Alekseev, N N

Bolshakov, A E

Goldin, L L

Nikolaev, V I

Onosovsky, K K

Ryabtsev, A S

Veselov, M A

Zavodov, V P

CERN Document Server

Particle Accelerators. 1990, Vol. 26, pp. 229-234Reprints available directly from the puhlisherPhotocopying pennitted by license oni.,© 1990 Gordon and Breach, Science Publishers, Inc.Printed in the United States' of AmericaN.N.ALEXEEV~ A.E.BOLSHAKOV, L.l.GOLDIN, V.I.NIKOLAEV~K.K.ONOSOVSKY~ A.S.RJABTSEV~ M.A.VESELOV~ V.P.ZAVODOVI ns.t i tute +or Theor-et. i cal i:lnd E~,~ pet'· i mental Physi cs,MC)':;C::OltJAbstract The current status of the ITEP proton and ionaccelerator complex which is being created now on bhe base of thetTEP 10 GeV Proton Synchrotron is described. The paper includesalso a brief overview of the ITEP accelerator complex futuredevelopment plans which are under intensive discussion now. Oneo of the p r' 0 pas c\ 1:::' un c! E~ t- dis c u s ~; ion i S~ +..: h e con s t r uc t ion o~: anactelerator with superconducting magnets far 30-40 GeV energy(protons) and 5·10A 12 pIs intensity~ and an ~-generator for >10 A 7~!5 with < 10A -4 momentum spread.I NiF:ODUCT I ONThe ITEP Proton Synchrotron is now being reconstructed into a protonand ion accelerator complex facility which will be able to accelerateions of all atoms with Various Z/A values [1,2]. The first stage ofthe reconstruction which~ when fini5hed~ will make it possible toaccelerate partially stripped heavy ions up toSWing" A new injEctor for ion acceleration has been constructed andtested. The ian guide from the new injector to the synchrotron hasbeen assembled and put to worke A new synchrotron vacuum chamber andhave been constructed and assembled (5J" Some parts of high power RFS)/Sit.em h.:r'/e bE~en mocJer'ni zE~d. {~ r'll::n-J, C::Hnputer :e:ontr·oll ed 1ow pO~·J€~r' F<Fsystem has been developed and put to work [3J.The slow extractiOnS\l~;t:.s~m h .:'t':> b 2€?n c:r.:lr:J::;t'.r'uct. ~~C! '::'tr'icl i ';i nO~'J b:€~':ri'lf~"'·t.E~;t.ed •F .....~ r<::_~lt_· ;:O","IC.; ,-,1: LJ~.';,2.+ ~l·':.l\ll.'-·~ t\~E'jr'\ .; 'r~ "'er+ec-l ~ "" .... Q t.h,,~4 _ \ ..i '"T rl ';"_ t .... , \ t;.:. J t:.: _, ...·l __1 ... '- t= '" ... , I l.- _ ~ synchro+..:rnrl andaccelerated to 4~3 GeV/A energy in the middle of 1988. First physicalexperiment with He~+ions accelerated in theITEP synchrotron had beenperformed in t~e 1989 May-June session. The intensity' of the beam wasap p ~- c;~ i ma. t 'E 1y ]A2V" 9 p 2.~'" tic: 1e f:5 / Pu 1s' t~ • Ci r~ C!...t 1 <:1, +..: ion 0 f abo Ll t l.:j ,. 1!2v" 9 N.....achieved in Ju~e of this yearu Ions were generated in a new injector229230 N. N. ALEXEEV ET AL.with a duoplasmotran source" We will be able to accelerate partlystripped ions as soon as we change for new the old internal targets'gears which do not permit us to achieve vacuum better than 10A -8 Torr.So we can accelerate now in the synchrotron light ions withZ!A 0.5 up to 4 GeV/A and will be able to deal with unfully strippedhE~c:rv"'r' i c)ns i n near' f utur'E~ (up t. C) 1 [;12') / A) •The next stage of the reconstruction includes installation of anadditional ring in the tunnel of the synchrotron. With this .ringf i il i ~;hedthE ace e1et- at i CJ n ~i c: hEun E~ ~AJ i 1 ], c: h i::\n9e " Heavy ion ~.; i nit i e:\ 11yaccelerated in the synchrotron with small Z I A value will be ejectedfrom the synchrotron~ stripped by foil ahd saved in the additionalmagnetic ring as long as the synchrotron is reajusted for a new chargevalue" Afterwards the ions will be reinjected from the saving ring(3--3. ~5 GeV/A).