Abstract: In a method for producing a TEM sample, an object is fastened to an element of an object holder such that a surface to be processed of the object is arranged substantially perpendicularly to an axis of rotation of the element. An ion beam is directed at the surface to be processed at grazing incidence, wherein the element adopts different rotational positions in relation to the axis of rotation, while the ion beam is directed at the surface to be processed.

Abstract: A charged particle beam inspection method conducted by disposing a sample on a stage and by performing a first scanning in a first beam scanning area on the sample by using one first charged particle beam out of a plurality of charged particle beams while the stage is moved so that a first inspection of a first inspection unit in the first beam scanning area is performed, and by performing a second scanning in a second beam scanning area on the sample by using one second charged particle beam out of the charged particle beams while the stage is moved so that a second inspection of a second inspection unit in the second beam scanning area is performed.

Abstract: An electron microscope includes: an optical system including an aberration correction device; and a control unit that controls the aberration correction device, wherein the control unit performs: processing for displaying, on a display unit, an image for designating a direction of aberration in superposition on an aberration pattern representing a state of aberration, processing for specifying the direction of aberration from the image that has been subjected to a rotation operation, and processing for controlling the aberration correction device to cause the aberration correction device to introduce an aberration in the specified direction.

Abstract: An Impact sensor for detecting strain or strain rate in a composite having one or more sensor nodes using a fracto-mechanoluminescent (FML) material, such as EuD4TEA crystals, encased in an optically transparent material such as PDMS. Optical fibers transmit light emitted by the FML material due to strain experienced by the composite. For honeycomb composites, the transparent material is disposed within cells of the honeycomb composite. A reflective material such as Mylar either surrounds the optically transparent material or lines the cell. The intensity of the light emitted by the FML material is related to the magnitude of strain or strain rate experienced by the composite as well as the distance of the FML material from the surface of the composite that receives the impact. Multiple sensor nodes disposed at different distances from the impact surface can provide a three-dimensional map of damage experienced by the composite.

Abstract: Techniques for high throughput electron channeling contrast imaging (ECCI) by varying electron beam energy are provided. In one aspect, a method for ECCI of a crystalline wafer includes: placing the crystalline wafer under an electron microscope having an angle of less than 90° relative to a surface of the crystalline wafer; generating an electron beam, by the electron microscope, incident on the crystalline wafer; varying an accelerating voltage of the electron microscope to access a channeling condition of the crystalline wafer; and obtaining an image of the crystalline wafer. A system for ECCI is also provided.

Abstract: Provided is a scanning probe microscope with which measurement data and a distribution image of differential data of the measurement data can be displayed selectively or together, an edge enhancement image can be obtained, and user convenience is improved. A scanning probe microscope (200) includes: a distribution image calculator (40a) configured to calculate a one-dimensional or two-dimensional first distribution image (201) of measurement data, and a one-dimensional or two-dimensional second distribution image (202) of differential data of adjacent data elements of the measurement data; and a display controller (40b) configured to instruct the distribution image calculator to calculate at least one of the first distribution image or the second distribution image, and to display the calculated distribution image on a predetermined display.

Abstract: Provided is a measurement method for measuring, in an electron microscope including a segmented detector having a detection plane segmented into a plurality of detection regions, a direction of each of the plurality of detection regions in a scanning transmission electron microscope (STEM) image, the measurement method including: shifting an electron beam EB incident on a sample S under a state where the detection plane is conjugate to a plane shifted from a diffraction plane to shift the electron beam EB on the detection plane, and measuring a shift direction of the electron beam EB on the detection plane with the segmented detector; and obtaining the direction of each of the plurality of detection regions in the STEM image from the shift direction.

Abstract: The invention relates to an image capture assembly and method for use in an electron backscatter diffraction (EBSD) system. An image capture assembly comprises a scintillation screen (10) including a predefined screen region (11), an image sensor (20) comprising an array of photo sensors and a lens assembly (30). The image capture assembly is configured to operate in at least a first configuration or a second configuration. In the first configuration the lens assembly (30) projects the predefined region (11) of the scintillation screen (10) onto the array and in the second configuration the lens assembly (30) projects the predefined region (11) of the scintillation screen (10) onto a sub-region (21) of the array. In each of the first and second configurations the field of view of the lens assembly (30) is the same.

Abstract: There is provided a method, system and computer program product to delayer a layer of a sample, the layer comprising one or more materials, in an ion beam mill by adjusting one or more operating parameters of the ion beam mill and selectively removing each of the one or more materials at their respective predetermined rates. There is also provided a method and system for obtaining rate of removal of a material from a sample in an ion beam mill.

Abstract: Provided is a cross-section processing observation method capable of easily and accurately forming a cross-section used to observe a sample's inside, and a cross-section processing observation apparatus for cross-section processing. The method includes a design data acquisition step acquiring design data of a three-dimensional structure of a sample having three-dimensional structure, a moving step moving the sample based on coordinate information of the design data, a surface observation step acquiring an observation image of a surface of the sample, a cross-section forming step irradiating the sample's surface with an ion beam to form a cross-section of the three-dimensional structure, a cross-section observation step acquiring an observation image of the sample's cross-section, and a display step displaying image data, among pieces of the design data, of surface and cross section corresponding to respective locations of the surface and the cross section.

Abstract: Methods and apparatuses are provided for automatically controlling and stabilizing aspects of a scanning probe microscope (SPM), such as an atomic force microscope (AFM), using Peak Force Tapping (PFT) Mode. In an embodiment, a controller automatically controls periodic motion of a probe relative to a sample in response to a substantially instantaneous force determined and automatically controls a gain in a feedback loop. A gain control circuit automatically tunes a gain based on separation distances between a probe and a sample to facilitate stability. Accordingly, instability onset is quickly and accurately determined during scanning, thereby eliminating the need of expert user tuning of gains during operation.

Abstract: A method is provided for performing electron diffraction pattern analysis upon a sample in a vacuum chamber of a microscope. Firstly a sample is isolated from part of a specimen using a focused particle beam. A manipulator end effector is then attached to the sample so as to effect a predetermined orientation between the end effector and the sample. With the sample detached, the manipulator end effector is rotated about a rotation axis to bring the sample into a predetermined geometry with respect to an electron beam and diffraction pattern imaging apparatus so as to enable an electron diffraction pattern to be obtained from the sample while the sample is still fixed to the manipulator end effector. An electron beam is caused to impinge upon the sample attached to the manipulator end effector so as to obtain an electron diffraction pattern.

Abstract: A charged particle beam apparatus which automatically prepares a sample piece from a sample, includes: a charged particle beam irradiation optical system configured to perform irradiation of a charged particle beam; a sample stage configured to move, the sample being placed on the sample stage; a sample piece relocation unit configured to hold and transport the sample piece which is separated and picked up from the sample; a holder fixing stage which holds a sample piece holder to which the sample piece is relocated; and a computer which performs positional control in relation to a target object based on a template and positional information which is obtained from an image of the target object, the template being generated based on an absorption current image of the target object which is acquired using the irradiation of the charged particle beam.

Abstract: System and method for Ultrafast Electron Diffraction (UED) and Microscopy (UEM) configured to image atomic motion in real time with sub-femtosecond temporal resolution. Presented methodology utilizes the interaction of the pump optical pulse with the initial electron pulse that has been gated with the gating optical pulse. The initial electron pulse is generated in the electron microscope by the pulse of auxiliary light. In one case, the pump and gating pulses have attosecond duration and are duplicates of one another. The use of attosecond optical pulse (with frequency spectrum extending over two octaves in the visible and flanking spectral ranges) for optical gating of a pulse of electrons.

Abstract: A device for imaging the surfaces of a sample having topography with the aid of confocal microscopy, in particular confocal Raman and/or fluorescence microscopy, comprising a first light source, in particular a laser light source for generating excitation radiation, in particular Raman radiation and/or fluorescence radiation and a second light source, wherein the first laser light source emits radiation in a first wavelength range and the second light source emits radiation in a second wavelength range, wherein the first wavelength range and the second wavelength range do not overlap.

Abstract: An electron beam device suitable for observing the bottom of a deep groove or hole with a high degree of accuracy under a large current condition includes: an electron optical system having an irradiation optical system to irradiate a first aperture with an electron beam emitted from an electron source and a reduction projection optical system to project and form an aperture image of the first aperture on a sample, detectors to detect secondary electrons emitted by irradiating the sample with the electron beam through the electron optical system. An image processing unit generates a two-dimensional image from detection signals obtained by irradiating the sample while the electron beam scans the sample two-dimensionally by scanning deflectors of the electron optical system. Further, generates a reconstructed image by deconvoluting electron beam intensity distribution information of an ideal aperture image of the first aperture from the generated two-dimensional image information.

