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Abstract We describ

suitable for uconducting radis the use of bunch comprethrough the linprior to accele("afterburner")at maximum circumvent soaspects of transporting aelectron bunchneed for a RF heater. Additiocapital and opafterburner and

A novel bunmatch”) is preavoid implemeoperational preduced capitanew longitudinof a standard clight sources is

STANDAThe standard

and consists of

1) Accelercorrelat

2) Use harphase sp

3) Implemenergy s

4) Partially5) Interme6) Fully co7) Acceler

____________________________

*Authored by JeContract No. DEnon-exclusive, pareproduce this ma# tennant@jlab.org

AN ELECRCONDUC

C. Thomas Jeffer

e an electron use in a lightdio frequency a recirculating

ession. Phasinnac is chosen teration to the ). The final bunenergy. This

ome of the mcurrent long

a fully comph through an exharmonic linea

onal benefits inperational costd utilizing all o

INTRODnch compressiesented which enting technicaprocedures bual and operational match and compression scs given.

ARD LONGd longitudinal mf the following

rate off-crest intion along the brmonic RF to lipace

ment a laser heaspread (optionay compress theediate acceleratompress the burate to final ene

________________

efferson Science E-AC05-06OR2317aid-up, irrevocableanuscript for U.S. Gg

TRON BUCTING RA

DR

Tennant#, S. Brson Nationa

bunch comprt source drive(SRF) linac. T

g linac to perfng of the secoto de-chirp the final energy innch compressischeme has t

most technicalgitudinal matpressed, high xtended SRF enarizer and the nclude a substats by running of the available

DUCTION ion scheme (ohas the poten

ally challenginut also offeronal costs. To

its benefits, a cheme utilized

GITUDINALmatch is illustr

g steps:

n L1 to induce bunch inearize the lon

ater (LH) to incal)

e bunch in BC1tion in L2 unch in BC2 ergy and de-ch

Associates, LLC 77. The U.S. Gove, world-wide liceGovernment purpo

UNCH COADIO FRE

RIVEN LIG

Benson, D. Dal Accelerato

ression schemen by a superThe key featurform the initiaond pass beam

electron buncn an SRF linaion is then donthe potential tlly challengintches; namel

peak currennvironment, thneed for a lase

antial savings ion-crest in th

e gradient.

r, “longitudinantial to not onlng hardware ans substantiallunderstand thibrief overview

d in linac drive

L MATCHrated in Fig. 1

a phase-energy

ngitudinal

crease intrinsic

1

hirp in L3

under U.S. DOEvernment retains aense to publish ooses.

OMPRESSEQUENCGHT SOU

Douglas, P. Eor Facility, N

me r-re al m ch ac ne to ng ly nt he er in he

al ly nd ly is w en

y

Figure 1:source an

NOA new

design a Fig. 2. Tfollows:

1) I2) A

e3) P

l4) D

p5) A6) P

Figure 2:longitudin

This sc

1) RobuThat the btuninthere

2) End tBy ehigh SRF

3) On-cBecapass far ospreaavaileffici

Ear

SION SCHCY LINEAURCE*

Evtushenko,Newport New

Schematic ofnd the elements

OVEL LONlongitudinal mrecirculating

The compressi

Inject beam at Accelerate throenergy correlatPerform the linearization inDe-chirp the bpass by runningAccelerate on-cPerform the fin

Schematic ofnal match.

heme offers se

ust compactionis, one can co

bunch is compng for nonlineeby eliminating

the match withending with a peak current blinac is avoide

crest Acceleratiause the de-chthrough the linff-crest in orde

ad. Furthermorable SRF graient/cost-effect

HEME FOAR ACCEL

, R. Legg ws, VA 23606

f a conventions required for a

GITUDINAmatch, which ilinac, is show

ion scheme c

Einj ough linac (L1tion along the b

first bunch n recirculator arbeam through g near zero-crocrest through tnal bunch comp

f the machine

everal importan

management wontrol how mupressed and prear correction g the need for h

h the final compcompression, t

bunch through ted.

ion through Afhirping is achinac, the beam er to remove thre, full advantadient which tive machine.

OR A LERATO

6, USA

nal linac drivena longitudinal m

AL MATCHincorporates inwn schematicaan be describ

1) to induce a pbunch

compressionrcs linac on the s

ossing (L2) the afterburnerpression

topology for

nt advantages:

with recirculatuch and how qrovides indepethrough high-

harmonic caviti

pression transporting a the largest sect

fterburner ieved in the sdoes not have he correlated etage is taken makes for a

OR

n light match.

