• P R Hannurkar

• Design, fabrication, and characterization of a solenoid system to generate magnetic ﬁeld for an ECR proton source

Solenoid coils with iron jacket (electromagnets) have been designed and developed for generation and conﬁnement of the plasma produced by an electron cyclotron resonance source operating at 2450 MHz frequency. The magnetic ﬁeld conﬁgurations designed using the solenoid coils are off-resonance, mirror, and ﬂat, satisfying electron cyclotron resonance condition along the axis of the plasma chamber. 2D Poisson software was used for designing. Details of design, fabrication, and magnetic ﬁeld mapping of the solenoid coils are presented in this paper.

• Compact solid state radio frequency ampliﬁers in kW regime for particle accelerator subsystems

Radio frequency and Microwave (RFM) infrastructure test facility is under development at RRCAT for evaluating and powering, subsystems of particle accelerator. As a part of this facility, design of 20–30 kW UHF solid state power ampliﬁers is in progress. For this work, design procedure has been formulated for the development of solid state ampliﬁer modules, radial combiner, divider and directional coupler; with speciﬁcations suited to RFM power system for particle accelerator. Methodology has been demonstrated by developing two different compact ampliﬁers with power output of 2 kW each, operating at 352 MHz and 505.8 MHz, respectively. This paper describes underlying design principles and indigenous development of these ampliﬁers, consisting of 270–300 W ampliﬁer modules, 8-way 2 kW radial combiner/divider and directional couplers. Design methodology for power combiner has been extended by physically realizing higher power (4 kW) 16-way power combiner and 2-way combiner (8 kW) for higher power (8 kW) ampliﬁer conﬁguration planned. Simple design, indigenous technology, high efﬁciency and ease of fabrication, are the main features of this design.

• Study of microwave components for an electron cyclotron resonance source: Simulations and performance

A high power (2 kW, CW) magnetron-based microwave system operating at 2.45 GHz has been designed, tested, characterized, and used to produce plasma. The system consists of a microwave source, an isolator, a directional coupler, a threestub tuner, a high voltage break, a microwave vacuum window, and a microwave launcher. These microwave components were simulated using microwave studio software. The low power and full term characterization of the microwave system has been done using vector network analyzer. The system was tested for 2 kW continuous wave of microwave power using glass-water load. The microwave system has been developed to study the microwave interaction with plasma at different operation regimes (Gases: Nitrogen, argon and hydrogen; Gas pressure : $10^{−5}–10^{−3}$ mbar; Microwave power : 300–1000W; Magnetic field: 875–1000 G) and to extract the proton beam current with hydrogen produced plasma. A plasma density $\sim 5 \times 10^{11}$ cm−3 and average electron temperature of ∼13 eV was obtained. This article describes various aspects of the microwave system including design, fabrication, characterization and performance studies of the microwave components.