Transcript Document 7920878

Progress with Linac and RF Systems
Jim Rose, RF group head
meeting for NSLS-II Project
May 10-11, 2011
8th ASAC
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Outline
•
Baseline
•
Progress since last ASAC meeting
•
Conclusions
• Scope, Cost, Schedule & Staffing
• Technical Progress
• Cost & Schedule Performance
• Risks & Lessons Learned
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NSLS-II RF Systems
Storage Ring: Two ~9m
RF straights each with
two 500 MHz SRF
cavities and one 1500
MHz passive bunch
lengthening cavity
Only one RF straight in
initial operations
3 GeV booster with
one 7-cell cavity
powered by 80 kW
IOT amplifier
RF building
housing two 300
kW klystron
amplifiers
Also houses 850 W
LHe refrigerator
200 MeV linac with
four 5.2 m TW
structures
powered by two 42
MW klystrons with
SS modulators and
third “hot spare”
Future expansion
for another 2 RF
systems
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Linac RF Systems
• 200 MeV S-band linac:
15 nC/pulse requires beam loading compensation using a
feedforward algorithm in the cavity field controller
• 500 MHz modulated gun with 500 MHz buncher, 3 GHz pre-buncher, 3 GHz TW buncher
and four 5.2m TW structures
• Two 42MW klystrons with Solid State Modulators using IGBT switches on multipleprimary, split-core pulse transformer
• Third “Hot Spare” klystron can be switched to either position
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Linac
Linac beam line component production well along:
•TW structure couplers complete
•TW braze stacks complete, waiting to solder
cooling channels- an improvement over previous
glued channels
•Sub-harmonic and Pre-buncher complete
•Solenoid coils complete, triplets(?)
•Linac front end delayed 3 months but overall
schedule ahead by 2 months
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Linac: Thales TH2100 klystron
TH2100B- 2.998 GHz
42 MW klystron 50 Hz
rep rate
First Linac klystron
completed at factory,
klystrons 2 and 3 to be
ready for FAT in JuneWill perform site visit to
Thales in Villezy to
witness tests
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Linac: Scandinova Modulators
Construction of all three modulators in progress, 1st unit ready for test mid
May. Modifications made in response to PSI workshop including wire lugs
replacing push-on connectors, improved mechanical design, fixed filament
current read back, klystron low impedance ground connection
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Storage Ring Transmitter- Klystrons
Two TH2161B-3 klystrons in production, FAT in
conjunction with Linac klystrons in June
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Storage Ring Transmitter: 540 kVA Cathode
supplies in production
3-phase delta-Y
HV transformers
PSM solid state switcher power supply includes improved output filtering, higher
and variable switching frequency as a result of NSLS-II LLRF tests at CLS
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Storage Ring Cavities
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Cavity redesigned for larger coupling: Qext = 65000
Original HFSS analysis repeated with Microwave
Studio (insert Murali slide next)
Niobium cavity redesigned for ASME pressure vessel
code: niobium thickness increased in fluted beam
tube, waveguide
Cavity MAWP increased from 1.49 to 1.55 bar to
accommodate pressure drop from cryomodule to He
compressor suction return line.
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Storage Ring Cavities
Contract award April 12th to AES for 2 turn-key
cavity cryomodule systems
•Meyer tool subcontracted to build cryomodule- built
6 prior for Cornell, CLS, TLS
•AES has excellent track record for ILC niobium
cavity production•Risk in cryomodule assembly in clean room: first
time for AES: Close proximity will allow frequent
review, placement of NSLS-II technician on site
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Storage Ring Helium Cryo-System
Cryogenic System contract award to LINDE
Turn key system to include:
•850 W Cold Box and 3500 L dewar
•250 kW Kaeser compressor with 2nd as redundant spare
•75 kW backup compressor- air cooled in the event of
power failure
•Medium pressure gaseous Helium storage
•Valve box
•All warm and cold piping
•Installation, commissioning and acceptance test on site
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RF Cryogenic System: Dedicated 850 W Helium refrigerator and LN2
+/- 2 mbar LHe
+/- 50 mbar LN2
For frequency stability
Dedicated LN2
distribution for RF
Cold box,
Compressor building
3000-l Dewar decoupled from
on RF building tunnel
mezzanine
SRF Cavities
in tunnel
Gaseous Helium
tank farm with
recovery
compressor
Valve boxes on
tunnel roof
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Successful Development of Cavity Controller
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Digital Field Controller
50 MHz IF
Tested at CLS on hardware
nearly identical to NSLS-II:
300 kW klystron and CESR-B
SRF cavity
Meets NSLS-II field spec. of
0.15 degree and 0.05%
H. Ma
CLS Analog
A=0.073%rms
φ=0.12° rms
NSLS-II
A=0.026%rms
φ=0.02°rms
CLS tests courtesy M. de Jong
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Preliminary tests of LLRF at CLS
CLS Analog
LLRF
feedback
Normal Ops
NSLS-II Digital
LLRF
feedback
Machine
Studies
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NSLS-II 3rd Harmonic Cavity
Coupled-two cell cavity allows 1 MV in compact cryomodule with external
tuner and small heat leaks however it requires care in controlling the 0
andπ-mode frequency separation to avoid exciting the 0-mode
0-mode
π-mode
Δ(0- π) fixed by coupling
Excitation
of π-mode
by RF 3rd
harmonic
0-mode not
excited
Parked
Two 2-cell cavities
3xRF –(n+1)Frev 3xRF –nFrev
3xRF
Tuning Fixture
Frev~380kHz
Cryomodule is complete and initial cold-test conducted verifying the frequency
tuning over a 1 MHz band while keeping 0 and π mode frequency separation
constant to within 10 %.
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Landau Cavity: cryomodule complete
First horizontal cold test complete completely validates
0-π mode tuning over 1 MHz bandwidth. Low Q loaded
(6e7 vs. 2e8) explained by trapped TE mode.
Need to design and fabricate
ferrite dampers, tuner mechanism
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Global Schedule
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Conclusion
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All major procurements awarded and vendor fab in progress
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Long lead items (SRF cavities, Cryosystem) fit within schedule
First systems delivery well ahead of required dates
• SR transmitter in August
• Linac in September
• BR transmitter in October
Early success with 3rd Harmonic SRF cavity
System performance demonstrated at Canadian Light Source
with NSLS-II digital cavity controller, nearly identical
transmitter-cavity system
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Acknowledgements
This work was performed by and under the guidance of
Alexei Blednykh, John Cupolo, Ray Fliller, Bill Gash, Feng Gao,
B. Holub,Y. Kawashima, Hengjie Ma, Andy Marone, Bob
Meier, Payman Mortazavi, George Mulholland, Jorge Oliva,
Satoshi Ozaki, Ed Quimby, Jim Rose, Timur Shaftan, Bob
Sikora, Nathan Towne, Ernst Weihereter, Ferdinand Willeke
and Takeshi Yanagisawa as well as the support of the entire
NSLS-II team.
We would also like to thank the SCRF groups at Cornell, KEK,
CLS, TPS and DLS for their continuing help and
encouragement, in particular Hasan Padamsee, Sergie
Belomestnykh, Valery Shemelin, Takaaki Furuya, Mark de
Jong, Chaoen Wang and Morten Jensen
We would like to acknowledge the excellent work by Niowave Inc.
in the fabrication of the 3 HC under the DOE SBIR
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