Transcript Rodriguez_CTF3_Kicker_CTF3Meeting07

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  


R's  2  Z c 
 sin 2 k  l 


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.