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MAGNET DEVELOPMENT AND INSTRUMENTATION 2009SEISM: A 60 GHz electron cyclotron resonance (ECR) ion source prototypeLinked to the EURISOL and EURO-ν projects (Designstudies for the second generation of exotic nuclei acceleratorand the future neutrino factory in Europe), the beta beamproject aims to use the β decay of radioactive ions to produceneutrinos beams. Within the Beta Beam work package(WP4), the ECR task is dedicated to the design of advancedmagnetic structures to be used in the ECR ion source technology.LPSC has proposed to develop a high frequency(60 GHz) pulsed ion source prototype for the beam preparation.A first ion source prototype was designed, basedon a cusp magnetic structure using the polyhelix coil technologyand was named SEISM for Sixty gigahertz Electroncyclotron resonance Ion Source using Megawatt magnets.Here we report progress in the construction of the prototypeand preparation for the first magnetic field measurementsscheduled in beginning 2010. This work has beencarried in the framework of an existing collaboration betweenLPSC and LNCMI.Simulations of the polyhelices have been carried out to finalizethe design. The temperature field in a coil dependingon the cooling water flow and on the geometry of the coil insulatorshas been investigated. The geometry and the numbersof insulators (glass fiber) to be positionned betweeneach turn of an helice has been specified in order to minimizethe pressure drop, maximize surface cooling and tosustain the 30 tons compression without any copper deformationthat could lead to short-circuit.The maximum electrical power needed is about 6 MW. Awater flow rate of ∼ 30 l/s in the two sets of coils is necessary.Thus, the average coils temperature varies from 80 to180 ◦ C while the peak temperature locally reaches 330 ◦ C.In these conditions, the maximum hoop stress in the coilsis 280 MPa, far below the copper alloy limit of elasticity(360 MPa). At full current, the two sets of coils repel eachother with a force of 300 kN. The CAD mechanical designof the magnetic structure, taking in account all these data,was performed at LPSC. Figure 172 represents a cut viewof the source. All mechanical parts will be ready for assemblingin December 2009.Figure 173: On-site implantation scheme for the magnetic fieldmeasurement at half-intensity. Hydraulic circuit is parallel to M5existing circuit, electrical cables are connected in series with M5magnet.Figure 172: (a) External CAD design of the ion source prototype,(b) internal view of the current and deionized water courses.M5 site was chosen as a temporary implantation site for themagnetic field validation at half-current. When suppliedwith 15 kA, each set of helices (injection set and extractionset) consumes only 0.75 MW of power from the currentsupply unit. Due to impedance tuning, the prototypeshould be electrically connected in series with an existing10 MW magnet, using flexible power cables. Water flowsof 24 l/s and 22 l/s at a pressure of 20 bars are respectivelyrequired at the injection and extraction. M5 hydraulic circuitwas modified in August 2009 in order to derive about50 l/s from the 150 l/s flow and a parallel hydraulic circuit isnow being installed (figure 173). The incoming water flowwill be controlled with tuneable valves and ultrasonic flowmeters. Hall probes will be mounted on step motor jacks inorder to establish a precise magnetic field map (1mm step).The test bench is planned to be upgraded with a high voltageplatform and a 28 GHz radiofrequency emitter to allowa first characterization of the plasma at the end of year 2010.These activities will be funded within the EURO-ν program(2008 - 2010).C. Trophime, F. Debray, J. Dumas, J. Matera, R. Pfister, N. VidalM. Marie-Jeanne, L. Latrasse, T. Lamy, T. Thuillier, C. Fourel, J. Giraud (LPSC, Grenoble, France)122