Search Results (2 total)

Based on the requirements from a conceptual design of a polarized positron beam for future linear colliders, we constructed a special collision system with a short focal length of 150 mm of the laser beams so as to produce γ rays through inverse Compton scattering. In order to achieve efficient laser-electron collisions, we created a special optics to produce very small e^--beam sizes of σ_ex0=7.6   μm and σ_ey0=5.4   μm in the horizontal and vertical directions at the collision point. Using laser light with a wavelength of 532 nm and an e^- beam of 1.28 GeV, provided from the ATF-damping ring at KEK, we generated 2×10⁵ γ rays with a time duration of 26 ps in rms, leading to a peak brightness of 1.7×10¹⁸/(mrad² mm² 0.1%bandwidth s) near to the maximum energy of 56 MeV.

Electron beams with the lowest, normalized transverse emittance recorded so far were produced and confirmed in single-bunch-mode operation of the Accelerator Test Facility at KEK. We established a tuning method of the damping ring which achieves a small vertical dispersion and small x-y orbit coupling. The vertical emittance was less than 1% of the horizontal emittance. At the zero-intensity limit, the vertical normalized emittance was less than 2.8×10^-8 rad m at beam energy 1.3 GeV. At high intensity, strong effects of intrabeam scattering were observed, which had been expected in view of the extremely high particle density due to the small transverse emittance.