Abstract: (Task) To repeatedly perform an operation of extracting a sample piece formed by processing a sample with an ion beam and of transferring the extracted sample piece to a sample piece holder. (Problem Solving Means) A charged particle beam apparatus includes a computer that sets a shaping processing region including a bottom portion of sample piece in a thickness direction of the sample piece corresponding to a depth direction at the time of processing a sample after a needle holds the sample piece, and controls a focused ion beam irradiation optical system to irradiate the shaping processing region with a focused ion beam to thereby shape the sample piece.

Abstract: A method of preparing a specimen in a dual-beam charged particle microscope having: an ion beam column, that can produce an ion beam that propagates along an ion axis; an electron beam column, that can produce an electron beam that propagates along an electron axis, comprising the following steps: Providing a precursor sample on a sample holder; Using said ion beam to cut a furrow around a selected portion of said sample; Attaching a manipulator needle to said portion, severing said portion from the rest of said sample, and using the needle to perform a lift-out of the portion away from the rest of the sample, particularly comprising: Configuring the manipulator needle to have multiple degrees of motional freedom, comprising at least: Eucentric tilt ? about a tilt axis that passes through an intersection point of said ion and electron axes and is perpendicular to said electron axis; Rotation ? about a longitudinal axis of the needle; Whilst maintaining said portion on said needle, using said ion bea

Abstract: A system for removing debris from a surface of a substrate, the system including a cantilever arm and a tip supported by the cantilever arm. The tip has a proximal portion and a distal portion such that the tip is supported by the cantilever arm via the proximal portion. The system further includes at least one nanofibril attached to the distal portion of the tip, and the at least one nanofibril is configured to elastically deform against or around the debris or the surface of the substrate.

Abstract: Processes may be performed with a plurality of FIB-SEM systems. A first process group includes recording an image with the electron beam column, depositing material with supply of a process gas, and performing ion beam etching. A second process group includes performing a sample exchange, exchanging a reservoir of a gas source for the process gas, and verifying an image that was recorded with the electron beam column. The processes of the second group are prioritized. The FIB-SEM systems are actuated to work through processes contained in process lists. If in a plurality of FIB-SEM systems processes of the second group are to be performed simultaneously, an instruction based on the prioritization is output to the user.

Abstract: Methods and systems for direct atomic layer etching and deposition on or in a substrate using charged particle beams. Electrostatically-deflected charged particle beam columns can be targeted in direct dependence on the design layout database to perform atomic layer etch and atomic layer deposition, expressing pattern with selected 3D-structure. Reducing the number of process steps in patterned atomic layer etch and deposition reduces manufacturing cycle time and increases yield by lowering the probability of defect introduction. Local gas and photon injectors and detectors are local to corresponding columns, and support superior, highly-configurable process execution and control.

Abstract: An automated tablet tooling inspection system (100) for inspecting defects in tablet tooling's including upper punch, lower punch and die. The system (100) comprising of a base plate (101), a punch holder (102), a punch stopper (103), a die holder (104), a LM rail and carriage assembly (105), a LED Micrometer (107) to measure parameters of said tablet tooling, a Laser sensor or con focal sensor (108) to measure parameters of said tablet tooling and a control unit. The automated tooling inspection and system (100) reduces the inspection time of said tablet tooling by minimizing manual intervention; wherein said manual intervention is reduced by eliminating the requirement of changing configuration of said system (100) when a different type of tablet tooling is inspected such as TSM/Euro, B, D, BD, BB and BBS and the like.

Abstract: The production and use of semiconducting nanopost arrays made by nanofabrication is described herein. These nanopost arrays (NAPA) provide improved laser ionization yields and controllable fragmentation with switching or modulation capabilities for mass spectrometric detection and identification of samples deposited on them.

Abstract: In one example, the present disclosure describes a device, computer-readable medium, and method for inferring the presence of an occluded entity in a video captured via drone. For instance, in one example, a video is obtained. The video is captured by a drone monitoring a field of view of a scene. It is determined, based on a combination of statistical reasoning and contextual modeling of the video, that an occluded entity is likely to be present, but not entirely visible, in the field of view. A signal is sent to the drone to instruct the drone to adjust its orientation to make the occluded entity more visible.

