An assembly for preventing an overdose of a charged particle beam during therapy to a patient includes a pixelated detector apparatus and a controller. The controller includes, for each pixel: a current integrator circuit that converts the local measured current into a total local detected charge integrated from a start time, the integrator circuit outputting an integrator voltage that corresponds to the total local detected charge; and a discriminator circuit that compares the integrator voltage with a reference voltage, the reference voltage corresponding to a maximum acceptable dose for the patient. A logic circuit generates an overdose fault signal if, at any of the pixels, the integrator voltage is higher than the reference voltage.

A method for initializing a first operation in a first module at a first start time value in a first time base, the method comprising generating a clock signal, generating a second time base in the first module based on the clock signal, determining a second sync value in the second time base, determining a first sync value in the first time base corresponding to a second sync value in the second time base, determining a start trigger value in the second time base based on the first sync value and the start time value in the first time base, and initializing the first operation in the first module based on the start trigger value and a current value of the second time base in the first module.

A device may include an electron source, a detector, and a deflector. The electron source may be directed toward a sample area. The detector may receive an electron signal or an electron-induced signal. A deflector may be positioned between the electron source and the sample. The deflector may modulate an intensity of the electron source directed to the sample area according to an electron dose waveform having a continuously variable temporal profile.

Apparatuses, systems, and methods for adjusting beam current using a feedback loop are provided. In some embodiments, a system may include a first anode aperture configured to measure a current of an emitted beam during inspection of a sample, wherein the first anode aperture is positioned in an environment that is configured to support a vacuum pressure of less than 3?10.sup.?10 torr and a controller including circuitry configured to cause the system to perform: generating a feedback signal when a difference between the measured current and a setpoint current exceeds a threshold value and adjusting a voltage of an extractor voltage supply based on the feedback signal during inspection of the sample such that a difference between an adjusted current of the emitted beam and the setpoint current is below the threshold value.

In one embodiment, a charged particle beam writing apparatus includes a current limiting aperture, a blanking deflector switching between beam ON and beam OFF so as to control an irradiation time by deflecting the charged particle beam having passed through the current limiting aperture, a blanking aperture blocking the charged particle beam deflected by the blanking deflector in such a manner that the beam OFF state is entered, and an electron lens disposed between the current limiting aperture and the blanking aperture. A lens value set for the electron lens is substituted into a given function to calculate an offset time. The offset time is added to an irradiation time for writing a pattern to correct the irradiation time. The blanking deflector switches between the beam ON and the beam OFF based on the corrected irradiation time.

In one embodiment, an electron beam drawing apparatus includes an electron gun including a cathode and an anode, a current control circuit controlling a total emission current, a first detector detecting a first emission current from an outer peripheral portion of the cathode, a second detector detecting a second emission current from an central portion of the cathode, and a controller that determines a coefficient, which is a ratio of an emission current from the outer peripheral portion of the cathode to the first emission current. During a period in which a pattern is drawn on the substrate, the controller estimates a value of the second emission current by subtracting a value, which is resulted by multiplying the first emission current by the coefficient, from the total emission current, and controls the current control circuit in a manner of holding the estimated value constant.

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 sensor is configured as a semiconductor device with a sensing layer that is oriented toward the source, in which: Each charged particle of said intercepted part of the beam generates electron/hole pairs in said sensing layer; Generated electrons are drawn to an anode of the semiconductor device; Generated holes are drawn to a cathode of the semiconductor device, thereby producing said intercept signal.

A device for generating a source current of charge carriers by a field emission and a method stabilizing a source current of charge carriers emitted by a field emission element are disclosed. In an embodiment the device includes at least one field emission element from which the charge carriers emerge during operation, which lead to an emission current in the field emission element, at least one extraction electrode in order to extract the charge carriers from the field emission element, wherein a first part of the extracted charge carriers contributes to the source current, and a second part of the extracted charge carriers impinges on the extraction electrode and leads to an extraction current in the extraction electrode, an additional electrode on which the source current of charge carriers impinges at least in part and which contributes to an electrode current in the additional electrode.

An ion implanter includes an energy analyzer electromagnet provided between an ion source and a processing chamber. The energy analyzer electromagnet includes a Hall probe configured to generate a measurement output in response to a deflecting magnetic field and an NMR probe configured to generate an NMR output. A control unit of the ion implanter includes a magnetic field measurement unit configured to measure the deflecting magnetic field in accordance with a known correspondence between the deflecting magnetic field and the measurement output, a magnetic field determination unit configured to determine the deflecting magnetic field from the NMR output, and a Hall probe calibration unit configured to update the known correspondence by using the deflecting magnetic field determined from the NMR output and a new measurement output of the Hall probe corresponding to the determined deflecting magnetic field.

A multi-layer charged particle beam characterization system is disclosed, and method for using the same. A typical embodiment includes a plurality of two-sided metal plates, arranged as a stack, each metal plate having an electrical contact tab extending from at least one common edge of the metal plate, and a plurality of insulator films disposed between adjacent metal plates, each insulator film is sized to match its corresponding metal plate. The tabs are coupled to a printed circuit board and connected to an external electrical connector to register a number of metal plates and insulator layers through which a charged particle beam has penetrated.