eric bong lcls fac injector-linac [email protected] april 7, 2005 lcls injector/linac...
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Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
LCLS Injector/Linac Systems LCLS Injector/Linac Systems UpdateUpdateE. BongE. Bong
LCLS FACLCLS FACApril 7, 2005April 7, 2005
LCLSLCLS
Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
LCLS Injector/Linac Systems Update
Plan Changes Since Last FAC
FY05 Schedule & LLP Activity
Shutdown Strategy
Design & Fabrication Status
Response to Last FAC Comments
Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
Nominal Nominal LCLSLCLS Linac Parameters for 1.5- Linac Parameters for 1.5-Å FELÅ FEL
Single bunch, 1-nC charge, 1.2-Single bunch, 1-nC charge, 1.2-m m sliceslice emittance, 120-Hz repetition rate… emittance, 120-Hz repetition rate…
(RF phase: (RF phase: rfrf = 0 is at accelerating crest)= 0 is at accelerating crest)
SLAC linac tunnelSLAC linac tunnel research yardresearch yard
Linac-1Linac-1L L 9 m9 m
rf rf 25°25°
Linac-2Linac-2L L 330 m330 mrf rf 41°41°
Linac-3Linac-3L L 550 m550 mrf rf 10°10°
BC-1BC-1L L 6 m6 m
RR5656 39 mm39 mm
BC-2BC-2L L 22 m22 m
RR5656 25 mm25 mm LTULTUL L =275 m=275 mRR56 56 0 0
DL-1DL-1L L 12 m12 mRR56 56 0 0
undulatorundulatorL L =130 m=130 m
135 MeV135 MeVz z 0.83 mm 0.83 mm 0.10 %0.10 %
250 MeV250 MeVz z 0.19 mm 0.19 mm 1.6 %1.6 %
4.54 GeV4.54 GeVz z 0.022 mm 0.022 mm 0.71 %0.71 %
14.1 GeV14.1 GeVz z 0.022 mm 0.022 mm 0.01 %0.01 %
SLAC linacSLAC linac 21-1b21-1b21-1d21-1d XX
Linac-Linac-XXL L =0.6 m=0.6 mrfrf= =
21-3b21-3b24-6d24-6d
25-1a25-1a30-8c30-8c
E-DumpE-Dump
Linac-0Linac-0L L =6 m=6 m
6 MeV6 MeVz z 0.83 mm 0.83 mm 0.05 %0.05 %
newnew
rfrfgungun
Drive Laser not shown Thanks Paul Emma
Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
System Changes Since Last FAC
Continuing resolution delayed project fundingOctober electrical accident halted accelerator operationsReview of SLAC Safety Management PlanHalt of program prompts revision of FY05 run and down schedulesFY05 down moved to October ’06, shortened to one monthInjector and Linac System Management CombinedInjector and Linac Systems engineering and design staff combined eliminating duplication of effortInjector WBS converted from geographical to product based. Manpower loaded schedule revised to condense structure into products rather than individual components. Schedule changed to better track cost performance.
Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
Plan Changes Since Last FAC
Design, fabrication and installation schedule updated to reflect change in Linac down dates.RF Gun design and fabrication moved in-house to mitigate schedule and technical risk.Added LLNL and ANL collaborations on drive laser temporal, spatial and THG studies.Added UCLA collaboration to develop single shot bunch length measurement device.Formed agreement with Klystron department for RF component design support including gun design.Utilizing ILC personnel for dual-feed structure design.
Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
FY05 Schedule & LLP Activity
The change in ‘05 down time reduced the scope of the planned installation in the Injector and changed the design emphasis from the Linac to the Injector side of the shielding wall.LLP consists of fabrication activities in the Injector which can be started in FY05, the X-Band system components and BC1 & BC2 dipoles$2M bulk vacuum purchase agreement – June 05The portion of the Injector system in the Linac Housing can not be fabricated in FY05.The Linac L1 segment design is complete and could be installed during the October 2005 down.
Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
Injector-Linac Installation Strategy
PORCU
PINE CATHODE
HOLDE
R
UHV A
LL METAL
GATE VALVES
SPOOLS FRO
M VALVE
SEAL
LONG B
ELLOWS
ASSEM
BLY
TREATMEN
T CHAM
BER
VACUU
M PUMPS
Laser System June 2006
Gun Region April 2006
Accel Region March 2006
Heater Region January 2006
Wall Region October 2005
Injection Region August 2006
Spect Region August 2006
Waveguide through wall and up penetration October 2005
Installation schedule sets design and fabrications deadlines
Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
Injector-Linac Installation Strategy
Quad + BPM, YCOR,XCOR,
QE, Toroid
Treaty Point LCLS Injector/LCLS Linac
LCLS Injector LCLS Linac
Emittance Diagnostics.
Bunch Compressor &
Diagnostics
Two short accelerator structures, refurbished
Quads+BPMs,X&YCOR
X-Band Structure
(NLC)
Linac 1 (L1)
Electrons
Bunch Compressor 1 (BC1)
L1 Fabrication could be complete for October 2005 Installation
X-Band Fabrication started – Installation FY06 Down
BC1 Articulation ready for fabrication now
BC1 installation FY06 Down
Remainder of Linac installation FY07
Remove 5 S-Band Structures
Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
Drive Laser Progress
Proposals received from vendors, evaluation in process.Pulse shaping and THG most difficult issues. As a result of BNL/DUVFEL pulse shaping studies, further collaboration set up with LLNL and ANL to study temporal, spatial and THG. Require studies to mitigate technical risk.Laser transport penetration tube design complete, earthquake safety approved, ready for fabrication. Integration and alignment of laser launch, RF gun and solenoid being investigated.3-D ellipsoidal distribution studies – C. LImborg
Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
Injector RF Design Progress RF Gun
Solenoid design complete. Relative alignment details under study.RF design altered due to review recommendations
Increased Mode separationZ-Coupling from Theta-CouplingRF design complete mechanical design started (in –house)Monolithic dual feed
Unresolved issues:Final design for bulk cooling systemLoad lock deferred
L0 Accelerator structuresDual feed RF design pieced-together for solenoid assemblyBoth L0A and L0B dual feed on inputMechanical design in process
Removed T-Cav from Li-11Injector waveguide routing through wall in design
Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
Linac RF Design Progress
X-Band SystemX-Band System layout reviewed.Waveguide components maximizing use of available components and designs.ILC cold decision X-Band system components available from NLC
Two partially completed XL4 Klystrons – fabrication resumedAvailable waveguide components selected and requestedX-Band structures selected
L1 Short accelerating structuresStructures available from spares, under evaluation for use.L1 design complete, drawings available. Can be installed 10-05
Support agreement made with Klystron Department for Injector and Linac RF work
Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
1 nC1 nC2.8 kA2.8 kA
0.2 nC0.2 nC2.0 kA2.0 kA
• Need 20% smaller emittance (0.8 Need 20% smaller emittance (0.8 m), but with m), but with 1/5 charge & 1/3 gun current (30 A)1/5 charge & 1/3 gun current (30 A)
• No more transverse wakes in linacNo more transverse wakes in linac• Almost no CSR in BC’sAlmost no CSR in BC’s• 2-times less peak-current jitter2-times less peak-current jitter• No undulator wakesNo undulator wakes• 3-times shorter X-ray pulse3-times shorter X-ray pulse• 1-nC still OK, but only ~twice the photons, and a 1-nC still OK, but only ~twice the photons, and a
muchmuch more challenging machine more challenging machine
no resistive wakeno resistive wake
Low Charge OperationsLow Charge Operations
1.11.110101212 photons photons
W. Fawley, W. Fawley, LBNLLBNL
no spikesno spikes
Z. Huang
Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
Response to October 2004 FAC 1 -Do gun tests as early as possible, at vendor maybe
Gun will be designed and built in-house to use strength of SLAC RF design and to control technical risk. RF tests will proceed along with fabrication process including cold tests during cold fit-up through to 120 Hz hot-tests of final assembly.
