Abstract: A high resolution energy-selecting electron beam apparatus and method for improving the energy resolution of electron-optical systems by restricting the energy range of admitted electrons, and optionally also for improving the spatial resolution by correcting chromatic and geometric aberrations. The apparatus comprises a plurality of magnetic or electrostatic prisms that disperse an electron beam according to the energies of the electrons into an energy spectrum, a plurality of magnifying lenses such as electromagnetic or electrostatic quadrupoles that increase the energy dispersion of the energy spectrum, an energy-selecting slit that selects a desirable range of energies of the electrons, and optionally also sextupole, octupole and higher-order lenses that correct chromatic and geometric aberration of the electron-optical system.

Abstract: A high resolution energy-selecting electron beam apparatus and method for improving the energy resolution of electron-optical systems by restricting the energy range of admitted electrons, and optionally also for improving the spatial resolution by correcting chromatic and geometric aberrations. The apparatus comprises a plurality of magnetic or electrostatic prisms that disperse an electron beam according to the energies of the electrons into an energy spectrum, a plurality of magnifying lenses such as electromagnetic or electrostatic quadrupoles that increase the energy dispersion of the energy spectrum, an energy-selecting slit that selects a desirable range of energies of the electrons, and optionally also sextupole, octupole and higher-order lenses that correct chromatic and geometric aberration of the electron-optical system.

Abstract: Aberration-corrected charged-particle optical apparatus improving the resolution of charged-particle optical systems by eliminating or minimizing optical aberrations. The apparatus comprises a source of charged particles and a plurality of charged-particle lenses including non-round lenses, energized in such manner so as to correct axial aberrations of orders up to and including fifth order. The non-round lenses comprise quadrupoles and octupoles disposed in such manner that fifth order combination aberrations are precisely controlled in addition to third order aberrations. The resultant apparatus very significantly improves on resolution attainable with non-aberration corrected charged-particle round lenses. It also improves on resolution attainable with correctors of third order aberrations only.

Abstract: Aberration-corrected charged-particle optical apparatus improving the resolution of charged-particle optical systems by eliminating or minimizing optical aberrations. The apparatus comprises a source of charged particles and a plurality of charged-particle lenses including non-round lenses, energized in such manner so as to correct axial aberrations of orders up to and including fifth order. The non-round lenses comprise quadrupoles and octupoles disposed in such manner that fifth order combination aberrations are precisely controlled in addition to third order aberrations. The resultant apparatus very significantly improves on resolution attainable with non-aberration corrected charged-particle round lenses. It also improves on resolution attainable with correctors of third order aberrations only.

Abstract: An autoadjusting charged-particle probe-forming apparatus improving the resolution of probe-forming charged-particle optical systems by minimizing optical aberrations. The apparatus comprises a source of charged particles, a probe-forming system of charged-particle lenses, a plurality of detectors optionally comprising a two-dimensional image detector, power supplies, a computer and appropriate software. Images are recorded by the two-dimensional detector and analyzed to determine the aberration characteristics of the apparatus. Alternately, multiple scanned images are recorded by a scanned image detector and also analyzed to determine the aberration characteristics of the apparatus. The aberration characteristics are used to automatically adjust the apparatus for improved optical performance.

Abstract: A method and apparatus are provided for CTD imaging device multiple read-out speeds with optimized operation at all of the available speeds. Image signals from a CTD imaging device are digitally sampled at a defined frequency with the read-out electronics being matched to the defined frequency for optimum operation at that frequency. Digital samples taken during both a first (reset reference) portion of each image signal and a second (image voltage) portion of each image signal are then discarded if taken during a noisy/unstable part of the image signal or accumulated and averaged if taken during a stable part of the image signal. The accumulated and averaged digital samples are then algebraically combined to produce signals representative of an image generated by the CTD imaging device. The read-out speed of the CTD imaging device is a fraction of the sampling speed and can be selected by setting an integer divisor for the defined sampling frequency.

Abstract: A large-format solid state imaging device which can detect optical images without loss of sharpness or resolution is provided and includes a solid state imaging device supported by and secured to a frame. To ensure that the imaging device does not deviate from its desired surface configuration, the device is pressed between an optical coupling plate and a support plate each having at least one matching surface whose curvature matches the other with a precision which permits the solid state imaging device to detect optical images without loss of sharpness or resolution and which conforms the imaging device into a desired configuration. Preferably, the frame is annular and the edges of the imaging device are secured to the frame by at least two spaced bonds.

Abstract: An energy filtering system of an EFTEM is automatically adjusted using a computer. The computer inserts an energy-selecting slit into the beam path and begins monitoring the position of the electron beam through a combination of the current sensors integral to the slit and the readout of an electron camera. The beam is centered within the slit by adjusting an energy dispersing element while monitoring beam sensors. After initial alignment, the slit is retracted and a reference aperture is inserted at the entrance to the energy filter. The electron camera captures an image of the reference aperture and the computer analyzes the deviations of the aperture image from its known physical dimensions in order to evaluate the electron optical distortions and aberrations of the filter. The computer uses the determined optical parameters to adjust the distortion and aberration correcting optical elements of the filter, whose effects are known due to previous calibration.

