Abstract: In one embodiment, a beam detector includes a first aperture plate including a first passage hole, a second aperture plate including a second passage hole that allows a single detection target beam passing through the first passage hole to pass therethrough, and a sensor detecting a beam current of the detection target beam passing through the second passage hole. The second aperture plate includes an electrically conductive material, a plurality of third passage holes are formed around the second passage hole, and the plurality of third passage holes allow light to pass therethrough.

Abstract: In one embodiment, a beam detector includes a first aperture plate including a first passage hole, a second aperture plate including a second passage hole that allows a single detection target beam passing through the first passage hole to pass therethrough, and a sensor detecting a beam current of the detection target beam passing through the second passage hole. The second aperture plate includes an electrically conductive material, a plurality of third passage holes are formed around the second passage hole, and the plurality of third passage holes allow light to pass therethrough.

Abstract: In one embodiment, a length measurer includes a first laser interferometer provided in a wall surface of the writing chamber, synthesizes a laser beam with the first frequency which has traveled back and forth between the first laser interferometer and the stage and a laser beam with the second frequency reflected in the first laser interferometer, and outputs a first beat signal. A wall surface displacement measurer includes a second laser interferometer provided in the wall surface of the writing chamber, synthesizes a laser beam with the first frequency which has traveled back and forth between the second laser interferometer and a fixed mirror and a laser beam with the second frequency reflected in the second laser interferometer, and outputs a second beat signal. The position of the stage is calculated based on a difference between the first beat signal and the second beat signal.

Abstract: According to one embodiment, a beam detector includes a first aperture substrate including a first passage hole smaller than a pitch between beams of a multi charged particle beam, a second aperture substrate including a second passage hole allowing one detection target beam which has passed through the first passage hole, and a sensor detecting a beam current of the detection target beam which has passed through the second passage hole. The second aperture substrate has light permeability, and includes a conductive material.

Abstract: The digital contents copying-inhibition apparatus comprises a guard data storage section which stores a guard data. This guard data is for appending to audio or video digital data which can be expressed as amplitude of the contained frequency component. Presence of this guard data becomes apparent only when the audio or video digital data is reproduced after the data has been compressed once.

Abstract: In the data protection processing device, the protection key adding position determining section or the protection key removal position determining section determines as to whether or not received digital data meets predetermined adding conditions. If the data meets the predetermined adding conditions, encoding and decoding are performed by adding or subtracting a predetermined protection key value to digital data when a predetermined number of items of digital data have been received after the above determination in the protection key adding position determining section or protection key removal position determining section.