ◽  
Contamination Control

Energy Filtering of Schottky Field Emission Gun Using Fringe Field Monochromator

1999 ◽  
Vol 5 (S2) ◽  
pp. 646-647
Author(s):  
H.W. Mook ◽  
A.H.V. van Veen ◽  
P. Kruit
Keyword(s):  
Field Emission ◽  
Low Voltage ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Electron Gun ◽  
Fringe Field ◽  
Objective Lens ◽  
Electronic Band ◽  
Energy Width ◽  
Energy Filtering

The energy resolution which can be attained in electron energy loss spectroscopy (EELS) is determined by the energy spread of the electron source. The energy width of a high brightness electron gun (typically 0.4 to 0.8 eV) blurs the energy spectrum. A pre-specimen energy filter or monochromator must be used to reduce the energy width of the beam below 0.1 eV to allow detailed EELS analysis of the electronic band structures in materials. The monochromator can not only improve EELS, but it is also capable of improving the spatial resolution in low voltage SEM, which is limited by the chromatic blur of the objective lens. A new type of monochromator the Fringe Field Monochromator has been designed and experiments in an ultra high vacuum setup show the monochromatisation of a Schottky Field Emission Gun.

Development of an ultra-high vacuum system for space application

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

scholarly journals Enhanced Ionic Conduction at the Film/Substrate Interface in LiI Thin Films Grown on Sapphire(0001)

1993 ◽  
Vol 318 ◽  
Author(s):  
D. Lubben ◽  
F. A. Modine
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Ionic Conduction ◽  
High Vacuum ◽  
Dislocation Motion ◽  
Ultra High Vacuum ◽  
Vacuum System ◽  
Substrate Interface ◽  
Interdigital Electrodes ◽  
Film Substrate

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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