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SPS 800 MHz RF Power upgrade. Progress report December 2013. Contents. IOTs CERN SPS 800 MHz system & why an upgrade to IOTs Major difficulties while commissioning the pre-series Series delivery Cavities New Antennae New Controls.
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SPS 800 MHzRF Power upgrade Progress report December 2013
Contents • IOTs • CERN SPS 800 MHz system& why an upgrade to IOTs • Major difficultieswhile commissioning the pre-series • Series delivery • Cavities • New Antennae • New Controls LIU-SPS meeting, 12th December 2013
CERN SPS 800 MHz system & why an upgrade to IOTs800 MHz power plant • Since 1980 the system is composed of 2 transmitters of 225 kW • One transmitter has4 x 58 kW Valvo klystrons with 3 dB combiners • Each transmitter is connected through~ 120 m waveguides to its Travelling Wave Cavity 2 x 225 kW transmitters LIU-SPS meeting, 12th December 2013 YL1198Klystron 800 MHz TWC
CERN SPS 800 MHz system & why an upgrade to IOTsObsolescence of the system • This RF power system is getting very old • We had major difficulties with klystron ceramic failures and with HV transformers Broken ceramic window of a klystron LIU-SPS meeting, 12th December 2013 Effect of age on HV transformers
CERN SPS 800 MHz system & why an upgrade to IOTsUpgrade proposal • keep all existing ancillaries and replaceKlystron Transmitters with new IOT Transmitters • First and only IOT at CERN • We wanted to get experience with this tube as it could be used for • LHC upgrade (crab cavities) • new CERN accelerator RF system (SPL ?) LIU-SPS meeting, 12th December 2013 New IOT transmitter
CERN SPS 800 MHz system & why an upgrade to IOTsLong purchasing process • 2009, 40 member states companies have been contacted • 2010, only six companies have been compliant to our specifications • 2010, Electrosyshas been selected • 2011, we received the pre-serie transmitter at cern Two companies per member state have been contacted LIU-SPS meeting, 12th December 2013
Main difficulties while commissioning the pre-seriesMajor troubles • All Factory Acceptance Tests have shown compliance • Pre-series Amplifier at CERN was ok with short duration tests • Long duration tests, we started to experience difficulties • HVSMPS • Conventional HVPS • Erratic faults from 3 to 6 am & from 4 to 7 pm LIU-SPS meeting, 12th December 2013
Main difficulties while commissioning the pre-seriesHVSMPS instabilities 2011 600 Hz 17 kHz HVSMPS HV DC (+ harmonics) IOT RF RF Power load LIU-SPS meeting, 12th December 2013 AM square Repetition rate
Main difficulties while commissioning the pre-seriesHVPS troubles 1st half 2012 • HV monitoring transformers • Ferrites in the IOT input circuit HV transformer Diodes rectifier HVPS Mains HV DC Capacitors stack Thyratron IOT RF RF Power load LIU-SPS meeting, 12th December 2013 AM square Repetition rate Burnt HV monitoring transformers for di/dt protection
Main difficulties while commissioning the pre-seriesHVPS troubles 2nd half 2012 • Repetitive faults from • 3:00 to 6:00 am • 4:00 to 7:00 pm HVPS Time between faults [h] IOT Time of the day the fault occurs [h] RF RF Power load LIU-SPS meeting, 12th December 2013 AM square Repetition rate
Main difficulties while commissioning the pre-seriesHVPS troubles 2nd half 2012 • We were not able to link it with any external ‘perturbation’ • CERN workers, security people or firemen checking the building • Automatic lighting of the building • GSM or Wifi antenna in the building • Traffic lights close to the building • Public lighting day & night light detection • Airport traffic: no planes before 7 am at Geneva airport • Train: old story with TGV disturbing LEP beams, not able to link with any train timetable • Etc… Time between faults [h] Time of the day the fault occurs [h] LIU-SPS meeting, 12th December 2013
Main difficulties while commissioning the pre-seriesHVPS troubles 2nd half 2012 • Not always detected by the Driver overdrive protection • Always triggering the di/dt tube protection • Faulty RF generator • Glitch on top of the RF pulse • Equivalent to 10 x power HVPS IOT RF RF Power load LIU-SPS meeting, 12th December 2013 AM square Repetition rate
Main difficulties while commissioning the pre-seriesHVPS troubles 2nd half 2012 • We solve the problem simply by replacing the RF generator • We were able to perform2,800 hours without a fault • We had to stop the test as we started LS1 HVPS IOT RF RF Power load LIU-SPS meeting, 12th December 2013 AM square Repetition rate
