High Power RF Systems, Control and Distribution in the HINS

Alfred Moretti, Brian Chase, Chris Jensen and Peter Prieto

Fermilab Accelerator Advisory CommitteeMay 10th – 12th , 2006

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Outline

• Genera description of Fermilab High Intensity Neutrino Source (HINS) Linac

• Description of (HINS) linac R&D Study.• Conclusions.

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325 MHz Klystron – Toshiba E3740 FERMI

115kV Pulse Transformer

Modulator Capacitor / Switch / Bouncer

ChargingSupply

RFQ

MEBT

RFDistributionWaveguide withDir Couplers

FerriteTuners

Single Klystron Feeds RT and SCRF Linacto E > 90 MeV

HINS 325 MHz Front END

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M

325 MHz RF System

Pulse Transformer& Oil Tank

IGBT Switch & Bouncer

CAP

BANK

10 kV110 kVCharging

Supply

300kW

MODULATOR: FNAL/TTF Reconfigurable for 1,2 or 3 msec beam pulse

Single Fermi

Klystron325MHz2.5 MW

WR2300 Distribution Waveguide

TO

SH

IBA

E37

40A

I

Q

M

E

I

Q

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B

I

Q

M

T

I

Q

M

R F Q

I

Q

M

Cables to Tunnel

Fast Ferrite Isolated I/Q Modulators

RF Couplers

S

I

Q

M

S

I

Q

M

R

I

Q

M

S

I

Q

M

S

I

Q

M

R

I

Q

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400kW 20 kW

D

I

Q

M

S

I

Q

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R

I

Q

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D

I

Q

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S

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Q

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R

I

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120 kW

10kV

H-

Medium Energy

Beam TransportCopper Cavities

Radio FrequencyQuadrupole

RT Copper Single-SpokeResonators

Cryomodule #2 Double-Spoke

Resonators

20 kW

There will be more power distribution splits than shown

5Fermilab

Simplified Layout of the RF Fan-out for 8 GeV HINS Linac

CIRCULATOR/ ISOLATOR

Magic Tee

FerriteLoaded Stub

CAVITYBEAM

1/8 Power Split (9.03 dB)

DIRECTIONAL COUPLER

1/7 Power Split (8.45 dB)

1/6 Power Split (7.78 dB)

1/5 Power Split (6.99 dB)

1/4 Power Split (6.02 dB)

1/3 Power Split (4.77 dB)

1/2 Power Split (3.01 dB)

E-H TUNER

KLYSTRON

35 footwaveguidefrom galleryto tunnel

This is simplified Layout of the high power RF distribution system• The 325 MHz high power line is as shown except it will have 3 power splitter for Powering 3 directional coupler Arms and the RFQ. • The 1300 MHz high power line because the base line klystron has two 5 MW power output Lines will have two 5 MW branches with several power splitters in each powering directional coupler arms.

Directional CouplersDing Sun’s Talk

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Key: Klystron-- , Hybrid-- , Load-- , Cavity--

Penetrations

Linac Tunnel

Linac Gallery

One 325 MHz Klystron Driving 58 Cavities and RFQ

H

H H

RFQ

1 -- - - - - ---- 18 Rm temp 19 - - - - - - - - - - - -- - - - - - - ---- - -39 Super C40 - - - - - - - - - - - - - -- - --- - -- ---- - - 58 Super C

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Status of Required Components

• Vendor quotes have been received for the required hybrid power splitters.

• Vendor quotes have been received for the string of directional couplers required to provide RF power to the cavities.

• In-house studies of directional coupler strings using HFSS is underway.

8Fermilab

Directional Coupling Factors along the 325 MHz section of the HINS Linac

•The chart shows that the Superconducting cavity coupling factors remain constant with changes in beam loading (Blue and Yellow curves).

•The red and black curves show the coupling factor change with beam loading with beam loading changes.

Coupling Factor for each Section in dB

-20

-18

-16

-14

-12

-10

-8

-6

-4

-2

0

2

0 10 20 30 40

Coupler Section Number

Series1 Series2 Series3 Series4

21 Couplerfirst SupC

17 CouplersSecond SupCSection

18 Couplers RT 26 mA18 Couplers

RT 8 mA

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HINS 325 MHz Klystron

Toshiba E3740AFermi325 MHz 2.5 MW

Specifications:

Beam V= 98 kV

Beam I= 51 A

Perveance=1.75uP

Gain= 47 dB

Efficiency=50 %

Modulating Anode grounded to make a diode tube.

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325 MHz kltsron in Meson Building on its wheels.

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325 MHz Components

Circulator

Modern Photo-multiplier for Arc detection

Miscellaneous required RF Components: Bends, Couplers, Bellows, straight pieces,etc.

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LAYOUT OF Test and HINS Area

LL RF Input

Klystron

Circulator

Load

Switch

Waveguide components, bends, straights, couplers, etc., to Experimental test area

Waveguide Components to HINS Area,

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Bouncer Modulator Circuit

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Bouncer Modulator Waveforms

• Switch connects main capacitor bank to transformer during pulse.

• Transformer steps up voltage to 120kV/130A (12:1)

• Main capacitor bank discharges by 20% during pulse

• “Bouncer” circuit compensates for cap bank droop.

Main Capacitor and Bouncer Capacitor Voltage

Klystron Voltage and Expanded Klystron Voltage

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Pulse Transformer 4 ms Pulse Length for HINS

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System ControlForward/Reflected Power

Photo Detector Video Pulse

Klystron Protection Interlock Boards

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VME_P1 VME_P2 CAV VAC1, VAC2, VAC3 TEMP MOD

STATUSSYS CONTROL

MOD_EN RF_INHIBIT

VME_P1 VME_P2VIDEO PULSERF LEAKAGE

WG PRESSURE1WG PRESSURE2

VME_P1 VME_P2KLY FWR PWRKLY REFL PWRCIR FWR PWRCIR REFL PWR

VME_P1 VME_P2PMT KLY WINDOW

PMT COUPLERPMT CH3PMT CH4

VME_P1 VME_P2PHOTODET_CH1PHOTODET_CH2PHOTODET_CH3PHOTODET_CH4

VME_P1 VME_P2

MVME 2401UPROCESSOR

EPICS

VME_P1 VME_P2E_FIELD PROBE1E_FIELD_PROBE2E_FIELD_PROBE3

Ext INTLKS

MOD INTLKS

VME64X BACKPLANE

LLRF & AMP

KLYSTRON

FAST SWITCH

text DIR COUPLER CIRWAVEGUIDE WAVEGUIDE

text

C

DIR COUPLER

text

C

XFMR

HIGH INTENSITY PROTON SOURCE AND SMTF RF INTERLOCK S

text

CO

UP

LER

PMT

HINS and SMFT Interlocks

18Fermilab

Conclusions

• All of the components for the 325 MHz klystron output RF power testing are on-hand. First RF power testing of 325 MHz klystron is scheduled for July of this year.

• Major Components of the modulator are on hand and testing of major assemblies is underway.

• Design of the of the equipment and safety interlocks has been completed. Construction and assembly and testing of the boards are underway.

• Conceptual design of the low level RF system has started in collaboration with LBL . Adaptations of In-house, Desy and SNS prototype control boards are under study .