Riding the Perfect Wave

Selecting the right wavelength for your sample can significantly improve the quality of the experiment

Molybdenum (Mo) radiation is most often the wavelength of choice for chemical crystallography and is most widely used for structure determination of a wide variety of samples. One of the reasons for Mo-radiation’s popularity is modern area detectors can cover reciprocal space to atomic resolution with just one detector setting for fast and convenient data acquisition.

Copper (Cu) radiation’s stronger interaction with the sample leads to stronger diffracted intensities. Bruker pioneered sophisticated data collection strategy software and initiated the renaissance of Cu-radiation for weakly diffracting organic molecules and absolute-configuration experiments.

Silver (Ag) radiation, even shorter in wavelength than Mo-radiation, has the benefits of lowest absorption and extinction effects, and allows data collection to higher resolution. Only with Bruker’s introduction of high-intensity Ag microfocus sources has the application of Ag-radiation become practical.

Indium (In) radiation is the shortest wavelength available for the home laboratory—exclusively from the METALJET source. Indium is an exciting new option for demanding experiments in solid-state chemistry, or high pressure and charge density research. Gallium (Ga) radiation is exclusive to the METALJET source. Like Cu radiation, Ga is ideal for weakly-diffracting organic samples and the determination of the absolute configuration.

Copper (Cu) radiation – 1.54 Å – is the most popular wavelength for macromolecular crystallography in the home-lab. X-rays at this wavelength provided by our IμS interact strongly with the light atoms in biological molecules and provide efficient diffraction. At Cu radiation’s wavelength sulfur and other common scatterers provide an anomalous signal for in-house SAD phasing.

The gallium (Ga) emission line (1.34 Å) is near that of Cu for maintaining the proven benefits of Cu-Kα radiation but adds a number of advantages, such as reduced radiation damage, increased data collection efficiency, reduced X-ray absorption by the sample, and reduced scattering by both mother liquor and air.

For your applications the D8 QUEST and the D8 VENTURE can be configured with a wide range of X-ray sources. Starting with fine focus sealed tubes at the entrance level intensity increases via our series of IμS microfocus sources and rotating anodes (TXS) in the medium intensity regime to the METALJET D2 X-ray source defining the high end X-ray source.

Very recently a new class of microfocus sources, the IμS DIAMOND series, became available, offering rotating anode intensity without maintenance.