The 11th Symposium on Accelerator Science and Technology, Harima ~cience Garden City, 1997

Stretdur Mode mKSR
AkiraiDDA, Makoto 1NOUE, YoshibisalWASHITA, Hironm IDNGW,Hi.rokaru FUJITA, Toshiyuki SHIRAI atd Takasli SUGIMURA
Institute fur Cllcmial Reseat:h, Ky<to Univm;ity
G>karn;oo, Qji-city, Ky<to, 611 JAPAN

Abstmct
KSR is at doctron st~ ring with maxirmm. energy atd
cin.:umfmn:e of :00 MeV atd 25.683 m, resp«tivdy. A p1Jsestre1dler mode of KS R fur 100 MeV doctron rean f<m the injedor
linac is reing JnPaed By m;ru,inatim ci three tum injedim atd
third ocderresonm.ce e~~:tra:tion with the repetition mte of 10Hz, thedlty :fader is e~~:p:ded 1o re miscrl f<m 2xl0'5 1o more that 0.9.
Av~ intemty of the doctron will re inaemro up to l.Sxl<f ws
withthereduarl~intemty ci 1.7x1<Pws, \\hil.eoom:spmding
values fOr the dired: w1put rean f<m the linac~re 1. 2x 111 ws atd
6x10 15 Jl>S, resp«tivdy.
llntrodudim

KSR was ociginally designed a; at doctron stmge :ring fur
syn:motrm light some When q>eraed with the maxirmm. energyof300 MeV, aitical Wcl\ekngthc:i.the lightf<m thedip>lesed:imis
17 nm, \\here the mdim of WIVaute is 835 nnn[U l rm:ls,oo\\evtl', more time atd rudget rei>re mmpletion of KSR a; a lightsourreMem.\\hi.le, the injedor doctron linac with s-lmxl discloalro type, \\hich is shown in Fig. 1, has rem oompletro in
Cboh:r, 1995 atd some e~~:periments utilizing its wtp.It rean m\e
rem statal[ 2]. Is JU1sewidhatd repetition tate, 00\\evtl', ~relimillrl relow 1JJS atd 2D Hz, resp«tivdy, \\hich resultS in a snuildlty ild:oc of2xl0"5• This imp>se se\ere limitltioni>re~~:periments,:Dr e:mnpe, a the e~~:periment ofPatametticX-mdiatim f<m aystl..
the doctron ~ aurert atd widh~re i>JCCrlto re less that1 mAatd
10 m, resp«tivdy in ocder to avcid the pie~ of si.gnas f<m thedetedm: In this oomitim, mly si.ng1e ev_ent is deteded in. a p1Jse,\\hichrm:lslongertime to a:wmulaeenwgh events.
In ocderto im~ this si.twtim, a stre1dlermode ci KSR hasrem pq>Oled 1o inaeme the dlty tild:oc of the doctronb eam[3lCombinatim of~tum injedim atd slow rean e~~:tra:tion with thirdocder resonm.ce with the repetition mte of 10 Hz is e~~:peded to a1ain
dlty tild:oc more that SU %. In the JRSeO: JDpeJ; w1lim of thestretdler mode of KS R is JRSenl:ro in the rext sed:im atd then. theJRSent stam of the lmdwa:-e JRPaatim is de!Dibtd

2 Outine d'tJ.e Statur MKie
The time stiudure ci the doctron rean puvided by the injedor
linac atd stretdler mode of KSR 1re shown in Fig. 2(a) atd (c~resp«tivdy, \\hil.ethe stmrl rean intmlity in KSR ismowninFig.
2(b). At themmitim ltilUedi>rPXRe~~:perimentlbovemertimrowith p11se~ atd widhof lmAatd 10m, resp«tivdy, theav~atd ~ intemties ~re 1.2x1<1 atd 6x1015 ws resp«tivdy. In thestretdlermode, rean is injeded in 0.3 JlS by ~tuminjedimatdthenliterthe oomitim fur thirdresonm.ce e~~:tra:tion is fuJfillro, the reanis e~~:tra:tro slowly.
JnFig. 3, thejila;espa:ep<t oftheinjedim reana thee!l:it
c:i.the in:O.«tocis gi\en 'Ihreettminjeded rean rolalfs in ajila;espa:edlip;ewith the a-eaof -60 1tnnninnd. The re1ative p>sition
ci the sqttm is shif1lrl with tum by p1Jse e~~:ciution of thepertubaoc. We ~re a;suming the momemnn Spreai of ::t2% i>r the(a) Oulput of lbe Ele!:lroa LiDacFig.2 1lme strudure ofthf:doctron linac(a~ stmrl rean inKSR(b)atd e~~:tra:tro rean f<m KSR(c}Sms-band Electron Unac
Buncher

