Observation of edge radiation from a straight section of SAGA-LS storage ring

Edge radiation generated by relativistic electrons passing between two bending magnets was investigated in a straight section of the SAGA-LS storage ring. Observations with correction of the closed orbit distortion (COD) and with large COD by single dipole kick were performed. Small but uncontrolled dipole kicks due to various magnets such as quadrupoles, sextupoles and steering magnets between the two bending magnets were considered to be non-negligible as a disturbance factor of the spatial distribution of the edge radiation. In addition, clear edge radiation was observed under the large COD due to a single dipole kick. The large COD was thought to generate a 'pure' straight subsection, which contained no magnets and was clearly off-axis with respect to other subsections. Calculation based on this consideration showed good agreement with our observations. (author)