Patent ID: 7826054

Claim:
A fuel cell system comprising: a fuel cell; a gas line in communication with said fuel cell, said gas line having a first window and a second window; a light source; a collimator system to collimate a beam from said light source into a first collimated beam directed through said first window and a second collimated beam directed through said second window; a first diffraction grating through which said first collimated beam passes subsequent to passage through said first window; a first focus system to focus said first collimated beam which has passed through said first diffraction grating on a first detector to receive said first collimated beam focused by said first focus system; a second diffraction grating through which said second collimated beam passes subsequent to passage through said second window; a second focus system to focus said second collimated beam which has passed through said second diffraction grating; and a second detector to receive said second collimated beam focused by said second focus system.