A Novel Source of X-Rays for Imaging Purposes
Physicists at LMU Munich and the Max Planck Institute for Quantum Optics have validated a novel laser-driven means of generating bright and highly energetic X-ray beams. The method opens up new ways of imaging the fine structure of matter.
For over a century, medical imaging has made use of X-rays produced in a specialized type of vacuum tube. The major disadvantage of this method lies in the poor quality of the emitted radiation. The source emits radiation from a large spot into all directions and over a broad energy range. These features are responsible for the relatively modest resolution attainable with this mode of imaging. X-rays generated in synchrotrons provide much higher resolution, but their dimensions and cost preclude their routine use in clinical settings. However, an alternative approach is now available, for two laser pulses can generate X-rays of similar quality to synchrotron radiation in devices with a far smaller footprint: One pulse accelerates electrons to very high energy and the other forces them into an undulating motion. Under these conditions, electrons emit X-radiation that is both highly energetic ("hard") and highly intense, and is therefore ideal for probing the microscopic structure of matter. Now, physicists based at the Laboratory for Attosecond Physics (LAP) at LMU Munich and the Max Planck Institute for Quantum Optics (MPQ) have developed such a laser-driven X-ray source for the first time. With the aid of two laser pulses, the researchers have generated ultrashort bursts of X-rays with defined wavelengths tailored for different applications. The new source can image structures of varying composition with a resolution of less than 10 micrometers. This breakthrough opens up a range of promising perspectives in materials science, biology and – in particular – medicine.