Abstract: A method of investigating a wavefront of a charged-particle beam that is directed from a source through an illuminator so as to traverse a sample plane and land upon a detector, an output of the detector being used in combination with a mathematical reconstruction technique so as to calculate at least one of phase information and amplitude information for the wavefront at a pre-defined location along its path to the detector, in which method: Said beam is caused to traverse a particle-optical lens system disposed between said sample plane and said detector; At a selected location in the path from said source to said detector, a modulator is used to locally produce a given modulation of the wavefront; In a series of measurement sessions, different such modulations are employed, and the associated detector outputs are collectively used in said mathematical reconstruction.

Abstract: The invention relates to an improved method of electron tomography. Electron tomography is a time consuming process, as a large number of images, typically between 50-100 images, must be acquired to form one tomogram. The invention teaches a method to shorten the time needed to acquire this amount images much more quickly by tilting the sample continuously, instead of step-by-step. Hereby the time needed to reduce vibrations between steps is eliminated.

Abstract: A method of investigating a wavefront of a charged-particle beam that is directed from a source through an illuminator so as to traverse a sample plane and land upon a detector, an output of the detector being used in combination with a mathematical reconstruction technique so as to calculate at least one of phase information and amplitude information for the wavefront at a pre-defined location along its path to the detector, in which method: Said beam is caused to traverse a particle-optical lens system disposed between said sample plane and said detector; At a selected location in the path from said source to said detector, a modulator is used to locally produce a given modulation of the wavefront; In a series of measurement sessions, different such modulations are employed, and the associated detector outputs are collectively used in said mathematical reconstruction.

Abstract: The invention relates to an improved method of electron tomography. Electron tomography is a time consuming process, as a large number of images, typically between 50-100 images, must be acquired to form one tomogram. The invention teaches a method to shorten the time needed to acquire this amount images much more quickly by tilting the sample continuously, instead of step-by-step. Hereby the time needed to reduce vibrations between steps is eliminated.

Abstract: The invention relates to a method of performing tomographic imaging of a sample comprising providing a beam of charged particles; providing the sample on a sample holder that can be tilted; in an imaging step, directing the beam through the sample to image the sample; repeating this procedure at each of a series of sample tilts to acquire a set of images; in a reconstruction step, mathematically processing images from said set to construct a composite image, whereby in said imaging step, for a given sample tilt, a sequence of component images is captured at a corresponding sequence of focus settings; and in said reconstruction step, for at least one member of said series of sample tilts, multiple members of said sequence of component images are used in said mathematical image processing. This renders a 3D imaging cube rather than a 2D imaging sheet at a given sample tilt.

Abstract: To avoid reset noise in a CMOS chip for direct particle counting, it is known to use Correlative Double Sampling: for each signal value, the pixel is sampled twice: once directly after reset and once after an integration time. The signal is then determined by subtracting the reset value from the later acquired value, and the pixel is reset again. In some embodiments of the invention, the pixel is reset only after a large number of read-outs. Applicants realized that typically a large number of events, typically approximately 10, are needed to cause a full pixel. By either resetting after a large number of images, or when one pixel of the image shows a signal above a predetermined value (for example 0.8 × the full-well capacity), the image speed can be almost doubled compared to the prior art method, using a reset after acquiring a signal.

Abstract: A method of determining the temperature of a sample carrier in a charged particle-optical apparatus, characterized in that the method comprises the observation of the sample carrier with a beam of charged particles, the observation giving information about the temperature of the sample carrier. The invention is based on the insight that a charged particle optical apparatus, such as a TEM, STEM, SEM or FIB, can be used to observe temperature related changes of a sample carrier. The changes may be mechanical changes (e.g. of a bimetal), crystallographic changes (e.g. of a perovskite), and luminescent changes (in intensity or decay time). In a preferred embodiment the sample carrier shows two bimetals, showing metals with different thermal expansion coefficients, bending in opposite directions. The distance between the two bimetals is used as a thermometer.

Abstract: The invention relates to a method of performing tomographic imaging of a sample comprising providing a beam of charged particles; providing the sample on a sample holder that can be tilted; in an imaging step, directing the beam through the sample to image the sample; repeating this procedure at each of a series of sample tilts to acquire a set of images; in a reconstruction step, mathematically processing images from said set to construct a composite image, whereby in said imaging step, for a given sample tilt, a sequence of component images is captured at a corresponding sequence of focus settings; and in said reconstruction step, for at least one member of said series of sample tilts, multiple members of said sequence of component images are used in said mathematical image processing. This renders a 3D imaging cube rather than a 2D imaging sheet at a given sample tilt.

Abstract: The invention relates to a method for correcting distortions introduced by the projection system (106) of a TEM. As known to the person skilled in the art distortions may limit the resolution of a TEM, especially when making a 3D reconstruction of a feature using tomography. Also when using strain analysis in a TEM the distortions may limit the detection of strain. To this end the invention discloses a detector equipped with multipoles (152), the multipoles warping the image of the TEM in such a way that distortions introduced by the projection system are counteracted. The detector may further include a CCD or a fluorescent screen (151) for detecting the electrons.

