M.J. Barnes CERN TE/ABT Also representing: Tony Fowler 1 , Gianfranco Ravida 1 ,

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


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.


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


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


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.


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



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:



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


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


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


(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


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


Screen-Dump: Local Controls(courtesy of Jan Schipper)

Diagnostics & Controls

Four Channel Integrator Card, for “Online” Local Diagnostics


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


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.


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


Questions ???


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

Documents

M.J. Barnes CERN TE/ABT Also representing: Tony Fowler 1 , Gianfranco Ravida 1 ,