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CTF3 Collaboration Technical Meeting TAIL-CLIPPER KICKER. M.J. Barnes CERN TE/ABT Also representing: Tony Fowler 1 , Gianfranco Ravida 1 , Iker Rodríguez 2 & Fernando Toral 2. 1 CERN 2 CIEMAT. OVERVIEW. - PowerPoint PPT Presentation
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M.J. Barnes January 29, 2009 1
M.J. Barnes CERN TE/ABT
Also representing: Tony Fowler1, Gianfranco Ravida1,Iker Rodríguez2 & Fernando Toral2
CTF3 Collaboration Technical Meeting
TAIL-CLIPPER KICKER
1 CERN2 CIEMAT
M.J. Barnes January 29, 2009 2
OVERVIEW
Review of design and status of tail-clipper – several measurements presented;
Outstanding work for tail-clipper;
Future kicker systems that would be required for CLIC.
M.J. Barnes January 29, 2009 3
CTF3 Programme
DL
CLEX 2007-2009building in 2006
20042005
2006
Thermionic gun
CR
TL2 2007
30 GHz production(PETS line)and test stand
: kicker
2007
2007
Linac
Photo injector / lasertests from 2006
Extraction kicker Striplines
installed Feb/Mar
2008
Tail Clipper Hut (bat 6102) containing
pulse generators
TailClipper
Striplines Jan 2009
M.J. Barnes January 29, 2009 4
CTF3 & CLIC Stripline Kickers
CTF3 CR Extraction
Tail Clipper
Beam energy 300 200 MeV
Total kick deflection angle (“B” & “E” Fields) 7 1.2 mrad
Stripline plate separation 40 40 mm
Stripline electrical length 1.7 4 x ~0.295 m
Available length (including transitions) 1.625 m
Field rise time (0.25% to 99.75%) ≤70 ≤5 ! ns
Pulse duration 200 Up to 140 ns
Flat-top reproducibility ± 0.1 NA %
Flat-top stability (including droop) ± 0.25 NA %
Field homogeneity ± 18 %
Repetition rateInitial 5 5 Hz
Nominal 50 50 Hz
Stripline Pulse voltage ±12.6±2.0 for 1.18m
±2.65 for 0.885mkV
Pulse current (into 50 Ω load) ±252±40 for 1.18m
±53 for 0.885mA
Timing Jitter ≤ 1 rms ns
Generator 2007; Striplines 02/2008 Jan. 2009
M.J. Barnes January 29, 2009 5
Tail Clipper: Overview
35A
140ns 140ns0A
KICK≤5ns
Beam Pulse from CR
35A
140ns 140ns0A
KICK≤5ns
35A
140ns 140ns0A
KICK≤5ns
Beam Pulse from CR
The beam pulse extracted from the CR is 35 A and 140 ns. The tail-clipper must have a fast field rise-time, of 5 ns or less, to minimize uncontrolled beam loss. The flatness of the kick pulse is not important as deflected beam is to be thrown away.
Beam Pulse
HVDC Z
ZBeam
Z
ZZZ
Termination resistor
Stripline platesTransmission line
Fast switchPFN
Copt From second pulse generator
Schematic of Tail-Clipper
Each pulse generator is composed of a 50Ω (Z) Pulse Forming Network (PFN), a fast semiconductor (Behlke) switch, 50 Ω stripline plates and a matched terminating resistor.
M.J. Barnes January 29, 2009 6
Tail-Clipper Striplines (1)
• Four sets of striplines.• Smooth transitions from coaxial feedthru to stripline. • Tapered electrodes preserving 50Ω characteristic impedance to
minimize reflections.• At a radius of 10mm the deflection is up to 4.3% less than the on-
axis deflection.• For an overall electrical length of 0.885m (3*0.295m), a current of
~53A into 50Ω provides the specified kick of 1.2 mrad.• A 4th set of striplines provides redundancy.• “Over-driving” striplines also reduces field rise-time.
