Abstract: An apparatus for regulating the shape of a focused ion beam irradiates a sample which is comprised of a pattern on a substrate with a scanning ion beam, detectors for detecting two kinds of secondary ions one emitted from the substrate and the other emitted from the pattern, comparators for comparing the detected signals with respective predetermined values and then converting the detected signals into binary signals, and a color display for displaying the shapes of the substrate and the pattern in the form of pictures of different colors on the basis of the binary signals corresponding to each kind of secondary ions. The spot shape of the ion beam is corrected with an astigmatic correction electrode and/or an object lens while observing the shape of the overlapping portions of the pictures of different colors.

Abstract: The present invention provides a barometer which includes a frequency control circuit connected to the input of the piezoelectric oscillator, a current-voltage converter connected to the output of the piezoelectric oscillator, a phase comparator connected to the output of the frequency control circuit and to the output of the current-voltage converter, a voltmeter connected to the current-voltage converter, a voltmeter connected to the phase comparator, a low-pass filter connected to the phase comparator, and input means for applying the output of the low-pass filter to the frequency control circuit. In the construction described above, the ambient pressure of the gas around the piezoelectric oscillator is represented by the a.c. voltage value of the piezoelectric oscillator.

Abstract: An electron microscope of scanning type comprises first and second detectors for detecting secondary electrons emitted from a specimen irradiated by a scanning electron beam are disposed across the magnetic field of an objective lens of an electron-optical system of the microscope. The detection signals obtained from the outputs of both detectors are subjected to simultaneous signal processings.