H nto the ally in bed as

phase-

n and

second

(L3)

a new

tor quickly endent -order, ies.

short, tion of

second to run

energy of the more

THPC105 Proceedings of IPAC2011, San Sebastián, Spain

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02 Synchrotron Light Sources and FELs

A06 Free Electron Lasers

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4) Minimizesat the wiggUnlike thebunch is espace (“penergy mmicrobuncmodulatiomicrobuncfinal achicarefully eliminatin

5) Reduces cBy eliminnot only spower souat the funenergy thharmonic achieved iacceleratetaking full

This schemethe longitudinability of the Maintaining balso presents a

GThe design

foremost, by producing devlattice serves tthe source andthose specificathe previous swhen it comesa number of vbunch length ((EL1=L2) and ththe bunch lengthe energy gaL3). To get aspace, an analthe bunch waslength, energyafter each loncompressor). Uphoton generavariables. Onethe model is ththe energy spentirely determabout the varia

s the effect of ggler e conventionaleffectively rotaparallel-to-poin

modulations thaching are

ons. Care still mching instabilitievable bunch

however, thng the need for

capital and openating the neesaves on hardwurces, but also ndamental frequhat is lost blinearizer. Furin the recircul

ed on-crest throl advantage of

e is not withounal match is

recirculator abeam quality tha challenge.

GREENFIEof any light the requireme

vice (i.e. wiggleto take a buncd transform it ations. The lonsection is strais to designing ariables: the in(t,inj), energy

he acceleration gth after the fin and phase

a handle on thlytic model of s developed [1

y spread and cengitudinal “elUltimately the ator can be wre of the importhat, for on-crespread at the pmined by the rables:

f CSR-induced

l longitudinal mated 90° in lonnt” focusing). at arise due to

converted must be taken ty as this will length (peak

his has the a laser heater.

erating costs d for harmoniware and highby not having

uency needed by decelerationrthermore, sincating linac, though the afterthe available S

ut challenges. critically dep

arc to preservehrough the fin

ELD DESIGsource is dic

ents specified er or undulatorh distribution in such a wa

ngitudinal matightforward cothe system, on

njection energygain in the rephase for each

first compressithrough the afe region of usthe longitudin

1]. Expressionsentroid energyement” (i.e. labsolute energritten in termstant results thatst operation in photon generarecirculator. A

microbunchin

match, here thngitudinal phas

Therefore ano CSR-induce

to temporato mitigate thnow affect thcurrent). Don

potential o

ic cavities, onh frequency RFg to buy cavitie

to make up thn through th

ce de-chirping ie bunch can b

rburner, therebSRF gradient.

The success opendent on the beam qualitynal compressio

GN tated, first anat the photo

r). The machingenerated from

ay that it meetch described i

onceptually, bune is faced wity (Einj), injecteecirculator linah pass (L1, L2)on (t,BC1), anfterburner (EL3sable parametenal evolution os for the bunc

y can be writtelinac or buncgy spread at ths of the desigt emerged fromthe afterburner

ating device ifew comment

g

he se ny ed al he he ne of

ne F

es he he is

be y

of he y. n

nd n

ne m ts in ut th ed ac ),

nd 3, er of ch en ch he gn m r, is ts

t,inj: wemittanEL1=L2: recirculL1: wexcessiL2: wrecircult,BC1: sminimuFor the

To asc

longitudinfunction were genL2 = 55° from ± 5°prevent athe specifenergy spspace whinterestinspread sprecirculataccelerateopens up,

Figure 3spread at acceleratiof the ene

Considcharge of1497 MHoperationrequirememust beapproximcompressrecirculataccelerate17° befor

ould like to innce growth due

is there an lator linac? ould like to ive RF curvatu

want to separalator (i.e. mustsubject to analum tolerable b sake of argum

certain what nal match schof {EL,L1} fo

nerated. Considshown in Fig.

denotes a reginy part of the fication at the pread provides here the macg results of thipecification, htor more tighe on the RF , however, as y

: Contour plothe photon ge

ion phase in thergy gain in the

SIMULAer a 1.5 GeV l

f 100 pC. AssumHz, injection

n of the afterbents that the ree less than

mately 1 kAs and toleratetor. Using thee through a 30re crest (represe

nject a longer be to space charg

optimal ener

run further ore sampled by ate beams byt be < 90°) ysis of CSR e

bunch length inment, assume 0.

constraints arheme, contour or specific valder the case fo. 3. The shadedion of operatiobunch falling photon generaguidance for r

chine can opis study is thathaving a highhtly constrainwaveform. Th

you go to lower

ot showing thenerator (in Mhe first pass the recirculator li

ATION RESight source opme a fundamen

energy of burner (L3 = 0elative energy s

0.1% and [2]. Also as

e a 0.5 ps l data from F

00 MeV linac iented as a posi

bunch to allevge rgy gain for

off-crest to avthe bunch y energy in

ffects, what isn the recircula.5 ps (rms).

re imposed bplots of EL2

lues of t,inj anor t,inj = 3.0 pd region that exon that is excluover crest. Knator for the abregions in para

perate. One ot, for a given eh gain linac ins where youhe parameter r linac energy g

he absolute eeV) as a functhrough the linainac.

