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Title: Studies on the coupling transformer to improve the performance of microwave ion source

A 2.45 GHz microwave ion source has been developed and installed at the Variable Energy Cyclotron Centre to produce high intensity proton beam. It is operational and has already produced more than 12 mA of proton beam with just 350 W of microwave power. In order to optimize the coupling of microwave power to the plasma, a maximally flat matching transformer has been used. In this paper, we first describe an analytical method to design the matching transformer and then present the results of rigorous simulation performed using ANSYS HFSS code to understand the effect of different parameters on the transformed impedance and reflection and transmission coefficients. Based on the simulation results, we have chosen two different coupling transformers which are double ridged waveguides with ridge widths of 24 mm and 48 mm. We have fabricated these transformers and performed experiments to study the influence of these transformers on the coupling of microwave to plasma and extracted beam current from the ion source.
Authors:
;  [1]
  1. Variable Energy Cyclotron Centre, 1- AF, Bidhannagar, Kolkata 700064 (India)
Publication Date:
OSTI Identifier:
22308834
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 85; Journal Issue: 6; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; 43 PARTICLE ACCELERATORS; BEAM CURRENTS; COMPUTER CODES; DESIGN; GHZ RANGE; IMPEDANCE; ION SOURCES; MICROWAVE RADIATION; PERFORMANCE; PROTON BEAMS; REFLECTION; TRANSFORMERS; TRANSMISSION; VARIABLE ENERGY CYCLOTRONS; WAVEGUIDES