Research
Research Group Detail
Development and utilization of novel quantum beam sources using a high energy electron beam
Electron beams, synchrotron radiation, gamma-rays, positrons
Our group develop new electromagnetic wave sources using a high energy electron beam. In the UVSOR-III electron storage ring at the Institute for Molecular Science, a 750-MeV electron beam can be generated. Electromagnetic waves in a wide frequency range from ultraviolet waves to gamma-rays are generated by interacting the electron beam with magnetic fileds and lasers.
Laser Thomson (Compton) scattering is a method to generate a high energy gamma-ray by the interaction between a high energy electron and a laser. We have developed ultra-short pulsed gamma-rays with the pulse width of sub-ps to ps range by using 90-degree laser Thomson scattering. We applied this ultra-short pulsed gamma-rays to gamma induced positron annihilation lifetime spectroscopy (GiPALS). A positron is an excellent probe of lattice defects in solids and of free volumes in polymers at the sub-nm to nm scale. GiPALS enables defect analysis of a thick material in a few cm because positrons are generated throughout a bulk material via pair production. Our group is conducting research on improving the properties of the material by using GiPALS.
Figure 1: Schematic illustration of 90-degree laser Thomson scattering.
Figure 2: Positron annihilation lifetime spectrum of pure iron measured using ultra-short pulsed gamma rays.