Indian Particle Accelerator Conference InPAC-2015 Date 21:12:2015 Category : RF based Accelerators (A2) Session : Poster session # 1 Paper No. : ID231 D. V. Ghodke*, R. K. Khare, Rajnish Kumar, Ranjan Kumar, B. K. Arya, M. Pathak, V. K. Senecha and S. C. Joshi MHz RF Based Ignition System for RF Driven H - Ion Source Proton Linac & Super Conducting Cavities Division, Raja Ramanna Centre for Advanced Technology, Indore , INDIA Paper No. ID231 * [1] Steve J. Hill, Book on “Inductively Coupled Plasma Spectrometry and Its Application,” Publisher Blackwell Publishing Ltd., second edition, [2] Roy Middleton, Book on “A Negative-Ion Cookbook,” University of Pennsylvania, OCT, [3] D. Marcuzzi, P. Agostinetti, M. Dalla Palma, H. D. Falter, B. Heinemann, R. Riedl, “Design Of The RD Ion Source For The ITER NBI”, Tranc. Fusion Engineering and Design, 82, (2007) pp [4] M. Kronberger, J. Lettry, R. Scrivens, “Finite Element Thermal Study of the LINAC4 Design Source at the Final Duty Factor,” Deliverable Report, [5] Stefano Mattei, “Plasma Ignition and Steady State Simulation of CERN’s LINAC4 H- Ion Source,” Linac4 ion source review, [6] R. F. Welton, M. P. Stockli, S.N. Murray, J. Carr and J.R. Carmichael, “A Plasma Gun Driver for the SNS Ion Source,” Proceedings of LINAC 2006, PP [7] J. Staples, T. Schenkel, “High-Efficiency Matching Network for RF-Driven Ion Sources,” Proceeding of the 2001 Particle Accelerator Conference, PP [8] D. Kuchler, Th. Meinschad, J. Peters, R. Scrivens, “A RF driven Source for LINAC4,” 12 th International conference on Ion source, Aug [9] Y. W. Kang, R. Fuja, R. H. Goulding, T. Hardek, S. W. Lee, M. P. McCarthy, M. C. Piller, K. Shin, M. P. Stockli, and R. F. Welton, “RF improvements for Spallation Neutron Source H- ion source,” Review of Scientific Instruments No. 81, 0A725, [10] V. Dudnikov, R. P. Johnson, S. Murrey, T. Pinnisi, C. Piller, M. Santana, M. Stockli, R. Welton,2 C. Johnson, and M. Turvey, “Improving Efficiency of Negative Ion Production in Ion Source with Saddle Antenna,” Review of Scientific Instruments No. 85, 02B111, CONCLUSION: A prototype inductively coupled plasma based RF ignition system was developed for use on H - ion source at RRCAT. The RF antenna was characterised, measurements were carried out. An impedance matching network was designed and simulated using LT-spice and ELSIE 2.55, the simulated results were reported in this paper. The maximum MHz RF power deliver the plasma was 700W and generated maximum ion current was 5 µA, at hydrogen gas purging at 50 SCCM. The current generated by ignition system will be used for seeding in the main plasma chamber for inductively coupled plasma heating. ABSTRACT: RF based H - ion source requires ignition system for initial seeding, for main inductively coupled hydrogen plasma generation. This paper presents the MHz RF based ignition system developed for RF driven H - ion source. The ignition system consists of a ignition chamber made of two alumina one end closed cylindrical tubes, 7 turn RF antenna coil made of 4 mm copper tube with water cooling arrangement, molybdenum electrode with 3.5 mm aperture and holding assembly made with copper, with provision for water cooling, hydrogen gas purging and viewing window for plasma, MHz 1 kW RF amplifier, impedance matching network for RF antenna and DC power source of RF amplifier. The antenna parameters measured using VNA, these parameters are used to for impedance matching network simulation. This impedance matching network is validated by experimental prototype test setup. The maximum diffused plasma stream current measured with plate mounted at exit of aperture was 5 µA at 50 SCCM and 110 W RF power and this ion current gets saturated with increasing RF power. The maximum RF power deposited was 700 W. 3D view of ion source plasma generator CAD drawing of ignition system Block diagram of MHz RF source, impedance matching network and measurement for ignition system Measured antenna parameters using VNA 1 KW RF SOURCE, RF POWER MEASUREMENT AND IMPEDANCE MATCHING NETWORK COMPONENTS Sr. No. ComponentsValue 1.RF signal generatorTektronix AFG3102C MHz, 140 W RF Amplifier Communication concept AN MHz 1 kW RF Amplifier Communication concept AR Directional Coupler for RF power measurement Bird Electronics, DPS 5010B, 100 µA. 5. Parallel capacitor to the source (C P ) 235 pF 6. Series capacitor to the RF antenna (C S ) 80 pF 7. Tektronix, voltage and current measurement probes Voltage probe: P5100A Current probe: P Connecting Cable and connectorRG218, N-type 7 TURN SOLENOID ANTENNA PARAMETERS Sr. No.ParametersValues 1.Inner diameter40 mm 2.Outer diameter48 mm 3. Conductor size with water cooling 4 mm dia. Copper Tube 4. Insulation on conductor with heat sinkable sleeve 0.2 mm thick insulation 5.No. of turns7 in single layer 6. Series Inductance at MHz 2.11 µH 7.Equivalent series resistance at MHz 5.03 Ω LT-spice model of RF source with impedance matching network and antenna. Simulated smith chart for input impedance of matching network for frequency 10, and 15 MHz. Simulated steady state antenna voltage and current. Simulated frequency response of current through antenna and its phase angle. Experimental test jig for testing RF based ignition system. Variable vacuum capacitor Impedance matching network along with 7 turn RF antenna. Visible image of hydrogen plasma generated by RF based ignition system. Fixed capacitor impedance matching network along with 7 turn RF antenna The reordered RF antenna voltage and current through it, (CH-1 200V/div. CH- 2, 1A/div. CH-M 100W/div.)