Automatic analysis apparatus and method for controlling automatic analysis apparatus

A method for controlling an automatic analysis apparatus including a photomultiplier tube configured to detect light from a reaction vessel, a light source, and a controller programmed to determine an output signal of the photomultiplier tube, the method comprising steps of:

• irradiating the photomultiplier tube with a first light from the light source;
• determining the output signal of the photomultiplier tube in a case where the photomultiplier tube is irradiated with the first light;
• determining a target irradiation amount of the photomultiplier tube with a second light from the light source to lower a sensitivity of the photomultiplier tube based on the output signal;
• and
• continuously irradiating the photomultiplier tube with the second until the target radiation amount is reached and the sensitivity of the photomultiplier tube reaches a target value.