ELECTRON SPIN RESONANCE DEVICE

PURPOSE:To arbitrarily vary the irradiation light quantity in a state that an irradiated area remains maintained by providing a lens moving means by varying the irradiated area of a convergent lens for condensing a light beam from a light source onto a sample to be inspected, and a diaphragm for varying the light quantity. CONSTITUTION:In a cavity resonator to which a microwave is supplied from a waveguide, at the time of measuring a liquid as a sample to be inspected, an optical lens 8 is moved in the distance from the sample in order to extend an irradiated area S1 to a wide range as shown in the figure (a). In this case, when the hole diameter of a diaphragm 12 is varied as shown by a dotted line from a full line, the light quantity can be varied as shown by a 2-dotted chain line A without varying a size of the irradiated area S1. Subsequently, when the sample to be inspected is a solid, an irradiated area S2 on the sample is made small by bringing the lens 8 close to the sample as shown in the figure (b), and the measuring center is irradiated with the light beam to the utmost. In this case, as well, the light quantity can be set arbitrarily by varying the hole diameter of the diaphragm 12.