Accelerator No.I

Accelerator No.2

Accelerator No.3

ElectrotiGun

Quadrupole
Magnet No.I

Quadrupole
Magnet No.2

Quadrupole
M&JDet No.3

Quadrupole
Magnet No.4

Fig. 1 lltymt of KSR atd its injedor linac-59-BeamDump

The 11th Symposium on Accelerator Science and Technology, Harima Science Garden City, 1997

d·-------

0.30

x' (mrad)5'' 7-•/--------~~~~I ':) '" .
1'-::__~;/2-1.;~0- )x (mm)(:_)(0-2'-w~. ~---~..---.---/ /!

60n:mm · mrad~u"'-s"'
eol::"!j"'w----~ ......

""-~···-~--······ ---------~

Trajectory of the Extracted Beam
0.25
0.20
0.15
0.10

~

-5

Fig. 3Phasespae ]ict of the injected l::ean a the exit of theinfitl.toc.

Distance along the Orbit (m}Fig.5
citculating l::ean in the ring. Bemuse the long straight sections areooubly a:lr<matic; al d.ectrons with momentum sprealhavethesamedascrl ocbits in the long sttaight sectim v.herethe infiectoc exists
The d.ectron l::ean injected into the strole trm.sveJSe{ilasespa::ed.lipse is enlru:ged in its l::etatron asciDatim an]iiture by ~plying
trm.sveJSe RF dectric fidd v.hich reson::te; with the l::etatron
asciDatim (RF Knock-out). When the OO!m rea:he> a these{Xmtrix,, v.hich is the bounday betwt:m the strole m.d unstd:Jle
regions of the l::etatron asciDatim, it romes ootside mther mpidly
amg the ootgoing sepmtrix as shOVIIn in Fig. 4. The tum
sepmtion of the extratcrll::ean is allculacrl to l::e 32 mm a the fiJSt
seJtum position 45 mm ootside :li:un the rentni ocbit, v.hichresultsin the extration efficien:y -97 % v.hen v.e use seJtum thickress ofO.lmm.
Electrons v.hich jump into the gap l::etwt:m dectrores of thedectrostaic seJtum(ESS) is refitl.tcrl by 18 mra:l m.d then finth:r
refitl.tcrl by a seJtum magna (SM) loattfrl 0. 7 m cbwil. strean frcm
the end of the FSS. In Fig. 5, the ~tl.tocie; of the extratcrll::eansare illustntcrl.
3 Appanms mr Slow Extrad:ion
The third ocrer resonm.re, 3vlp7, is excitfrl by a single
sextupole magnet, SXR, loattfrl just downstream of the infitl.tcr as
indiatcrl in Fig. 1. ls strength, B''VBp, is 0. 8 T/m2 m.d is ve:ry:faint rompaed wilh thase of dnomaicity rorrtl.tion, v.hile themagna with the same resign as the dnomaicity rorrtl.tionis utilim
0.010·l··············i··············l····....

T~tl.tme. of the extratcrll::eans.

Bemuse the fiJSt seJtum is required to have vety thin seJtum
width, it shoold l::e the dectrrntaic me The seJtum thickress
assumcrl a the moment is 0.1 mm. In Fig. 6, the crass sectiona
view of the FSS is shOVIIn The seJtum position is resigned to l::ea:ljustabl.e with use of 4lin:a-motion i.IDtlrooghs. The gapl::etwt:mdectrores <.an l::e dl.m.gcrl frcm 5 to 35 mm. The length of thedectrore is set to l::e 0.3 m to refitl.t dectn'>ns with 100 MeV as lruge
as 18 mra:l by the dectric :fidd of 70 kV/cm, v.hich seans mtherronsavaive value

Fig. 6 Crass Section oftheEI.ectrostaic SeJtum (ESS).
The l::ean refitl.tcrl by the FSS is sepmtcrl frcm the citculating
l::ean envelqJe as lruge as 20 mm as shown in Fig.5. Using thisspa:e :fbr sep:um ooil m.d vawum channr w.ill, a sep:um magnawith the magnaic fiddof0.5 T with the gap reigli:of20mmistol::e
set 0. 7 m oownstrearn frcm the ffi s. The seJtum magna is
resigned to l::e instalcrl ootside the varuum dl.anl:x:r m.d have auvcrl~erture to avoid the sagitta. as lrugeas 22 mm in atse of rectmgulcr
sh~e,.-...

0.005]

@"-"

><
0.000

......t............

~::::::::::::t::::........ ' ...
-0.005 ':--'----"-'----"-....i-~:--__i....-.L.---i..-_i_-;:-,!
-0.05
0x(m)
Fig. 4 PhaseSpa::ePlct a theEntralce oftheFSS.

4 VaruumSyskm
In Fig. 7, the VclQJUm system ofKSR is shOVIIn Themagnd:sof the KSR v.ere {I't:eisely aigm:l in Match 1995 with the p-ecisim
of:!O.l mm. Varuum dl.anl:x:rs in the.emagnd:s V>ereinstalcrllast
summt:r. The ere section just oown streanoftheinfitl.toc hasarealy
eva:uacrl by roughing JXImps romprned of rotaty m.d tutbo
molea:dcr {XltnpS m.d 5x 10-6 Torr has l::een ootained withoot seri oo;
lelk. Frcm the residual gas m.aysis, the main romp<rent is :fOund
to l::e warer. We expect_ tha the sutfae of the varuum dl.anl:x:r isdeanenoogh Ap]iirntim ofOOking togetrer with q>eraim of-60-

The lith Symposium on Accelerator Science and Technology, Harima Science Garden City, 1997®--

@ootc~OIIhodltianilallon . . .

.. .... ......

®~Fig. 7 Vaannn system ofKSRion p.nnps md 11 getter JUmpS a; indiatal in Fig. 7 will reai2e thevaa.nnn Jressure a; shown in Fig. 8, \\hich is \\ell retter thm theJressure retrial fbr the stretdler mo00(3x10-6 Torrl4l Some
imJro\ement is required fur the q>tntirn a; syocllotrrn light soune
I nstallatirn of alditionalion md 11 getter_(Umpsin the long stmight
sectirns md sectirn !rCUnl the RF cavity is reing stwm.
1 o- r-~~,-----r-~~,--~--,----,r-r--~--,----,~~--..---,---,Fig. 9 Rerent Overal View ofKSR
oompld:al. These items !l"e to re oompld:al lDltil the md of thisb:a yea md \\e ex:JX!ct the :fitst rea:n citculati.rn in rext spring.

....
....
-Aclm.omulgonmt
The ruthas ~mld like to Jreselt their siocere thmks to IX. Y.
S02uki a JAERifur his :lhilful suggestionmdmoouagemmtfbrtheJreselt -ootk. Their thmks !re aso we to ooq>emtirn of IX. KMashiko. They !l"e gnteful fur l\1r. I Ka2ama fbr his oontinurusooq>emtirn through the \\hole oonstructirn st~e of KSR The
oonstructirn cf Stretdler More cfKSR is su_wc:rtal with Gmt-inAid fbr Scientific Resem:h fum Ministry of Fda:airn, Scie~
Spcrts md Cuhure of Japm.

-----~---····---~-------1------------·····~.

ii

Distance from the Innector Position (m)Fig. 8 Estimaal varuum JresSII."e in KSR with (sdid lire)mdwithcut (da;hrllire)citculati.ng tiectron OO!rns.
5 Pnsmt Sta:us IBJ.d TIDE Schedule

The Jreselt stau; is 'Mlll shown in Fig. 9, \\here al magnets
md their vawum cha:nOO:s !l"e arealy set, \\bile the long stmiglt
sectirns !l"eem)::ty. We !l"enow oonstructing theEitx:1rost!ticSe]::tum(ESS) md Se]::tum Magna (SM). Varuum cha:nhrs in the ctrer
spa:eofthe long strnight sectirns lre a so to refutricatedciterthe:final
retennination cf the ex:tration system in this :tan.
Prepaatirn of the trmS{X>rt lire fum the injector linac is aso
unoorway md \\e will make instalairn of these magnets a thereginning cf rext yea. In Jllm]lel with this, the oontni cf varicus
txj_ui_rments such a; magna JX>'Mlf su_wlies axl RF JX>'M!rsol.llUl inthe shielOOd 10001 fum the cutsioo oontrol 10001 shculd re[1] A Noda a a., 'D!sign of m Eltx:1ron St~ Ring fbr

Syocllotrrn Radi!tirn", Proc. cf the 4th EP AC, I..onlrn, Unital
Kingd:m (19941>45.
1_2] Y. Ha)"dkawaa a., 'OJsetvatirn cfPammetticX-RayRadi!tirni"001lD MeV Fltx:1ron Beans", Bean Scie~ md Tedurl~y. 2(199~.

[3] A Noda a a., ''Btx:1ron St~ md Stretdler Ring KSR'', Proc.
cf the 5th EP AC, Bamona, Span (1996)451.
[4] H Tongw a a.,'Stau; of Pulse Stretdler, KSR'', Proc. cf the
22rrl line!!" Acceleraoc Mecting, Serda, Japm (1997) in Jrint 6nJapurse).

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