Photographic data acquisition technique

Cinematography. This data acquisition technique is straightforward in principle but tedious in practice. A high-speed movie camera photographs the mass spectral display on the oscilloscope screen. When the camera operates at 400 frames per sec and the mass spectrometer at a repetition rate of 10 kHz, each frame of the film contains the information of 25 mass spectra. This arrangement permits time resolution of 2.5 msec. A 150-m film records data for approximately 50 sec which is adequate for most stress MS experiments. 

Still Photography. The use of a still camera to record the mass spectral data displayed on the oscillographic screen is an alternate photographic data acquisition technique. The simplest method is to photograph the oscilloscope display for a fixed time during which the sample is stressed and/or fails. This technique does not permit resolution of changes in the mass spectra with time but provides a way to record qualitative information with readily available equipment. 

---