~~CCELEHATI ON DF Fr.~PT I I~)LL.Y ETF~~ I PPED I ClNSThe twa step scheme of acceleration of heavy ions that includes as thefirst step the acceleration of partially stripped ions in thesynchrotron gives us the possibility to use-a low energy injector and10 v-J Z ,I A v ell u e ~~ cd: ~. C) n ::; • Th E~ c:l i -:i .::\dvc\.n t. el ~J €~ c} f t. h E~ ~; c: heme i -::; t h E~necessity of very high vacuum <Qf the order of 10A~10 Torr) in thesynchrotron ring. These reqUirements, though, are net tbo severe formodern vacuum technology~ and we succeeded in construction of thevacuum chamber and the pumping system meeting all our needs.Heavy Ion InjectorA simple resonator structure with few accelerating gaps can beeffectively used for acceleration of ions with various Z I A values.We use nbw a structu~e that contain 4 accelerating gaps. The frequencyof the accelerating field is about 3 MHz and the amplitude voltagereached nowadays is about 2 MV. We hope to reach 2.5-3 MV in nearestfuture" Calculations confirm that 0.5X momentum spread can be sequredfor Z ! A values from 0.05 to 0.15 with injector phase acceptance ofabout 18{2'o.ITEP PROTON SYNCHROTRON RECONSTRUCTION 231We are going to use several ion sources. Light ions (up to Ne orAr) can be generated in ordinary duoplasmotron sources which producerather high ion fluxes in low charge states (up to 3+). Some versionsof C02 laser sources and a MEVVA i.on source are being developed toproduce heavy ions from solid substances.We have developed a CO~ laserBeam Transport LineThe ion guide from the new injector to the synchrotrory has beenassembled and tested~ It is placed in the part of the synchrotrontunnel which is very densely occupied by bulky equipment of secondarybeam transfer lines. The trajectory of the injected beam goes aroundit and has five bends. The parameters of the transported beam are:energy - up to 24CZ/A)A2 MeV/A~transverse emi~tance - 100~ mm.mrad inevery plane,momentum sp~ead - up to 0.5%. The ion beam transfer linehas been put to work. As was said before circulation of a beam of N~ions in the synchrotron ring had been achieved in June 1989.RF Low Power SystemThe new RF-manipulation system for ion acceleration had been developed(3J. As was already mentioned~ the synchrotron has to accelerate ionswith different Z I A values.· The RF-manipulation system is to beeasily reajusted from one ion type to another. Intensity of ian beams,e~;peci 2~11 y C)·f he2:\vy C)nE~-::;, lil'::'ty b€~ low. (.ic:c:or'di ngl y, bf~c:Hn PC)4Eii ti onobservation and radial feedback seem to be embarrasing. Therefore thesystem has to reproduce the dependence of the acc~lerating frequencyon the magnetic field induction without radial feedback as accuratelyas; po,:;;si bl e. The ne~J ~;'t'st.€~m ITlLlSt. per'mi t ..::\1 so to change the tlarmoni c:number in the course of acceleration because the frequency range ofthe accelerating stations is unsufficient far heavy ion acceferation.The new system and the algorithm of its tuning as well asharmonic number change procedure have been tested with protons and He2~ions. Relative deviations of frequency values (wihtout feedback) didnot exceed 10A -4 from those given by calculations. This accuracy issufficient for ion acceleration.232Va.cuum S~ytS tE-?mN. N. ALEXEEV Er AL.w€~ h':l\!l::~ c::h~,ng~:~d trlE~ s;ynchr·crt'. i'" on \laC:UUI1l c:h.