Parameters

The full parameters of the EBS can be found here.

The goal of the accelerators is to provide a highly brilliant beam for experiments. The greater the brilliance, the more photons of a certain wavelength can be concentrated on a sample per unit of time. Brilliance is obtained with electron beam parameters such as high current and low emittance. The emittance of the main light sources as a function of their circumference is given in the image below.

web-parameters.jpg

The horizontal emittance of different light sources as a function of the circumference. The blue line represents existing machines and the red line represents projects to upgrade existing machines (for more data see www.lightsources.org).   

The following table lays out the most important parameters (energy, current, etc) of many high energy synchrotron light sources world-wide.

Name Location Energy (GeV) Circumf. (m) Current (mA) Emittance (nmrad)
Spring-8 Japan 8 1436 100 3.0
APS United States 7 1104 100 3.0
ESRF France 6 844 200 3.8
ESRF-EBS France 6 844 200 0.134
PETRA-III Germany 6 2304 100 1
MAX-IV Sweden 3 528 500 0.33
NSLS-II United States 3 792 500 0.55
TPS Taiwan 3 518.1 500 1.6
DIAMOND Great Britain 3 565.3 500 3.22
ALBA Spain 3 268.8 200 4.33
SSRF China 3 431.84 500 2.61
ASP Australia 3 216.28 500 7.12
SIRIUS Brazil 3 518.4 500 0.25
SOLEIL France 2.75 354 500 3.68

Summary of the main parameters (energy, circumference, current and emittance) of synchrotron light sources around the world. More details can be found at lightsources.org (link to external site).

 

  ESRF ESRF-EBS
Energy (GeV) 6.03 6
Circumference (m) 844.391 843.977
Beam current (mA) 200 200
Bunch length (mm) 4.28 2.91
Energy spread 1.06 10-3 0.93 10-3
Synchrotron frequency (kHz) 2.10 1.30
Oper. Emittance (H/v) (pm) 4000/5 110/5

Summary of more detailed parameters of the ESRF electron beam in the storage ring (currently, and for EBS).

 

Filling Pattern   Uniform 7/8+1     Hybrid    16-bunch 4-bunch
Number of bunches   992 870+1 24x8+1 16 4
Maximum current (mA) 200 200 200 90 40
Lifetime (h) 50 45 30 16 9
Rms energy spread (%) 0.11 0.11 0.11 0.12 0.16
Rms bunch length (ps) 20 20 25 48 55

The current, lifetime, bunch length and energy spread depend on the filling pattern. they are given for different filling patterns.

 

    Even ID section (ID2, ID6, ...) Odd ID section (ID1, ID3, ...) Bending Magnet (3mrad) Bending Magnet (9mrad)
Field (T) depends on ID depends on ID 0.4 0.85
Horiz. Beta Functions (m) 35.2 0.5 1.41 0.99
Horiz. Dispersion (m) 0.137 0.037 0.061 0.045
Horiz. rms e- beam size (µm) 402 59 100 77
Horiz. rms e-divergence µrad) 10.7 90 116 111
Vert. Beta Functions (m) 2.52 2.73 34.9 34.9
Vert. rms e- beam size (µm) 7.9 8.3 29.5 29.5
Vert rms e- divergence (µrad) 3.2 3 0.85 0.85

The main optics functions, electron beam sizes and divergences at the various points are given below for the uniform filling modes and apply to almost all filling patterns, except the single bunch, for which a slightly larger size and divergence is reached due to the increased energy spread of the electron beam.