| 摘要 |
PROBLEM TO BE SOLVED: To provide an electron lens and a charged particle beam apparatus which can prevent the deformation of a magnetic path without changing the temperature of the magnetic path of an electron lens even when a magnetic excitation current passing through a magnetic excitation coil is changed, and which are less likely to be affected by image blurring, and drift of view field position.SOLUTION: An electron lens 40 comprises: a magnetic excitation coil 41; a magnetic path 42; a non-magnetic metal cover 48 interposed between the magnetic excitation coil 41 and the magnetic path 42 and covering the magnetic excitation coil 41; and a heating part including hot medium circulation pipes 51ou, 51do, 51ui and 51id for heating the non-magnetic metal cover 48. In the beginning of sample observation start, the heating part heats the non-magnetic metal cover 48 at target set temperature Tset consisting of temperatures equal to or higher than a temperature when the magnetic path 42 stays into a thermal equilibrium state, and lower than the heatproof temperature of constituent parts of the electron lens 40 in the case of forcing a frequently used magnetic excitation current to go through the magnetic excitation coil 41, and makes the temperature of the magnetic path 42 a target temperature equal to or higher than a temperature when the magnetic path 42 goes into the thermal equilibrium state by use of a magnetic excitation current of a previously set sample observation condition. |