SULTS erating with a ntal RF freque10 MeV, on0°), subject tospread at the w

the peak csume that wlong bunch iig. 3 we chooin the recirculaitive angle in F

viate

the

void

the

s the ator?

by the 2 as a nd L2 ps and xtends

uded to nowing bsolute ameter of the energy in the u can space

gains.

energy tion of ac and

bunch ncy of n-crest o the

wiggler current e can in the ose to ator at

Fig. 3).

Proceedings of IPAC2011, San Sebastián, Spain THPC105

02 Synchrotron Light Sources and FELs

A06 Free Electron Lasers 3135 Cop

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Using thesematch has beenthe key featuparticles in lothe transversecollective effeNevertheless, enough to begbrief descriptioFigs. 4-6:

Figure 4 (a) An injecteinjected at 10 M(b) The bunchfirst pass of the

Figure 5 (a) The momenchosen to bothand also to cophase space. (b) The bunchtime 55° afterthat the rms reto 0.28%.

Figure 6 (a) The bunafterburner to t(b) After the fcurrent of 1.1 (rms).

Figure 4: (a) first pass throu

Figure 5: (a) Epass through li

e values a prn simulated wi

ures of the scngitudinal pha

e dynamics isects were inclu

the results gin thinking aboon is provided

ed bunch 3.00 MeV.

h is acceleratede linac to a fina

ntum compactih compress theorrect the nonl

h is acceleratedr crest to a finelative energy s

nch is accelethe final energ

final compressokA with a rela

Injected bunchugh the linac.

Exit of the reciinac.

roof-of-principith LiTrack [3]cheme. LiTracase space – nos required. Fu

uded (space chaachieved werout a more det

d for the screen

ps (rms) × 1

d 17° before cral energy of 29

ions of the recie bunch down linearities of t

d through the nal energy of 4spread is reduc

rated on-cresgy of 1.5 GeV. or the bunch pative energy sp

h at 10 MeV

irculator (b) Ex

ple longitudina] demonstratinck only tracko knowledge ourthermore, narge and CSR)re encouragintailed design. Anshots shown i

5 keV (rms) i

rest through th97 MeV.

irculator arc arto 0.5 ps (rms

the longitudina

linac a secon469 MeV. Notced from 0.84%

t through th

produces a peapread of 0.09%

(b) Exit of th

xit from secon

al ng ks of no ).

ng A in

is

he

re s) al

d te %

he

ak %

he

nd

Figure 6:compress

A newappropriacontinuoupotential A proof-ofull 6D phdesign is

It is intthe recircJefferson cryomodumodules, necessaryfor 300 Mproject [4slightly fra 180° arcafterburnerecirculatbending design wox-ray souinfrastruc

The aLaborator

[1] C. Ten[2] S. Ben[3] P. Em[4] C. Ten

(a) Exit of asor.

SUMMARYw longitudinal mate for linac us-wave (cw) to both reduce

of-principle simhase space (lonrequired to fulteresting to notculator is arou

Laboratory Fules which,

could proviy. It is also trueMeV has been4]. Due to site lfrom the schemc after the recier – which wotor. Maintaininpresents a foould allow a curce to fit oncture of the FEL

ACKNOWauthors wouldry FEL Team f

REFnnant et al., JLnson, private c

mma and K. Bannnant and D. D

afterburner (b)

Y AND OUmatch has beendriven light ssources. The

e risk and costmulation has bengitudinal and lly assess perfote that the optiund 300 MeV

FEL Upgrade Dif replaced wide the 300 e that a notionan designed forlimitations, the

matic presentedrculator to red

ould run paralleng beam brightnormidable chacompact designn-site and levL.

WLEDGEMd like to thfor their fruitfu

FERENCESLAB TN 11-02communicationne, Proc. PAC

Douglas, JLAB

Exit of final

TLOOK n presented whsources, partic

scheme offet of future maceen done, howtransverse) ma

ormance. imal energy ga

V (see Fig. 3)Driver consistwith high grMeV energy

al recirculator dr the extant JLe design wouldd in Fig. 2 by adirect the beam el to the linac ness through 5allenge, yet sn for a 1.5 GeVverage the ava

MENTS hank the Jeful discussions.

S 2 (2011). . , p. 4266 (2005

B TN 10-023 (2

bunch

hich is cularly rs the

chines. wever a

achine

ain for ). The s of 3 radient y gain design LAMP d differ adding to the in the 40° of uch a V soft ailable

fferson

5). 2010).

THPC105 Proceedings of IPAC2011, San Sebastián, Spain

3136Cop

yrig

htc ○

2011

byIP

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02 Synchrotron Light Sources and FELs

A06 Free Electron Lasers