Electron & Photon Beam Sizes
Electron Beam Parameters
| Energy | [GeV] | 6.04 | |
| Max Current | [Amp] | 0.2 | |
| Horizontal Emittance | [nm] | 3.9 | |
| Vertical Emittance | [nm] | 0.039 | |
| 200 mA | RMS Energy Spread | [%] | 0.11 |
| RMS Bunch Length | [ps] | 21 | |
| 90 mA 16 bunch | RMS Energy Spread | [%] | 0.12 |
| RMS Bunch Length | [ps] | 43 | |
| 16 mA 1 bunch | RMS Energy Spread | [%] | 0.19 |
| RMS Bunch Length | [ps] | 61 | |
| High Beta ID | Horizontal Beta | [m] | 35.6 |
| Vertical Beta | [m] | 2.5 | |
| Low Beta ID | Horizontal Beta | [m] | 0.5 |
| Vertical Beta | [m] | 2.73 | |
| Bending Magnet | Horizontal Beta | [m] | 2.2 |
| Vertical Beta | [m] | 34.9 |
RMS Photon Beam Sizes and Divergences
| Source | Plane | Electron Beam | Undulator Radiation | |||||
| Photon Energy [keV] | 3 | 10 | 30 | 3 | 10 | 30 | ||
| Undulator Length [m] | 1.65 | 1.65 | 1.65 | 3.3 | 3.3 | 3.3 | ||
RMS Divergence [micro-rad] |
||||||||
| High Beta ID | Horizontal | 10.5 | 15.3 | 12.1 | 11 | 13.1 | 11.3 | 10.8 |
| Vertical | 3.9 | 11.9 | 7.3 | 5.3 | 8.8 | 5.9 | 4.7 | |
| Low Beta ID | Horizontal | 88.3 | 89 | 88.5 | 88.4 | 88.7 | 88.4 | 88.4 |
| Vertical | 3.8 | 11.8 | 7.2 | 5.2 | 8.8 | 5.8 | 4.5 | |
| Bending Magnet | Horizontal | 108 | ||||||
| Vertical | 1.1 | |||||||
RMS Source Size [microns] |
||||||||
| High Beta ID | Horizontal | 395 | ||||||
| Vertical | 9.9 | |||||||
| Low Beta ID | Horizontal | 57 | ||||||
| Vertical | 10.3 | |||||||
| Bending Magnet | Horizontal | 126 | ||||||
| Vertical | 36.9 | |||||||
Remarks
High Beta beamlines are located on straight sections with even numbers : ID2, ID4, ID6.... ID32
Low Beta beamlines are located on straight sections with odd number : ID1,ID3,... ID31
Wiggler radiation presents a much greater divergence in both the horizontal and vertical planes. The beam sizes at the source are similar for most wavelength of interest if one selects the radiation around the axis of the electron beam.
In general, the divergence of the undulator radiation depends on the undulator length, photon energy, electron energy spread and undulator tuning. The values given in the table correspond to an undulator operated on a sufficiently low harmonic to neglect the contribution from the electron energy spread. The tuning of the undulator corresponds to a maximum of the spectral flux per unit surface on axis of the electron beam. There exists one such maximum for each odd harmonic of the spectrum. Tuning the photon energy to higher (lower) values or equivalently the magnetic gap to lower (higher) values may result in a narrower (wider) divergence . In most cases these figures are correct to 15% or better.