1. Revised Commissioning Strategy
Sven Reiche :: SFBD :: Paul Scherrer Institut
Revised Commissioning Strategy
Commissioning Workshop 2016

2. Introduction Strategy driven by beam dynamics and FEL objectives
Requisite for hardware given by objectives
Hard requisites: e.g. X-band operational for Compression
Commissioning should stop and allow for installation and repair if no further commissioning objectives can be achieved
Soft requisites: e.g. Amplitude laser not available, but Jaguar is.
Commissioning can continue but requires to return and repeat this commissioning step once the requisite is fulfilled.
Missing soft requisites must be evaluated if it makes sense to continue
Example 1: Setting up TDS and measurement procedures with jaguar is useful
Example 2: Slice emittance optimization with jaguar is a waste of commissioning time
Commissioning should not happen for the sake of filling the commissioning time slot if no further objectives can be fulfilled

3. Injector I - Gun Goal (Minimal Goal):
Demonstrate generation of electron beam
Set-up gun phase procedure
Hard requisite:
Gun RF commissioned,
Laser available,
Gun spectrometer functional
Both screens, a BPM and one charge measurement (WC or ICT) ready in SINEG01
Soft requisite:
Stability in jitter and drift: 5 times the SwissFEL tolerance values
Diagnostic resolution: 5 times the SwissFEL design values
200 pC charge

4. Injector II – Transport, Optics & Proj. Emittance
Goal (Minimal Goal):
Transport beam to injector spectrometer
Achieve 150 MeV beam energy
Establish stable beam optics for transport
Measure projected emittance of uncompressed beam
Hard requisite:
SINSB01 and SINSB02 RF commissioned
All BPMs, Screens in SINLH01, SINBC01, SINDI01, S10DI01 and S10BD01
All magnets except Bunch Compressor and Laser Heater
Soft Requisite:
Stability in jitter and drift: 5 times the SwissFEL tolerance values
Diagnostic resolution: 5 times the SwissFEL design values
200 pC charge

5. Injector III – Slice Emittance, Optimization
Goal:
Set-up TDS measurement
Measure slice emittance and longitudinal phase space
Optimize slice emittance and mismatch for uncompressed bunch
Hard Requisite:
TDS RF commissioned
Soft Requisite:
Amplitude Laser available
Stability in jitter and drift: 5 times the SwissFEL tolerance values
Diagnostic resolution: 5 times the SwissFEL design values except camera S10DI01 and S10BD01 with nominal resolution
200 pC charge

6. Injector IV – Bunch Compression
Goal:
Set-up nominal bunch compression
Demonstration and optimization of slice emittance values
Hard Requisite:
BC1 movable and operational
All RF stations operational
Soft Requisite:
Amplitude Laser available
Stability in jitter and drift: 5 times the SwissFEL tolerance values
Diagnostic resolution: 5 times the SwissFEL design values except cameras in S10DI01 and S10BD01
200 pC charge

7. Injector V – Laser Heater
Goal:
Demonstrate induced energy modulation with laser heater
Hard Requisite:
LH chicane and undulator operational
LH laser pulse available
LH diagnostics operational
Soft Requisite:
Stability in jitter and drift: 5 times the SwissFEL tolerance values
Diagnostic resolution: 5 times the SwissFEL design values
200 pC charge

8. Injector VI – Stability & Reproducibility
Goal:
Demonstrate reproducible and stable operation of the injector
Commissioning of the beam-based feedback system
Hard Requisite:
All feedback-related diagnostics available
Soft Requisite:
Jitter and drift are fulfilling SwissFEL tolerances
Diagnostics has nominal resolution
100 Hz operation
BS data aquisition

9. Linac I - Transmission Goal (Minimal Goal):
Transport of the beam to the Aramis beam dump
Acceleration with C-Band to 500 MeV
Hard Requisite:
S10CB01 operational
BPMs and screens available
All magnets operational except BC2 and septum magnet / Resonant kicker
Soft Requisite:
200 pC
Stability in jitter and drift: 5 times the SwissFEL tolerance values
Diagnostic resolution: 5 times the SwissFEL design values

10. Linac II – Optics (e.g. Collimator, Switchyard)
Goal:
Establish nominal beam transport
Commissioning energy collimator
Hard Requisite
Energy collimator operational
Soft Requisite
BAM in SARBD01
Stability in jitter and drift: 5 times the SwissFEL tolerance values
Diagnostic resolution: 5 times the SwissFEL design values

