klystron and microwave department capabilities and x … · january 5, 2011 erik jongewaard kmd and...

January 5, 2011Erik Jongewaard

KMD and X-Band OverviewSlide 1

Klystron and Microwave Department Capabilities and X-Band Klystron

Overview



KMD Overview



KMD Overview

• Staff– 12 Engineers / Physicists– 31 Technicians– 7 machinists, 2 mechanical designers, 2 support personnel, and

one administrative assistant

• Facilities– Klystron Test Lab Highbay

• ~22500 sq ft– B44 First floor

• ~13125 sq ft– B44 Second Floor

• ~5625 sq ft



KMD Overview

• Four Groups:– Manufacturing

• Design, assembly, machine shop, QC, brazing, coatings, vacuum processing

– RF Engineering and Accelerator Maintenance• LLRF design, RF systems upgrades (AIPs), SLAC RF systems

maintenance

– Tube R&D• RF, magnetostatic, e-beam, and RF/e-beam interaction

simulations and design

– Klystron Test Lab• 10 High Power Pulsed Modulators and two High Power CW

Test Stands



Machine Shop: In-process Machining



Quality Assurance/Metrology



Tube Shop



Hydrogen Furnace Brazing



Cathode Processing



Vacuum Processing



West Side of Test Lab

PEP II RF Bunker

Odd Numbered Test Stands

Even Numbered Test Stands



Klystron Test Lab- East Side

Thyratron Test Stands

Weld Room

Dress Area

ASTA BunkerSLED

Delay Lines

Sub-booster Test



5045 Klystron

SLAC linac RF source, in continuous production since 1983. To date 1113 tubes have been

produced with a current MTBF of over 60k hrs and 20 tubes still running with over 100k hrs of

filament time. Current yield is 100%.

Specs:

Operating frequency: 2.856 GHz

Power output: 65 MW peak, 45 kW average

Focusing: Solenoid



B-Factory Klystron

PEP-II storage ring (B-Factory) RF source. Designed in cooperation

with CPI under a CRADA. Prototype completed in 1994. To

date 12 tubes have been produced and tube S/N 1 has over 42k

filament hrs.

Specs:

Operating frequency: 476 MHz

Power output: 1.2 MW CW

Focusing: Solenoid



150MW Klystron (DESY)



XL-4 Klystron

X-band source tube for NLCTA, ASTA , LCLS, and RF breakdown experiments. Last iteration

of a line of 100 and 50 MW solenoid focused tubes. To date 15 tubes have been produced

with several tubes having over 10k hrs of filament time.

Specs:


Power output: 50 MW peak, 9 kW average

Focusing: Solenoid



XL5 Klystron

• Tubes for PSI, Trieste & CERN• XL4 variation to higher freq• 11.992 – 11.994 GHz• 1.0 – 1.5us• 100 - 50Hz• 50MW• 50MHz 3dB BW• 410 - 450kV



X-Band PPM Klystron

NLC/ILC x-band source prototype. Last of a line of 50 and 75 MW PPM focused tubes for the

room temperature NLC/ILC design.

Specs:


Power output: 75 MW peak, 13.5 kW average

Focusing: Periodic Permanent Magnet



W-Band Sheet Beam Klystron

W-band sheet beam klystron prototype. Proof-of-principal test of sheet beam transport and RF

interaction.

Specs:

Operating frequency: ~95 GHz

Small signal gain: 31db

Focusing: Periodic Permanent Magnet



Components



LCLS RF Gun



LSBK Diode at TS02



LCLS XL-4 Klystron



X-band Accelerator Structure



LCLS RF Phase Cavities



PEP-II RF System

1.2 MW Klystron

Circulator

Control Racks

Penetration

Load



PEP Transverse Feedback

New Measurement System

LBNL New Digital DelayNew Kicker Electrodes



PEP-II Longitudinal Kicker

HFSS Measured

Frequency (GHz) 1.071 1.074

Bandwidth (MHz) 224 216

Loaded QL 4.78 4.97



SPEAR 3 RF StationSingle klystron four

cavity station



Spear 3 RF Distribution and Bucket Select System

Electronics to inject into any of the 476.3MHz SPEAR ring buckets from the 357MHz Booster ring.

