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An automated apparatus is presented that allows a user to measure the mass spectrum or velocity map images of photofragments during tuning of the dye-laser radiation wavelength and its second harmonic, which interact with an investigated substance in a molecular beam. The NI LabVIEW environment was used for automation. The apparatus was successfully tested when studying the resonant ionization of oxygen molecules. The automation software makes it possible to extend the possibilities of measuring spectral dependences by creating additional modules without modifying the existing program code.

A broadband near-IR photodetector based on a large-area G12180-250A InGaAs photodiode (Hamamatsu) with a 5-mm-diameter photosensitive area was developed and tested. It is designed for detecting the IR luminescence of singlet oxygen. A circuit for signal amplification is assembled on the basis of broadband low-noise operational amplifiers with the subsequent filtering of a signal with an adjustable passband f varied from 15 to 600 kHz, thus allowing one to obtain a time resolution of better than 1 µs, a sensitivity level of 107–109 V/W, and a noise equivalent power NEP [W/Hz1/2] ≈ 1.4 × 10–14λ–1[µm] f [kHz] in a frequency band of 15–600 kHz.