LIQUID LEVEL DETECTION DEVICE, LIQUID LEVEL DETECTION METHOD, HIGH-TEMPERATURE PLASMA SOURCE MATERIAL SUPPLY DEVICE, AND EXTREME ULTRAVIOLET LIGHT SOURCE DEVICE

摘要

Disclosed is a liquid level detection device for appropriately detecting the liquid level (contained amount) of a high-temperature plasma source material in a liquid state, such as molten tin, within a reservoir containing the high-temperature plasma source material. This liquid level detection device is provided with an upper limit level sensor (41) for detecting when the liquid level of a tin (Sn) high-temperature plasma source material has risen from below and reached an upper limit level La (first liquid level), and a refill level sensor (42) and a lower limit level sensor (43), for detecting when the liquid level of tin has fallen from above and reached a refill level Lb or a lower limit level Lc (second liquid level). The detection responsiveness of the upper limit level detector (41) to the liquid level is higher than the detection responsiveness of the refill level sensor (42) and the lower limit level sensor (43) to the liquid level, and the liquid level detection ability of the refill level sensor (42) and the lower limit level sensor (43) is higher than the liquid level detection ability of the upper limit level sensor (41).