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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# [email protected]
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
AC
’11/
EPS
-AG
—cc
Cre
ativ
eC
omm
onsA
ttri
butio
n3.
0(C
CB
Y3.
0)
02 Synchrotron Light Sources and FELs
A06 Free Electron Lasers