-Consider creation of a gun test facility
Over the past eight years the GTF has revealed several problems with the prototype gun including correlated energy spread, tilt (transverse position to time correlation) on the beam and asymmetric beam at the gun exit to name just a few. These issues have been addressed in the LCLS design by increasing the 0 and pi mode separation, adding a dual feed coupler with racetrack geometry to both the gun and linac sections and adding a dipole and quadrupole corrector in the solenoid. In addition several diagnostic techniques for determining the beam correlations have been developed over the years that will be used in the LCLS injector to improve the overall beam quality.
A new gun test facility will be proposed. However, the facility is beyond the financial scope of the LCLS project. It is suggested that future SLAC funds be allocated to a new gun test facility which could have more benefit to SLAC than LCLS gun testing alone.
Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
Response to October 2004 FAC 2 -Order 2 guns
Parts for two guns will be machined. Tests performed on the first set of parts will be used to dimensionally adjust the second set. The second set will be fully assembled. Hot tests on the second set will be used to dimensionally adjust the first set for final assembly.
-Recommend continued testing of laser pulse shaping at DUVFEL
Additional pulse shaping, third-harmonic-generation and launch optics testing will be conducted in collaboration LLNL and ANL.
-Consider doing electron beam tests at DUVFEL
Electron beam bunch length measurement tests will be performed at SPPS in collaboration with UCLA. Additional beamline component and controls tests are also planned in SPPS.
Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
Response to October 2004 FAC 3 -Consider collaboration with LLNL on gun laser development
We are collaborating with LLNL on drive laser development. -Recommend a hot spare laser
A hot spare laser is not in the project baseline. However, it is planned to use contingency money, if available, will be used to purchase a second drive laser in FY08. The second laser may be a new design.
-Recommend the formation of a laser group
An LCLS laser group will be formed. A requisition is in place for a laser group leader. -Consider doing tests of "lock-in" detection of low gain at DUVFEL -Consider x-band waveform modulation as the input modulation for lock-in detection
Lock-in low gain FEL signal detection using X-Band waveform modulation was not investigated. The XTOD System investigated other low gain detection schemes.
Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
Response to October 2004 FAC 4 -Show analysis and simulations of collimator performance at the
next review, including shower computations
Collimator simulations will be presented at the FAC. The simulations include dark current from the gun and various RF structures, linac and LTU collimation, and undulator protection. Shower calculations will be done soon, but may not be ready for the April 2005 FAC.
-Continue work on ESASE
ESASE work continues. LBNL is taking the lead on this study.
-Recommend x-y scanners for wire monitor, rather than diagonal
Performing modal analysis on existing design to determine if there is any real benefit to tripling the number of wire scanners in the project budget.
Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
Response to October 2004 FAC 5 -Consider the design of a feedback loop that adjusts the laser based on electron beam measurements
Signal sources for laser feedback have been defined including bunch charge and bunch timing signals.
-Consider options for the ULTIMATE LCLS Master Oscillator
A reliable oscillator of proven technology will be installed for LCLS. Development work for the ULTIMATE master oscillator may be done in the future as an upgrade.
-Continue tests of THz measurement techniques at SPPS
THz bunch length measurements in SPPS will continue once the SLAC Linac resumes operations.
Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
Response to October 2004 FAC 6 -Consider schemes to modulate X-band phase for optimal set-up -Place appropriate emphasis on challenging phase/amplitude control of X-band system
Absolute phase and amplitude control of the X-Band system is not as demanding as was understood. The shot-to-shot (fast) jitter tolerances are fairly tight (0.5 deg-X and 0.25% amplitude, rms). This does not mean that the absolute X-band phase and amplitude need to be held at their design values to this level. The bunch length and energy feedback, described by Juhao Wu, will also compensate for X-band phase and amplitude changes of up to 10 degrees and 5%, as long as these variations occur slowly compared with 120 Hz. The compensation is implemented by Linac-1 S-band phase and amplitude corrections, but the net effect is to maintain a constant post-BC1 bunch length and beam energy. A “dither” feedback, suggested by the FAC, is therefore not as effective since it takes many pulses to dither the system, and variations on this time scale will already be compensated by the bunch length and energy feedback system. Perhaps a dither feedback can be implemented for very slow time scales of more than one minute, but the absolute regulation demands will then be quite loose (e.g., 2 degrees and 2%).
Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
Response to October 2004 FAC 7 -Consider schemes to modulate X-band phase for optimal set-up -Place appropriate emphasis on challenging phase/amplitude control of X-band system
Absolute phase and amplitude control of the X-Band system is not as demanding as was understood. The shot-to-shot (fast) jitter tolerances are fairly tight (0.5 deg-X and 0.25% amplitude, rms). This does not mean that the absolute X-band phase and amplitude need to be held at their design values to this level. The bunch length and energy feedback, described by Juhao Wu, will also compensate for X-band phase and amplitude changes of up to 10 degrees and 5%, as long as these variations occur slowly compared with 120 Hz. The compensation is implemented by Linac-1 S-band phase and amplitude corrections, but the net effect is to maintain a constant post-BC1 bunch length and beam energy. A “dither” feedback, suggested by the FAC, is therefore not as effective since it takes many pulses to dither the system, and variations on this time scale will already be compensated by the bunch length and energy feedback system. Perhaps a dither feedback can be implemented for very slow time scales of more than one minute, but the absolute regulation demands will then be quite loose (e.g., 2 degrees and 2%).
Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
Response to October 2004 FAC 8
-By 1/2005, force a decision on undulator design changes for AC wake field-
Resistive wall wakefield studies were performed (SLAC/ANL.) A low charge machine configuration now looks like a very attractive operating point where resistive-wall wakefields are not a problem. In addition, a semi-elliptical undulator vacuum chamber with aluminum coating reduces the wakes to an acceptable level even at the 1-nC charge level. No other large changes to the undulator design have been necessary to further mitigate the wakes.
Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
Injector/Linac SummaryProgress Made On
Laser Purchase, Laser Study CollaborationsRF Gun & Structure DesignX-Band System Design & Klystron FabricationCollimator StudiesMechanical Design – Area Integration, ComponentsMagnet and Vacuum Procurement
Injector and Linac Design Staff IntegratedBCR to Modify Injector Manpower Loaded Schedule Incorporating Linac Down Schedule Changes, Better Cost-Performance TrackingAdded staff for magnet procurement and diagnostics design
Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
End
Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
LCLS Injector/Linac Organizational Chart
RF engineering, design and fabrication matrixed from Klystron Department
ILC engineering & design matrixed for dual feed structure design
Mechanical Design matrixed from SLAC Mechanical Design Department
Injector/Linac SystemsEric Bong: ManagerCarl Rago: Deputy
Leif ErikssonL1, L2, L3 BC1,
BC2 Integration, Vacuum
Tim MontagneLTU & E-Dump
Integration, Diagnostics
LCLS Injector/Linac Mechanical Engineering
Carl RagoMech. Data, RF
