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*Work supported Wisconsin, Madis#jkulpin@src.wis

THE USEA SU

J. Kulp

Abstract A solid state

200 MHz opefrequency (Rsuperconductinconsists of thand one moniemploys ruggkilowatt drawmaximum conpower of the output throughlow level RF the 200 MHz phase.

The SynchUniversity of electron gun Electron Laserthe electron gtelevision tranthrough Transtation locatedsystem was vefrequency andbefore disasseThe transmitteof a custom bpower input superconductin

TRThe transm

Series HT-30Broadcast Comfield effect traamplifier drawfull power ope

The 30 kWone computer and two high outputs of thquadrature RFan RF circulato

________________

by DOE award Dson. sc.edu

E OF A SOUPERCON

pin#, K. Klem

R.

e analog televieration is bein

RF) power amng electron gree separate Ritor and contr

ged field effecers that are in

ntinuous powertransmitter sy

h a standard csystem is empsignal and pre

INTRODhrotron RadiatWisconsin is dsuitable as thr (FEL) [1]. Tgun is being nsmitter. The

nscom, Corpord on Peavine erified to oper

d fully tested toembling and sher was reassembbuilt room to pand radio freng electron gun

RANSMITTmitter system i

HS analog ummunications ansistors (FETwers that alloweration [4].

W system consicontrol systempower 15 kW

he cabinets c hybrid combinor to the superc

E-SC0005264, and

OLID STANDUCTIN

man, Synchr

. Legg, Jeffe

ision transmittng commissionmplifier on tgun cavity. RF power comrol cabinet. Tct transistors ndividually hor output. The

ystem is 30 kWcoaxial transmployed to digitecisely control

DUCTION tion Center developing a she injector forThe RF power

provided by e transmitter ration from Mountain, Nerate at the coro 25 kW at thehipping the unbled at the SRCprovide adequequency transmn cavity [3].

TER SYSTEis a solid statnit manufactuDivision. Th

T’s) built into w swapping in

ists of four cam, one driver am

W RF amplifiercombine withner that directsconducting RF

d the University o

ATE ANANG ELEC

rotron RadiaStoughton,

erson Lab, N

ter designed foned as a radithe WisconsiThe amplifie

mbiner cabinetThe transmittebuilt into on

ot swappable atotal combine

W at 200 MHmission line. A

tally synthesizl amplitude an

(SRC) at thuperconductin

r a future Frerequired to rua used analowas purchasethe KRXI-TV

evada [2]. Thrrect power ane mountain sitnit to the SRCC facility insidate air coolingmission to th

EM te Platinum IIured by Harrihe system use1 kW modula

n or out durin

abinets housinmplifier cabiner cabinets. Thh an outboars power througF gun cavity [5]

f

ALOG TELTRON GU

ation Center,WI 53589, U

Newport New

or o n

er ts er ne at d

Hz A ze nd

he ng ee un g d V he nd te C. de g, he

II is es ar ng

ng et he rd h ].

All RF ptransmissof the tran

The en15 kW poac and deused to po

Figu

The amclass A aamplifier the pre-aamplifier paralleledcombinedThis proveach ampthe 3dB houtput pothe ampli

The pcontrolledstanding

CompContrCabin

1KW AmplifiDrawer

17-wayGeysel Combin

15KWPower Suppli

LEVISIONUN POWE

, University USA

ws, VA 23606

power is transion line. Figunsmitter system

ntire system is ower supplies eliver 50 voltsower the RF am

ure 1: Front and

mplifier driveramplifier stage

block. The dramp outputs a

modules. Td class AB bld by a 17-wayvides the total oplifier cabinet. hybrid RF comower. Figure 2fier chain.

phase and gad with a mecha

wave ratio

puter rol net

ier rs

y

ners

W r ies

N TRANSER AMPL

of Wisconsi

6, USA

nsmitted througure 1 shows a m.

