摘要:
In the magnetic optical system of a transmission electron microscope (TEM), the increased strength of a second objective lens is used to increase the longitudinal energy dispersion by forming an image at a magnified second back-focal plane. The electric current distribution of other lenses in the microscope is reconfigured to compensate for any offsets introduced by the modified second objective lens. A plurality of deflectors are installed which enable the manipulation of the electron beam electronically between the specimen and the second back-focal plane. The magnified second back-focal plane is projected onto the selected-area aperture, allowing the use of the existing selected-area aperture as an objective aperture to achieve an energy filtering effect which improves the image contrast and resolution.
摘要:
A hybrid luminescent device for converting ionizing and penetrating radiation energy such as x-rays, gamma rays, neutrons, ions, electrons, and the like into visible light for imaging applications. The hybrid luminescent device includes a phosphor screen disposed on an entrance face fiber optics scintillator which, in turn, may be removably coupled to a camera or like recording media. The hybrid luminescent device of the present invention is capable of providing enhanced radiation absorption efficiency, higher spatial resolution and enhanced brightness or luminescence output over that which is achievable by the phosphor screen and/or fiber optics scintillator when used separately as an intensifying screen for imaging of ionizing and/or penetrating radiation.
摘要:
An apparatus for use with an electron beam for imaging a sample. The apparatus has a down-conversion detector configured to detect an electron microscopy signal generated by the electron beam incident on the sample, a direct bombardment detector adjacent to the down-conversion detector and configured to detect the electron microscopy signal, and a mechanism selectively exposing the down-conversion detector and the direct bombardment detector to the electron microscopy signal. A method using the apparatus is also provided.
摘要:
A preferred method for transmission electron microscopy includes a step of generating a microscopy signal. The microscopy signal is then detected with an active pixel detector that includes a plurality of pixels. Each of the pixels includes at least one photodiode. Each pixel integrates an incident signal over a collection time period. Using a massively parallel on chip analog to digital conversion, very fast read out times can be achieved, e.g., many frames per second. In a preferred embodiment, the read out time permits there to be a single electron event recorded per pixel, indicating either a single electron or the lack thereof. This permits simple accumulation of the pixel counts for each pixel in read-out and storage electronics.