scholarly journals A Cloud Chamber for the Study of Particles of Low Energy

1953 ◽  
Vol 24 (11) ◽  
pp. 1051-1054
Author(s):  
T. C. Merkle ◽  
J. L. Need
Keyword(s):  
Cloud Chamber ◽  
Low Energy

Cloud-Chamber Observation on Low Energy PortionRaEBeta-Spectrum

1948 ◽  
Vol 74 (6) ◽  
pp. 699-700 ◽  
Author(s):  
Arthur Waltner ◽  
F. T. Rogers
Keyword(s):  
Cloud Chamber ◽  
Low Energy

Determination of the Ranges and Straggling of Low-Energy Alpha Particles in a Cloud Chamber

1954 ◽  
Vol 96 (3) ◽  
pp. 673-678 ◽  
Author(s):  
S. Barile ◽  
R. Webeler ◽  
G. Allen
Keyword(s):  
Alpha Particles ◽  
Cloud Chamber ◽  
Low Energy

ELECTRON SHOWER CURVES IN LEAD FOR ENERGIES OF 3 TO 40 Bev

1962 ◽  
Vol 40 (5) ◽  
pp. 573-585 ◽  
Author(s):  
Margaret D. Wilson ◽  
I. B. McDiarmid
Keyword(s):  
Cloud Chamber ◽  
Low Energy ◽  
Photometric Method ◽  
Energy Cutoff ◽  
Shower Maximum ◽  
The Mean ◽  
Electron Photon ◽  
Shower Energy ◽  
Electron Shower

Electron–photon showers in lead have been studied in a multiplate cloud chamber at energies up to 40 Bev. The numbers of electrons under various thicknesses of lead have been determined by a photometric method combined with scintillator measurements. Experimental shower curves for several energies are given as well as the mean number of electrons at the shower maximum as a function of shower energy. The results are compared with standard shower theory under Approximation A with an assumed low-energy cutoff.

Magnetic-Cloud-Chamber Observations of Low-Energy Cosmic-Ray Electrons

1965 ◽  
Vol 138 (1B) ◽  
pp. B300-B302 ◽  
Author(s):  
James W. Schmoker ◽  
James A. Earl
Keyword(s):  
Magnetic Cloud ◽  
Cosmic Ray ◽  
Cloud Chamber ◽  
Low Energy

The production of V -particles in low-energy interactions

1954 ◽  
Vol 221 (1146) ◽  
pp. 412-413 ◽  
Keyword(s):  
Total Energy ◽  
Cloud Chamber ◽  
Low Energy ◽  
Heavy Mesons ◽  
The Third ◽  
Chamber Experiment ◽  
Lead Plate ◽  
Secondary Interactions ◽  
Photographic Emulsions

The events described earlier showing the production of slow heavy mesons in photographic emulsions were interactions in which many shower particles were also produced. I should like to draw attention to three photographs which have been obtained in a cloud-chamber experiment carried out at the Jungfraujoch by a group from Manchester. These show the production of F-particles in interactions of very low multiplicity. In two of these events (Astbury, Chippindale, Millar, Newth, Page, Rytz & Sahiar 1952) slow-charged F-particles are produced in secondary interactions in a lead plate in the cloud chamber. The only other visible products of these interactions are one and two shower particles respectively. The third event is a star in the gas of the cloud chamber from which a neutral V -particle emerges. The total energy of the star is estimated as less than 1010 eV. This event is fully described by Astbury, Buchanan, James, Millar, Newth, Page, Rytz & Sahiar (1953).

Dissociated Σ=27 boundaries in silicon

1988 ◽  
Vol 46 ◽  
pp. 624-625
Author(s):  
A. Garg ◽  
W.A.T. Clark ◽  
J.P. Hirth
Keyword(s):  
Electron Diffraction ◽  
Local Minimum ◽  
Boundary Energy ◽  
Coincidence Site Lattice ◽  
Boundary Plane ◽  
Low Energy ◽  
Theoretical Understanding ◽  
Site Lattice ◽  
Kikuchi Pattern ◽  
Analysis Techniques

