Seminars Archive

Horizontal opening of Synchrotron radiation from Bending magnet and an it’s effect to incoherent depth of the field for horizontal beam size measurement via spatial coherence.

Abstract
The horizontal beam size measurement through the spatial coherence of Synchrotron radiation (SR) has an effect of incoherent depth of the field. Due to this effect, observed spatial coherence gives always bigger beam size than expected beam size which is evaluated form lattice parameters. This incoherent depth of the field is come from opening of the SR in horizontal. The general theory for SR is established by Schwinger, but he did not take care about horizontal opening. K.J. Kim gave a qualitative theory for both of the vertical and horizontal opening of the SR, and he concluded horizontal instantaneous opening is same as in vertical. Since we need quantitative theory for horizontal opening of the SR for the discussion in the effect of incoherent depth of the field, I studied this issue in recent few years. At the beginning, I used quantum optical treatment, but in later I focused classical electromagnetic derivation for the theory. In my lecture, I will start with the effect of incoherent depth of the field in horizontal beam size measurement, and next I will refer the Schwinger theory, and in third, I will introduce my work on horizontal opening of SR. The result of quantitative treatment is horizontal instantaneous opening is same as vertical opening. I also introduce horizontal beam size measurements at ATF, KEK, SPEAR3, SLAC, Australian Synchrotron and ALBA.