Abstract: The invention relates to a method of forming sections for inspection in an electron microscope and a fluorescent light microscope. Conventionally these sections are made by for example the Tokuyama method, which involves freeze substitution and fixing at cryogenic temperatures. A problem is the time that it takes to come from a sample to sections, as the diffusion speed of the chemicals (organic solvents and fixatives) is extremely low. The invention comprises the sectioning of the sample at cryogenic temperature and fixing afterwards. As the sections are much thinner (e.g. 100 nm or less) than the sample (often >1 ?m), the total time it takes to come from a sample to a section ready for inspection is less than 8 hours. This makes it possible to achieve results relevant for health care within one workday.

Abstract: A method of using a direct electron detector in a TEM, in which an image with a high intensity peak, such as a diffractogram or an EELS spectrum, is imaged on said detector. As known the high intensity peak may damage the detector. To avoid this damage, the center of the image is moved, as a result of which not one position of the detector is exposed to the high intensity, but the high intensity is smeared over the detector, displacing the high intensity peak before damage results.

Abstract: A charged particle apparatus is equipped with a third stigmator positioned between the objective lens and a detector system, as a result of which a third degree of freedom is created for reducing the linear distortion. Further, a method of using said three stigmators, comprises exciting the first stigmator to reduce astigmatism when imaging the sample, exciting the second stigmator to reduce astigmatism when imaging the diffraction plane, and exciting the third stigmator to reduce the linear distortion.

Abstract: A charged particle apparatus is equipped with a third stigmator positioned between the objective lens and a detector system, as a result of which a third degree of freedom is created for reducing the linear distortion. Further, a method of using said three stigmators, comprises exciting the first stigmator to reduce astigmatism when imaging the sample, exciting the second stigmator to reduce astigmatism when imaging the diffraction plane, and exciting the third stigmator to reduce the linear distortion.

Abstract: In a transmission electron microscope detector system, image data is read out from the pixels and analyzed during an image acquisition period. The image acquisition process is modified depending on the results of the analysis. For example, the analyses may indicate the inclusion in the data of an image artifact, such as charging or bubbling, and data including the artifact may be eliminated form the final image. CMOS detectors provide for selective read out of pixels at high data rates, allowing for real-time adaptive imaging.

Abstract: A detector system for a transmission electron microscope includes a first detector for recording a pattern and a second detector for recording a position of a feature of the pattern. The second detector is preferably a position sensitive detector that provides accurate, rapid position information that can be used as feedback to stabilize the position of the pattern on the first detector. In one embodiment, the first detector detects an electron energy loss electron spectrum, and the second detector, positioned behind the first detector and detecting electrons that pass through the first detector, detects the position of the zero-loss peak and adjusts the electron path to stabilize the position of the spectrum on the first detector.

Abstract: A method of determining the temperature of a sample carrier in a charged particle-optical apparatus, characterized in that the method comprises the observation of the sample carrier with a beam of charged particles, the observation giving information about the temperature of the sample carrier. The invention is based on the insight that a charged particle optical apparatus, such as a TEM, STEM, SEM or FIB, can be used to observe temperature related changes of a sample carrier. The changes may be mechanical changes (e.g. of a bimetal), crystallographic changes (e.g. of a perovskite), and luminescent changes (in intensity or decay time). In a preferred embodiment the sample carrier shows two bimetals, showing metals with different thermal expansion coefficients, bending in opposite directions. The distance between the two bimetals is used as a thermometer.

Abstract: A detector system for a transmission electron microscope includes a first detector for recording a pattern and a second detector for recording a position of a feature of the pattern. The second detector is preferably a position sensitive detector that provides accurate, rapid position information that can be used as feedback to stabilize the position of the pattern on the first detector. In one embodiment, the first detector detects an electron energy loss electron spectrum, and the second detector, positioned behind the first detector and detecting electrons that pass through the first detector, detects the position of the zero-loss peak and adjusts the electron path to stabilize the position of the spectrum on the first detector.

Abstract: In a transmission electron microscope detector system, image data is read out from the pixels and analyzed during an image acquisition period. The image acquisition process is modified depending on the results of the analysis. For example, the analyses may indicate the inclusion in the data of an image artifact, such as charging or bubbling, and data including the artifact may be eliminated form the final image. CMOS detectors provide for selective read out of pixels at high data rates, allowing for real-time adaptive imaging.

Abstract: A method of using a direct electron detector in a TEM, in which an image with a high intensity peak, such as a diffractogram or an EELS spectrum, is imaged on said detector. As known the high intensity peak may damage the detector. To avoid this damage, the centre of the image is moved, as a result of which not one position of the detector is exposed to the high intensity, but the high intensity is smeared over the detector, displacing the high intensity peak before damage results.

Abstract: The invention relates to the extraction of a frozen hydrated sample for TEM (Transmission Electron Microscope) inspection, such as a vitrified biological sample, from a substrate and the attaching of said sample to a manipulator. Such a hydrated sample should be held at a cryogenic temperature to avoid ice formation. By melting or sublimating a part of the sample material outside the area to be studied in the TEM and freezing the material to the manipulator (10), a bond is formed between sample (1) and manipulator. This makes it possible to transport the sample from the substrate to e.g. a TEM grid. In a preferred embodiment a part (2) of the manipulator (10) is held at a cryogenic temperature, and the melting or sublimation is caused by heating the tip (3) of the manipulator by electric heating of the tip and then cooling the tip of the manipulator to a cryogenic temperature, thereby freezing the sample (1) to the manipulator.