1. Ron Akre, Dayle Kotturi LCLS LLRF FACakre@slac.stanford.eduakre@slac.stanford.edu, dayle@slac.stanford.edudayle@slac.stanford.edu April 16, 2007 Linac Coherent Light Source (LCLS) Low Level RF System New RF System Commissioning Experience April 16, 2007

2. Ron Akre, Dayle Kotturi LCLS LLRF FACakre@slac.stanford.eduakre@slac.stanford.edu, dayle@slac.stanford.edudayle@slac.stanford.edu April 16, 2007 Safety Hazards in the LLRF system RF 1kW at 120Hz at 5uS = 0.6 Watts average, 2 Watt average amps at 2856MHz, 60W average amps at 476MHz Hazards – RF Burns Mitigation – Avoid contact with center conductor of energized connectors. All employees working with LLRF systems are required to have the proper training. 110VAC Connector Hazards - Shock Mitigation - Don’t touch conductors when plugging into outlet. All chassis are inspected by UL trained inspector (EEIP).

3. Ron Akre, Dayle Kotturi LCLS LLRF FACakre@slac.stanford.eduakre@slac.stanford.edu, dayle@slac.stanford.edudayle@slac.stanford.edu April 16, 2007 LCLS Layout P. Emma

4. Ron Akre, Dayle Kotturi LCLS LLRF FACakre@slac.stanford.eduakre@slac.stanford.edu, dayle@slac.stanford.edudayle@slac.stanford.edu April 16, 2007 Scope of Work for Injector Turn-on 1 Linac Sector 0 RF Upgrade All 3 RF Chassis completed and Installed Control Module (IQPAU) needs modifications Sector 20 RF distribution system - Phase and Amplitude Controllers (PAC) - Operational Phase and Amplitude Detectors (PAD) - Operational Phased Locked Oscillator – Use SPPS unit for Turn On LO Generator - Operational Multiplier – 476MHz to 2856MHz - Operational 4 distribution chassis - Operational Laser Phase Measurement – Needs some signal processing X-Band Reference – Chassis built, require testing and installation LLRF Control and Monitor System 1 kW Solid State S-Band Amplifiers – 5 units PADs – 6 Klystron units in Fabrication PADs – Gun, L0A, L0B, L1S – Operational : Tcav, L1X in test PACs – Gun, L0A, L0B, L1S –Operational : TCav, L1X in test Beam Phase Cavity PAD in test Pill box cavity with 2 probes and 4 tuners – Complete

5. Ron Akre, Dayle Kotturi LCLS LLRF FACakre@slac.stanford.eduakre@slac.stanford.edu, dayle@slac.stanford.edudayle@slac.stanford.edu April 16, 2007 Scope of Work for Injector Turn-on 2 LLRF VME control system Local feedback loops on RF phase and amplitude RF Gun Cell loop tested in lab at 360 Hz and in operation at 10 Hz L1-S loop tested in lab at 360 Hz and in operation at 30 Hz L0-A and L0-B loops tested in lab at 100 Hz Gun Tune temperature loop testing in progress Event system and timing triggers configured for accelerate and standby External interfaces Beam-synchronous acquisition LEM, SCP Correlation plots Channel Archiver – active for all installed channels Alarm Handler – initial layout done by J. Rock. Alarm limits TBD Global beam-based longitudinal feedback on L0-B and L1-S - untested

6. Ron Akre, Dayle Kotturi LCLS LLRF FACakre@slac.stanford.eduakre@slac.stanford.edu, dayle@slac.stanford.edudayle@slac.stanford.edu April 16, 2007 SLAC Linac RF – New Control The new control system will tie in to the IPA Chassis with 1kW of drive power available. Reference will be from the existing phase reference line or the injector new RF reference I and Q will be controlled with a 16bit DAC running at 102MHz. Waveforms to the DAC will be set in an FPGA through a microcontroller running EPICS on RTEMS. Existing System

7. Ron Akre, Dayle Kotturi LCLS LLRF FACakre@slac.stanford.eduakre@slac.stanford.edu, dayle@slac.stanford.edudayle@slac.stanford.edu April 16, 2007 Processing RF Stations Gun – About 1 Week to Full PowerL0A – About 2 Weeks to Full Power Most stations were and still are gassy by the klystron.

8. Ron Akre, Dayle Kotturi LCLS LLRF FACakre@slac.stanford.eduakre@slac.stanford.edu, dayle@slac.stanford.edudayle@slac.stanford.edu April 16, 2007 Processing RF Stations L0B – About 2 weeks to Full PowerL1S – Easy 1 Week to Full Power

9. Ron Akre, Dayle Kotturi LCLS LLRF FACakre@slac.stanford.eduakre@slac.stanford.edu, dayle@slac.stanford.edudayle@slac.stanford.edu April 16, 2007 Gun High Power RF Pulse Shaped by PAC L0A and L0B look similar Amplitude Waveform flat to +-2% Phase Waveform flat to +-2 Degrees Pulse width of 1.2uS and >600nS of waveguide eliminates klystron power change due to reflected power and need for circulator.

10. Ron Akre, Dayle Kotturi LCLS LLRF FACakre@slac.stanford.eduakre@slac.stanford.edu, dayle@slac.stanford.edudayle@slac.stanford.edu April 16, 2007 L1S High Power RF SLED Pulse Shaped by PAC SLED Amplitude WaveformPhase Waveform flat to +-2 Degrees Over fill time of structure

11. Ron Akre, Dayle Kotturi LCLS LLRF FACakre@slac.stanford.eduakre@slac.stanford.edu, dayle@slac.stanford.edudayle@slac.stanford.edu April 16, 2007 Operational Units S-Band Reference System Laser SPAC Gun PAC L0-A PAC L0-B PAC L1-S PAC

12. Ron Akre, Dayle Kotturi LCLS LLRF FACakre@slac.stanford.eduakre@slac.stanford.edu, dayle@slac.stanford.edudayle@slac.stanford.edu April 16, 2007 PADs – Ready for Commissioning

13. Ron Akre, Dayle Kotturi LCLS LLRF FACakre@slac.stanford.eduakre@slac.stanford.edu, dayle@slac.stanford.edudayle@slac.stanford.edu April 16, 2007 Injector/L1 Units Remaining to Commission TCav PAC Gun (done 4/12/07), L0-A, L0-B, L1-S, TCav PADs Klystron PADs Sector 0 IQPAU X-Band System VME based Feedbacks (Gun Cell Done) Diagnostic data analysis

14. Ron Akre, Dayle Kotturi LCLS LLRF FACakre@slac.stanford.eduakre@slac.stanford.edu, dayle@slac.stanford.edudayle@slac.stanford.edu April 16, 2007 To Follow PAC software – more analysis in FPGA PAD software – evaluate speed Second network – to send waveforms out while running Switch to final network configuration putting embedded IOCs on private network Switch access to waveforms to use CA gateway VME – quantify CPU usage as each station is added