=\mb€~r· ~lnd i t. 5 pump i n~Jsystem. The new vacuum system can be heated up to 400 0 C. For pumping,we use ion pumps and getter elements which are stretched in the vacuumvolume along the Vacuum chamber walls. To produce these elements wec: C) v r::~ r' s; t ~d n1E~~;S s; t. E:~ t:~1 t. L\ b€~ '::; b ';l PC)r' aL\ ';;; t:. i t: 2in i Llm• r he titani U IT\ i. s;activated when the tubes are vacuum heated by electrical current. Theabsl:)r·pt.i c)n c.::\pabi 1i ty 0+ t.hE~ ~.IettE~r· Ccln bl~~ i nc:rec\s€~d €~,,=;senti all y i·fthe stainless tubes are coaled by liquid nitrogen. We have reached1·10A -10 Torr in several' sections of the synchrotron vacuum chamber.Tothe end of this year we will replace the internal targets~ gears bynew ones and hope to reach 1·10A -10 Tarr in the whole volume of thesynchrotron chamber.For slow extraction we excite transverse oscillations of the particlesin the ver~ical plane by a third order resonance. The particles withbig enough oscillation amplitudes jump over the iran septu~ of aLambertson magnet. The vertical magnetic field of the magnet deflectsthen the particles in horizontal plane and directs them into the beamtransfer line. Such a scheme of extraction made it possible to get 40%ejection efficiency. The development of the system to get betterejEcti.on ef·fi.ciency is continued.We must add here t~at the traditional schemes of slow extractionare hardly possible in our synchrotron because of large nonlinearity0+ the m':\~Jnet.ic ~:ielcl in t.hE~ hOf·i2:c.lnt.e:\1 plane.Savi n(a F:i ngAs had already been said it is impossible to get fully stripped heavyions at injection because of low injection energy. Therefore the ionswill not reach maximum ehergy. It will be possible to do it aftersavi ng magnet i C t-i ng install ati on. Accel erated in the synchrotronheavy ions with low Z I A value will be stripped in the foil placed inthe transfer line linking the synchrotron with the saving ring. Theiens will circulate in the ring as long as the synchrotron systems areready to accelerate ions with new charge value. Then the ions will bereinjected into the synchrotron and accelerated there up to themaximum energy (3-3.5 GeV/A).ITEP PROTON SYNCHROTRON RECONSTRUCTION 233The saving ring has FODD structure and consists of 21 cellsformed by 42 bending magnets and 42 quadrupole lenses. The magneticfield in the ring is constant and there are no acceleration stations(small RF-voltage can be used for beam bunching only). By now all themagnets and lenses are installed on their supports with the presizionbetter than 0.1 mm. The power supply'system and cooling system arebeing assembled. The vacuum chamber production and installation are infull swing. The equipment for the beam transfer lines from thesynchrotron to the saving ring and back as well as the equipment ofthe injection and ejection systems are being manufactured.Control SystemThe c: C)n t r 0 1 If;ys t em C)+ t. h €~ h E~a \/ 'l i Cl ri C:\ c: c: .::~ 1 t~~ Y" c'l t Gr' c: C)mp 1 E~:< i Si b 2:\ S f::~ cI C) nthe e>~isting proton s~lnchrot.:.ron c:oiltrol s·..,lstem and is rathet- itsfurther development. Several mini-computers are linked at the samehierarchical level bya single communication line. Mini;-·computers aree qui. PP€~ cl lt~ i t r, p c:> ~"4 €~ r' ·f u 1 '::i t:. C} r" .::'1 ~J E~ r.:! E:~vic: E~ ~~ c't n cl E~}~ E~ c: u t: €~ t h E:~ 1: un c tic) Ii S C) 1:the central processing and the data basing. The distributed equipmentof the accelerator complex is linked with the central processors bymultidrop buses. The length of the buses is up to 400 m~ bit-rate is 5Mb/s. Interface crates connected to the multidrop buses play the roleof knot. e ~t t·::\ +.: ion 5 VJ ri i c: h m2 '/ b E'~ U S E~ cI f 0 r- m0 c:1 u 1esinC c:J r p 0 rat i (]nandmultidrop bus and branch buses, and the othersmulti-processorknotbetween theclri ven by ~\Some 01: t..: het:.YP€~Sbetr"ansl ator'sassemblies ..datel~J(Ji n~jsimplecanted nmicroprocessor ormultidrop bus branching. We arestations. Some of them aremi. c:r'C)-"pr'C)c:E~'::;sor" cont.Y"o11 €~cl knc;t:.