Abstract:
A microchannel plate for detecting neutrons includes a hydrogen-rich polymer substrate that defines a plurality of channels extending from a top surface of the substrate to a bottom surface of the substrate, where neutrons interact with the plurality of channels to generate at least one secondary electron. A top electrode is positioned on the top surface of the substrate and a bottom electrode is positioned on the bottom surface of the substrate. A resistive layer is formed over an outer surface of the plurality of channels that provides ohmic conduction with a resistivity that is substantially constant. An emissive layer is formed over the resistive layer. Neutron interaction products interact with the plurality of channels defined by the substrate and the emissive films to generate secondary electrons that cascade within the plurality of channels to provide an amplified signal related to the detection of neutrons.
Abstract:
A system and method for identifying an optimal landing energy of a probe current in a scanning electron microscope system. A probe current having a known landing energy is directed at a sample for producing a signal electron beam. The current of the signal electron beam is measured by directing the beam to a current detector for calculating a current yield, which is the ratio of the signal current to the probe current. The landing energy can then be changed for subsequent measurements of the signal current to identify the landing energy which produces a desired current yield. Once identified, the landing energy value can be used to produce a signal electron beam directed towards an imaging detector to generate topographic images of samples.
Abstract:
A charged particle filter such as a Wien filter in which components used as the pole pieces and electrodes are precisely and reliably secured to a supporting structure through which they extend and to which they are brazed. Electrical insulating gaps in the magnetic circuit are located very remotely from the pole faces of the pole pieces so as to minimize any adverse effect of the gaps on the produced magnetic field.
Abstract:
A microchannel plate for detecting neutrons includes a hydrogen-rich polymer substrate that defines a plurality of channels extending from a top surface of the substrate to a bottom surface of the substrate, where neutrons interact with the plurality of channels to generate at least one secondary electron. A top electrode is positioned on the top surface of the substrate and a bottom electrode is positioned on the bottom surface of the substrate. A resistive layer is formed over an outer surface of the plurality of channels that provides ohmic conduction with a resistivity that is substantially constant. An emissive layer is formed over the resistive layer. Neutron interaction products interact with the plurality of channels defined by the substrate and the emissive films to generate secondary electrons that cascade within the plurality of channels to provide an amplified signal related to the detection of neutrons.
Abstract:
A microchannel plate includes a substrate defining a plurality of channels extending from a top surface of the substrate to a bottom surface of the substrate. A resistive layer is formed over an outer surface of the plurality of channels that provides ohmic conduction with a predetermined resistivity that is substantially constant. An emissive layer is formed over the resistive layer. A top electrode is positioned on the top surface of the substrate. A bottom electrode positioned on the bottom surface of the substrate.
Abstract:
An image intensifying device includes a lens that is positioned at a light input that forms an image of a scene. The image intensifying device also includes an image intensifier tube that includes a photocathode that is positioned to receive the image formed by the lens. The photocathode generates photoelectrons in response to the light image of the scene. The image intensifier tube also includes a microchannel plate having an input surface comprising the photocathode. The microchannel plate receives the photoelectrons generated by the photocathode and generating secondary electrons. An electron detector receives the secondary electrons generated by the microchannel plate and generates an intensified image of the scene.
Abstract:
A microchannel plate includes a substrate defining a plurality of pores extending from a top surface of the substrate to a bottom surface of the substrate. The plurality of pores includes a resistive material on an outer surface that forms a first emissive layer. A second emissive layer is formed over the first emissive layer. The second emissive layer is chosen to achieve at least one of an increase in secondary electron emission efficiency and a decrease in gain degradation as a function of time. A top electrode is positioned on the top surface of the substrate and a bottom electrode is positioned on the bottom surface of the substrate.
Abstract:
A fixture and method is provided for aligning optical elements in a microscope. The fixture attaches to an objective lens plane of the microscope and supports an alignment optical element. During optical component alignment, an alignment beam is directed along the illumination and imaging paths of the microscope through the objective lens port and into the fixture for reflection by the alignment optical element. The fixture allows an alignment optical element positioned in a single location to be used for aligning the microscope components and for adjusting the microscope objective lens.
Abstract:
In order to improve the resolution of an electron beam in a scanning electron microscope or the like in which a Wien filter is employed for particle detection purposes, the beam is caused to have an envelope with a crossover point within, and preferably centrally located with respect to, the Wien filter.
Abstract:
A process for reinforcing porous refractories with fillers, such as carbon particles, is provided. First, filler particles are mixed with a liquid resin to produce a liquid mixture. The mixture is allowed to seep into the pores of the refractory, preferably by immersing the refractory in said mixture in an evacuated tank. The refractory can be removed from the mixture and excess mixture can be allowed to drip from the refractory. The refractory is then cured, preferably by heating. The refractory is strengthened by the process to better withstand heat fluctuations encountered, for example, in the steel refining process.