A compact low-noise photodiode detection system for chemiluminescence nitric oxide analyzer

A compact, low noise, and high gain photon detector with the size of 50 mm × 50 mm × 48 mm has been developed for a nitric oxide (NO) chemiluminescence analyzer based on a temperature-stabilized photodiode (PD). A deviation of 0.01 °C was realized based on the design of a highly precise temperature control system to avoid signal fluctuation and baseline drift caused by environmental temperature fluctuation. At an optimized temperature of 23 °C, the noise level of 0.088 mV of the PD detector with a gain of 1011 V/A was obtained. The limit of quantitative detection for NO achieved was 25 ppb (S/N = 10), and the coefficient of determination R2 was 0.999 in the range of 0.1-20 ppm.