double beam double-focusing mass spectrometer
double beam electric-null infrared spectrometer
double beam grating spectrophotometer
double beam interferometer
double beam mass spectrometer
double beam microspectrophotometer
double beam molecular absorption spectrometer
double beam oscillography
double beam oscilloscope
double beam electric-null infrared spectrometer
double beam grating spectrophotometer
double beam interferometer
double beam mass spectrometer
double beam microspectrophotometer
double beam molecular absorption spectrometer
double beam oscillography
double beam oscilloscope
double beam mass spectrometer