7:15 SPB reports large background from non-lasing SASE3 bunches. BKR is informed.  

7:50 BKR analysed situation. Everything concerning the orbits is OK, so the background is due to the standard spontaneous background (about < 1% level of FEL beam). With SASE3 running currently 255 lasing bunches and SASE1 single bunch the intensities will be on a similar level. Recommendation to SPB to close SRAs from 3 mm to maybe 1.5 mm to reduce background.