1. J. Jacob: RF developments at ESRF: HOM free Cu Cav. & SSA
RFTech 2nd workshop PSI Villigen, 2-3 December RF Developments at ESRF: HOM damped Cu cavities *) & Solid State Amplifiers
[SDMS]
Jörn Jacob, Vincent Serrière, Jean-Maurice Mercier, Michel Langlois, Georges Gautier,
ESRF
[ELTA]
* This work, carried out within the framework of the ESRFUP project, has received research funding from the EU Seventh Framework Programme, FP7.
RF Tech 2, PSI, 2-3 Dec. 2010
J. Jacob: RF developments at ESRF: HOM free Cu Cav. & SSA

2. Existing 352.2 MHz ESRF RF system
Cell 5
Cav 1 & 2
Cell 7
Cav 3 & 4
Existing MHz ESRF RF system
6 GeV
e- Storage Ring
Existing Operation at 200 mA
1.3 MW klystron transmitters: Redundancy in case of any transmitter failure (waveguide switching)
Suppression of HOM driven Longitudinal Coupled Bunch Instabilities by Cavity Temperature regulation
Klys1
Klys2
Teststand
5-cell cavities: strong HOM !
Klys0
SY Cav 1 & 2
ESRF upgrade: 300 mA option
No transmitter redundancy
Need LFB to stabilize HOM driven instabilities
Increased voltage to master Robinson Instability
26.6 M
Booster
352 MHz 1.3 MW Klystron
Thales TH 2089
Klys3
Long term
Only 1 manufacturer left for this type of klystrons
 decision to develop an alternative
Cell 25
Cav 5 & 6
RF Tech 2, PSI, 2-3 Dec. 2010
J. Jacob: RF developments at ESRF: HOM free Cu Cav. & SSA

3. Recent review of ESRF upgrade strategy
RF upgrade concept
Cell 5
Cell 7, length 5 m  7 m
18 new single cell HOM damped cavities for 300 mA operation
2004 start R&D
Today: 3 prototypes close to delivery
Solid State Amplifiers
Extremely Modular,
Intrinsic redundancy,
High global operation MTBF, …
4 x 150 kW SSA for the Booster
18 x 150 kW SSA for the Storage Ring
1st batch: 7 SSA in fabrication by ELTA
In house development of SSA using a Cavity Combiner ID ID
150 kW
150 kW
150 kW
150 kW
150 kW
Klys2
150 kW
150 kW
150 kW
Teststand
150 kW
150 kW
pulsed
SY Cav 1 & 2
150 kW
Recent review of ESRF upgrade strategy
300 mA option not retained for Phase 1 of ESRF upgrade  cavity series fabrication frozen
Budget savings  no additional beam line in cell 7  no cavity transfer to cell 23
SSA still a priority as alternative to klystrons however, also SSA program will be adapted
Storage Ring
150 kW
Booster
150 kW
150 kW
150 kW
150 kW
150 kW ID ID
Cell 25
Cell 23, length 5 m  7 m
RF Tech 2, PSI, 2-3 Dec. 2010
J. Jacob: RF developments at ESRF: HOM free Cu Cav. & SSA

4. RF upgrade phase 1 Storage Ring Booster Klys1 Klys2
Cell 5
Cav 1 & 2
RF upgrade phase 1
Cell 7
Cav 3 & 4
Klys1
Klys2
Teststand
3 SSA from ELTA for SR
Initially for 3 new cavities in cell 23
Now foreseen to replace Klystron 3
Commissioning of SSA mid 2012
SY Cav 1 & 2
150 kW
4 SSA from ELTA for the booster:
Commissioning on the ring early 2012
150 kW
pulsed
150 kW
Storage Ring
150 kW
Booster
150 kW
3 prototype HOM damped cavities will be qualified with beam, cavity by cavity in existing RF section:
Starting in 2011 with klystron 3
Continuation with SSA
Cell 25
Cav 6 & new cavity for test
RF Tech 2, PSI, 2-3 Dec. 2010
J. Jacob: RF developments at ESRF: HOM free Cu Cav. & SSA

5. 1. 352.2 MHz Single cell NC HOM damped cavity
9 MV with 12 to 18 cavities (4.7 ± 0.4 M)
Planned operation at 300 mA
Power capability to sustain up to 500 mA
DESIGN, checked with aluminum model: all the longitudinal HOM impedances are well below the threshold of 1A / 18 cavities:
HOM absorbers:
Ferrite loaded tapered ridges
1A threshold
RF finger contacts on the ridges
HOM dampers = ridge waveguides
frf < cut off < lowest HOM freq
3 power prototypes in fabrication:
validate the design
validate 2 different manufacturing procedures
qualify 3 companies: RI, SDMS, CINEL
obtain 3 operational cavities for cell 23 according to initial upgrade concept
Based on 500 MHz BESSY, MLS, ALBA design
[E. Weihreter et al.]
* This work, carried out within the framework of the ESRFUP project, has received research funding from the EU Seventh Framework Programme, FP7.
RF Tech 2, PSI, 2-3 Dec. 2010
J. Jacob: RF developments at ESRF: HOM free Cu Cav. & SSA

