Table 2. Optimal fraction of undulator radiation focused to the diffraction limit (λ = 1 Å).
are the r.m.s. electron beam sizes in the horizontal and vertical direction, respectively, and T is the fraction of the undulator radiation transmitted through the nanofocusing optic. 
is separable into a horizontal (
) and vertical (
) contribution [cf. equation (28)]. The parameters are taken from (Sette, 2012 ▶) and http://photon-science.desy.de/facilities/petra_iii/machine/parameters/index_eng.html.
 (µm) |
 (µm) |
|
|
T | ||
|---|---|---|---|---|---|---|
| ESRF | High-β | 395 | 3.9 | 0.0017 | 0.29 | 0.05% |
| Low-β | 50 | 3.9 | 0.002 | 0.29 | 0.06% | |
| ESRF | Upgrade II | 23.5 | 3.7 | 0.035 | 0.30 | 1.05% |
| PETRA III | High-β | 141 | 4.9 | 0.0057 | 0.22 | 0.13% |
| Low-β | 34.6 | 6.3 | 0.0077 | 0.18 | 0.14% | |
| DLSR | 10 pm rad round | 1.3 | 1.3 | 0.49 | 0.49 | 24% |