LCLS-II Linac LLRF Control System – L1, BC1 Zheqiao Geng Final Design Review May 7, 2012

LCLS-II L1 and BC1 L1 (11-1) and BC1 (11-2 and Beam Phase Cavity PH02) L1 contains a single S-band station 11-1 (L1S) L1 contains a single S-band station 11-1 (L1S) LX contains a single X-band station 11-2 (L1X) LX contains a single X-band station 11-2 (L1X) Beam Phase Cavity PH02 Beam Phase Cavity PH02

Outline Introduction Requirements Scope Architecture and Design Test Results at LCLS Installation and Cabling Cost and Schedule Lessons Learnt from LCLS Summary Slide 3

Introduction RF controls of L1S and L1X are physically part of the LLRF system installed in the RF HUT at Sector 10 The design completely follows the design of LCLS-II Injector LLRF System Slide 4

Physics Requirements Slide 5 LCLS-II Linac Requirements - PRD

Scope of L1/BC1 LLRF System Slide 6 Phase and amplitude control of L1S and L1X, including field stability control and phase and amplitude settings Measurement of Beam Phase Cavity 02 (PH02) installed after BC1 Control infrastructure (VME, EVR and so on) and EPICS software

Interface and Context Slide 7 LCLS-II Injector LLRF System: Provides reference, LO and clock to both L1S and L1X Station 11-1 (L1S): Controlled and measured by PAC, SSSB and PADs Station 11-2 (L1X): Controlled and measured by PAC, TWT amplifier and PADs Beam Phase Cavity PH02: Measured by PADs Timing System: Provides EVG fibers to LLRF BCS: Provides gate signals to SSSB of station 11-1 AC Power Supply System: Provides remotely controllable power switch to LLRF chassis Water Cooling System: Provides temperature stabilized cooling water to LLRF chassis Fast Feedback System: Provides phase and amplitude set points to L1S Physics Applications: Gets LLRF data and sets LLRF parameters Details will be described in the LCLS-II ESD: LCLS-II Linac LLRF System Requirements Specification (SLAC-I )

Architecture of L1S Control Slide 8 Green boxes and lines are for L1S control Reference, LO and Clock are provided by LCLS-II Injector LLRF System A PAC chassis is used to control the phase and amplitude of L1S Two PADs chassis are used to measure RF signals Critical cables are routed in the tunnel for temperature stabilities

Architecture of L1X and PH02 Control Slide 9 Green boxes and lines are for L1X and PH02 control Reference, LO and Clock are provided by LCLS-II Injector LLRF System An X-band PAC chassis is used to control the phase and amplitude of L1X Two X-band PADs chassis are used to measure RF signals Critical cables are routed in the tunnel for temperature stabilities

Components Design Slide 10 Design of S-band PAC, PAD and SSSB has been described in the PDR and FDR of LCLS-II Injector LLRF System – L1S needs 1 PAC chassis, 2 PAD chassis and 1 SSSB chassis Design of X-band PAC, PAD and TWT amplifier will follow the design for LCLS and FACET – L1X needs 1 PAC chassis, 2 PAD chassis and 1 TWT amplifier chassis Low Risk – X-band PAC and PAD will use the same digital boards used in S-band PAC and PAD. There was no failure reported from X-band PAC, PAD and TWT amplifier installed at LCLS Components Selection:  VME CPU: Motorola PowerPC mvme6100  PAC and PAD CPU: Arcturus uCdimm Coldfire 5282  OS: RTEMS  Control System: EPICS  EVR: Micro Research EVR230 and RTM  SSSB: Microwave Amplifiers Ltd, AM S kW Pulsed Amplifier Details will be described in the LCLS-II ESD: LCLS-II Linac LLRF System Design Specification (SLAC-I , in progress)

Test Results at LCLS Slide 11 Test results of LCLS L1S and L1X are applicable to LCLS-II due to the same design

Installation and Cabling Slide 12 Installation  L1S SSSB chassis will be installed in the existing rack of 11-1 in the klystron gallery  L1X TWT amplifier chassis will be installed in the existing rack of 11-2 in the klystron gallery  PACs and PADs of L1S and L1X (total 6 chassis) will be installed in the RF HUT at Sector 10. They will be arranged into four racks together with the chassis of LCLS-II Injector LLRF System  VME crate for centralized LLRF control will be installed in the RF HUT Cabling  1/2 inch superflex coax cable with N-type connectors will be used for RF signal picking up and delivery  Cables for critical signals (SSSB drive cable from PAC, ACC In/Out cables to PAD) will be directly connected to PAC and PAD chassis  Cables for diagnostic signals (klystron drive, klystron beam voltage and klystron out cables to PAD) will be connected to a patch panel on the top of the rack and then routed to the PAD chassis with thinner cables for easier cabling and better maintainability  Ethernet and timing cables will be taken care of by global control system  All cables will be clearly labeled with consistent format

Proposed Installation at RF HUT Slide 13

Cost and Schedule Slide 14 ItemM&S Cost ($K)Labor (hour) L1 LLRF Systems (PAD, PAC, SSSB, Cabling and Components) L1 LLRF Installation128 BC1 LLRF Systems (PAD, PAC, SSSB, Cabling and Components) BC1 LLRF Installation160 L1/BC1 LLRF: FDR by Aug L1 LLRF: Hardware ready for rack installation by Feb L1 LLRF: Rack installation finished by July 2016 L1 LLRF: Production software release by Aug BC1 LLRF: Hardware ready for rack installation by Sept BC1 LLRF: Rack installation finished by April 2015 BC1 LLRF: Production software release by April 2015

Lessons Learnt from LCLS Slide 15 L1S is the most critical station requiring high RF field stabilities. Klystron modulator should be upgraded and well tuned to achieve the stability Measurement of the RF reflection from accelerator structures will be helpful to understand the behavior of the system Intra-pulse feedback may be required to improve the field stability of L1S (not available with the PAD/PAC design)

Summary Slide 16 The L1/BC1 LLRF design presented in this talk is a copy of the working system of LCLS, so the risk is low

Thank you!