Distribution Magnets
Bob Dalesio LCLS Controls
Joe Stieber
Paul StephansJoe Franklin
Nick Braughton
Bill BrooksJim Stanfield
Ng Wing
SLAC Mechanical Design
Stanford ME Grad. RAAshish Mitra
Venkat Srinivasan
Dave SchultzRF Systems
Klystron Department
Klystron Department EngineersDesigners
Fabrication
Injector/Linac Systems Physicists
Paul Emma: LinacC. Limborg: Injector
Sasha GilevichInjector Laser
Alan Miahnahri
Richard F. BoyceInjector
Integration
Mike Palrang
Peter McIntoshLinac RF
Alan HillInjector RF
RF Gun
Richard M. BoyceLCLS Installation
Manager
LCLS Physics SupportDave Dowell
John SchmergePaul Bolton
Zhirong HuangJuhao Wu
Recent additions:
J Langton, Roger Carr
Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
Injector Launch Feedback Model
Ron Akre, D. Kotturi
Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
Injector L0 Feedback Model
Ron Akre, D. Kotturi
Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
feedback offfeedback offfeedback offfeedback off feedback on (Integral gain:0.5)feedback on (Integral gain:0.5)feedback on (Integral gain:0.5)feedback on (Integral gain:0.5)
% 09.0/
%; 0007.0/
std
EE
EE % 09.0/
%; 0007.0/
std
EE
EE
%5.8/
%;10.0/
std
II
II %5.8/
%;10.0/
std
II
II
ps
ps
std 15.0
;003.0
t
t ps
ps
std 15.0
;003.0
t
t
Juhao Wu (SLAC)Juhao Wu (SLAC)
LCLS Longitudinal Feedback SimulationDetails in Breakout J. Wu
LCLS Longitudinal Feedback SimulationDetails in Breakout J. Wu
Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
Injector Wall Region Design
Beamline segment piercing Injector vault shielding wall.
Includes valves, quadrupoles, OTRs, wire scanners, BPMs, pumps, gages, support stands, vacuum chambers.
Beamline layout assembled into wall assembly model.
Design effort broken into diagnostics, magnets, vacuum and integration.
Quadrupole order April 1, 2005
OTR body ready for vendor bid.
Wire scanner in design evaluation.
Installation scheduled October 2005
Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
Injector Heater Region Design
Beamline segment Between Accelerators and Shielding Wall
Includes laser heater, transverse structure, dipoles, quads, correctors otrs.
Installation scheduled January 2006
Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
Injector Waveguide Design
Waveguide network feeds gun, Structures L0a & L0b, and T-Cav
Gun and structures fed from Li-20-6, 7 & 8 klystrons, T-Cav fed from Li-20-5d structure exhaust.
3-D Layout integrated into Injector system assembly
Design effort broken into penetration-wall runs, Gallery and Vault runs.
Installation penetration-wall October ’05
Installation Vault & Gallery Spring ’06
Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
L1 Region DesignBeamline segment in Sector 21 Between Injector insertion and X-Band structure.
Includes two shortened accelerator structures, quads, correctors and Bethe hole couplers.
3-D Layout integrated into Linac Girder model.
Design complete. Drawings complete except couplers.
Fabrication could begin April 2005
Installation-early October ‘05
Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
BC1 Region DesignBeamline segment in Sector 21 From X-Band system, through compressor to emittance diagnostics section.
Includes articulated compressor, inter-bend diagnostics, emittance wire scanners, OTRs, quadrupoles and vacuum components.
3-D Layout integrated into Linac Girder model.
Design effort broken into chicane articulation, diagnostics, magnets, vacuum and integration.
Fabrication and testing of articulation could begin April 2005
Installation – August 2006
Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
X-Band System Design
XL4 Klystron in fabSelected NLC waveguide components designed for 8-Pack
60cm structure from FermiX-Band Layout Integrated into beamline layout
Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
Linac L2, BC2, L3 Mechanical Design
System schematics complete
3-D models of area backgrounds complete
File management structure for 3-D models complete
L2 and L3 modification ready to begin
BC2 design scheduled for FY06
Eric BongLCLS FAC Injector-Linac Update [email protected] 7, 2005
Main Dump and Safety Dump
Main dump electromagnets allow energy and energy spread measurementsSafety dump permanent magnets deflect e-beam on BYD failureRay traces show no beam transported through wall in any failure conditionWorking with SLAC Radiation Safety for approval of design