0 1 .10 5 2 .10 5 3 .10 5 4 .10 5 5 .10 5 6 .10 5 7 .10 5 8 .10 5 9 .10 5 1 .10 4200

150

100

50

0

50

100

150

200Scope Trace

Time

Degre

es

195

192

ScopeDatak

9.999 10 5.0 TimeScalek

0 0.002 0.004 0.006 0.008 0.01 0.012 0.014 0.016 0.018 0.02200

150

100

50

0

50

100

150

200Scope Trace

Time

Degrees

179

174

ScopeDatak

0.020 TimeScalek

Switching – Not Phase Continuous Switching – Phase Continuous



SLAC Main Drive Line Phase Noise

Noise Floor -120dBc/38Hz = -136dBc/Hz = 120fS rms Jitter in 5MHz BW

Old Oscillator New Oscillator

New Oscillators Have a noise floor of -157dBc/Hz @ 476MHz

Noise Floor -143dBc/38Hz = -158dBc/Hz < 16fS rms Jitter in 10MHz BW



E-163 RF Systems

900W S-Band Solid State Amplifier

Low Noise Frequency Generation Chassis

Laser Oscillator Noise SpectrumFirsts tests to show that Lasers can be locked to RF

with less than 0.5ps rms jitter.



LCLS RF System 0.1ps rms Stability



LCLS LLRF Systems



X-Band Klystron Overview



Brief History

X-band klystron work began at SLAC in the mid to late 80’s to develop high frequency, high power RF sources for the linear collider designs under consideration at that time. This lead to a long lineage of x-band klystrons: the XC, XL, and PPM series, and most recently, the XL5 (a total of 40+ klystrons and diodes built to date).



The XC Series• Goal: 100 MW,1μs pulse length

at 440 KV and 520 A (K=1.8 μP)• Eight tubes were built exploring:

– Output cavity designs (seen at right)• Single cell, 2 cell CC, 4 cell TW, 2

independent cell, 4 cell SW– Output window design

• Thin pillbox, thick pillbox, none– Beam focusing and transport

• All of the tubes suffered from RF breakdown prior to reaching design power and pulse length



The XL Series

• Drawing on the XC experiences the XL series was launched to produce RF sources for the NLCTA.

• Goal: 50 MW, 1.5µs 440kV at 350 A (K=1.2 μP)– Used single TE01 output window– Used multi-gap outputs (SW and TW)

• Design goals achieved with the fourth tube in the series, the XL4 (4 cell TW output and gun ion pump)



XL4

• This is our current “work horse” x-band RF source– 18 tubes built to date (not counting rebuilds)– Four in use in the KTL to feed the ASTA bunker (TS-06 and TS-

08) and HGB experiments at TS-02 and TS-04– Seven sockets in ESB, five for NLCTA and a two-pack socket (not

all occupied currently)– One tube and spare for LCLS linearizer, more contemplated for

deflector structure installation and future injector(s)

• Incremental design improvements– Larger TE01 output window from PPM tube work– Large radius coupling cell irises from XL5 work



The XL Series

0

20

40

60

80

100

250 300 350 400 450 500

Output Power vs Beam Voltagefor the XL4 Klystrons

XL4-2 (1.5 microsec)XL4-1 (1.5 microsec.)XL4-1 (1.2 microsec.)

Beam Voltage (KV)

(100 ns.)

aev-3/24/97



The PPM Series• For the large linear collider RF systems under consideration, it was

clear that the power hungry XL series solenoids had to be eliminated. This lead us to investigate PPM (or more accurately PCM) focused klystrons.