6. J. Jacob: RF developments at ESRF: HOM free Cu Cav. & SSA
Initially specified mechanical design & manufacturing procedure applied by RI Research Instruments
e-beam welding of HOM coupling sections
Continuous, no gap e-
Brazing:
cooling circuits
outlets
flanges
Frequency tuning
Brazing end plates
Photos at
RI Research Instruments:
Cavity body after electron beam welding of the HOM coupling sections, before machining the beam stop (extra thickness)
RF Tech 2, PSI, 2-3 Dec. 2010
J. Jacob: RF developments at ESRF: HOM free Cu Cav. & SSA

7. J. Jacob: RF developments at ESRF: HOM free Cu Cav. & SSA
Alternative design proposed by SDMS, engineered by V. Serrière / ESRF applied by SDMS and CINEL
e-beam welding
CINEL: 3 body sectors after machining of the water cooling channels, September 2010
Brazing
Brazing
Brazing
&
SDMS parts of end discs ready for e-beam welding
Brazing
Final assembly by e-beam welding
SDMS: Body after e-beam assembly of the 3 sectors, November 2010
RF Tech 2, PSI, 2-3 Dec. 2010
J. Jacob: RF developments at ESRF: HOM free Cu Cav. & SSA

8. J. Jacob: RF developments at ESRF: HOM free Cu Cav. & SSA
HOM absorbers
C48 ferrite tiles brazed on Cu plate
RI: Ferrite HOM absorber for IR thermal test at ESRF
SDMS: direct brazing to stainless steel – successful IR thermal test at ESRF
Ferrite/Cu plate brazed on tapered stainless steel absorber
RF Tech 2, PSI, 2-3 Dec. 2010
J. Jacob: RF developments at ESRF: HOM free Cu Cav. & SSA

9. Status of HOM damped cavities
RI: Delivery expected in March 2011
SDMS: RF tuning next week, then final e-beam welding of end discs, delivery in December 2010
CINEL: Delivery in March 2011
Tests with beam on Storage Ring: cavity by cavity in cell 25, after removal of SR cavity 5, from mid 2011
RF Tech 2, PSI, 2-3 Dec. 2010
J. Jacob: RF developments at ESRF: HOM free Cu Cav. & SSA

10. 2. Contract for 7 SSA of phase 1 with ELTA
650 W RF module
352.2 MHz
BLF 578 / NXP
Gain: 20.3 ± 0.2 dB
Circulator:
Ins. Loss < 0.2 dB
Isolation >26 dB
Milestones / Schedule:
February 2010: Successful test of the first RF module, validation of the design:
hmodule > 72 % (measured)
expected total hSSA > 55 % (> spec)
July 2010: Successful test of the first combination of 16 RF modules, including 500 hours ON/OFF fatigue test (7500 x 4 min on/off cycles)
January 2011: Acceptance test of the first 75 kW tower at ESRF
January 2012: commissioning of the 4 x 150 kW SSA connected to the ESRF booster cavities
August 2012: commissioning of 3 x 150 kW SSA for the Storage Ring
ELTA 150 kW amplifier for the ESRF
Coaxial combiner
Offer essentially along the initial SOLEIL design
New 6th generation LDMOS-FET transistors allow for a more compact design with only 2 towers to obtain 150 kW:
315 W  650 W per module
Coaxial combiners: 650 kW x 8 x 8 x 2 – losses = 75 kW / tower
November 2009, contract with ELTA for 7 x 150 kW SSA
First 75 kW tower built in close collaboration between SOLEIL and ELTA (transfer of technology)
RF Tech 2, PSI, 2-3 Dec. 2010
J. Jacob: RF developments at ESRF: HOM free Cu Cav. & SSA

11. 2 booster cavities x 2 couplers
400 V ac / 280 V dc power supply for the booster SSA
Constant power 250…350 kW
Peak DC power 1000…1200 kW
Reduced power consumption
10 Hz
Mains 400 V ac
Constant
current
600 kW RF
280 V dc
Power
Supply
400 kW
average
Anti-flicker
C  3 F
2 booster cavities x 2 couplers
Driver
1 W
RF Tech 2, PSI, 2-3 Dec. 2010
J. Jacob: RF developments at ESRF: HOM free Cu Cav. & SSA

