scholarly journals Publisher’s Note: “Radically tunable ultrafast photonic oscillators via differential pumping” [J. Appl. Phys. 127, 083103 (2020)]

2020 ◽  
Vol 127 (13) ◽  
pp. 139902
Author(s):  
Yannis Kominis ◽  
Anastasios Bountis ◽  
Vassilios Kovanis
Keyword(s):  
Differential Pumping

Studies on Water in the Hydration Chamber of a Modified Electron Microscope

1970 ◽  
Vol 28 ◽  
pp. 544-545
Author(s):  
R. C. Moretz ◽  
G. G. Hausner ◽  
D. F. Parsons
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electron Microscope ◽  
Steady State ◽  
Room Temperature ◽  
Small Mass ◽  
Equilibrium Pressure ◽  
Biological Objects ◽  
Mechanical Pump ◽  
Differential Pumping

Use of the electron microscope to examine wet objects is possible due to the small mass thickness of the equilibrium pressure of water vapor at room temperature. Previous attempts to examine hydrated biological objects and water itself used a chamber consisting of two small apertures sealed by two thin films. Extensive work in our laboratory showed that such films have an 80% failure rate when wet. Using the principle of differential pumping of the microscope column, we can use open apertures in place of thin film windows.Fig. 1 shows the modified Siemens la specimen chamber with the connections to the water supply and the auxiliary pumping station. A mechanical pump is connected to the vapor supply via a 100μ aperture to maintain steady-state conditions.

Residual Gas Reaction in the Electron Microscope: II The Design of a Gas-Control Chamber for Quantitative Observations

1969 ◽  
Vol 27 ◽  
pp. 82-83
Author(s):  
Chester J. Calbick ◽  
Richard E. Hartman
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Local Environment ◽  
Chamber Pressure ◽  
Objective Lens ◽  
Ion Pump ◽  
Quantitative Studies ◽  
Precise Knowledge ◽  
Differential Pumping ◽  
And Control

Quantitative studies of the phenomenon associated with reactions induced by the electron beam between specimens and gases present in the electron microscope require precise knowledge and control of the local environment experienced by the portion of the specimen in the electron beam. Because of outgassing phenomena, the environment at the irradiated portion of the specimen is very different from that in any place where gas pressures and compositions can be measured. We have found that differential pumping of the specimen chamber by a 4" Orb-Ion pump, following roughing by a zeolite sorption pump, can produce a specimen-chamber pressure 100- to 1000-fold less than that in the region below the objective lens.

Development of a Field Emission VP-SEM and Some Initial Applications

2001 ◽  
Vol 7 (S2) ◽  
pp. 882-883
Author(s):  
Masako Nishimura ◽  
Sukehiro Itoh ◽  
Steve Joens
Keyword(s):  
Field Emission ◽  
Chamber Pressure ◽  
Variable Pressure ◽  
Natural State ◽  
Backscattered Electrons ◽  
Pumping System ◽  
Multi Stage ◽  
Gas Molecules ◽  
Residual Gas ◽  
Differential Pumping

The use of variable pressure SEMs (VP-SEMs) is increasing in various fields of science and industry, allowing microscopy in a variable pressure environment of 1 ∼ 270 Pa utilizing backscattered electrons for imaging. The VP-SEM allows microscopy of insulated samples without the need for sample preparation. Charging artifacts can be minimized as well. When the VP-SEM is operated with a cooling stage, which allows cooling of samples at −20° and above, vaporization of water from samples is reduced. This permits microscopy of wet samples at close to the natural state for extended periods of time.Poor S/N ratio and deterioration of resolution, both of which are due to collisions among residual gas molecules and primary/backscattered electrons, have limited the performance of VP-SEMs. For resolving these limitations, we have completed the development of a new field emission VP-SEM which operates with a stable Schottky field emission source, a new environmental secondary electron detector (ESED), and a multi-stage differential pumping system. Fig. 1 shows a sectional view of the column with the differential pumping system. This design allows stable gun vacuum conditions with variable specimen chamber pressure 10 through 3,000 Pa, permitting a pressure difference from the gun by 1011 Pa without problems.

scholarly journals Measurement of the gas-flow reduction factor of the KATRIN DPS2-F differential pumping section

Vacuum ◽  
2012 ◽  
Vol 86 (8) ◽  
pp. 1126-1133 ◽  
Author(s):  
S. Lukić ◽  
B. Bornschein ◽  
L. Bornschein ◽  
G. Drexlin ◽  
A. Kosmider ◽  
...  
Keyword(s):  
Gas Flow ◽  
Reduction Factor ◽  
Flow Reduction ◽  
Differential Pumping

Deposition of novel nanocomposite films by a newly developed differential pumping co-sputtering system

2012 ◽  
Vol 30 (1) ◽  
pp. 011502 ◽  
Author(s):  
Masateru Nose ◽  
Takeshi Kurimoto ◽  
Atsushi Saiki ◽  
Kenji Matsuda ◽  
Kiyoshi Terayama
Keyword(s):  
Nanocomposite Films ◽  
Differential Pumping ◽  
Sputtering System

scholarly journals Cr(Al)N/Al2O3 nanocomposite coatings fabricated by differential pumping cosputtering

2015 ◽  
Vol 21 (S3) ◽  
pp. 1027-1028 ◽  
Author(s):  
Masahiro Kawasaki ◽  
Masateru Nose ◽  
Ichiro Onishi ◽  
Kenji Matsuda ◽  
Makoto Shiojiri
Keyword(s):  
Nanocomposite Coatings ◽  
Differential Pumping

scholarly journals Environmental SEMs: A New Way to Look at Samples

1995 ◽  
Vol 3 (8) ◽  
pp. 14-15
Author(s):  
Don Chernoff ◽  
Mohammad Salim Mujallid
Keyword(s):  
High Vacuum ◽  
Chamber Pressure ◽  
Variable Pressure ◽  
New Class ◽  
The Past ◽  
Order Of Magnitude ◽  
Differential Pumping ◽  
New Applications ◽  
Magnitude Increase ◽  
Environmental Sem

A new class of SEM has evolved over the past few years which provides some startling capabilities never before available to electron microscopists. These instruments, typically referred to as environmental SEMs or variable pressure SEMs. have opened up a host of new applications that are difficult or impossible with a standard SEM. Many of the constraints of sample preparation and handling that exist with a conventional SEM do not apply to environmental SEMs.An environmental SEM functions like a conventional SEM except that you can introduce air or any other gas into the chamber and raise the chamber pressure above the normal high vacuum range of 10-5 or 10-6 Torr. Inmost instruments the vacuum can be raised to as much as 1 Torr. This represents a 6 order of magnitude increase in chamber pressure. Environmental SEMs can achieve this high chamber pressure without damage to the electron source by using differential pumping apertures in the column.

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