scholarly journals Empirical assessment of the detection efficiency of CR-39 at high proton fluence and a compact, proton detector for high-fluence applications

2014 ◽  
Vol 85 (4) ◽  
pp. 043302 ◽  
Author(s):  
M. J. Rosenberg ◽  
F. H. Séguin ◽  
C. J. Waugh ◽  
H. G. Rinderknecht ◽  
D. Orozco ◽  
...  
Keyword(s):  
Detection Efficiency ◽  
High Fluence ◽  
Empirical Assessment ◽  
High Proton ◽  
Proton Detector

Fresnel interference in point-projection imaging of purple membrane

1995 ◽  
Vol 53 ◽  
pp. 846-847
Author(s):  
X. Zhang ◽  
J. Spence ◽  
W. Qian ◽  
D. Taylor ◽  
K. Taylor
Keyword(s):  
Detection Efficiency ◽  
Mean Free Path ◽  
Purple Membrane ◽  
Unit Cell Dimension ◽  
Experimental Point ◽  
Membrane Thickness ◽  
Low Energies ◽  
Channel Plate ◽  
Point Projection ◽  
Inelastic Mean Free Path

Experimental point-projection shadow microscope (PPM) images of uncoated, unstained purple membrane (PM, bacteriorhodopsin, a membrane protein from Halobacterium holobium) were obtained recently using 100 volt electrons. The membrane thickness is about 5 nm and the hexagonal unit cell dimension 6 nm. The images show contrast around the edges of small holes, as shown in figure 1. The interior of the film is opaque. Since the inelastic mean free path for 100V electrons in carbon (about 6 Å) is much less than the sample thickness, the question arises that how much, if any, transmission of elastically scattered electrons occurs. A large inelastic contribution is also expected, attenuated by the reduced detection efficiency of the channel plate at low energies. Quantitative experiments using an energy-loss spectrometer are planned. Recently Shedd has shown that at about 100V contrast in PPM images of thin gold films can be explained as Fresnel interference effects between different pinholes in the film, separated by less than the coherence width.

Effect of energy filtering on micro-diffraction in the SEM

1994 ◽  
Vol 52 ◽  
pp. 604-605
Author(s):  
James F. Mancuso ◽  
Leo A. Fama ◽  
William B. Maxwell ◽  
Jerry L. Lehman ◽  
Hasso Weiland ◽  
...  
Keyword(s):  
Detection Efficiency ◽  
Ccd Camera ◽  
High Gain ◽  
Microchannel Plate ◽  
Electrostatic Energy ◽  
Energy Filtering ◽  
Electron Channelling ◽  
Low Energy Electrons ◽  
Low Sensitivity ◽  
Angular Field Of View

Micro-diffraction based crystallography is essential to the design and development of many classes of ‘crafted materials’. Although the scanning electron microscope can provide crystallographic information with high spatial resolution, its current utility is severely limited by the low sensitivity of existing diffraction techniques (ref: Dingley). Previously, Joy showed that energy filtering increased contrast and pattern visibility in electron channelling. This present paper discribes the effect of energy filtering on EBSP sensitivity and backscattered SEM imaging.The EBSP detector consisted of an electron energy filter, a microchannel plate detector, a phosphor screen, optical coupler, and a slow scan CCD camera. The electrostatic energy filter used in this experiment was constructed as a cone with 5 coaxial electrodes. The angular field-of-view of the filter was approximately 38°. The microchannel plate, which was the initial sensing component, had high gain and had 50% to 80% detection efficiency for the low energy electrons that passed through the retarding field filter.

Trace nanoanalysis

1994 ◽  
Vol 52 ◽  
pp. 940-941
Author(s):  
D. E. Newbury ◽  
R. D. Leapman
Keyword(s):  
High Performance ◽  
Secondary Ion Mass Spectrometry ◽  
Detection Efficiency ◽  
Volume Element ◽  
And Performance ◽  
Trace Constituents ◽  
Secondary Ion ◽  
Concentration Levels ◽  
Structure Properties

Trace constituents, which can be very loosely defined as those present at concentration levels below 1 percent, often exert influence on structure, properties, and performance far greater than what might be estimated from their proportion alone. Defining the role of trace constituents in the microstructure, or indeed even determining their location, makes great demands on the available array of microanalytical tools. These demands become increasingly more challenging as the dimensions of the volume element to be probed become smaller. For example, a cubic volume element of silicon with an edge dimension of 1 micrometer contains approximately 5×1010 atoms. High performance secondary ion mass spectrometry (SIMS) can be used to measure trace constituents to levels of hundreds of parts per billion from such a volume element (e. g., detection of at least 100 atoms to give 10% reproducibility with an overall detection efficiency of 1%, considering ionization, transmission, and counting).

An Empirical Assessment of Post-Burlington Claims of Retaliation in Employment

2011 ◽  
Author(s):  
Elizabeth Grozman ◽  
Anne Marie D. Haddock ◽  
Lindsey M. Lee ◽  
Lisa S. Moore ◽  
Amy Gammon ◽  
...  
Keyword(s):  
Empirical Assessment

Nasty and Brutish? an Empirical Assessment of the Violence Hypothesis

2017 ◽  
Author(s):  
Karl Widerquist ◽  
Grant S. McCall
Keyword(s):  
Historical Evidence ◽  
Contemporary State ◽  
Empirical Assessment ◽  
Early States ◽  
Consensus View

This chapter empirically investigates two hypotheses often used to support the claim that virtually everyone is better off in state society than they could reasonably expect to be in any stateless environment. “The strong violence hypothesis” is the claim that violence in stateless societies is necessarily intolerable. “The weak violence hypothesis” is the claim that violence in stateless societies tends to be higher than in state society. Section 1 uses anthropological and historical evidence to examine violence in prehistoric stateless societies, early states, and contemporary states. Section 2 reviews evidence from modern stateless societies. Section 3 attempts to assemble anthropologists’ consensus view of violence in stateless societies. Section 4 evaluates the strong and weak hypotheses in light of this information, arguing that societies in which sovereignty is most absent maintain the ability to keep violence at tolerable levels. Although it is reasonable to suppose that stateless societies tend to have higher violence than contemporary state societies, some stateless societies have lower violence than some states. Because these findings reject 350 years of accumulated theory of sovereignty, Section 5 briefly discusses how bands are able to maintain peace without state-like institutions. Section 6 concludes.

Criminality and Homeless Men: An Empirical Assessment

1989 ◽  
Vol 36 (5) ◽  
pp. 532-549 ◽  
Author(s):  
David A. Snow ◽  
Susan G. Baker ◽  
Leon Anderson
Keyword(s):  
Empirical Assessment ◽  
Homeless Men
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