Abstract: A precision-controlled slit mechanism having an adjustable width which is both accurate and reproducible is provided for apparatuses which are designed to exclude portions of an energy spectrum prior to analysis such as energy-selected imaging filters in electron microscopes. The slit mechanism includes a pair of slit halves, a light source for directing light between the slit halves, a detector for measuring the intensity of light passing from the light source through the slit halves, and an actuator for adjusting the width of the opening between the slit halves in response to the intensity of light measured by the detector.

Abstract: An apparatus designed to be positioned in the projection chamber of an electron microscope to detect electron images and/or diffraction patterns from a sample and convert those electron images into light images is provided. The apparatus transfers light images to an imaging sensor for recording while enhancing resolution of the light images by absorbing substantially all laterally scattered light before it reaches the imaging sensor.

Abstract: An apparatus for improving the resolution of images produced by an electron microscope is provided and includes an electron beam forming an electron image, a support structure mounted in the path of the electron beam, with the support structure transmitting the electron image. Scintillating material is coated onto the side of the support structure opposite that on which the electron image is incident, the scintillating material converting the electron image into a light image. A mirror is provided for deflecting the optical path of the light image into a CCD camera positioned to receive and record the light image.

Abstract: A method and an apparatus comprising a transmission electron microscope, an electron camera, a computer, and microscope control electronics. The electron camera captures an image produced by the electron microscope, the computer transforms the image into a digital diffractogram, and determines the microscope defocus and astigmatism by analyzing the diffractogram. The computer uses the determined astigmatism and defocus values to stigmate the microscope, and to set the defocus to a user-selected value. The computer also changes the direction of electron illumination to different values, and works out the true location of the optic axis of the microscope from the changes in the diffractograms recorded for the different illumination directions.

Abstract: A method and an apparatus comprising an electron gun, two energy analyzers, an energy-selecting slit with intensity sensors, a feedback circuit, a sample, and an electron detector. The beam produced by the electron gun is dispersed according to the energies of the electrons by the first energy analyzer. The dispersed beam impinges on a slit which monochromates the beam by selecting a narrow pass-band of energies. The two halves of the slit are equipped with electron intensity sensors whose output is used by a feedback circuit to stabilize the position of the dispersed beam on the slit so as to counteract instabilities in the power supplies of the electron gun and of the analyzer. The monochromated electron beam then passes through a sample, and the transmitted beam is dispersed according to the energies of the electrons by the second energy analyzer. The power supplies of the two analyzers are linked so that the energy selected by the second analyzer tracks the energy selected by the first analyzer.

Abstract: An apparatus comprising a cooled slow-scan charge-coupled device camera mounted in a chamber attached to a projection or specimen chamber of an electron microscope, and a vacuum valve separating the camera chamber from the microscope chamber. The operation of the vacuum valve is linked to the microscope vacuum system such that the valve remains open while the microscope chamber is under vacuum, but closes if the microscope chamber is about to be let up to atmospheric pressure, and stays closed until the microscope chamber is evacuated again. In an alternate embodiment of the invention, the camera is inserted by a pneumatically operated piston to the microscope chamber, and is withdrawn and sealed off in a separate vacuum chamber in the microscope chamber is about to be let up to air.

Abstract: Quadruple lenses 30, 31 and 32 and sextupole lenses 40, 41, 42, and 43 are interposed between a energy-dispersing device 17 and an electron imaging device 50 in an energy-selected electron imaging filter. The energy-dispersing device produces a focussed spectrum 21 of electron energies in the plane of an energy-selecting slit 20, and the quadrupole and sextupole lenses transform the spectrum into an energy-selecting slit may also be either removed or opened wide, and the quadrupole lenses may be refocussed, so that the electron imaging device directly observes a magnified spectrum of the electron energies.

Abstract: An electron beam attenuator decreases the intensity of an electron beam incident on a parallel electron detector by alternately deflecting the electron beam onto and away from the detector. A power supply controlling the attenuator is synchronized with the operation of the detector such that the electron beam only strikes the detector when the detector is not being read-out. The ratio of the time that the electron beam is incident on the detector to the time that the beam is off the detector is varied to give an adjustable attenuation of the detected electron signal. The intensity of the electron beam incident on the detector is monitored by a sensor separate from the parallel detector. When the beam intensity exceeds a pre-determined threshold, the attenuator is automatically activated, in order to prevent damage to the detector.

Abstract: Quadrupole electron lenses 21, 22, 23 and 24 are disposed between an energy-dispersing device 15 and a parallel detector 50 in an electron energy-loss spectrometer. The power and polarity of the quadrupole lenses may be adjusted to simultaneously provide the desired energy dispersion of the spectrum, and a precise match between the width of the spectrum and the width of the parallel detector. Additional quadrupole lenses may be interposed between quadrupole lens 24 and the detector 50 to further increase the energy dispersion.