Bisch, M.

Bourgarel, M.P.

Bricault, P.

Lehérissier, P.

Leroy, R.

Pacquet, J.Y.

Rataud, J.P.

Sortais, P.

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Latest developments on multicharged E.C.R. ion sourcesat GANILP. Sortais, M. Bisch, M.P. Bourgarel, P. Bricault, P. Lehe´rissier, R. Leroy,J.Y. Pacquet, J.P. RataudTo cite this version:P. Sortais, M. Bisch, M.P. Bourgarel, P. Bricault, P. Lehe´rissier, et al.. Latest developments onmulticharged E.C.R. ion sources at GANIL. EPAC 92 - Third European Particle AcceleratorConference, Mar 1992, Berlin, Germany. pp.990-992, 1992. <in2p3-00666101>HAL Id: in2p3-00666101http://hal.in2p3.fr/in2p3-00666101Submitted on 3 Feb 2012HAL is a multi-disciplinary open accessarchive for the deposit and dissemination of sci-entific research documents, whether they are pub-lished or not. The documents may come fromteaching and research institutions in France orabroad, or from public or private research centers.L’archive ouverte pluridisciplinaire HAL, estdestine´e au de´poˆt et a` la diffusion de documentsscientifiques de niveau recherche, publie´s ou non,e´manant des e´tablissements d’enseignement et derecherche franc¸ais ou e´trangers, des laboratoirespublics ou prive´s.Latest Developments on Multicharged E.C.R. Ion Sources at GANIL P. Sortais, M. Bisch, M.P. Bourgml, P. Bricault P. Leh&issier, R. Leroy, J.Y. Pacquet, J.P. Rataud GANIL B.P. 5027 - 1402 1 Cam CEDEX France Abstract Since now ten years, the field of multicharged ECR ion source sholvs a continuous development in order IO improve performances, technology and reliability of sources. A review of the very last developments made at (;?\NII, and useful for accelerator ,applications is given. A new method of soufcc luning, called afterglow tuning, for the production of pulsed curmits begins to be operational on the copy of lXR4 source for its applrcation on CEKN accelerators. A new tyJx 01 multicharged 1XK ion source, called NANCKAN made entirely with permanent magnets is presented. Very first results of multicharged stable and radioactive ion productIon are also reported. I IN-IRODI JCI’ION Multicharged IIC’R ion sources are now well-known for their applications to cyclotron iI!)ectiou or low energy beams for alomic pliysics[ I]. Thcsc ion sources have shown a very good long term stabilitv for the produclion of continuous beams. After the realization of sources like MINIMAFJOS 16 GHz [2] or (‘AJ’RJCJ-Y [1] where the role of frequency and magnetic f:leld has been shown, (he realization of a superconducting JIC‘K is a logical development in order to produce highly charged ions[4]. J Jowever in the same time the necessity of simplifying the technological structure has induced the .realization of the first ECRIS made entirely wlth permanent magnets: NJX)h4AJ~IOS [ 51. Recent developments like the use ‘of electron gun [6][7] or polarized probes [X][9J have shown that it is possible to improve JXRJS performances without changing the global structure of the source but the reliability of such xy5tom remains to be demonstrated. With the technological improvements 01 IX’RIS, their application5 on high voltage platforms 1 lO][ 1 1 ] or on line isotopic separator [ 1211 31 are now possible. lliia paper will give a more exhaustive deccriplion of recent developments on the pulsed operating mode and the ucw compact JSC’KIS made entirely with ~rmanent magnets. NAN(X;AN operriting at 10 (iII7. 2. l’lJI.!~l3~ OPIXR’I‘JON WI’I‘ll II(‘K4 14.5 (;Jmlz l+XX ion1 sources can produce (‘.W. current but at the same time and without any physical modification they can bc tuned lo produce short pulses of intensity much higher tlim during the C.W tuning and called “afterglow pulsed currents”. This phenomenon can be understood as a plasma potential disruption inducing a rapid diffusion of highly charged ions of the plasma[ 141. With the realization of a copy of the J!CE4 14 5 GJJz source from (;ANIJ, for its application on the (XRN Jxad injcctor[ IS], it is now possible to study the beam characteristics of the afterglow currents Figures 1 and 3 show the time dependence of typical afterglow and IrJJF power pulses for Art3+ ions. I f&4) 70 .~~~,...I,.,..,.... 