Table 1 presents a summary of the characteristics of the storage ring’s electron beam.

Table 1: Principal characteristics of the electron beam.

 

Table 2 gives the main optic functions, electron beam sizes and divergences at various source points. For insertion device source points, the beta functions, dispersion, sizes and divergences are calculated in the middle of the straight section.

Table 2: Beta functions, dispersion, rms beam size and divergence for the various source points.

Two representative source points for each type of bending magnet (even or odd number) have been selected, corresponding to observation angles of 3 and 9 mrad from the exit. The associated source point originates from a location in the bending magnet with a different magnetic field. Electron beam profiles are Gaussian and the size and divergence are presented in terms of rms quantities.

The associated full width half maximum sizes and divergences are 2.35 times higher. Horizontal electron beam sizes and divergences are given for the uniform filling modes and apply to almost all filling patterns except for the single bunch, for which a slightly larger size and divergence is attained due to the increased energy spread of the electron beam. Vertical electron beam sizes and divergences apply to the uniform, 2 x 1/3 and hybrid filling modes only. To increase the lifetime of the stored beam, the vertical beam sizes and divergences are increased by about 50% in the 16 and 4 bunch filling patterns.

The lifetime, bunch length and energy spread mainly depend on the filling pattern. These are given in Table 3 for a few representative patterns. Note that in both the 16-bunch and 4-bunch filling patterns, the energy spread and bunch length decay with the current (the value indicated in the table corresponds to the maximum current). The bunch lengths are given for the usual radio frequency (RF) accelerating voltage of 9 MV (8 MV for 16-bunch and 4-bunch).
 

Table 3: Current, lifetime, bunch length and energy spread for a selection of filling modes.