MISALINGMENT TOLERANCE OF A HOLE-COUPLING OPTICAL RESONATOR FOR JAERI ERL-FEL

The misalignment tolerance of a hole-coupling optical resonator for the JAERI ERL-FEL is estimated with a wavelength of 22 µm by a Fox-Li procedure simulation code. To ensure the high-power and stable FEL operation, the misalignment tolerance has to be clear, because the FEL power depends on the misalignment of the optical resonator. It is found that the misalignment tolerance of the hole-coupling mirror is less than the non-coupling mirror and the offset effect of the non-coupling mirror is compensable the mirror tilting. The misalignment tolerance is sufficiently large for the FEL power fluctuation of 1%.