60 j-;t~+-jz~;~mzoT 1 50 ‘lo 3F 20 ~~ IO : 0 : -10; ’ ’ ’ ’ ’ ’ ’ ’ ’ s ’ ’ ( ’ . ’ ’ j 1 2 3 4 ’ (ms) Figure 1 Afterglow peak current for Arl 3+ -‘I 2 8 -4 0 4 8 12 Horizontal posnlon (mm! 1Ggure 2 I3cam profile during the afterglow for Ar 1% ‘l’he synchrt,rii~ati(~Ii signal (figures 1 and 3) is used as integration time for profile monitor so figures 2 and 4 show the beam profile for one pulse respectively during the afterglow and the IJHF power pulse. The observation of a classical ECRJS beam profile during the afterglow shows that this currenl is useful for accelerator applicalions. The 1toriLontal profile during the afterglow seems slightly different than during the steady state. The optical characteristics or the beam energy may be modified during the afterglow due to a plasma sheath potential perturbation which induces the horizontal shift observed between figures 2 and 4. We plan now to install a rapid pulsed high voltage generator 991 on the beam Line in order to make precise emittancc measurements with an arbitrary time integration window diameter of the source is only 13 cm, the plasma chamber has a diameter of 30 mm and the distance between the resonance zone and the target is typically 10 cm. The axial mirror magnetic field is created with several slices of UGISTAB 300H FeNdB permanent magnets and the minimum IBI magnetic structure shows magnetic values very similar to the ECR3/CAPRICE ones [ 181. The l.JHF coupling system is a rectangular to coaxial wave guide transition, like on CAPRICE or ECR4 14.5 GHz [ 19][20], but smaller and no pump is necessary so the total weight of the source is typically 10 Kg. - IY 0 25 50 75 100 1 (ms) Figure 3. Beam current during the Ullf: pulse for Ar13+ -12 -8 -4 0 4 8 12 Horconlal positron (mm1 Figure 4. Beam profile during the 1 JHF pulse for Ar13+ 3. NAY0GAN 10 GHz : A hlIJI.‘I‘I-I’lJl~‘OSI: Ml JL’T-ICHARGET~ ECR ION SO1 JRCE 3.1 General characteristic.~ With the demand for production of radioactive species and the perspective of their post-acceleration, at high energy, GANII, decided to build a new small and purely permanent magnet ECRIS just in order to test the possibility of production of multicharged radioactive ions. This source, called NANOGAN. is made of FeNdB permanent magnets. This device is associated to a nuclear physics experiment intended to determine production rates of radioactive isotopes produced with a high energy heavy ion heam (up to 100 hleV/A). The choice of an ECR device is due to the very good gas efficiency of this kind of ion source associated to the production of multicharged ions [ 161 Another important property is the production of “metallic” species without any fundamental limitation[ 171. The design cbf the as small as possible It(:RIS is made in order to minimire the distance between the target production and the ionizatk,)n vnlur~x and also to simplify the technical implantation near the highly radioactive target. The outer as. METAL VAPOR OR RAMcaSoTOPE INECllaY SlSTEU J SIUPLE OR ““LTl ELEcnwoE EKTRAclloN PLASMA SYSTEM CWAIBER O”p 1 -‘;;;a,, **s Figure 5. Nanogan 10 Gllz schematic drawing The NAN0GAN project at GANII. began in April 1991, the assembly of the source h:s been made in December 199 1 and the first beam was produced in January 1992. Figures 6 and 7 show very preliminary results obtained with Nanogan during its two first weeks of functioning. The production of typical ECRIS spcctrurns of multicharged ious shows that Nanogan is a simple, easy to run and reliable ion source. The typical IJIIF power consumption is 70 W. A power of 25 to SO W is enough for producing low charge states like Arl+ I WA) 5 85 85 !05 115 125 155 (45 I dipole (AI l:igure h. Nanogan 10 (ilIz:Argon charge sl;lte distribution optimized for highly charged ions to Apt md 100 W’ are better for high charge states like 06+. O7 +, Ar8+, Ar’+ or Xt’ 7t. The prt)duction of an Ar spectrum whcrc the highest c’kctrlc;il currait is obtained 011 992 the charge 8’ (fig. 6) shows that it is possible to maintain a typical ECRIS spectrum even in a much smaller and simplified ion source. With the reduction of the piasnla volume by a factor of ahout 20, it seems that the reduction of the extracted current is the most impXtant effect compared to the weak decrease of the avemge extracted charge state (Ar6’: 22 ItAe with Nanogan and 300 @e with 1XR3 /(1APRI(‘E) [ l!J]. l\earns ‘Of 1 .7 r11Ac of IIt x1+ ,0.3 mAc of N2+, 60 pAe of .A@+ and 22 fle of Ar6+ were also produced 77 5 100 122 5 145 I dlpols (A) Figure 7. Nanogan 10 CrlIz:Neon charge state distribution optimized for Ne6+. 