Abstract: Methods and systems for temporal compressive sensing are disclosed, where within each of one or more sensor array data acquisition periods, one or more sensor array measurement datasets comprising distinct linear combinations of time slice data are acquired, and where mathematical reconstruction allows for calculation of accurate representations of the individual time slice datasets.

Abstract: A method of using a Transmission Charged Particle Microscope comprising: A specimen holder, for holding a specimen; A source, for producing a beam of charged particles; An illuminator, for directing said beam so as to irradiate the specimen; An imaging system, for receiving a flux of charged particles transmitted through the specimen and directing it onto a sensing device; A controller, for controlling at least some operational aspects of the microscope, in which method the sensing device is chosen to be an EELS/EFTEM module comprising: An entrance plane; An image plane, where in EELS mode an EELS spectrum is formed and in EFTEM mode an EFTEM image is formed; A slit plane between said entrance plane and image plane, where in EFTEM mode an energy dispersed focus is formed; A dispersing device, between said entrance plane and slit plane, for dispersing an incoming beam into an energy-dispersed beam with an associated dispersion direction; A first series of quadrupoles between said dispersing device and sli

Abstract: The present invention enlarges a range of movement of field of view by beam deflection with a simple deflector configuration and suppresses deterioration of a signal electron detection rate caused by the beam deflection. A scanning electron microscope according to the present invention is provided with a first deflection field setting module that sets plural deflectors to move a scanning area on a specimen by a primary electron beam to a position deviated from an axis extended from an electron source toward the center of an objective lens and a second deflection field setting module that sets the plural deflectors so that trajectories of signal electrons are corrected without changing the scanning area set by the first deflection field setting module. The control unit controls the plural deflectors by adding a setting value set by the second deflection field setting module to a setting value set by the first deflection field setting module.

Abstract: A sample observation device images a sample placed on a movable table by irradiating and scanning the sample with a charged particle beam of a microscope. A degraded image having poor image quality and a high quality image having satisfactory image quality which are acquired at the same location of the sample by causing the charged particle microscope to change an imaging condition for imaging the sample are stored. An estimation process parameter is calculated for estimating the high quality image from the degraded image by using the stored degraded image and high quality image. A high quality image estimation unit processes the degraded image obtained by causing the charged particle microscope to image the desired site of the sample by using the calculated estimation process parameter. Thereby, the high quality image obtained at the desired site is estimated, and then the estimated high quality image is output.

Abstract: A charged particle apparatus including a charged particle source unit; a blanking electrode unit that blanks a charged particle beam launched from the charged particle source unit; a deflecting electrode unit that deflects the charged particle beam; an objective lens unit that converges the charged particle beam deflected by the deflecting electrode unit and radiates the charged particle beam to a surface of a sample; a secondary charged particle detection unit that detects a secondary charged particle generated from the sample; a signal processing unit that processes a signal obtained by detecting the secondary charged particle; and a control unit that corrects a transient signal when the blanking of the charged particle beam is turned off by the blanking electrode, such that an image with no distortion can be obtained even when the blanking electrode is operated to turn on and off at a high speed.

Abstract: There is provided a method, system and computer program product to delayer a layer of a sample, the layer comprising one or more materials, in an ion beam mill by adjusting one or more operating parameters of the ion beam mill and selectively removing each of the one or more materials at their respective predetermined rates. There is also provided a method and system for obtaining rate of removal of a material from a sample in an ion beam mill.

Abstract: Radiation treatment planning includes determining a number of beams to be directed into a target, determining directions (e.g., gantry angles) for the beams, and determining an energy level for each of the beams. The number of beams, the directions of the beams, and the energy levels are determined such that the beams do not overlap outside the target and the prescribed dose will be delivered across the entire target.

Abstract: The disclosure is related to a method and apparatus for transmission electron microscopy wherein a TEM specimen is subjected to at least one thinning step by scratching at least an area of the specimen with an SPM probe, and wherein the thinned area is subjected to an SPM acquisition step, using the same SPM probe or another probe.

Abstract: Methods and systems for quantifying and correcting for non-uniformities in images used for metrology operations are disclosed. A metrology area image of a wafer and a design clip may be used. The metrology area image may be a scanning electron microscope image. The design clip may be the design clip of the wafer or a synthesized design clip. Tool distortions, including electron beam distortions, can be quantified and corrected. The design clip can be applied to the metrology area image to obtain a synthesized image such that one or more process change variations are suppressed and one or more tool distortions are enhanced.