295mm
1.52m
M.J. Barnes January 29, 2009 7
Tail-Clipper Striplines (2)
380mm (1.27ns) 295mm
Pu
lse A in
@ T
0
Pu
lse A to
50Ω
Pu
lse C in
@
T0 + 2.54n
s
Pu
lse C to
50Ω
Pu
lse D in
@
T0 + 3.80n
s
Pu
lse D to
50Ω
Pu
lse B in
@
T0 + 1.27n
s
Pu
lse B to
50Ω
BEAMfrom CR
BEAMto DUMP(Collimator)
BEAMto CLEX
1.2mrad deflection. Striplines fed from CLEX end. Pulse voltage: ±2.0kV for 1.18m; or ±2.65kV for 0.885m
Pu
lse A to
50Ω
Pu
lse B to
50Ω
Pu
lse B in
@
T0+
1.27ns
Pu
lse A in
@
T0
Pu
lse C to
50Ω
Pu
lse C in
@
T0+
2.54ns
Pu
lse D to
50Ω
Pu
lse D in
@
T0+
3.80ns
+ve:
-ve:
M.J. Barnes January 29, 2009 8
Tail-Clipper Striplines (3)
Striplines in situ in TL2
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
-2.E
-09
-1.E
-09
0.E
+0
0
1.E
-09
2.E
-09
3.E
-09
4.E
-09
5.E
-09
6.E
-09
7.E
-09
8.E
-09
Time (s)
S1
1 R
ea
l
Cable Only
Top Plate #1 Only Driven
Measured pulse response with only one plate of a set of
striplines driven:
Mismatch (S11=0.06): Z ≈ 56Ω.Impedance of 56Ω is due to only one-plate being driven (confirmed from simulations). To do: Double-check using a hybrid.
2.87ns: 2 way delay of striplines & feedthrus
Virtual Ground
+ve
-ve
M.J. Barnes
Tail Clipper: Block Diagram
Beh
lke
Sw
itch
Str
ipli
nes
50Ω
T
erm
inat
or
HT
C-5
0-7-
2
Pos
itive
HV
dist
ribut
ion
Neg
ativ
e H
Vdi
strib
utio
n
Negative HV PS
Positive HV PS
ControlUnit
BP1
BP2
BP3
BP4
BN1
BN2
BN3
BN4
SP1
SP2
SP3
SP4
SN1
SN2
SN3
SN4
GATE DRIVER
PCB
Timing In
TP1
TP2
TP3
TP4
TN1
TN2
TN3
TN4
PFN P1
PFN P2
PFN P3
PFN P4
PFN N1
PFN N2
PFN N3
PFN N4
τP1
τP2
τP3
τP4
τN1
τN2
τN3
τN4
2 x
Cu
rre
nt
Tra
nsf
orm
ers
PFN: 50Ω, 170ns (+ve) [HTC-50-7-2]PFN: 50Ω, 170ns (−ve) [HTC-50-7-2]Coax: 50Ω, adjust delay (τP? & τN?)
HTC-50-7-2: Coax, 50Ω, 10m
HT
C-5
0-7-
2
To minimize relative jitter: same Gate Driver used for all 8 Behlke Switches.
BEAM
Remote
Local
M.J. Barnes January 29, 2009 10
Behlke Switch: Very Low Inductance Connections
10V Trigger from Gate Driver PCB
PFN
To Load
Tail-Clipper Hardware9 Parallel 50Ω Outputs
Gate Driver PCB (9 Parallel 50Ω Outputs
[8 Behlke Switches])Previous measurements on Behlke switches show need for fast rising
(few ns) trigger pulse ≥ 7V.
Input Trigger (5V)Peaking
Capacitor
M.J. Barnes January 29, 2009 11
Current in 50Ω load, 5.6kV PFN: (2.5ns rise 10% to 90%)
5V Trigger Pulse
Output of Gate Driver (2.5ns rise 0.5V to 7.5V)
56A (53A [40A] reqd. for 3 [4] sets of striplines).Field rise-time of ~4.0ns [~3.2ns] predicted using
PSpice (with td of 1.27ns), 0.25% to 99.75%, with measured current waveform, for 56A.
Meas. Waveforms: Normal Op.
0.38field rT T
c
S/N 847409; 5x10pF
Low noise within electronics & on trigger cable
M.J. Barnes January 29, 2009 12
(No significant reflections: 3 off DSEE-55-24N1F diodes, on HV board, terminate reflection from short-circuit).
5V Trigger Pulse
Current in short-circuit load.~104A amplitude (5.6kV PFN).
