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)• LX contains a single X-band station 11-2 (L1X)• 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-060-102-113-00)

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, AM84-2.856S2-40-60 1kW Pulsed Amplifier

Details will be described in the LCLS-II ESD: LCLS-II Linac LLRF System Design Specification (SLAC-I-060-102-114-00, 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

Item M&S Cost ($K) Labor (hour)

L1 LLRF Systems (PAD, PAC, SSSB, Cabling and Components) 49.97 664

L1 LLRF Installation 128

BC1 LLRF Systems (PAD, PAC, SSSB, Cabling and Components) 30.81 888

BC1 LLRF Installation 160

• L1/BC1 LLRF: FDR by Aug. 2012

• L1 LLRF: Hardware ready for rack installation by Feb. 2016

• L1 LLRF: Rack installation finished by July 2016

• L1 LLRF: Production software release by Aug. 2016

• BC1 LLRF: Hardware ready for rack installation by Sept. 2014

• 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!