g.mcmonagle, 8 th july 2011 clic project meeting x band stand alone power source at cern stand alone...
TRANSCRIPT
G.McMonagle, 8th July 2011
CLIC Project Meeting
X Band Stand Alone Power Source at CERN
•Stand Alone Power Source (SAPS) •The story so far ....................
•Future requirements for SAPS at CERN•CPI order•Modulator requirements•Where to install at CERN
•Conclusions
G.McMonagle, 8th July 2011
CLIC Project Meeting
Stand Alone Power Source
• Beginning of 2008 CERN decided that to complement the testing being done at KEK and SLAC a high power X band power source is necessary for testing structures on site at 12GHz
• Market survey showed that there was no source available from industry at that time
• Initial contact with SLAC klystron department for a collaboration to develop a 12Ghz klystron based on the existing 11.4 GHz tube was positive
• Wheels in motion for a collaboration between CERN and SLAC with financial contribution from CERN.
• Memorandum of collaboration was finally signed 1 year later. During this time PSI and Sincretrone Trieste joined in the collaboration. The MoU was signed under a “best efforts” agreement
• In total 5 klystrons were ordered, one for CERN
G.McMonagle, 8th July 2011
CLIC Project Meeting
CEA SACLAY (Modulator and RFcomponents)
CERN
SAPS to be installed and run at CERN in the CTF3 facility
SLACKlystron XL5 Based on XL4Best efforts agreement
Special French Contribution
Financed by CLIC Project
PSI Trieste
G.McMonagle, 8th July 2011
CLIC Project Meeting
SAPS Installation and Requirements
Klystron
50 MW1500 ns 50 Hz
test slot
200 MW, 0 ... 100 nsor100 MW, 0 ... 350 ns
phasemodulation
hybrid
Modulator
pulse compression
CTF2
KlystronGallery
G.McMonagle, 8th July 2011
CLIC Project Meeting
F-Cup+Isolator
Stand alone Test Stand in CTFII
Concrete block
girdergirder girdergirder girdergirder
ACC
pump
Pump Tee
load
coupler
Circular WG
Mode converter
WG valve
0.5 m
0.5 m
Courtesy: S. Doebert
G.McMonagle, 8th July 2011
CLIC Project Meeting
XL5 X Band Klystron specParameters Specifications units
RF Frequency 11.9942 GHz
Peak RF power 50 MW
RF gain dB
Efficiency %
RF pulse length 1.5 µs
Pulse repetition rate 50 (100) Hz
Duty cycle %
Klystron voltage 410-470 kV
Klystron current A
Inverse klystron voltage 100 max kV
Heater voltage 20 max V
Heater current 30 max A
Heater start up surge current ?max A
Preheating period 60 min
G.McMonagle, 8th July 2011
CLIC Project Meeting
Modulator
• Exceptional financial contribution to CERN from France• modulator and some RF components
came via CEA Saclay collaboration • Modulator specification based on SLAC
parameters, and limited space available in the klystron gallery
• Call for tender launched • Four offers• 2 were of similar priced 1 line type modulator
and 1 solid state• Contract was awarded to Scandinova, mainly
based on footprint of modulator, delivery schedule and our interest in using new technology
G.McMonagle, 8th July 2011
CLIC Project Meeting
CLIC WS 10/2009 KM Schirm BE-RF 8
1
High Voltage Modulator
Specification :
High Voltage : 450 kV
Current : 335 A
Flat pulse length: 1.5 µs
Pulse length at 50%: 2.3 µs
Repetition rate: 50 Hz
HV ripple: ďż˝ 0.25 %
Pulse to pulse stability: ďż˝ 0.1 %
(1.8 x 3 x 2 m3)
HVPSPULSE
TRANSFORMERSOLID STATE
