Table 1. Overview of X-ray parameters for various example settings on the SPB/SFX instrument.
The pulse energies in settings 2–4 are comparable as the accelerator is usually running at 2.26 MHz and electron bunches are delivered interleaved to SASE1 and SASE3 (i.e. maximum 1.13 MHz delivered to each of SASE1 and SASE3). The number of X-ray pulses per 10 Hz train can be varied, leading to different intra-train repetition rates.
| Example values | ||||
|---|---|---|---|---|
| Parameter | 1 | 2 | 3 | 4 |
| Pulse duration (fs) | ca 100 | |||
| Photon energy (keV) | 3–16 | 9.3 | 9.3 | 9.3 |
| Pulse energy (mJ) | 4 | 1–2 | 1–2 | 1–2 |
| Beam size (µm) | ca 3 | |||
| Photon flux (photons pulse−1) | 1.0 × 1012 | |||
| Photon flux (photons s−1) | 2.7 × 1016 | 1.4 × 1016 | 6.8 × 1015 | 2.0 × 1015 |
| Brilliance [photons s−1 mm−2 mrad−2 (0.1% bandwidth)−1] | 5 × 1033 | |||
| No. of pulses per train | 2700 | 1350 | 352 | 202 |
| Time between two pulses (ns) | 221.6 | 443.3 | 886.5 | 1773.0 |
| Duration of pulse train (µs) | 598 | 598 | 312 | 358 |
| Intra-train rep. rate of pulses (MHz) | 4.51 | 2.26 | 1.13 | 0.564 |
| Time between two trains (ms) | 100 | |||
| Repetition rate of trains (Hz) | 10 | |||
| No. of pulses per second | 27000 | 13500 | 3520 | 2020 |
| Jet gap-to-gap spacing (µm) | ∼11 | ∼22 | 44† | ∼88 |
| Jet velocity (m s−1) | 49.6 | |||
†
Observed spacing between two gaps along the irradiated liquid jet (displacement between two pulses) in 1.13 MHz mode.