| 摘要 |
PURPOSE:To facilitate the on-the-spot observation of damage due to the irradiation of radiation, by detecting the quantity of electron beam energy lost due to a sample, and by measuring the thickness of the sample in terms of the detected quantity. CONSTITUTION:When a CPU 12 has applied a control signal to a D/A converter 13 for a prescribed time in order to measure the thickness of a sample 3 during the observation of the minute structure of the sample, an electron beam 1 is directed to an energy detector 8 so that a pulse signal proportional to the energy of the electron beam is sent out. An integrator 9 integrates the pulse signal to sent out an analog signal corresponding to the total electron beam energy detected for the prescribed time The analog signal is applied to the CPU 12 through a D/A converter 10. The quantity of the total electron beam energy, which is newly entered into the CPU 12, and that of the total electron beam energy, which is stored in a memory 11 when the energy is not lost in the least, are compared with each other by the CPU to calculate the quantity of the energy lost due to the sample 3. The thickness of the sample 3 is then calculated in terms of a formula representing the relationship between the quantity of the lost energy and the thickness. The calculated thickness is applied to a CRT 14.
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