1. RF PROCESSING OF RFQ COUPLERS CDR2 | Michel Desmons 8-9 DEC 2015

2. CONTENTS | PAGE 2 CEA Saclay/Irfu projet ESS | DATE Pour personnaliser le pied de page et la date : « Insertion / En-tête et pied de page » Personnaliser la zone de de pied de page Cliquer sur appliquer partout Cavity for RF processingP.03 Scattering parameters P.04 Field maps P.05

3. CAVITY FOR RF PROCESSING | PAGE 3CEA Saclay/Irfu projet ESS | DATE Goal : RF processing on matched load up to 1MW peak and 5% duty cycle Input data: about 8000 A/m magnetic field needed at the RF Loop location to get 1MW coupled power at 352.2MHz Solution: 2 RF couplers connected via a Quarter-wave resonator, the first one being connected to the klystron and the second one to a matched load Cavity inner conductor (stem) ended with mushroom shape part to decreese the length of the resonator :  decrease the RF losses of the cavity  decrease the cavity voltage (for easier X-ray shieding) E (V/m)H (A/m) Electric field Emax.....10.4 V/m (0.56 kilpatrick) Cavity voltage Vcav... 99.693kV Incident RF power......1000 kW Transmitted power..... 962 kW RF losses...................36.3kW Stem…………….....…20kW Cavity body…….........9kW Tuner……………........1.3kW PumpingGrid…..........2.6kW RF Loop………….......2.4kW (2x1.2kW)

4. | PAGE 4 CEA Saclay/Irfu projet ESS | DATE SCATTERING PARAMETERS  f (MHz) Transmitted RF power (W) | s 11 | RF Loop surface current density Im(s 11 ) Re(s 11 ) s 11 in the complex plane Blue : at the input of 100mm long feeder Red : de-embeded with 172.3mm coaxial line Black : parallel RLC network The 72.3 mm extra length is close to the RF Loop length (2 x 14 + pi x 14.4 = 73.2mm) P max = 962 kW  f 3 dB = 3.382 MHz Q L = 104 |s 11 | min = 0.01865

5. | PAGE 5CEA Saclay/Irfu projet ESS | DATE FIELD MAPS log 10 ( ||H A/m || ) Magnetic field : H max = 25 000 A/m One pumping port One tuner port ||H A/m || Magnetic field : Hmax = 16 300 A/m ||E V/m || Electric field : E max = 12.9 MV/m (0.7 kilpatrick) ||E V/m || E max = 10.6 MV/m (0.58 kilpatrick) @ d = 2.1 mm E max = 11.7 MV/m (0.64) @ d = 1.7 mm (+3 MHz)

6. DSM Irfu Commissariat à l’énergie atomique et aux énergies alternatives Centre de Saclay | 91191 Gif-sur-Yvette Cedex T. +33 (0)1 69 08 xx xx | F. +33 (0)1 69 08 99 89 Etablissement public à caractère industriel et commercial | RCS Paris B 775 685 019 | PAGE 6 CEA Saclay/Irfu projet ESS | DATE