In the last twenty years, a significant amount of work has been done in the theoretical understanding of grain boundaries. The various proposed grain boundary models suggest the existence of coincidence site lattice (CSL) boundaries at specific misorientations where a periodic structure representing a local minimum of energy exists between the two crystals. In general, the boundary energy depends not only upon the density of CSL sites but also upon the boundary plane, so that different facets of the same boundary have different energy. Here we describe TEM observations of the dissociation of a Σ=27 boundary in silicon in order to reduce its surface energy and attain a low energy configuration.The boundary was identified as near CSL Σ=27 {255} having a misorientation of (38.7±0.2)°/[011] by standard Kikuchi pattern, electron diffraction and trace analysis techniques. Although the boundary appeared planar, in the TEM it was found to be dissociated in some regions into a Σ=3 {111} and a Σ=9 {122} boundary, as shown in Fig. 1.

Transfer optics for high spatial resolution electron spectroscopy

1988 ◽  
Vol 46 ◽  
pp. 666-667
Author(s):  
G. G. Hembree ◽  
Luo Chuan Hong ◽  
P.A. Bennett ◽  
J.A. Venables
Keyword(s):  
Magnetic Field ◽  
Scanning Transmission Electron Microscope ◽  
Low Energy ◽  
Objective Lens ◽  
State University ◽  
Arizona State University ◽  
Initial Field ◽  
Resolution Electron ◽  
Scanning Transmission ◽  
Low Energy Electrons

A new field emission scanning transmission electron microscope has been constructed for the NSF HREM facility at Arizona State University. The microscope is to be used for studies of surfaces, and incorporates several surface-related features, including provision for analysis of secondary and Auger electrons; these electrons are collected through the objective lens from either side of the sample, using the parallelizing action of the magnetic field. This collimates all the low energy electrons, which spiral in the high magnetic field. Given an initial field Bi∼1T, and a final (parallelizing) field Bf∼0.01T, all electrons emerge into a cone of semi-angle θf≤6°. The main practical problem in the way of using this well collimated beam of low energy (0-2keV) electrons is that it is travelling along the path of the (100keV) probing electron beam. To collect and analyze them, they must be deflected off the beam path with minimal effect on the probe position.

Performance Evaluation of a Novel Type of Low-Energy Electron Microscope

1990 ◽  
Vol 48 (1) ◽  
pp. 354-355
Author(s):  
Bertholdand Senftinger ◽  
Helmut Liebl
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Field Strength ◽  
Numerical Aperture ◽  
Low Energy ◽  
Energy Electron ◽  
High Resolution Imaging ◽  
Lens System ◽  
Resolution Imaging ◽  
Low Energy Electron

During the last few years the investigation of clean and adsorbate-covered solid surfaces as well as thin-film growth and molecular dynamics have given rise to a constant demand for high-resolution imaging microscopy with reflected and diffracted low energy electrons as well as photo-electrons. A recent successful implementation of a UHV low-energy electron microscope by Bauer and Telieps encouraged us to construct such a low energy electron microscope (LEEM) for high-resolution imaging incorporating several novel design features, which is described more detailed elsewhere.The constraint of high field strength at the surface required to keep the aberrations caused by the accelerating field small and high UV photon intensity to get an improved signal-to-noise ratio for photoemission led to the design of a tetrode emission lens system capable of also focusing the UV light at the surface through an integrated Schwarzschild-type objective. Fig. 1 shows an axial section of the emission lens in the LEEM with sample (28) and part of the sample holder (29). The integrated mirror objective (50a, 50b) is used for visual in situ microscopic observation of the sample as well as for UV illumination. The electron optical components and the sample with accelerating field followed by an einzel lens form a tetrode system. In order to keep the field strength high, the sample is separated from the first element of the einzel lens by only 1.6 mm. With a numerical aperture of 0.5 for the Schwarzschild objective the orifice in the first element of the einzel lens has to be about 3.0 mm in diameter. Considering the much smaller distance to the sample one can expect intense distortions of the accelerating field in front of the sample. Because the achievable lateral resolution depends mainly on the quality of the first imaging step, careful investigation of the aberrations caused by the emission lens system had to be done in order to avoid sacrificing high lateral resolution for larger numerical aperture.

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