Search

Particle acceleration driven by a high power Ti: sapphire laser has invoked great interest worldwide because of the ultrahigh acceleration gradient. For the aspect of electron acceleration, electron beams with energies over GeV have been generated using the laser wakefield acceleration mechanism. For the optimization of the electron generation process, real-time electron parameter monitors are necessary. One of the key parameters of a high energy particle beam is the temporal distribution, which is closely related with the timing resolution in a pump-probe application. Here, we introduced the electro-optic sampling method to laser wakefield acceleration. Real-time multibunch structures were observed. Careful calculations on the physical processes of signal generation in an electro-optic crystal were performed. Discussions of the methodology are elaborated in detail.

We have developed a femtosecond high-intensity laser system that combines both Ti:sapphire chirped-pulse amplification (CPA) and optical parametric CPA (OPCPA) techniques and produces more than 30 J broadband output energy, indicating the potential for achieving peak powers in excess of 500 TW. With a cleaned high-energy seeded OPCPA preamplifier as a front end in the system, for the compressed pulse without pumping the final amplifier, we found that the temporal contrast in this system exceeds 10(10) on the subnanosecond time scales, and is near 10(12) on the nanosecond time scale prior to the peak of the main femtosecond pulse. Using diffractive optical elements for beam homogenization of a 100 J level high-energy Nd:glass green pump laser in a Ti:sapphire final amplifier, we have successfully generated broadband high-energy output with a near-perfect top-hat-like intensity distribution.

High brightness X-rays via laser-Compton scattering (LCS) of laser photons stored in an optical cavity by a relativistic electron beam is useful for many scientific and industrial applications such as X-ray imaging. The construction of compact Energy Recovery Linac (cERL) is now in progress at KEK to generate low-emittance and high-current electron beams. In order to demonstrate the generation of high brightness LCS X-rays, it is necessary to develop a high average power injection laser and an optical four-mirror ring cavity with two concave mirrors which is used to produce a small spot laser beam inside the cavity. In this presentation, we will show the result of the development of the high average laser system, the LCS X-rays generation, and the X-ray imaging., Proceedings of the 6th Int. Particle Accelerator Conf., IPAC2015, Richmond, VA, USA

A nondestructive assay system of isotopes by quasi-monochromatic gamma-rays by laser Compton scattering (LCS) is under development. In order to demonstrate the accelerator and laser performance required for the gamma-ray source, an LCS experiment is planned at Compact ERL (cERL) at KEK. An optical resonant cavity is under construction for the LCS experiment. The new optical cavity is designed by combination of two bow-tie cavities to achieve fast optical polarization switching. The performance of the optical cavity is presented in detail., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

A high-flux photon source from the laser Compton scattering (LCS) by an electron beam in an energy-recovery linac (ERL) is a key technology for a nondestructive assay system to identify nuclear materials. In order to demonstrate accelerator and laser technologies required for a LCS photon generation, a LCS photon source is under construction at the Compact ERL (cERL). The LCS photon source consists of a mode-locked fiber laser and a laser enhancement cavity. Flux monitors and a data aqcuisition system are also under construction. The commissioning of the LCS photon source will be started in February 2015 and LCS photon generation is scheduled in March 2015. The demonstration result of the LCS photon source will be presented in detail., Proceedings of the 6th Int. Particle Accelerator Conf., IPAC2015, Richmond, VA, USA

A nondestructive assay system of isotopes by quasi-monochromatic gamma-rays and nuclear resonance fluorescence is under development in JAEA. The quasi-monochromatic gamma-rays are generated by laser Compton scattering (LCS) based on energy-recovery linac accelerator and laser technologies. In order to demonstrate the accelerator and laser performance required for the gamma-ray source, an LCS experiment is planned at Compact ERL (cERL) at KEK. A mode-locked fiber laser, laser enhancement cavity, beamline, and experimental hatch are under construction for the LCS experiment. Up-to-date construction status is presented in detail., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany