| 摘要 |
<p>PURPOSE:To perform the stable measurement of electrons while eliminating a measuring error caused by the effect of the humidity in an electron detection part, by limiting the supply amount of gas so as to make the value of the number of electrons in a background counting mode min. CONSTITUTION:After a state generating voltage of -30V is set to a pulse generator 22, a flow rate controller 32 is gradually opened from a flow rate zero state to supply dry gas into an electron detection part 1 through gas supply piping 30. Since the humidity in the electron detection part 1 lowers with the increase in the flow rate of the gas, a counting rate N as background noise caused by the humidity also lowers. At the point of time when said counting rate N reaches a saturated flow rate, the control of the flow rate is stopped. In this state, a background measuring mode is released to set a specimen measuring mode and light is allowed to irradiate the surface of a specimen 10 from a light source 13 and the electron discharged to the outside through the membrane 10b on the specimen by the irradiation of light is counted by the electron detection part 1 to measure the thickness of the membrane.</p> |
