Beam Size in the Environmental SEM: a Comparison of Model and Experimental Data

1998 ◽  
Vol 4 (S2) ◽  
pp. 298-299 ◽  
Author(s):  
S. A. Wight
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Electron Scattering ◽  
Small World ◽  
Beam Current ◽  
Chamber Pressure ◽  
Environmental Scanning ◽  
Scattered Electron ◽  
Beam Scattering ◽  
Scanning Electron

Knowledge of the magnitude of the scattered electron skirt in the environmental scanning electron microscope (ESEM) or low vacuum scanning electron microscope (LVSEM) is important to the understanding of the analytical spatial resolution of energy dispersive spectrometry (EDS). The extent of beam scattering is a function of the distance from the final aperture to the specimen, composition of the gas present, chamber pressure, accelerating voltage, and beam current. This work compares model predictions of electron scattering to experimental measurements of electron scattering. Several of the popular Monte Carlo programs written for electron-solid interactions were not designed for low vacuum conditions. Joy has developed a model that takes into account the electron scattering which takes place in the chamber before interacting with the specimen; thus it is useful for LVSEM conditions. That model is incorporated in Electron Flight Simulator - E (Small World, Vienna VA)1 and is used in this work.

Magnetic Domain Observation of an Amorphous Fe-Si-B Ribbon by Means of a High Voltage Scanning Electron Microscope

1981 ◽  
Vol 39 ◽  
pp. 320-321
Author(s):  
K. Tsuno ◽  
Y. Harada ◽  
T. Sato
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
High Voltage ◽  
Amorphous Ribbon ◽  
Image Resolution ◽  
Objective Lens ◽  
Magnetic Domains ◽  
Scattered Electron ◽  
Voltage Scanning ◽  
Scanning Electron

Magnetic domains of ferromagnetic amorphous ribbon have been observed using Bitter powder method. However, the domains of amorphous ribbon are very complicated and the surface of ribbon is not flat, so that clear domain image has not been obtained. It has been desired to observe more clear image in order to analyze the domain structure of this zero magnetocrystalline anisotropy material. So, we tried to observe magnetic domains by means of a back-scattered electron mode of high voltage scanning electron microscope (HVSEM).HVSEM method has several advantages compared with the ordinary methods for observing domains: (1) high contrast (0.9, 1.5 and 5% at 50, 100 and 200 kV) (2) high penetration depth of electrons (0.2, 1.5 and 8 μm at 50, 100 and 200 kV). However, image resolution of previous HVSEM was quite low (maximum magnification was less than 100x), because the objective lens cannot be excited for avoiding the application of magnetic field on the specimen.

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.

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