- An instrument used to analyze crystal structure by using X-rays. In it, a beam of collimated X-rays strikes the crystal, and a detector measures the angles and intensities of the reflected beam. Applying Bragg's law to these measurements yields details about the crystal structure. Used, for instance, for X-ray diffraction studies that determine the structure of crystalline DNA. DNA is the abbreviation of deoxyribonucleic acid, and in its strands are contained the chemical basis of heredity. Also known as crystal spectrometer, ionization spectrometer, or crystal diffraction spectrometer.