powered withthat operate o

s dc at 300 ammplifiers in eac

d back view of

r modules coes which driverivers are used and drive the

The power amlocks that are

ay Geysel Netoutput of 15 kW These in turn

mbiner to make2 shows a bas

ain of the canical phase sh

(VSWR) i

SMITTERLIFIER*

in-Madison,

gh standard cfront and back

h six Basler Eon three phase

mps. These unch cabinet.

f RF transmitte

ontain two cas a parallel claprimarily to am

e 1 kW RF mplifier module summed andtwork combineW of RF powen are combinee 30 kW of tosic block diagr

ombiner systehifter and the vis monitored

R AS

coaxial k view

Electric e 208V nits are

r.

scaded ass AB mplify power es are d then er [6].

er from d with

otal RF ram of

em is voltage

with

THPPC071 Proceedings of IPAC2012, New Orleans, Louisiana, USA

ISBN 978-3-95450-115-1

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07 Accelerator Technology and Main Systems

T08 RF Power Sources

h

bWr

h

t

directional couhas been succefacility at the t

Figure 2:

SUPERCOA niobium s

been manufacWisconsin . Tresonant frequaccelerating gran unloaded Qhelium to 4.2 Kand cryostat.

RF is transdesigned coupthrough. Thecavity and eaddition, a puand focussed oinside the cavfrom the cathofield inside thea layout of the

Figure

uplers. Each essfully testedtime of this wri

: Block diagram

ONDUCTINsuperconductinctured by NioThe cavity is a uency of 199radient of 40 M

Q of 3x109. ThK inside of a cu

smitted to thepler and klystro coupler is delectron bunch

ulsed laser is aonto a cathode

vity. The laserode which aree quarter wave electron gun c

3: Supercondu

individual amto 12 kW at t

iting.

m of RF amplif

NG ELECTng RF electronowave for thequarter wave s

9.6 MHz [7, MV/m is requhe cavity is cooustom designe

e cavity throuon type ceramicesigned to allohes to travel aimed down the located at ther is used to libe then accelerastructure [9].

cavity.

ucting RF elect

mplifier cabinethe synchrotro

fier chain.

RON GUNn gun cavity hae University ostructure with

8]. A peaired along witoled with liquid helium vesse

ugh a uniquelc window feedow RF into th

outward. Ihe coupler tube nose cone tiberate electronated by the RFFigure 3 show

ron gun.

et n

as of a

ak th d el

y d- he n

be p

ns F

ws

A new developedproduce tamplitudecavity [10cavity as amplitude

A steppthe cavitythe operatThis occalgorithmprogrammits desiregeneratorvery close

These chassis (chassis. Tresonant fSchwarz [12]. Theand are sbeing spli

Figu

LOW Llow level rad

d and supplithe 199.6 MHe and phase of0]. The system a feedback se and phase. per motor and y close to resotional gradient

curs with a m that is promable gate arraed gradient, r driven resonae to the referenoperations are(FCC) and a The FCC unit frequency by mSMA100A lo

e two signal geet to 149.7 MHit to drive a hig

ure 4: LLRF sy

Figure 5: LLR

LEVEL SYSdio frequency ied by Jeffer

Hz signal and pf the supercondm uses a probesignal to mon

actuator are uonance before t of the cavity tdigital self eogrammed intay (FPGA). Othe LLRF s

ator (GDR) monce [11]. e performed in

separate stepsynthesizes th

mixing signalsow phase noisenerators are pHz and 79.84 gh repetition ra

ystem installed

RF system bloc

STEM (LLRF) systemrson Laboratoprecisely contrducting electroe antenna in thitor and contr

used to coarselthe system cato a reference excited loop to an Altera

Once the cavitysystem switchde to keep the

nside a field cpper motor c

he 199.6 MHz s from two Rose signal gene

phase locked toMHz with the

ate laser. Thes

in control rack

ck diagram.

