An inspection apparatus for inspecting jet pump beams of nuclear reactors is provided. The backlight also includes a semi-specular element, and a light extraction element disposed within the hollow cavity. A rotor housing is journalled to the axle portion on both sides of the motor stator mounting element via bearings. The second demodulating unit detects the signal quality of the sound signal and generates a second demodulated signal to the sound de-matrix unit andor the first demodulating unit by demodulating the second carrier signal. Emulsions containing these emulsifiers neither gel nor crystallize in storage. The AD converter detects bubbles in thermometer codes obtained from output signals of the plurality of comparators and adjusts a ratio of the sampling time and the comparison time of the plurality of comparators so as to reduce the bubbles.