SWITCHKLYSTRON
L1L2
L3
1000VDC 1000V 450kV
Development of a new solid state modulator by
SCANDINOVA
Klystron XL5
Magnet
Solid State Switch modules
Magnet and Ion pump power supplies
Water cooling circuit
Oil tank with pulse transfomer
Tuning circuitOil pump and filter
K2-SYSTEM PULSES, 265kV / 262A
K2-SYSTEM PULSE FLATNESS <0.4%
K2-SYSTEM PULSE-PULSE STABILITY <0.04%
G.McMonagle, 8th July 2011
CLIC Project Meeting
External Water Cooling System
Filament DCPS 0-30A
Core Bias DCPS
HVPS#1 - N
Control System Unit
Power Distribution Unit
L1L2L3
GND
Water Cooling Distribution
SW#3
SW#1
SW#2
SW#n
RF-Source
RF-Amplifier
Solenoid PS #1-3
Ion Pump PS 5X
Modulator >45 L/min
Collector >120 L/min
Body>10 L/min
Solenoid >10 L/min
TrigIpulse
Upulse
Remote RS232
12GHz
400VAC50Hz
Safety Interface
3-phase 480VAC
1-phase 120VAC
Local RS232
K2 Solid State ModulatorPulse
Transformer Oil Tank
RF 3GHz
3x185A
CT
CVD
Water Flow Interlocks
Vacuum Interlock
Current Interlock
Waveguide pressure Int., Arc Int, VSWR Int.
L1N
GND230VAC5
0Hz
MODULATOR AND RF SYSTEM, OVERVIEW
G.McMonagle, 8th July 2011
CLIC Project Meeting
Modulator delivered to CERN(only tested in dummy load waiting for klystron)
G.McMonagle, 8th July 2011
CLIC Project Meeting
XL5 performance at SLAC
“This is a 50MW Klystron not 60MW!”Daryl Sphren , SLAC
Voltage, Current and rf waveforms at 57MW 1.25us
G.McMonagle, 8th July 2011
CLIC Project Meeting
Klystron Delivered to CERN
G.McMonagle, 8th July 2011
CLIC Project Meeting
Klystron installation in modulator
Oil was removed fromtank after dummy load testssome very small metal pieceswere noticed at the bottom ofThe tank. This worried our SLAC colleaguse
G.McMonagle, 8th July 2011
CLIC Project Meeting
Pause to resolve some issues
• Modulator oil tank was not airtight and we were not convinced the whole gun was covered with oil.
• Modification to tank to allow the transformer side to be higher than klystron by inserting a shim plate
• Klystron removed for this operation
G.McMonagle, 8th July 2011
CLIC Project Meeting
First signs of trouble
• When klystron was reinstalled we turned Ion Pump supplies on and they indicated that the klystron was up to air ... Disaster as klystron is sealed unit with pinch off
• Contacted SLAC and we decided a leak test may be possible, SLAC sent engineer to participate
• While waiting for SLAC engineer, we removed the tube and contacted our vacuum group to see what was the best way to proceed
G.McMonagle, 8th July 2011
CLIC Project Meeting
Leak test showedceramic feed throughon ion pump was leaking
New ion pump and valve installedtube pumped down vacuum ok
G.McMonagle, 8th July 2011
CLIC Project Meeting
Bakeout
Tube was baked out at 200 degrees for 4 daysActivated cathode during the bake out periodSuccess tube ready for reinstallation
G.McMonagle, 8th July 2011
CLIC Project Meeting
Reinstallation of klystron in modulator
• Several issues with believing current and voltage calibration of the modulator
• But tube was pulsing !!!
• If we believe the figures from the voltage and current waveforms the perveance on the tube is lower than what was seen at SLAC
• Temperature probes were installed at input and output of collector water cooling and also a precision flow meter in order to do a calorimetric check.
