Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
CERN, January 17, 2007 CTF3 Extraction Kicker Status I. Rodríguez, L. García-Tabarés, F. Toral - CIEMAT F. Marcellini, D. Alesini – INFN CERN, January 17, 2007 CTF3 Kicker Status Original specifications to meet Straight section design Analytical calculations HFSS simulations HOM considerations Manufacturing issues Pulsed power supply Conclusion CERN, January 17, 2007 CTF3 Kicker Status • Original specifications to meet: MAGNITUDE VALUE UNITS 300 MeV 5 mrad Transverse voltage (V ) 1.5 MV Rise/Fall-times (0-100%) ≤70 ns Pulse length (max.) 200 ns Flat-top reproducibility ±0.1 % Flat-top stability (including droop) ±0.25 % Repetition rate (Initial-Nominal) 5-50 Hz Available length (flange to flange) 2000 mm Vertical aperture ≥40 mm Horizontal aperture ≥40 mm Field homogeneity (±1%) 30 mm Energy Deflection Angle Changed to 7 or 8 mrad CERN, January 17, 2007 CTF3 Kicker Status • Straight section design: Circular electrodes Circular round-edged electrodes Pulso 1.2 1 Aperture radius: 22 mm Tube radius: 35 mm Coverage angle : 90.5º Electrode width : 2 mm Z0 = 50.08 Ω 0.8 0.6 0.4 0.2 0 -0.2 0 20 40 60 80 100 Tiempo (ns) Aperture radius: 21 mm Tube radius: 35 mm Coverage angle : 91º Electrode width : 2 mm Z0 = 49.95 Ω 120 140 160 180 200 Contenido en frecuencias del pulso 0.8 Planar electrodes rectangle aperture Planar electrodes square aperture 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 0 Aperture: 46 mm Electrode height: 46 mm Tube radius: 50 mm Border angle : 39º Border length : 5 mm Main frequencies Electrode width : 2 mm from Z0 = 50.04 Ω 10 20 30 40 50 Frecuencia (MHz) 60 70 80 90 DC to 30 MHz 100 Aperture: 41 mm Electrode height: 44 mm Tube radius: 54 mm Border angle : 42º Border length : 8.2 mm Electrode width : 2 mm Z0 = 49.99 Ω CERN, January 17, 2007 CTF3 Kicker Status • Analytical calculations: Beam Energy = 300 MeV Relativistic calculations and kick angle β, Δp Needed transverse voltage (V) = 2.4 MV (for 8 mrad) Transverse shunt impedance (687 kΩ): 2 tanh 2 h sin 2 k l R's 2 Z c k h 700000 600000 500000 400000 300000 Electrodes voltage: ±14.4 kV 200000 100000 5 10 7 1 10 8 1.5 10 8 2 10 8 CERN, January 17, 2007 CTF3 Kicker Status • HFSS simulations (1): Circular electrodes Planar electrodes rectangle aperture Homogeneity: ±15% Homogeneity: ±0.74% Integrated Homogeneity: ±0.69% CERN, January 17, 2007 CTF3 Kicker Status • HFSS simulations (2): Electric field Magnetic field E field (plane Y=0) E field (plane X=0) CERN, January 17, 2007 CTF3 Kicker Status • HFSS simulations (3): Reflection frequency response (S11) Transverse voltage (V): l V ( E v B) dz o 2,418,789 V at DC 700000 |2=<0.03% |S11 (0 to 50 MHz) 600000 500000 400000 300000 200000 Electrodes Voltage: l V E dl 14,513 V Electrodes Current: 290.4 A 100000 o 5 10 I H dl c 7 1 10 8 1.5 10 8 2 10 8 CERN, January 17, 2007 CTF3 Kicker Status • HOM considerations: As input pulse frequency is very low, no HOM can be excited from the coaxial inputs. Possible HOMs can only be excited by the beam up to cut-off frequency of the beam pipe (5.74 GHz for 20 mm radius beam pipe first TM mode) No TM modes that could affect longitudinal motion have been found in HFSS simulations close to the first pass beam frequency (3 GHz). Also, all the modes found had low Q. In addition, as the beam only rotates 5 times in the CR, is extremely difficult to excite any HOM inside the kicker. CERN, January 17, 2007 CTF3 Kicker Status • Manufacturing issues (1): 3D EM model exported from HFSS to SolidWorks and modified on that basis. Main drawings with some small modifications to make the