G.McMonagle, 8 th 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, 8 th 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, 8 th July 2011 CLIC Project Meeting CEA SACLAY (Modulator and RF components) CERN SAPS to be installed and run at CERN in the CTF3 facility SLAC Klystron XL5 Based on XL4 Best efforts agreement Special French Contribution Financed by CLIC Project PSI Trieste

G.McMonagle, 8 th July 2011 CLIC Project Meeting SAPS Installation and Requirements Klystron 50 MW 1500 ns 50 Hz test slot 200 MW, ns or 100 MW, ns phase modulation hybrid Modulator pulse compression CTF2 Klystron Gallery

G.McMonagle, 8 th July 2011 CLIC Project Meeting F-Cup+Isolator Stand alone Test Stand in CTFII Concrete block girder ACC pump Pump Tee load coupler Circular WG Mode converter WG valve 0.5 m Courtesy: S. Doebert

G.McMonagle, 8 th July 2011 CLIC Project Meeting XL5 X Band Klystron spec ParametersSpecificationsunits RF Frequency GHz Peak RF power50MW RF gaindB Efficiency% RF pulse length1.5µs Pulse repetition rate50 (100)Hz Duty cycle% Klystron voltage kV Klystron currentA Inverse klystron voltage100 maxkV Heater voltage20 maxV Heater current30 maxA Heater start up surge current ?maxA Preheating period60min

G.McMonagle, 8 th 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, 8 th July 2011 CLIC Project Meeting CLIC WS 10/2009KM Schirm BE-RF 8 K2-SYSTEM PULSES, 265kV / 262A K2-SYSTEM PULSE FLATNESS <0.4% K2-SYSTEM PULSE-PULSE STABILITY <0.04%

G.McMonagle, 8 th July 2011 CLIC Project Meeting External Water Cooling System Filament DCPS 0-30A Core Bias DCPS HVPS #1 - N Control System Unit Po w er Di str ib uti on U nit L1 L2 L3 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 Trig I pulse U pulse Remote RS232 12GHz 400VAC5 0Hz Safety Interface 3-phase 480VAC 1-phase 120VAC Local RS232 K2 Solid State Modulator Pulse Transformer Oil Tank RF 3GHz 3x185 A CT CVD Water Flow Interlocks Vacuum Interlock Current Interlock Wave guide press ure Int., Arc Int, VSW R Int. L1 N GND 230VAC5 0Hz MODULATOR AND RF SYSTEM, OVERVIEW

G.McMonagle, 8 th July 2011 CLIC Project Meeting Modulator delivered to CERN (only tested in dummy load waiting for klystron)

G.McMonagle, 8 th 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, 8 th July 2011 CLIC Project Meeting Klystron Delivered to CERN

G.McMonagle, 8 th July 2011 CLIC Project Meeting Klystron installation in modulator Oil was removed from tank after dummy load tests some very small metal pieces were noticed at the bottom of The tank. This worried our SLAC colleaguse

G.McMonagle, 8 th 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, 8 th 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, 8 th July 2011 CLIC Project Meeting Leak test showed ceramic feed through on ion pump was leaking New ion pump and valve installed tube pumped down vacuum ok

G.McMonagle, 8 th July 2011 CLIC Project Meeting Bakeout Tube was baked out at 200 degrees for 4 days Activated cathode during the bake out period Success tube ready for reinstallation

G.McMonagle, 8 th 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, 8 th July 2011 CLIC Project Meeting Some measurements Two possible causes for this 1. Cathode pollution, not getting uniform electron beam from cathode 2. Gun misalignment Varied filament heater current with constant klystron Voltage. From results looks as though cathode performs as expected Probably rules out cathode pollution

G.McMonagle, 8 th July 2011 CLIC Project Meeting Ruling out cathode pollution and with 10% body interception (nominal <1%) This leaves gun misalignment investigation Tube removed again

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G.McMonagle, 8 th July 2011 CLIC Project Meeting Conclusive that there is a misalignment although we don't really know how it happened what 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, 8 th 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 quickly Waiting for instructions from SLAC

G.McMonagle, 8 th 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, 8 th July 2011 CLIC Project Meeting Planning Kick of meeting with CPI on 25 th and 26 th 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) ? SM18 X Excluded no space

G.McMonagle, 8 th July 2011 CLIC Project Meeting B.2002 Possible in old EPA kicker magnet area But may be difficult to get 2 test areas in zone Good location beside CTF3

G.McMonagle, 8 th July 2011 CLIC Project Meeting B.152 LINAC 4 Test Stand Depends on planning For this area

G.McMonagle, 8 th 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 2 nd (or even 3 rd ) 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, 8 th July 2011 CLIC Project Meeting Thank you for your attention