Meas. Waveforms: S.Cct Load
M.J. Barnes January 29, 2009 13
Kicker Cabinet During Assembly5 x Positive
Polarity Switches
5 x Negative Polarity
SwitchesHVPS
Spare Switches
FRONT VIEW BACK VIEW
“Top” CT to Control Room
“Bottom” CT to Integrator or Local Diagnostics
M.J. Barnes January 29, 2009 14
Screen-Dump: Local Controls(courtesy of Jan Schipper)
Diagnostics & Controls
Four Channel Integrator Card, for “Online” Local Diagnostics
M.J. Barnes January 29, 2009 15
Striplines received at CERN early December 2008:– Shock detector activated during shipment !, but no problems apparent;– Impedance checked: 1 plate of a pair driven 56Ω (as per predictions); – HV pulses applied to striplines in air (6kV pulses to one plate at a time; ±5.6kV pulses to both plates of a stripline, simultaneously) . No breakdowns;– Results from Jan Hansen, re vacuum: • Leak rate <1x10-10mbar•l/s; • 8.8x10-8mbar pressure on downstream gauge after 72 hours pumping; expected pressure in TL2 line of ~1x10-7mbar downstream of the kicker with the taper installed and using a standard CTF3 pumping port; • 3.4x10-9mbar pressure on downstream gauge 5 days after a 120°C bake out for 24 hours expected pressure in TL2 line of ~7x10-9mbar downstream of the kicker with the taper installed and using a standard CTF3 pumping port (no bake out of striplines foreseen in the machine).– Situated in TL2.– Fruitful collaboration with CIEMAT on BOTH TL2 Tail Clipper & CR Extraction kicker !
Tail-Clipper Status
M.J. Barnes January 29, 2009 16
Tail-Clipper Status & Ongoing Works
• Tests on TL2 Pulse Generator: – show excellent (fast) rise-time; – system has been reliable– low noise levels within pulse generator.
• Kicker cabinets installed in building 6102, January 2009. • Method developed to measure relative timing of Behlke
Switches: method to be applied and, if necessary, relative timing modified.
• Radiation will be higher than originally appreciated, therefore cable connecters with ceramic insulators ordered (to replace existing connecters with plastic insulators).
• Cables between cabinets & striplines to be made, pulled & relative timing of pulses at striplines checked (before week 11 !!).
• FID (Fast Ionization Dynistor) expected delivery in 2 months time!! – will be evaluated.
M.J. Barnes January 29, 2009 17
DRIVE BEAM Combiner Ring #1 Extraction (2.4GeV; ~830kHz burst rate for 63 pulses; 100Hz rep-
rate; 240ns flattop; voltage may be very high?? – depending on aperture). Combiner Ring #2 Extraction (2.4GeV; ~320kHz burst rate for 42 pulses; 100Hz rep-
rate; 240ns flattop; voltage may be very high?? – depending on aperture). Decelerating ring kickers (extraction into decelerating structure) – 42 systems!; Pulse to
pulse stability may be important. Phase feedback kickers (<100ns latency) – 96 kickers per side!.
MAIN BEAM Injection and Extraction. Extraction requires a high stability flattop. Inter-train feedback kickers at intersection points (pulse to pulse correction). 1TeV,
1nrad, <40ns latency (10ns preferred). Beam Abort Kickers?? (e.g. 1 kicker per drive beam sector, 21st (final) kicker per side (1.5
TeV) 1T•m, 150Hz: R.W. Assmann, F. Zimmermann, “Efficient Collimation And Machine Protection For The Compact Linear Collider”, EPAC06).
DAMPING RING EXTRACTION High precision (e.g. ±1x10-4), 2.9GeV, 50Hz, 160ns pulse width, 1μs rise & fall, ~5mm
aperture.
Table of preliminary parameters, for above, to be presented to kicker group, for discussion, in next couple of weeks ! – important for our input into CDR.
Future Kicker Requirements
M.J. Barnes January 29, 2009 18
Questions ???
M.J. Barnes January 29, 2009 19
Tail Clipper: Deflection
From CTF3 CR
To CLEX
Beam (e-)
Strip-line at positive voltage
Strip-line at negative voltage
Fe
Deflection due to Electric Field:
From CTF3 CR
To CLEX
Beam (e-)
I
I
FmB
B
B
B B
B
Deflection due to Magnetic Field: Strip-lines fed from CLEX end+V
-V
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