prototype. Three stand-offs instead of two to increase stiffness Slightly longer kicker tube to allow flanges and feedthroughs to fit Minor modifications to the electrodes and kicker tube due to mechanical issues CERN, January 17, 2007 CTF3 Kicker Status • Manufacturing issues (2): Electrodes One fixed hole to support middle stand-off Two sliding holes to allow thermal expansion Screws in both ends to fix feedthrough connections Electrodes made by folding and edges finished by milling CERN, January 17, 2007 CTF3 Kicker Status • Manufacturing issues (3): Stand-offs support (electrodes side) Ceramaseal steatite stand-offs (ref. 10420-04-A) Fixed stand-off just screwed to the electrode Other stand-offs screwed interleaving a separator ring to allow sliding CERN, January 17, 2007 CTF3 Kicker Status • Manufacturing issues (4): Stand-offs support (kicker tube side) Screwed to the tube using a machined screw to allow air evacuation. Hollow cylindrical shape support to fix the stand-off to the cylindrical tube. Caps to hold the vacuum and internal hole to allow the air evacuation CERN, January 17, 2007 CTF3 Kicker Status • Manufacturing issues (5): Feedthroughs Ceramaseal SHV 20 kV feedthroughs (ref. 18089-02-W). Not 50 Ohm, but no reflection expected because of the low frequency of the pulse External steel ring to allow easy welding with the thicker kicker tube CERN, January 17, 2007 CTF3 Kicker Status • Manufacturing issues (6): Feedthrough connection to electrodes Made by Ceramaseal set screw contacts and highly flexible copper cable to allow thermal expansion of the electrodes. CERN, January 17, 2007 CTF3 Kicker Status • Manufacturing issues (7): Flanges Standard 150 mm CF flange modified to improve characteristics: No welding slot to allow smooth internal surface CF inner diameter is equal to inner kicker tube diam. CERN, January 17, 2007 CTF3 Kicker Status • Manufacturing issues (8): Conical transitions Conical transitions from CF150 to CF63. CF150 flange shape modified to get conical transition in 200 mm (Frascati specification). Internal hole of CF63 of same diameter as beam tube. CERN, January 17, 2007 CTF3 Kicker Status • Manufacturing issues (9): Conclusions Stainless steel used for both electrodes and structure to improve combined thermal and mechanical behaviour. Stand-off supports could be modified to improve stiffness and steatite reliability. Longer and thicker stand-offs would be needed and steatite will be supported by an interference fit cap welded to the kicker tube. The main building procedure used is correct and could be used for other prototypes CERN, January 17, 2007 CTF3 Kicker Status • Pulsed power supply: Started the collaboration with CERN and Spanish Industry (Greenpower) to build a pulsed power supply based on series connected MOSFETs. Fast Fiber optics technology may be used for triggering the MOSFETs, based on LHCs Timing, Trigger and Control (TTC) system. CERN will build first card prototype for end-February Several cards and trigger boards should be built and tests will be done by Greenpower in Spain for May 2007. If 7 mrad maximum deflection is finally chosen, only 12.6 kV and 256 Amps will be needed from the power supply (very realistic values for stacked MOSFET technology). CERN, January 17, 2007 CTF3 Kicker Status • Conclusion: First prototype already built and waiting for EM tests in Frascati at midFebruary. Some minor modifications to the design could be made to improve standoff bindings. If the EM tests are OK, the kicker prototype could be installed at CERN in several weeks. About power supply, the engineering and development will continue as it is scheduled.