• XL-PPM, 50 MW, 1.5 μs, K=.6 μP design– One diode, one klystron built, achieved: 50 MW at 2.4 μs and 120 Hz for

two minute bursts (heating and x-ray limited)• XP1: 75 MW with K=.75 μP design

– One klystron built, achieved: 79 MW at 2.8 μs, limited to 10 Hz due to body heating

• XP3: 75 MW, 1.6-3.2 μs, K=.75 μP design– One diode, five klystrons built, achieved: 75 MW at 1.62 μs and 120 Hz

• Work terminated when cold ILC decision was made



XP3-1 With Clamp-on Magnets



XL5• During 2008 and 2009 MOUs were established between

SLAC and three European labs (CERN, PSI, and ST) for the development and fabrication of a 50 MW 12 GHz klystron scaled from the XL4 (total of five tubes)

• Design features– Uses XL4 beam optics (same gun, solenoid, collector)– Keeps XL4 cavity spacing to allow maximal part commonality– Scale cavities and other frequency dependent parts only (output,

mode converter, windows)

• First three tubes tested, the first has been shipped and installed at CERN. The last two awaiting bake.

• Testing progressing well after reconfiguring customer supplied RF load hardware.



XL5 Simulations

25

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45

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55

60

0 200 400 600 800 1000

Gain (purple) and MW out vs input (blue) - AJDSK runs of the XL5 design at 420kV and MAGIC (yellow)



XL5 KlystronThis is a 50MW Klystron not

60MW!



XL5 Processing

Baseline rf fwd and reflected fromthe coupler after the output window(downward slope is due toinstrumentation).

Example of breakdown downstreamof the coupler (load side, the morecommon event).

Example of breakdown upstream ofthe coupler (tube side) duringprocessing.



0

2000

4000

6000

09/21 09/23 09/25 09/27 09/29 10/01 10/03 10/05 10/07

Aver

age

rf,

Wat

t

0

50

100

09/21 09/23 09/25 09/27 09/29 10/01 10/03 10/05 10/07

Joul

es p

er

puls

e

0

200

400

600

09/21 09/23 09/25 09/27 09/29 10/01 10/03 10/05 10/07

Bea

m k

V

FWHM =1.8us, 2.3us, 2.8us, 3.2us

9-21 to 9-27 DC beam processing to 410kV full pulse width9-28 to 10-1 rf processing to 50MW 1500ns (4.5kW)10-2 to 10-2 rf processing to 60MW 1500ns (5.4kW)10-3 to 10-7 Post rf processing and measurements

XL5-1B 2010Processing Performance

50MW * 1500ns = 75 J60MW * 1500ns = 90 J

0

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70

250 300 350 400

MW at max drive (~630W) vs. kV beam

0

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0 200 400 600 800

MW out vs. W in at 411kV

53.0

53.5

54.0

54.5

55.0

55.5

56.0

11940 11960 11980 12000 12020 12040 12060

GAIN at 20MW output across 90MHz band



XL5 50MW Breakdown Rate

• Matched load, RF fwd/refl trigger interrupt system• XL5-1A: (very hard to say, no coupler) 1 per hour.• XL5-2A: (hard to say, no coupler) 1 per 12 hours.• XL5-3A: 0 per 24 hours.• XL5-1B: After processing, and for operation at ≥50MW at 60Hz for at least 7 hours we detected no rf breakdown in the tube (any disturbances of the rf were after the external output rf coupler)…or…0 breakdowns per 7 hours.



X-band Klystrons Today

• Building five XL5s for European labs• Building one XL4 for BNL• Building one XL4 now for the LLNL Megaray

Program, another to follow.• Plans underway to industrialize the XL4 klystron

– Participated in x-band technology workshop to spark interest in x-band technology

– Provided drawings/fabrication documentation to microwave tube vendors

– Purchasing sample klystron(s) from tube vendor(s)– Purchased focusing solenoid from outside vendor



Conclusion

• Rich history of x-band klystron development• Still working on improving devices• Increasing interest domestic and internationally

with x-band technology• New applications arising at SLAC each requiring

a new XL socket– LCSL II injector– X-band deflector

• The future looks bright for x-band RF

klystron and microwave department capabilities and x … · january 5, 2011 erik jongewaard kmd and...

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