3.2 Preliminary on line churacterlslics A first on line experiment with NANCXiAN has been performed during March 92 on the new isotopic separator at (;ANiI, [Zl] (collah. (;ANli,/II’N ORSAY/~‘SNSM/‘Ll’(‘ (YAIJN). ‘ihe primary he:un of 20 nAp of 20Ne (200 nAe on charge IO+) at 96 MeVIA hits a target of sintered MgO of 15 mm in diameter. 20 mm in length, and divided in 30 slices ot 0.3 mm in order to increase the outgassing surface. The tarset has been hc.sted at about 550 “C with an ohmic heating (300,~ / 1.8V) and the heam power deposition was 40 W. The results of table 1 show very clearly that it is now possible to maintain a typical highly charged ion distribution of an ECR ion source during an on line experiment and that a very minority specie5 of the plasma ( “NC) has the same kind of charge state ,distrihution than a most abundant one (20Ne or ‘60, tTig.7). A first estimate gives R bc;un intensity of ‘“Ne, on the nuclear detection device (primary bein1 4 nAp), Table 1 Clharge state distribution of stable and radioactive Nc ions obtained with NANO<;AN 3. CONCLIJSION ‘These new results associated with new applications ot E(TR ion sources show that it would be now possible to design new E(IR &vices especially adapted to pulse operation or highly charge mdick?ctive ion production. 5. RH~13KEN~l:S [l] R. Geller. “E(XIS- the electron cyclotron resonance ~crn source”, Annu. Rev. Part. Scl., 1990, 40 p 15-43. (21 R. Geller et al., “The upgradIng of the ion source MINIMAFIOS”, N.I.M., A243, 1986, p.224.229. [3] B. Jacquot et al., “The new 10 GHz CAPRICE source”. 10th Int. Work. 011 ECRIS, Knoxville, USA, Nov. 90, p 133-155. [4] T. Antaya. “ECRIS for highly charged ion”, 4th Int. Conf. on Ion Source. Bensheim, Germany, R.S.I.. 63. 4 April 92. [S] P. Sortais et al., “Study of a magnetic structure for a permanent magnet ECRIS NEOMAFIOS”, Int. Conf. on ECRIS and Appl., East i.ansing. USA, Nov. 87, p, 334-352. [h] C. Lyneis et al., “Prehminary performances of AECR”, 10th Int. Work. on ECRIS, Knoxville, IJSA, Nov. 90. p 47-62. 171 V.D. Dugar-Jabon et al..“Influence of an electron beam injection on C.S.D. in an ECRIS”, 4th Int. Conf. on Ion Source, Bensheim, Germany, R.S.I.. 63, 4 April 92. IS] G. Melin et al., “Recent Developments on ECRIS”, 10th Int. Work. on ECRIS, Knoxville. USA, Nov. YO, p l-16 [9] A.G. Drentje et al., “Gas mixing in ECRIS “, 4th Int. Conf. on Ion Source. Bensheim, Germany, R.S.I., 63, 4 April 92. [lo] C. Pardo et al., “The ATLAS PII-ECR I. S.“,Int. Work. on ECRIS, Grenoble, J. Phys., Jan. 89, 50 p. 695-706. [l I] C. Ricaud et al.,“The OAI project at GANIL”, 2th E.P.A.C., Nice, France, April 90 [ 121 C I.oiselet et al., “A single stage ECRIS on line”, 10th Int. Work. on ECRIS. Knoxville, USA, Nov 90. p 133-155. [I31 (‘. Buchman et al, “‘Farget and Ion source development at ‘I‘ISOL”, N.I.M., A295 , l9YO. p. 29 l-298. I141 I’ Sortals, “Pulsed E(‘RIS using the afterglow mode”. 4th ht. C’onf’. on Ion Source. Bensheml. (Germany, R.S.I.,63, 4 Aprrl Y2. 1 IS] (i. Amcndola et al. “A heavy eon 11n;tz for (‘MN accelerator complex”. these prcjceedings. [lh] P Brlcault et al.,“E(‘RIS development for on line isotopic separator”. 4th Int. (‘onf. on Ion Source, Bensheim. Germany, R.S.I.. 63. 4 April 92. [ 171 M 1’ Bourgarel ct al., “Develvpmenl cri metallic 10n al GANII.“, 4thInt. Conf. on I<jn Source. Benshelm, Germany, R.S.I.. 63. 4 April 92. [IX] 1’. Sortals et al., “GANII. l?(:RIS status “, Inl. Work. on [XZRIS, Grenoble, J. Phys., Jan. X0. 50 p. 6YS-706. ]19] H. Jacquot. “CAPRICE a new compact ECK ton source ” 6th Int Work. on ECRIS, Berkeley, USA. Jan. 85. p. 174-188. [20] P. Sortais et al., “Results of the new E(‘R4 I4.5GHz” 10th Int. Work. on ECRIS, Knoxville, IJSA, Nov. 90, p 35-46. (211 A. Chabert et al., “The GANIL RNB project”, 2th Int. Conf. on Radio. Nucl. Beams, Louvain-la-neuve, Belgium, Aug. 91, p.115.120. greater tlurn li 105 p/s on the charge state I+ and for a heam obtained witllou[ any optimization. Ijean~s of I3N, *‘Ne and 24Ne were also observed. 

Latest developments on multicharged E.C.R. ion sources at GANIL

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Latest developments on multicharged E.C.R. ion sources at GANIL

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