XTCAV
X-Band Transverse Deflecting Cavity
Project Overview
Patrick Krejcik
Yuantao Ding, Joe Frisch
Layout of the Undulator to Dump Beam Line
Simulation example - Yuantao Ding
low charge 20pC soft x-rays
OTRDMP
FEL ON
FEL OFF
head
Current “measurement”
X-ray “measurement”
Penetration
Penetration
to B921
XTCAV Proposed Location
Conceptual sketch
of the x-band
structure and
waveguide on the
beam line.
Structure Fabrication
• One structure built and tested
• Second structure
Item
Fab 2nd deflector
structure
Shop labor
Direct
labor
$98,448
$16,800
M&S
Program
support
Indirects
Total
$10,000
$1,680
$61,743
$188,671
• Support stand, beam line and
vacuum installation
• ~$390k
1m
B921 and undulator tunnel elevation view showing
penetration for waveguide to the XTCAV
Excerpt from the floor plan of B921 with
proposed modulator and klystron locations
B921 floor space for modulator and klystron
Penetration
B921 cross-section showing available elevation
with respect to cable trays and ceiling
Commercially available Modulator
installation housing the SLAC XL4 klystron.
•
•
•
•
•
Much better pulse stability than SLAC modulator: 30 ppm versus 100 ppm
Complete system houses klystron, magnet, oil tank and output transformer
EPICS controls interface
“turn-key” system purchase price ~$650k
LCLS motivated to evaluate this modulator for other applications e.g. L1S
• Also purchased by LLNL, Trieste, CLS, CERN …
Output from the klystron goes through a mode
converter to circular waveguide for lower power loss
Fabrication and installation of
waveguide components:
including converters splitters,
couplers, loads and vacuum
components,
all based on existing SLAC Xband designs
~$365k
LLRF Phase reference
– Share the low-noise 476 MHz heliax from the linac
with the beam phase monitor
– Beam based feedback corrects slow drifts
476 MHz
XTCAV
Cavity
EPICS Controls
•
•
•
•
LLRF - (next slide)
Vacuum - status of new pumps, gauges and valves
Profile Monitor OTRDMP - present camera is only 10 Hz (upgrade?)
Feedback
– orbit at BPMUE1, BPMUE2 and BPMUE3 after the XTCAV to stabilize
the RF phase of cavity and keep the bunch at the zero phase crossing
• PPS
– Modulator interlocked to Access state
– Review to show existing BTMs give adequate coverage
• BCS
– New spoiler at end of XTCAV
– Review to show existing PICs give adequate coverage
• MPS
– Set threshold of MPS BLMs lower than BCS PICs
Why PPS, BCS and MPS are important
• Beam at the wrong phase can be kicked by up
to 10 mrad
– Lowest energy beam, highest amplitude RF, phase
at crest
• Beam leaves the beam pipe within the XTCAV
already
• Existing safety systems
have large acceptance
angle. e.g. BTMs
LLRF EPICS Controls
• Use LCLS PADs and PACs with EPICS IOC and BSA
• Use either MKSU II for klystron and modulator interlocks, or
Scandinova integrated controls
• In the linac CAMAC PDU still provides timing to the modulator
via the PIOP module
• Consider the LLRF control system as a whole:
– The XTCAV will be the first stand-alone RF station with EPICS-only controls
– There are choices of platforms on which to implement EPICS
•
•
•
Linac Phase I upgrade with EPICS driver for CAMAC
Replace CAMAC modules with VME modules and EPICS timing, similar to existing EPICS architecture.
Develop a new mTCA platform
– Need to be able to this in < 2 years
– The choice we make here will set a precedent for the LCLS-2 injector project
Cost Summary
System
Fabrication of second XTCAV structure
Mechanical and vacuum installation
Waveguide system
Klystron and focusing magnet
Modulator and klystron tank
Electrical AC Service
Cooling systems
LLRF Drive system
LLRF controls
PPS, BCS and MPS
Profile Monitor
Total
Including 25% Contingency
Including
Estimated Cost Indirects
$126,928
$188,671
$390,240
$365,200
$492,227
$745,000
$115,000
$128,000
$271,500
$352,000
$100,000
$20,000
$390,240
$564,900
$690,675
$855,000
$168,130
$157,564
$334,295
$505,027
$150,000
$30,000
$3,106,095
$4,034,502
$5,043,128