X-ray spectra can be measured either by energy dispersive or wavelength dispersive spectrometers. There are even benchtop nuclear magnetic resonance spectrometers. Orbitrap instruments are similar to Fourier transform ion cyclotron resonance mass spectrometers (see text below). Circular dichroism spectrometers contain a monochromator, for example. These effects are exploited in some types of magnetometers, EFNMR spectrometers, and MRI imagers. One way is to measured with gas chromatograph-mass spectrometers. Echelle gratings are, like other types of diffraction gratings, used in spectrometers and similar instruments. X-ray beam excitation is used in X-ray fluorescence (XRF) spectrometers. Techtron is a manufacturer of Atomic Absorption Spectrometers and Spectral lamps. The first FTIR spectrometers were developed for far-infrared range. These instruments are typically low field NMR spectrometers. HgCdTe is a common material in photodetectors of Fourier transform infrared spectrometers. These spectrometers utilize the phenomenon of optical dispersion. Those filaments are widely used in mass spectrometers, ion gauges and photoflash lamps in photography. Peptide mass fingerprinting is the most popular analytical application of MALDI-TOF mass spectrometers.