11. Linac III – Undulator Alignment
Goal:
Beam based alignment of QFF magnets
Beam based alignment of undulator modules
Evaluation of settings for entrance and exit correctors and earth magnetic coil
Hard Requisite:
All undulator modules operational
Soft Requisite:
1.7 GeV beam energy
200 pC
Stability in jitter and drift: 5 times the SwissFEL tolerance values
Diagnostic resolution: 5 times the SwissFEL design values

12. Linac IV – Bunch Compression
Goal:
Bunch compression with BC2
Emittance optimization with two-stage compression
Compression set-up
Hard Requisite:
BC2 operation
C-Band TDS operational
Soft Requisite:
Amplitude laser
200 pC
Full Linac 1 energy
Stability in jitter and drift: 2 times the SwissFEL tolerance values
Diagnostic resolution: 2 times the SwissFEL design values

13. Linac V – Stability and Reproducibility
Goal:
Demonstrate reproducible and stable operation of the linac and undulator line
Commissioning of the beam-based feedback system
Hard Requisite:
All feedback-related diagnostics available
Soft Requisite:
Jitter and drift are fulfilling SwissFEL tolerances
Diagnostic has nominal resolution
100 Hz operation
BS data aquisition

14. FEL I – FEL Gain Observation
Goal (Minimal Goal):
Demonstration of FEL signal on Screen
Hard Requirement:
Same as Linac III
Soft Requisite:
Linac IV concluded

15. FEL II – FEL Characterization
Goal:
Commissioning of photon diagnostics and optics in front-end and optical hutch
Photon beam alignment with spontaneous radiation
Measurement of FEL gain curve, photon energy, spectrum and pulse energy
Hard Requisite:
Front-end and optical hutch hardware operational
Beam energy 2.1 GeV
Soft Requisite:
Beam energy 3 GeV
Nominal two-stage bunch compression achieved
Amplitude laser
200 pC
Stability in jitter and drift: 2 times the SwissFEL tolerance values
Diagnostic resolution: 2 times the SwissFEL design values

16. FEL III – FEL Saturation and Optimization
Goal:
Achieving photonics milestone at 3 GeV (saturation, pulse energy, stability)
Hard Requisite:
Full instrumentation of front end and optical hutch
Beam energy 3 GeV
Soft Requisite:
Amplitude laser
200 pC
Nominal two-stage bunch compression achieved
Stability in jitter and drift: 2 times the SwissFEL tolerance values
Diagnostic resolution: 2 times the SwissFEL design values

17. FEL IV – Operation at 1 A, Stability, Rep Rate
Goal:
Demonstrate photonics milestone at 1 Angstrom
Commissioning of experimental stations
End of Commissioning for Aramis at 200 pC
Hard Requisite:
Full Instrumentation of SwissFEL
Machine jitter and drift within SwissFEL tolerances
Diagnostics resolution within specification.

18. Causal Dependence of Commissioning Steps
150 MeV
350 MeV
Injector I
(Gun)
Injector II
(Transport)
Injector III
(Emittance)
Injector IV
(BC1)
Injector V
(LH)
Injector VI
(Stability)
500 MeV
1.7 GeV
2.1 GeV
Linac I
(Transport)
Linac II
(Optics)
Linac III
(Alignment)
Linac IV
(BC2)
Linac V
(Stability)
2.1 GeV
FEL I
(Demonstr.)
Minimal Goal Milestones
Twice relaxed nominal stability
3.0 GeV
5.8 GeV
FEL II
(Charact.)
FEL III
(Optimiz.)
FEL IV
(Stability)
Nominal stability

19. Time Line (Ideal, Soft Requisites Fulfilled)
PIC plan slot for injector
PIC plan slot for injector, linac, undulator and front end
PIC plan slot for full machine, including end stations
Relaxed Stability (x2)
Much Relaxed Stability (x5)
Nominal Stability
2.1 BC2
4.7 GeV
150 MeV
350 MeV
540 MeV
2.7 GeV
5.8 GeV
2016
2017
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Inj I-III
Inj IV
Lin I+II
Inj V
Lin III
Fel I
Lin IV
Fel II+III
Inj VI
Lin V
Missing:
Fel IV: 28 weeks (15 weeks for 1st user station)
10 pC Mode
Large Bandwidth Mode
Switchyard and Athos
Two Bunch Operation
During User Operation
~1 week per month