Book Review: Under Construction: Technologies of Development in Urban Ethiopia

A magnetic spectrometer to be attached to the Johns Hopkins S. T. E. M. is under construction. Its main purpose will be to investigate electron interactions with biological molecules in the energy range of 40 KeV to 100 KeV. The spectrometer is of the type described by Kerwin and by Crewe Its magnetic pole boundary is given by the equationwhere R is the electron curvature radius. In our case, R = 15 cm. The electron beam will be deflected by an angle of 90°. The distance between the electron source and the pole boundary will be 30 cm. A linear fringe field will be generated by a quadrupole field arrangement. This is accomplished by a grounded mirror plate and a 45° taper of the magnetic pole.

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Radiation Damage Studies with the HVEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100096655 ◽

1972 ◽

Vol 30 ◽

pp. 680-681

Author(s):

J. J. Laidler ◽

B. Mastel

Keyword(s):

Radiation Damage ◽

Stainless Steels ◽

Volume Expansion ◽

Austenitic Stainless Steels ◽

Test Facility ◽

Fast Breeder Reactors ◽

Breeder Reactors ◽

Under Construction ◽

Development Laboratory ◽

Insight Into

One of the major materials problems encountered in the development of fast breeder reactors for commercial power generation is the phenomenon of swelling in core structural components and fuel cladding. This volume expansion, which is due to the retention of lattice vacancies by agglomeration into large polyhedral clusters (voids), may amount to ten percent or greater at goal fluences in some austenitic stainless steels. From a design standpoint, this is an undesirable situation, and it is necessary to obtain experimental confirmation that such excessive volume expansion will not occur in materials selected for core applications in the Fast Flux Test Facility, the prototypic LMFBR now under construction at the Hanford Engineering Development Laboratory (HEDL). The HEDL JEM-1000 1 MeV electron microscope is being used to provide an insight into trends of radiation damage accumulation in stainless steels, since it is possible to produce atom displacements at an accelerated rate with 1 MeV electrons, while the specimen is under continuous observation.

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Description of a New High Resolution Scanning Transmission EM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100095340 ◽

1972 ◽

Vol 30 ◽

pp. 418-419

Author(s):

Michael Beer ◽

J. W. Wiggins ◽

David Woodruff ◽

Jon Zubin

Keyword(s):

High Resolution ◽

Field Emission ◽

Energy Dispersive Spectrometer ◽

Scanning Transmission Electron Microscope ◽

Objective Lens ◽

Condenser Lens ◽

Transmission Electron ◽

Pattern Size ◽

Scanning Transmission ◽

Under Construction

A high resolution scanning transmission electron microscope of the type developed by A. V. Crewe is under construction in this laboratory. The basic design is completed and construction is under way with completion expected by the end of this year.The optical column of the microscope will consist of a field emission electron source, an accelerating lens, condenser lens, objective lens, diffraction lens, an energy dispersive spectrometer, and three electron detectors. For any accelerating voltage the condenser lens function to provide a parallel beam at the entrance of the objective lens. The diffraction lens is weak and its current will be controlled by the objective lens current to give an electron diffraction pattern size which is independent of small changes in the objective lens current made to achieve focus at the specimen. The objective lens demagnifies the image of the field emission source so that its Gaussian size is small compared to the aberration limit.

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