Abstract: A method of operating a Fourier Transform (FT) mass analyzer, which has a plurality of selectable resolving power settings, includes storing an optimized voltage value in association with each one of the plurality of selectable resolving power settings. More particularly, the optimized voltage values for at least two of the selectable resolving power settings differ from one another. When a user selects one of the plurality of selectable resolving power settings, the optimized voltage value that is stored in association therewith is retrieved. At least one voltage setting of the FT mass analyzer is controlled, based on the retrieved optimized voltage value, and an analytical scan is performed at the selected one of the plurality of selectable resolving power settings for a population of ions within the FT mass analyzer.

Abstract: A method for analyzing a plurality of molecules with cryogenic vibrational spectroscopy including the steps of providing a packet of molecules in a ionized form, injecting the packet into an ion mobility section, spatially separating the ions of the packet into subpackets according to their collisional cross section (CCS), recompressing the subpackets, by removing an empty space between them, loading the ions into a cryogenic ion trap by keeping subpackets with different collisional cross section in a respective separate compartment, cooling the ions in collisions with a buffer gas, tagging the ions by attaching a messenger molecule, sending a pulse to the trap to excite vibrations of the cold, trapped, and messenger-tagged ions, and separately ejecting ion subpacket from the trap into an extraction region of a time-of-flight mass spectrometer and measuring the number of remaining messenger-tagged ions and untagged ions for each subpacket.

Abstract: Target values for quality metrics associated with the radiation treatment plan are accessed. Cost function contours are generated; each of the cost function contours includes a respective first set of values of the quality metrics calculated with a respective cost function based on a respective one of the target values. A region that includes a second set of values of the quality metrics is defined; the region is bounded by the cost function contours. A final (optimized) radiation treatment plan is selected from a set of radiation treatment plans that have values of the quality metrics that are within the region.

Abstract: A measurement substrate for measuring a condition pertaining in an apparatus for processing production substrates during operation thereof, the measurement substrate including: a body having dimensions compatible with the apparatus; a plurality of sensor modules embedded in the body, each sensor module having: a sensor configured generate an analog measurement signal, an analog to digital converter to generate digital measurement information from the analog measurement signal, and a module controller configured to output the digital measurement information; and a central control module configured to receive the digital measurement information from each of the module controllers and to communicate the digital measurement information to an external device.

Abstract: Various configurations of electrically conductive, gas-sealed connections between two pieces of aluminum are described along with methods of making an electrically conductive, gas-sealed connection between two pieces of aluminum.

Abstract: A method for generating a synthetic image of a region of an object, includes: generating, by a charged particle microscope, a charged particle microscope image of the region of the object; calculating a sparse representation of the charged particle microscope image; wherein the sparse representation of the charged particle microscope image comprises multiple first atoms; generating the synthetic image of the region, wherein the synthetic image of the region is formed from multiple second atoms; wherein the generating of the synthetic image of the region is based on a mapping between the multiple first atoms and the multiple second atoms; wherein the charged particle microscope image and the multiple first atoms are of a first resolution; and wherein the synthetic image of the region and the multiple second atoms are of a second resolution that is finer than the first resolution.

Abstract: The system described herein relates to a method for generating a composite image of an object using, for example, a particle beam device such as an electron beam device and/or an ion beam device. A composite image is generated by relatively arranging a first sub image to a second sub image such that the first sub image overlaps the second sub image in the entire common region, a calculated first image position of a first marking in the first sub image is arranged on the first image position of the first marking in the second sub image, and a calculated second image position of a second marking in the first sub image is arranged on the second image position of the second marking in the second sub image.

Abstract: A Neural Circuit Probe (NCP) combines a multi-electrode array (MEA) with an automated local probe, wherein the probe is positioned to interact with one or more cells, such as neurons of a neural circuit, grown on or about one or more electrodes of the multi-electrode array. The probe may interact with the cells by electrically recording signals from the multi-electrode array that are assigned to a specific one of the cells. The probe may interact with the cells by locally delivering chemicals to the cells, which transiently and reversibly modulate the electrical behavior of the cells. The probe may interact with the cells by harvesting the cells using a pipette, so that the harvested cells can be sequenced.

