Fig. 1. Schematic layout of the TDS diagnostic section. The overall length is ∼35m, whereas the waveguide lengths from the klystron output to the TDS inputs are ∼11 and 12 m for TDS1 and TDS2, respectively. See text for more details.

Fig. 2. Two X-band TDSs. See text for more details.

Fig. 3. Measurement optics. (a) β functions along the lattice for matching at the TDS (solid lines), current profile measurements at S1 (dots), and LPS measurements at S2 (dashes). (b) Sketch of the measurement setup, where s corresponds to the longitudinal distance from the undulator exit, the big green circle indicates the X-band TDSs, the red crosses indicate the profile monitors S1 and S2, the small blue rectangles correspond to quadrupole magnets, and the large rectangle represents the dipole magnet before S2.

Fig. 4. Demonstration of variable polarization. (a) Images on screen S1 for different polarization angles. The deflecting voltage was 85 MV for the polarization angles between 0 and 105 deg and 73 MV for the polarization angles between 120 and 180 deg. (b) Position of the beam centroid on a BPM placed downstream of the TDS. Each color represents a different direction of the streaking field with a polarization angle step of 5 deg and a full RF phase scan. The deflecting voltage was ∼2MV.

Fig. 5. Sub-femtosecond resolution measurement. (a) Single-shot streaked images for different RF TDS phases. (b) Single-shot unstreaked image. (c) Measured and fitted beam centroid variation as a function of the RF TDS phase. See text for more details.

Fig. 6. FEL power profile measurement. (a) Single-shot LPS images with lasing-on (left) and lasing-off (right) conditions. The horizontal and vertical scales are the same for both images. (b) Single-shot FEL power profile reconstruction. See text for more details. The horizontal and vertical scales are the same for all power profile plots.