Study on X-ray enhancement in Laser-Compton scattering for auger therapy

Abstract

Purpose

Monochromatic hard X-rays with high brightness are desired for medical applications including Auger therapy. One can generate such X-rays through laser-Compton scattering (LCS) by allowing photons from a compact laser system to interact with electrons accelerated by a compact electron accelerator. In this paper, after a brief description of laser-Compton X-ray sources, a scheme called crab crossing to enhance the X-ray intensity is proposed. The effect of crab crossing is evaluated, and we report our dedicated laser system for the crab crossing LCS research.

Materials and methods

The luminosity enhancement factor by crab crossing is evaluated. For the electron beam, a rf deflector will be used to generate a tilted electron beam. For the laser system, chirped pulsed amplification is adopted. Yb-doped optical fibers and a Yb:YAG thin-disk is used for the laser gain media.

Results

The luminosity enhancement factor by crab crossing is expected to be 3.8 when the crossing angle is 45 degrees. 10mJ pulse energy was achieved by thin-disk regenerative amplifier. The pulse duration after the pulse compressor was about 1.5 ps.

Conclusion

We are going to demonstrate the LCS X-ray enhancement by crab crossing of electron beam and laser pulse. The expected enhancement factor is 3.8. We have successfully finished the laser development and the proof-of-principle experiment will be conducted soon.

Keywords:

• X-ray source
• laser-Compton scattering
• auger therapy
• electron accelerator
• laser

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Japan Society for the Promotion of Science KAKENHI [Grant No. 18H01233].

Notes on contributors

Yuya Koshiba

Yuya Koshiba received Master of engineering from Waseda University in 2014. He is currently a Ph.D. student and also a research associate in Waseda University. His research interests are electron accelerators and lasers.

Ryosuke Morita

Ryosuke Morita is a Bachelor student in Waseda University. He has put his effort on developing the laser system, especially the thin-disk regenerative amplifier in this research.

Koki Yamashita

Koki Yamashita is a Bachelor student in Waseda University. He has put his effort on developing the laser system in this research.

Masakazu Washio

Masakazu Washio, received a doctorate from the University of Tokyo in the field of nuclear engineering in March 1981. In 1998, he joined the Research Institute for Science and Technology, Waseda University as a professor. He is currently a professor in the Department of Applied Physics and the Cooperative Major in Nuclear Energy, the Graduate School of Advanced Science and Engineering. His research interests are advanced accelerator science and advanced polymer science related to quantum beam technology.

Kazuyuki Sakaue

Kazuyuki Sakaue, received a Ph.D. degree in Accelerator Science from Waseda University by an experimental demonstration of laser-Compton X-ray using pulsed laser storage cavity.He has been active in the area of electron accelerators and laser-beam interactions for over 10 years. His current research involves study of laser-material interactions and the laser enhancement super-cavity system for various use. He is now a Principal Researcher of Graduate School of Engineering, the University of Tokyo.

Takeshi Higashiguchi

Takeshi Higashiguchi is a professor. He received his Ph.D. in engineering from Utsunomiya University. His research activities have focused on short-wavelength extreme ultraviolet (EUV) and soft x-ray sources, laser-plasma interaction, high-repetition rate thin disk lasers, and related applications.

Junji Urakawa

Junji Urakawa, received a Ph.D. degree in Nuclear Physics from Tokyo Institute of Technology in 1981. He started his career at KEK in 1983 as an Associate Researcher and currently a Research Administrator of KEK. He is also a Guest Professor at Waseda University. He has put his efforts on the development of high-quality electron accelerators and the realization of the International Linear Collider project.