A simple method to resolve the features that are characteristic of hydroxyl radicals in sonoluminescence (SL) spectra from aqueous solutions has been developed. Using a modified version of cavitation threshold (CT) cell in which single band filters were sandwiched between the UV grade fused silica window and the photomultiplier tube (PMT) in the cell, photon emission in the wavelength range of 280 to 400 nm was measured. Four different single band filters, 280-305.5 nm, 300-340 nm, 335-375 nm and 374.5-397.5 nm were used. The results for air and Ar saturated DI water are consistent with those reported in the literature and obtained using expensive spectrometers. The SL signal collected in ammonium hydroxide solutions indicated that at higher power densities the signal intensity may not be relatable to the generation rate of hydroxyl radicals in their ground state.
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