A simple photoacoustic detector for highly corrosive gases.

In this work, we present a new design of a cantilever-type photoacoustic (PA) detector with high chemical resistance to be used for a broad range of gaseous samples including highly corrosive gasses. A thin mica cantilever used to sense the PA pressure is the only part that comes into direct contact with the sample gas as its deflection is sensed by a probe laser from outside of the gas cell. The design of the detector is simple, compact, and affordable. It can be constructed without any special fabrication procedure in laboratories equipped with a standard mechanical and electronic workshop. The detector has been tested and its performance evaluated in combination with commercially available pulsed IR tunable optical parametric oscillator and amplifier delivering 2-10 mJ of energy per pulse sampling highly corrosive HCl and HBr gasses. The ro-vibration PA spectrum of the first overtone (ν = 0 → ν = 2) of HCl molecules in the range from 5315 to 5855  cm-1 is presented.