12. J. Jacob: RF developments at ESRF: HOM free Cu Cav. & SSA
2 five-cell cavities
x 2 couplers
Booster RF : kW amplifiers
4 Waveguide switches to
4 water loads
Directional couplers
SY: Booster Synchrotron
75 kW tower
Existing transmitter room
SYRF
RF Tech 2, PSI, 2-3 Dec. 2010
J. Jacob: RF developments at ESRF: HOM free Cu Cav. & SSA

13. 3. R&D – SSA using a Cavity Combiner [M. Langlois, ESRF RF Group]
ALBA Cavity Combiner:
MWS design / ALBA
100 % match for 2 IOTs
One IOT off and detuned:
Adjust tuning plunger in output waveguide
Re-establish match > 99%
Frequency trimming
Input IOT 1
Input IOT 2
Output WR1800
Matching post (inserted for single IOT operation)
IOT
SSA
For ESRF application:
6 raws x 22 Columns x [600 …800 W per transistor module]
75 … 100 kW
More compact than SOLEIL type coaxial combiners
Coupling: ßwaveguide  nmodule x ßmodule >> 1
Easy to tune if nmodule is varied
Substantial reduction of losses  higher h
RF Tech 2, PSI, 2-3 Dec. 2010
J. Jacob: RF developments at ESRF: HOM free Cu Cav. & SSA

14. Strongly loaded E010 resonance
Modest field strength
Cavity at atmospheric pressure
1 dB - Bandwidth  500 kHz
SSA with Cavity Combiner
Mechanical design ready to build a 10 kW prototype (18 modules)
Tendering for mechanical subassemblies
Important issue: develop an adequate electrical & mechanical interface between RF modules & cavity
In parallel:
In house development of amplifier modules, using latest LDMOS-FET:
BLF 578 / NXP
MRF6VP41KH / Freescale
Goal:
Develop expertise in SSA design,
Contribute to design improvements
Prepare the future operation follow up
Set references for coming procurements
Prepare next step:
Full scale prototype at 75…100 kW
H field
Homogenous magnetic coupling of all input loops
E field
Strong capacitive coupling to the output waveguide
RF Tech 2, PSI, 2-3 Dec. 2010
J. Jacob: RF developments at ESRF: HOM free Cu Cav. & SSA

15. J. Jacob: RF developments at ESRF: HOM free Cu Cav. & SSA
Mechanical design of 75 to 100 kW SSA using a cavity combiner
Fabrication of 10 kW prototype with 3 wings in 2011
RF Tech 2, PSI, 2-3 Dec. 2010
J. Jacob: RF developments at ESRF: HOM free Cu Cav. & SSA

16. J. Jacob: RF developments at ESRF: HOM free Cu Cav. & SSA
4. New coupler using LHC window - CERN-ESRF-SOLEIL collaboration [Our thanks to Eric Montesinos, CERN]
LHC window directitly brazed into copper collars:
No sharp edges
Well defined current paths
Sustains very high power: tested at 575 kW full reflection without damage
Develop couplers for ESRF and SOLEIL using LHC window to
Increase the power capability and improve the reliability
Obtain a new standard and high performance plattform for high power couplers
Electrical & mechanical compatibility with existing LEP coupler for both NC and SC applications
ESRF: 1 prototype for high power tests + 2 production prototypes
SOLEIL: 2 production prototypes
Including waveguide transformers
CERN’s interest
Re-develop the brazing and subsequent electron beam welding in the CERN workshops
Safeguard specialized know-how and guarantee durability of this strategic component
Possible application to next CERN accelerators
Status
Successful ceramic / copper brazing at CERN (inspection of a cut sample)
Prototype expected in December 2010
Production prototypes for ESRF and SOLEIL in June 2011
Existing coupler with LEP type window
New coupler with LHC window
RF Tech 2, PSI, 2-3 Dec. 2010
J. Jacob: RF developments at ESRF: HOM free Cu Cav. & SSA

17. Thank you for your attention !
Jörn Jacob
Jean-Maurice Mercier
Eric Rabeuf
Thank you for your attention !
ESRF Linac / Injection-Extraction / RF Group
Baroudi Boucif
Paul De Schynkel
Marc Dubrulle
Hervé Delamare
Philippe Chatain
Michel Langlois
Alain Panzarella
Vincent Serrière
Georges Gautier
Nicolas Michel
Massimiliano De Donno
Pierre Barbier
Anna Triantaphyllou
Denis Vial
Didier Boilot
RF Tech 2, PSI, 2-3 Dec. 2010
J. Jacob: RF developments at ESRF: HOM free Cu Cav. & SSA