| 摘要 |
<p>The invention relates to the method and measurement arrangement for measuring optical and acoustic properties of turbid material (12). In the method a pulsed, low energy laser pulse (11 ) is passed through said material (12) thereby creating in the turbid material scattered photons (19a, 19b) and a photoacoustic source (16a), which transmits a photoacoustic signal (13). Said scattered photons are received by absorbers (14, 15), which converts received photons to other two photoacoustic signals. The three photoacoustic signals are detected by one detector (17). By changing the distance between the absorber (14) and the incident laser beam (11 ), it is possible to deduce the absorption coefficient µ<SUB>a</SUB> and the reduced scattering coefficient µ<SUB>s</SUB>' of turbid material (12). The amplitude ratio of two signals produced by absorbers (14, 15) is proportional to the acoustic attenuation of the turbid material.</p> |
