LCLS Linac Long Lead Procurements Peter McIntosh and Carl Rago Lehman Review August 10-12, 2004

Linac LLP Outline LINAC Long Lead Procurements BC1 and BC2 Dipole Magnets Requirements LLP X-Band RF System Challenges Budget and Resources Conclusions and Summary

LINAC Long Lead Procurements (LLP) BC1 and BC2 magnets  commercial build to specification X-band system  in-house build to print

Typical Chicane Layout collimator BPM quadrupole dipole screen BX1 dipole magnets (4) required for BC1 BX2 dipole magnets (4) required for BC2

Magnet Specifications ESD sample for individual chicane dipole

BX1 Preliminary SLAC Design Mechanical envelope for build to specification

Linac Magnet LLP LCLS LINAC bend magnet specifications (ESD 1.03-101) complete and under change control Design proposal with preliminary magnetic analysis complete ES&H safety covers - latest SLAC standard incorporated Costs and schedules are baselined: Basis of Estimate verified by Thomas Jefferson Laboratory (TJLab)

BX1 and BX2 Procurement Plan Primary procurement method: Commercial Build to specification  low technical risk Vendors identified Statement of work in process with SLAC purchasing Alternative procurement method: MOU Build to specification by TJLab Work plan consistent with TJLab process

X-Band RF System Layout Klystron Gallery Klystron Window Waveguide XL-4 Klystron Accelerating structure Beam Tunnel

The X-Band RF System A 60cm long (NLC type) X-band structure will be used to linearize the energy-time correlation (or gradient) across each bunch from L0 and L1 Operates on the negative RF crest to decelerate the beam, reducing the non-linear components of the correlation  more efficient compression in BC1 and BC2 Non-linear correlation components  CSR instabilities in the chicanes. Beam energy is reduced by 18 MeV, from 268 to 250 MeV X-band structure accelerating gradient is ~32 MeV/m Bunch length compressed from 830 to 190 m c.f. 400 m without the X-band station LCLS X-Band RF Requirements (PRD 1.03-009) complete and under change control

NLCTA Comparison with LCLS Requirements Parameter LCLSTarget Achieved NLCTA Units Structure Length 60 cm Structure Voltage 19 30 MV Phase -160 - deg Klystron Power 21 50 MW Repetition Rate 120 Hz Pulse length 0.1 1.6 ms LCLS requirements easily achieved using technology developed and achieved on NLCTA: LCLS klystron power ~60% less than NLCTA LCLS structure voltage ~40% less than NLCTA

X-Band RF System Challenges RF stability and reliability issues need to be addressed for LCLS No reason to believe the XL-4 klystron phase and amplitude sensitivity to modulator stability will be much greater than that of a SLAC S-band klystron LLRF development needed to ensure the X-Band system meets LCLS stability requirements NLCTA has not run at 120 Hz repetition rate: The reliability of the klystrons at 120 Hz needs to be evaluated Good reliability expected if tube is run at a lower average power of ~30 MW  LCLS requires 21 MW Spare klystron required to reduce downtime in case of failure and minimize any operational risk

X-Band RF System LLP X-band Klystron (WBS 1.03.06.05.01): In-house manufacture to existing design, identical to 13 units already built for NLCTA 2 klystrons required (including spare) @ 1 year/tube manufacture timeframe Modulator and Pulse Transformer (WBS 1.03.06.05.02): Modified SLAC S-band modulator with redesigned klystron tank RF Distribution (WBS 1.03.06.05.03): To be designed and manufactured in-house, have extensive experience manufacturing wide variety of NLCTA X-band components X-Band Structure (WBS 1.03.06.06): Existing NLCTA (FXB-003) device (no cost burden to LCLS), achieved 65 MV/m at 63 MW input power  LCLS requires 32 MV/m at 21 MW Support and removal structure to be designed and manufactured in-house LLRF System (WBS 1.03.06.04): Adopt LLRF system developed for NLCTA and integrate with existing S-band RF system controls In-house fabrication considered most effective method of procurement for X-band RF system components – justifications identified in APP Resources from various SLAC departments needed to complete X-band RF system to budget and schedule - included in the WBS

X-Band Budget and Resource Schedule $1.2 M required in FY05: procurement of klystron and waveguide systems design/development of LLRF system and various mechanical supports

Conclusions and Summary BC1 and BC2 dipole magnets: Minimal technical risk for BC1 and BC2 dipole magnets LLP option initiated on a build to spec from commercial vendor Alternative TJLab MOU option identified if needed Physics specifications complete Statement of work and APP under review for procurement X-Band RF System: Adopting the X-Band high power RF technology developed for NLC minimizes technical and budgetary risk for LCLS SLAC has extensive in-house manufacturing experience for X-band klystron and waveguide systems APP development in progress X-band klystron and RF distribution ready for procurement Oct 1st LLRF system design commences Oct 1st