Main difficulties while commissioning the pre-seriesTime spent per problem 24.06.12 green light for Series production 20 months before launching the series production LIU-SPS meeting, 12th December 2013 6 months 5 months 4 months HVSMPS HV monitoring transformers & Input circuit ferrites RF Generator & Faulty Overdrive protection
Series deliverySeries production PLC clock, minimum ms • We asked for several modifications • Driver overdrive protection • Additional air cooling for coaxial lines • Direct access to hardware interlocks through a monitoring panel with ‘blinking first fault’ Hardware Electronic PLC Remote GUI LIU-SPS meeting, 12th December 2013 Hardware Electronic PLC Real time Local GUI & First fault Remote GUI
Series deliverySeries production Remote GUI In addition we have a panel for quick identification of faults (LEDs) & with direct access to hardware interlocks (BNC) for real time monitoring LIU-SPS meeting, 12th December 2013 External probes with risky possible false contacts
Series deliverySeries tests at CERN • Due to LS1, lack of water has limited tests up to 60 kW total maximum, i.e. one transmitter at a time • Between June and December 2013 we received all eight transmittersand commissioned them individually #2 #1 #3 LIU-SPS meeting, 12th December 2013 • Transmitter #1 connected to main combiners • Transmitter #2 connected to RF load for CERN Acceptance Test • Transmitter #3 not yet connected
Series deliverySeries tests • Seven transmitters have been fully commissioned • We miss the tube for the last transmitter, should be delivered before end 2013 • It has already been validated with the tube of transmitter 7 Gino testing one of the transmitter All eight transmitters in BB3 LIU-SPS meeting, 12th December 2013
Series deliveryWhat is a commissioning ? • Long and detailed reception process • Static tests • Mechanical inspection • Water pressure test • Ancillaries checks • Electrical tests • Emergency stop test • HV test with an external HVPS by steps of 5 kV per minutes • Crowbar without tube and with tube (thin wire in short circuit) • RF Low Power tests • Tuning the amplifier LIU-SPS meeting, 12th December 2013 • BW-1dBmust be > 6 MHz (+/- 3 MHz)with Ibeam = 0.45 A • Phase variation < +/- 30° • over 6 MHz (+/- 3 MHz)
Series deliveryWhat is a commissioning ? • RF High Power tests • Increase the power by step of 10 kW up to 60 kW • Check all values, Vbeam, Ibeam, Pfwd, Prev, Pdriver, Ibody, Vfocus, Ifocus • At mid power, retune the cavity for Pmax • Measure • Thermal power load • Efficiency = RFout / HVin • Long duration tests with several cycles • Minimum four hours per cycle • Observe any characteristic variation LIU-SPS meeting, 12th December 2013 • Long duration test description
Series deliveryCirculator WG switch Cavity • Thales asked us to protect the tubes with a circulator against full reflection that could occur while conditioning the couplers • We fully approved it regarding other applications difficulties (ESRF, ALBA, …) • We kept our Waveguide switch to allow quick test onto a power load Short Load WG switch To cavity LIU-SPS meeting, 12th December 2013 Short Circulator Load TCU Circulator – WG switch (cavity or short) – Power load
Series deliveryStill to be done • Test of the four amplifiers together with both systems • Onto the load • Onto the cavity • Beginning 2014 with a low total power of60 kW (lack of water) • From April 2014 with full total power of240 kW (water back) ~ Short 2014 Cavity #2 Load LIU-SPS meeting, 12th December 2013 Short Cavity #1 Load
Cavities New Antennae • A new antenna has been re-designed • It is fully compatible with the existing model and with the TWC 200 MHz • There were two antennae per cavity, LLRF asked for one per iris • 100 antennae have been produced • 37 cells per cavity have been equipped New antenna design Sébastien adding a new antenna on all 66 cells LIU-SPS meeting, 12th December 2013
Cavities New Controls New controls unit front panel • With the obsolescence of the ECAs and controls of the TWC 200 MHz systems, as we were upgrading Power Amplifiers, we decide to also upgrade TWC 800 MHz controls • This is underway, and we will have a new system ready beginning 2014 New controls unit PLC LIU-SPS meeting, 12th December 2013
Schedule 2014 Dec Jan Feb May Mar Apr Jun Jul Aug SPS closed 8 Individual transmitters TWC 1 60 kW total TWC 2 60 kW total TWC 1 220 kW total LIU-SPS meeting, 12th December 2013 TWC 2 220 kW total TWC 1 & 2 2 x 220 kW total + Cavity conditioning LLRF antennae calibration LLRF commissioning SPS setup with beam
Conclusion All 8 systems are expected to be operational before the end of this year Even if it has not been easy, High Power systems are pretty well as scheduled LIU-SPS meeting, 12th December 2013