Universal ESEM

1993 ◽  
Vol 51 ◽  
pp. 786-787
Author(s):  
G.D. Danilatos
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
High Vacuum ◽  
Natural Extension ◽  
Necessary Condition ◽  
Environmental Scanning ◽  
Detection Systems ◽  
Small Gain ◽  
Detection Medium ◽  
Scanning Electron

The environmental scanning electron microscope (ESEM) has evolved as the natural extension of the scanning electron microscope (SEM), both historically and technologically. ESEM allows the introduction of a gaseous environment in the specimen chamber, whereas SEM operates in vacuum. One of the detection systems in ESEM, namely, the gaseous detection device (GDD) is based on the presence of gas as a detection medium. This might be interpreted as a necessary condition for the ESEM to remain operational and, hence, one might have to change instruments for operation at low or high vacuum. Initially, we may maintain the presence of a conventional secondary electron (E-T) detector in a "stand-by" position to switch on when the vacuum becomes satisfactory for its operation. However, the "rough" or "low vacuum" range of pressure may still be considered as inaccessible by both the GDD and the E-T detector, because the former has presumably very small gain and the latter still breaks down.

Microcharacterization of Induced Electric Fields in Poorly Conducting Specimens Irradiated in an Environmental Scanning Electron Microscope

2001 ◽  
Vol 7 (S2) ◽  
pp. 786-787
Author(s):  
Marion A. Stevens-Kalceff
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Electric Fields ◽  
High Vacuum ◽  
Charge Trapping ◽  
Environmental Scanning Electron Microscope ◽  
Variable Pressure ◽  
Environmental Scanning ◽  
Excess Charge ◽  
Scanning Electron

In a conventional scanning electron microscope, a thin, grounded conductive coating is applied to specimens that are poor electrical conductors to prevent retarding and deflection of the incident electron beam. in a variable pressure or environmental scanning electron microscope (ESEM), excess charge on the surface of uncoated poorly conducting specimens is balanced using ionized environmental gas. Ionized gas in environmental mode and grounded conductive coatings in conventional or high vacuum mode minimize charging at the specimen surface, however significant charge trapping may still occur in the implanted sub-surface regions of poorly conducting materials. A small fraction (<10-6) of the incident electrons are trapped at irradiation induced or pre-existing defects within the irradiated specimen. The trapped charge induces a highly localized electric field which can result in electro-migration and micro-segregation of charged mobile defect species within the irradiated micro-volume of specimen.

What Do We Need to Look Out for When Doing Energy Dispersive Xray Analysis in the Environmental Scanning Electron Microscope?

1999 ◽  
Vol 5 (S2) ◽  
pp. 290-291
Author(s):  
Scott Wight
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Quantitative Analysis ◽  
Scanning Electron Microscope ◽  
High Vacuum ◽  
Environmental Scanning Electron Microscope ◽  
Energy Dispersive ◽  
Environmental Scanning ◽  
Eds Analysis ◽  
Scanning Electron

The environmental scanning electron microscope (ESEM) is not typically used for quantitative analysis by energy dispersive x-ray spectrometry (EDS) because the electron beam is scattered by the chamber gas forming a broad tail or skirt rather than a focused spot. Scattered electrons can contribute x-rays from areas not directly under the beam, which compromises the spectrum for quantitative analysis. For specimens compatible with high vacuum, quantitative EDS analysis in a conventional electron microscope is preferred. However, the ESEM has found its niche in providing a vehicle for investigating those specimens that for any of a variety of reasons are not suitable for high vacuum electron microscopy and microanalysis. For these specimens, it is important that we find the most accurate way to perform EDS analysis in the low vacuum environment.Research has focused on reducing, accounting for, predicting, or measuring the electron scattering on a simplified system. Instrumental tricks to reduce the scattering of the primary electron beam have been reported in the past.

scholarly journals Electron Beam Current Loss at the High-Vacuum– High-Pressure Boundary in the Environmental Scanning Electron Microscope

2001 ◽  
Vol 7 (5) ◽  
pp. 397-406 ◽  
Author(s):  
Gerasimos D. Danilatos ◽  
Matthew R. Phillips ◽  
John V. Nailon
Keyword(s):  
High Pressure ◽  
Electron Beam ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Electron Probe ◽  
High Vacuum ◽  
Environmental Scanning ◽  
Probe Current ◽  
Prototype Instrument ◽  
Scanning Electron

AbstractA significant loss in electron probe current can occur before the electron beam enters the specimen chamber of an environmental scanning electron microscope (ESEM). This loss results from electron scattering in a gaseous jet formed inside and downstream (above) the pressure-limiting aperture (PLA), which separates the high-pressure and high-vacuum regions of the microscope. The electron beam loss above the PLA has been calculated for three different ESEMs, each with a different PLA geometry: an ElectroScan E3, a Philips XL30 ESEM, and a prototype instrument. The mass thickness of gas above the PLA in each case has been determined by Monte Carlo simulation of the gas density variation in the gas jet. It has been found that the PLA configurations used in the commercial instruments produce considerable loss in the electron probe current that dramatically degrades their performance at high chamber pressure and low accelerating voltage. These detrimental effects are minimized in the prototype instrument, which has an optimized thin-foil PLA design.

Mounting an individual submicrometer sized single crystal

1996 ◽  
Vol 211 (6) ◽  
Author(s):  
R. B. Neder ◽  
M. Burghammer ◽  
Th. Grasl ◽  
H. Schulz
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Single Crystal ◽  
Single Crystals ◽  
High Vacuum ◽  
Nanometer Resolution ◽  
Micro Manipulator ◽  
Scanning Electron

AbstractWe developed a new micro manipulator for mounting individual sub-micrometer sized single crystals within a scanning electron microscope. The translations are realized via a commercially available piezomicroscope, adapted for high vacuum usage and realize nanometer resolution. With this novel instrument it is routinely possible to mount individual single crystals with sizes down to 0.1

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