Abstract: A system for stochastically-aware metrology includes a controller to be communicatively coupled to a fabrication tool. The controller receives a production recipe including at least a pattern of elements to be fabricated on a sample and one or more exposure parameters for exposing the pattern of elements, identifies candidate care areas of the pattern of elements susceptible to stochastic repeaters including fabrication defects predicted to occur stochastically when fabricated according to the production recipe, selects one or more care areas from the candidate care areas by comparing one or more predicted likelihoods of the one or more stochastic repeaters to a defect likelihood threshold, modifies the production recipe to mitigate the stochastic repeaters within the one or more care areas within a selected tolerance, and directs the fabrication tool to fabricate at least one sample according to the modified production recipe.

Abstract: In a method of electronic image stabilization, a processor buffers image data into a memory buffer, the image data being obtained by the processor from an image sensor disposed in an electronic device. The processor obtains motion data from a motion sensor disposed in the electronic device, wherein the motion data corresponds with a time of capture of the image data. The processor analyzes the motion data to determine a stabilization correction to apply to the image data. The processor applies the determined stabilization correction to the image data to achieve stabilized image data. The determined stabilization correction is applied, and the stabilized image data is achieved, by the processor without requiring a transfer of the image data from the memory buffer to a graphics processing unit. The stabilized image data is output.

Abstract: An apparatus is disclosed for use in a charged particle instrument which defines an inner volume therein. The apparatus comprises an adaptor (22) having a first portion adapted for attachment to a part (20) of a gas injection system (18) of a charged particle instrument which is located within an inner volume of such an instrument; and a second portion arranged to receive a tool (24) adapted for interaction with a sample (14) located in the inner volume of such an instrument.

Abstract: A charged particle beam apparatus includes a charged particle beam column for irradiating a sample with a charged particle beam, and a sample stage unit for moving the sample relative to the charged particle beam column. The sample stage unit includes a rotary stage section having a base portion and a rotary mover rotatable about a rotary axis relative to the base portion. A rotary connector is disposed coaxially with and rotatable about the rotary axis and fitted between the base portion and the rotary mover for electrically connecting wirings between relatively rotating elements. A connection electrode is disposed on the sample stage unit in electrical connection with the rotary connector. In the charged particle beam apparatus, the sample is able to be rapidly placed and replaced.

Abstract: A conductive probe includes a protruding portion provided on an elastic member, a conductive metal film covering at least a tip of the protruding portion; and an insulating thin film covering the conductive metal film provided on the tip of the protruding portion.

Abstract: Disclosed are an inspection method, an inspection system, and a method of fabricating a semiconductor package using the same. The inspection method comprises obtaining a reference value by measuring a surface profile of a reference pattern, scanning reference images of the reference pattern by using a plurality of optical inspection conditions, obtaining estimation values of the reference pattern that are measured from the reference images, selecting an desired optical inspection condition among the plurality of optical inspection conditions by comparing the reference value with the estimation values, scanning a target image of a target pattern by using the desired optical inspection condition, and obtaining an error value by quantitatively comparing the target image with a design image of the target pattern.

Abstract: Multi-beam scanning electron microscope inspection systems are disclosed. A multi-beam scanning electron microscope inspection system may include an electron source and a beamlet control mechanism. The beamlet control mechanism may be configured to produce a plurality of beamlets utilizing electrons provided by the electron source and deliver one of the plurality of beamlets toward a target at a time instance. The multi-beam scanning electron microscope inspection system may also include a detector configured to produce an image of the target at least partially based on electrons backscattered out of the target.

Abstract: Described herein are technologies to facilitate the fabrication of substrates, such as semiconductor wafers. More particularly, technologies described herein facilitate the correct placement of patterns of lines and spaces on a substrate. The resulting patterned substrate is the product of photolithography process and/or the pattern transference (e.g., etching) that occurs during the fabrication of substrates (e.g., semiconductor wafers). The scope of the present invention is pointed out in the appending claims.

Abstract: A method of operating a charged particle microscope comprising the following steps: Providing a specimen on a specimen holder; Using a source to produce a beam of charged particles that is subject to beam current fluctuations; Employing a beam current sensor, located between said source and specimen holder, to intercept a part of the beam and produce an intercept signal proportional to a current of the intercepted part of the beam, the beam current sensor comprising a hole arranged to pass a beam probe with an associated probe current; Scanning said probe over the specimen, thereby irradiating the specimen with a specimen current, with a dwell time associated with each scanned location on the specimen; Using a detector to detect radiation emanating from the specimen in response to irradiation by said probe, and producing an associated detector signal; Using said intercept signal as input to a compensator to suppress an effect of said current fluctuations in said detector signal, wherein: The beam current