1. Optimize SASE for Seeding

The goal is to make all the undulators contributing to SASE with a straight orbit, especially for the (2-3) cells near the chicane location. This would help to imporve the transverse overlap between e- beam and the seed afterwards.

1. Save a machine file (if not done yet)
2. Make sure that Graphite filter upstream of XGM is in (in photon display panels one can find the filter in SASE2 beamline and double click to check the status).
3. Setup HIREX and cross-calibrate with XGM → pay attention that HIREX signal amplitude signal should be below 3000!
4. Disable quadratic taper and document SASE level (with >17 cells closed, we should have >300 uJ level with linear taper @9keV).
5. SASE tuning with linear taper, try to find optimum linear taper (one can use the linear taper scan tool)
6. After changing taper, phase shifters may be needed to be scanned again
7. Simplified gain curve or XGM readout to check
   1. 12-16 segments across the chicane contribute equally
   2. 1-10uJ incident on crystal
8. Check stability of orbit with chicane on (within +/-10 um), if not stable, find reasons (compression? IBFB?)
9. Setup SASE2 orbit feedback (separated by launching and orbit after 1^st and/or 2nd chicane). Deactivate the BPMs after chicane for launch feedback. Downstream of chicane use SASE22 orbit feedback with all the CAX and CAY. (one can find it on the HXRSS panel). → see examples for the feedbacks on the right →
10. Open or detune undulators after 2^nd chicane (U2) and check SASE contribution from U1+U2 (disable orbit feedback during undulator movement) see HXRSS_layout.png → this is impinging intensity on C2.
11. Open or detune undulators after 1^st chicane (U1) and check SASE contribution from U1→ this is impinging intensity on C1.
12. If the SASE contribution from U1 is below 1 uJ and we want to seed with 1st chicane, try to optimize the orbit to get more cells contributing.
    1. performe phase shifter scans to check if the cells are contributing 
    2. one may need to close more cells downstream to get above 20 uJ level for the optimization
13. If the SASE contribution from U12 is above 10 uJ, open the first undulators and leave around 8 cells before the chicane, and close 8-10 afterwards. Remember to close the downstream undulators again.
14. Save another file after optimization

2. Seed with SASE

This step would help to check the lasing window and the transverse overlap

(see HXRSS panel HXRSS_panel.png also shown in the detail on the right ->)

1. Take machine file and reference orbit (normally saved in the file, but can be done in commen orbit display by pressing "set as reference").
2. Switch on the chicane (use 1^st chicane if SASE level before 1^st chicane is above uJ), one can find the chicane control on the HXRSS panel (see detail on the right) or on the chicane server panel.
3. Increase delay dt step-wise checking that orbit is not changing much (max +/-10 um).
4. While increasing the delay step-wise (2-5 fs/step until XGM signal is below uJ, wait 10 seconds in between for the orbit feedback to react), measure XGM pulse energy readout as function of delay (normally automaticly displayed on the SASE viewer). Send the SASE viewer curve to logbook (example below). Signal should drop after 1-2 fs (micro bunching washed out) and then continue to drop slowly up to one point that there is no more lasing (this period is approx. our lasing window). If the signal doesn’t drop with the increase of delay (after wash out of microbunching), then we have problem with transverse overlap.
5. Optimize the transverse overlap (using air coils after chicane).

4. Set-up Monochromator and find seeded signal

1. Disable the MPS bit to insert crystal
2. Switch on chicane (with > 30 fs delay)
3. Set-up the cameras for bragg refelction and for crytal observation (see details on the right side ->)
4. Insert crystal using the Monochromator panel (XFEL main task panel -> photon -> SASE2 -> HXRSS → Mono control) (please refer to the crystal position and angles listed below in the reference)
   
5. Find bragg reflection (if not visible, increase number of bunches to 100, see details on the right side ->)
6. Scan and adjust chicane delay (10-20 fs) to find the seeded signal
7. Scan and fine tune the crystal angle,one should be able to see the movement of the seeded peak on the HIREX spectrum as shown on the last image on right side ->
   
8. If one can not find seed signal, detune U3 to check the effect

5. Optimization of seeded signal

1. Fine tune the delay again (using Correlation2D function from PyHirex → see the example on the right side)
   
2. Fine tune the photon energy for color 1, 2 and 3 (see example on the right side)
3. Air coil optimization after the chicane (manually or using seeded signal in Ocelot), start with launching correctors for SA22 or SA23 or global lauching

4. Procedure to optimize orbits for seeding (or diagnose that there is something wrong) → see image on the right side:

   • detune the seeded undulator by 40eV
   • ensure there is no seeding with SASE
   • reduce attenuation to see two SASE signals on HIREX (make sure not to seed accidentally, otherwise 
     you'll damage HIREX)
   • disable all SASE2 orbit feedbacks
   • change the SASE launch (by few urad) and observe intensities on HIREX. Both should go down when 
     launching is detuned. Otherwise - consider optimizing.
   • seed line shadow should be visible on the U1(2) SASE. Consider optimizing its position to the 
     peak spec density
5. Undulator phase shifter scans using seeded signal (first for undulators downstream of chicane, then also for the upstream undulators?)
6. Signal to Noise Ratio optimization (open or close some cells before or after undulator for optimization, do air coil and phase shifter optimization for these cells while keeping the orbit in other cells constant using orbit feedback)
7. Taper optimization
   
8. Laser heater optimization
9. Check the effect of compression
10. Seeded peak signal: XFEL.UTIL/DYNPROP/MISC/HIREX_AMPL 

6. Switch from HXRSS back to SASE

1. Retract the crystals (all of them) by set the X position to park
2. Set back the MPS protection for the crystals (only by RCs)
3. Switch off HIREX (or put all the attenuators in)
4. Set chicane delay to 0 and degauss the chicanes (to allow parallel operation in other beamlines, please insert the first vacuum valve in T1) → see the image on right side
5. Switch off the SA22 and SA23 feedback
6. Use the photon energy switch tool to prepare a photon energy file from the file saved before HXRSS set-up
7. Use seq. to change photon energy to apply the file settings
8. Check if the trim coils for the chicanes are back to 0 and switched off
9. Launch optimization using adaptive feedback if needed
10. If SASE level is still not back to the file value
    1. scan phase shifters near the two chicanes
    2. use ocelot optimizer to optimize orbit near the two chicanes (using air coils)