~:; ,::'I~"f:~ c::c:rH"'lec:tE~cl lt~i t.h E:~,=lc:h C)t!")f::~r' t)''ladditional serial data links to reduce the informational load of- themultidrop bus. Local control of various types of accelerator equipmentwill be fulfilled by microprocessor modules of several types.OUTLOOK IN THE FUTUREIn last years the ITEP proton synchrotron has been working forphysitl:\l e>~per"iment~, ::'~5rZH?~ - 4!,'Z',ZJ'Zf houres/year with average intensity~:. • 1. ~!' ..... 1. l P / 5 • ::> t::~ c: C) nd c\ r" '/ p E:i. r" t. i c:: l.€~ b ~~am:l .=:\ r e ~J en er (:l t. E~ cI i. n i n t. E~ r n c\ 1targets by p~oton5 of up to 9.3 GeV. In addition, protons with 70-200234 N. N. ALEXEEV ET AL.MeV energies are used for applied purposes (mostly for medicine).A+t:. €~ r r e c: Qns;t. r Ll c: t. i C) n ~~e IfJ i, 11 b e ,,::\b1 E~ t c} .c:\ c: c: €~1 E~ "" c\ t €~ V c:H" i C) Us; t. y p e:~S C) 1:ions up to 3-4 GeV/Au We will direct slow extracted ions and protonsi n t. C) t. h E:~ c: h c'l nn E~1':;; t. h C't t ,:;'tl'" ~~ u ~; E:~d n Cl \t'J +C) Y" S ~,~ c: [)nc\ ar' Il partic 1e tl e:~atTl s;The plans of future development of the ITEP accelerator complexare now under discussion and not yet finally determined. We considerWc'lyS; t.o i ncr'E~~:"t'=;e pr'c)t.on E~nE~r~JY u~) t.o l ~5 -- ,lJ·~!1 GeV c\nd becHTl i nt€~nsi t. y t.oThe construction of an atiproton facility to generate more than1. - rQV'·:.' P/ S 0 f 3m -- L~m [,e ~j ~'\I i. t h 1r~vo. - 4 m0 noc rll'- amc\ tis i t Y i 5 disc ussed.(To have such an intensity of antiprotons one needs at least 2' 10A 12pIs of 30 GeV energy).An interesting program of experiments with suchThe problems that must be solved are not in the acceleratortechnology field only. Severely limited territory of ITEP that issituated among the densely populated blocks of th~ sity limits thesize of installations.The ecological problems which arise because ofthe aboveground position of the now existing proton synchrotron mustbe very carefully considered in future development plans.We are working now at the project of the 40 GeV synchrotron(protons) that will be situated in an underground tunnel wit.h about700 m circumference. Such an accelerator will permit to construct theinclude the possibility of ion accele~ation.REFEF~ENCES1.. N. N. A1 €~ ~< r::~ €~v ~ ;1 • I~. t.,/ t::o~ 'f) E:~]. Cl V ~ L. L. Go1c! i I"'r E~ t 2:\ 11 , I TEP CC) en p 1 €~;{ ·f CJ rooProton and Heavy Ion Acceleration. IEEE Trans. on nucl~sc.,1985~Vol.32~ N 5~ p.p. 1693-94.2. N.N.AIEn~eev!l (.i.E.Bc:)ls;h';'lkC)v~ L.L.tjc)lcli.n €~t: e:\11 , ~~c:c:E~ler'c\tc)l" -f:orProtons and Heavy Ions. Proc. of XIII Inter. Conf. on High EnergyAcc., 1987~ Vol. 1, p.p. 234-36.3. N.NftAiexeev~ VuP.Piskunov~ A.S.Rjabtsev et al1~ Computer ControlledSy ':; t e:~ I'n f C) "" PF- In 2:\nipu 1':'\ tiC) n i ri t. h €~ I TEP Pr' C) t:. C) n E> y nc: h r' C) t.l''' C) n U-- t !!1 •Proc.of Europ. Part. Ace" Confn, Rome. 1988.4. 8.L.lo+fe, Preprint ITEP, N 143, 1987.5. L.L.Goldin, Ju.B.Zudinov, N.Enlvanov et all~ Vacuum Chamber forProton-Heavy Ion Synchrotron. Proc.of the 1987 IEEE Part.Acc.Ccnf.,Vel. 2~p.p.876-77.

Itep Proton Synchrotron Reconstruction

Itep Proton Synchrotron Reconstruction

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