PROBLEM TO BE SOLVED: To provide a technique for suppressing noise generated from a light reflecting member which reflects scattered light on a subject surface as little as possible in backward detection type PAT (photoacoustic tomography).SOLUTION: An acoustic wave detector includes: a transducer and the light reflecting member which is positioned between the transducer and the subject surface that is irradiated with the light, and which reflects the scattered light on the subject surface. The light reflecting member includes a first reflecting surface and a second reflecting surface positioned closer to the transducer than the first reflecting surface, and a distance between the first reflecting surface and the second reflecting surface is an odd multiple of a half wavelength of a predetermined wavelength included in an acoustic wave generated from the light reflecting member by the scattered light.COPYRIGHT: (C)2012,JPO&INPIT【課題】後方検出型PATにおいて、被検体表面での散乱光を反射するための光反射部材自体から発生するノイズを可及的に抑える技術を提供する。【解決手段】音響波検出器が、振動子と、前記振動子と光が照射される被検体表面との間に位置し、前記被検体表面における散乱光を反射するための光反射部材と、を備え、前記光反射部材は、第1の反射面と、該第1の反射面よりも前記振動子側に位置する第2の反射面とを有し、前記第1の反射面と前記第2の反射面との間の距離が、前記散乱光によって前記光反射部材から発生する音響波に含まれる所定の波長の半波長の奇数倍である。【選択図】図1