SMA100A Signal Generators

Field ContChassis

Stepper Motor Chassis

m was ory to rol the on gun he gun rol the

ly tune an lock signal. (SEL)

field y is at

hes to cavity

control control cavity

ohde & erators

ogether e latter e

k.

trol

Proceedings of IPAC2012, New Orleans, Louisiana, USA THPPC071

07 Accelerator Technology and Main Systems

T08 RF Power Sources

ISBN 978-3-95450-115-1

3453 Cop

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2012

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signals are input to the FCC box which produces the cavity drive signal that is fed to the RF transmitter amplifier chain. The FCC box receives feedback signals from the cavity probe and forward and reflected power signals. These signals along with interlocks are used to operate and control the entire RF system. Figures 4 and 5 show a picture and block diagram of the LLRF system.

SUMMARY A solid state analog television transmitter is being used

as a superconducting RF electron gun power amplifier at the University of Wisconsin Synchrotron Radiation Center (SRC). The system was purchased from a television station in Nevada and was reassembled and tested in Wisconsin. It is currently being commissioned as the power amplifier for a unique superconducting RF cavity gun design. The system is capable of producing 30 kW of power at 200 MHz and is controlled by a custom designed LLRF system produced by the Jefferson Laboratory.

ACKNOWLEDGMENTS The author would like to thank Dana Myers and Mike

Finley from Harris Broadcast Communications Division. Additional thanks to KRXI-TV in Reno, Nevada. Also, a thank you to Curt Hovater and Tomasz Plawski of the Jefferson Laboratory, and the staff at SRC.

REFERENCES [1] J. Bisognano, M. Bissen, R. Bosch, M. Green, K. Jacobs,

H. Hoechst, K. Kleman, R. Legg, R. Reininger, R. Wehlitz, W. Graves, F. Kaertner, D. Moncton, "The Wisconsin Free

Electron Laser Initiative," Proceedings of the 2009 Particle Accelerator Conference, Vancouver, BC, Canada (TRIUMF, Vancouver, 2010).

[2] Transcom Corporation URL at http://www.fmamtv.com [3] R. Legg, J.J. Bisognano, M. Bissen, R. Bosch, D. Eisert,

M. Fisher, M. Green, K. Kleman, J. Kulpin, J. Lawler, G. Rogers, M. Severson, D. Yavuz , “Status of the Wisconsin SRF Gun,” Proceeding of this Conference, New Orleans, LA (2012).

[4] Harris Broadcast Communications Division, “Platinum Series Technical Manual,” Rev. C, p. 1-1 (2000).

[5] David M. Pozar, “Microwave Engineering,” 3rd ed., (John Wiley & Sons, Inc., 2005), p. 333.

[6] U. Gysel, "A New N-way Power Divider/Combiner Suitable for High-Power Applications," IEEE Intl., Microwave Symposium, (1975).

[7] Niowave Inc., URL at http://www.niowaveinc.com [8] H. Padamsee, “RF Superconductivity: Science,

Technology, and Applications,” (WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim, 2009), p. 26.

[9] R.A. Bosch, K.J. Kleman, R. Legg, “Simulated Performance of the Wisconsin Superconducting Electron Gun,” Proceeding of this Conference, New Orleans, LA (2012).

[10] C. Hovater, T. Allison, R. Bachimanchi, G. Lahti, J. Musson, T. Plawski, C. Seaton, D. Seidman, “Status of the CEBAF Energy Upgrade RF Control System,” Proceedings of LINAC2010, pp. 280-282, Tsukuba, Japan, (2010).

[11] T. Allison, K. Davis, H. Dong, C. Hovater, L. King, J. Musson and T. Plawski, “A digital Self Excited Loop for Accelerating Cavity Field Control,” Proceedings of PAC07, pp. 2481-2483, Albuquerque, New Mexico (2007).

[12] Rohde & Schwarz GmbH & Co. KG, online at http://www2.rohde-schwarz.com

THPPC071 Proceedings of IPAC2012, New Orleans, Louisiana, USA

ISBN 978-3-95450-115-1

3454Cop

yrig

htc ○

2012

byIE

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–cc

Cre

ativ

eC

omm

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butio

n3.

0(C

CB

Y3.

0)—

ccC

reat

ive

Com

mon

sAtt

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tion

3.0

(CC

BY

3.0)

07 Accelerator Technology and Main Systems

T08 RF Power Sources