LIGHT INTENSITY MEASURING DEVICE

PROBLEM TO BE SOLVED: To provide a light intensity measuring device capable of measuring intensity of light generated by interaction with an object, with a widened dynamic range, and with practical accuracy.SOLUTION: The light intensity measuring device includes: an irradiation system; a measurement system; and a variable neutral density filter. The irradiation system irradiates an object to be inspected with irradiation light. The measurement system measures intensity of light generated by interaction between the irradiation light and the object to be inspected. The variable neutral density filter dims at least one of the irradiation light and the light generated by interaction, with different dimming rates that can be consecutively changed. Before the measurement of the light generated by interaction, the measurement system counts photons of the light dimmed with the respective dimming rates, using a photon counter. Then, using calibration values of the dimming rates calculated on the basis of the count result of photons, the measurement system calculates the intensity of the light generated by interaction, in a case where neither the irradiation light nor the light generated by interaction is dimmed, or in a case where at least one of the irradiation light and the light generated by interaction is dimmed with the same dimming rate.SELECTED DRAWING: Figure 1 【課題】より大きなダイナミックレンジかつ実用的な精度で物体との相互作用によって生じる光の強度を測定することが可能な光強度計測装置を提供することである。【解決手段】光強度計測装置は、照射系、計測系及び可変減光フィルタを備える。照射系は、被検物体に照射光を照射する。計測系は、照射光と被検物体の相互作用で生じた光の強度の計測を行う。可変減光フィルタは、照射光及び相互作用で生じた光の少なくとも一方を、連続的に変化させることが可能な異なる減光率で減光する。計測系は、相互作用で生じた光の計測に先だってフォトンカウンタを用いて減光率で減光された光の光子をそれぞれ計数し、光子の計数結果に基づいて求められた減光率の校正値に基づいて、照射光及び相互作用で生じた光が減光されていない場合又は少なくとも一方が同一の減光率で減光された場合において相互作用で生じる光の強度を求める。【選択図】 図１