• Unfortunately the calorimetric measurement confirmed the low perveance and allowed us to believe that the voltage and current measurements were correct
G.McMonagle, 8th July 2011
CLIC Project Meeting
Some measurements• Two possible causes for this
1. Cathode pollution, not getting uniform electron beam from cathode2. Gun misalignment
Varied filament heater current with constant klystron Voltage.From results looks as though cathode performs as expectedProbably rules out cathode pollution
G.McMonagle, 8th July 2011
CLIC Project Meeting
Ruling out cathode pollutionand with 10% body interception
(nominal <1%)This leaves gun misalignment
investigationTube removed again
G.McMonagle, 8th July 2011
CLIC Project Meeting
G.McMonagle, 8th July 2011
CLIC Project Meeting
G.McMonagle, 8th July 2011
CLIC Project Meeting
G.McMonagle, 8th July 2011
CLIC Project Meeting
G.McMonagle, 8th July 2011
CLIC Project Meeting
G.McMonagle, 8th July 2011
CLIC Project Meeting
G.McMonagle, 8th July 2011
CLIC Project Meeting
G.McMonagle, 8th July 2011
CLIC Project Meeting
Conclusive that there is a misalignmentalthough we don't really know how it
happenedwhat do we do ?• First option
• We send the tube back to SLAC for repair• As its a best effort collaboration will cost
us 200k$ and at least 6 months delay• Second option
• Long shot, try and realign gun at CERN• Risky but if it doesn't work the tube will
have to be sent back anyway• Extra 4 week delay but worth the risk?
• Good news• Latest communication from SLAC
G.McMonagle, 8th July 2011
CLIC Project Meeting
“I think we have some very good news to share but I'd like to discuss it with the rest of our group before making a formal statement.
Last Friday we stretched the eyelet joint on an old 5045 (same seal and eyelets as the XL) while it was under vacuum... We found that although the joint would spring back closed after small displacements, it would stay open with increased stretching. We stretched it enough to stay open ~1.5mm (0ne side only so tilted just like XL5-2). At that point we simply clamped it back down using 2 bar clamps (one at the high point and one at 180 deg)... not much force was required. We found that the joint stayed closed and matched original dimensions within .001 to .002". As we don't know how the XL5 seal was disturbed, the results may not be duplicated but I think we will request a try once we discuss details and cautions etc. -Andy”
There is still some hope that we can recover quicklyWaiting for instructions from SLAC
G.McMonagle, 8th July 2011
CLIC Project Meeting
Future SAPS at CERN• In autumn last year we decided that we want to
order two more XL5 klystrons • 1 for spare and 1 for second test area
• In contact with our SLAC colleagues• If possible would like an industrialised klystron,
SLAC of same opinion for their XL4• Price enquiry made to industry 3 firms contacted• Thales, CPI, and Toshiba• Thales declined as they could not meet time
schedule (minimum 5 years estimate from them as they have no in house experience at this frequency)
• Toshiba made offer but conditional on receiving XL4 order as well• They did not get the SLAC order and withdrew
from CERN tender• CPI only valid tender• Finance committee approved order for two
klystrons plus option of third with CPI in June this year
• First klystron due at CERN beginning 2013
G.McMonagle, 8th July 2011
CLIC Project Meeting
Planning
• Kick of meeting with CPI on 25th and 26th July• Once parameters are confirmed
• Call for tender for modulator (one or two?)
• Order TWT klystron driver and RF components
• Decide on location for next test stand(s) ?
SM18XExcludedno space
G.McMonagle, 8th July 2011
CLIC Project Meeting
B.2002
Possible in old EPA kicker magnet areaBut may be difficult to get 2 test areas in zoneGood location beside CTF3
G.McMonagle, 8th July 2011
CLIC Project Meeting
B.152
LINAC 4 Test StandDepends on planning For this area
G.McMonagle, 8th July 2011
CLIC Project Meeting
CONCLUSIONS• Difficult times over last couple of years• Still optimistic in getting the SAPS running
soon• Challenging program with very limited
resources to get 2nd (or even 3rd) SAPS running for start of 2013
• Any location suggestions for these test stands welcome
• Some new ideas for further test stands (see Igor’s talk)
G.McMonagle, 8th July 2011
CLIC Project Meeting
Thank you for your attention