A Study on Enhancement of Sensitivity of a PhotoAcoustic Detector Cell for Non-invasive Measurements Based on Finite Element Method Analysis

Abstract

In order to measure noninvasively living body information using photoacoustic spectroscopy(PAS), fundamental investigation regarding a high sensitivity detector was carried out by the finite element method(FEM). The mathematical model reflecting the physical mode regarding a signal generation, propagation and detection of PA signal was used, and the analysis for optimizing PA detector cell was carried out. First, in order to detect the PA signal with high sensitivity, it was shown that it is necessary to make total volume of a cell small. Next, the influence on sensitivity due to in the gap between a target sample and a detector cell was evaluated. As a result, it was shown that there is not a large influence on the detection of the PA signal, even if both degree of adhesion changes slightly. Furthermore, the sensitivity of a resonant type cell and a non-resonant type cell was compared, and it was shown that the sensitivity of the resonant type is about 9-120 times that of the non-resonant type. From these results, the conditions for achieving the PA detector cell with high sensitivity were suggested.