RESUMEN
The simplest way to produce high density hydrogen plasmas is to form an arc between the arcing electrode and the plasma chamber (cathode). For arc-based hydrogen plasma generation, a pulsed power supply that delivers 2 ms-long constant current pulse has been developed. This pulsed power supply employs a high frequency buck converter topology with a nonlinear filter inductor. This paper describes the development and testing of a constant current pulsed power supply that operates at 50 A and 550 V with a pulse width of 2 ms and a pulse repetition rate of 2 Hz. By changing the arc current, the arc impedance and the positive hydrogen ion current were also measured. The extraction of positive hydrogen ions was carried out using a three-electrode extraction design, which results in a current of 80 mA of positive hydrogen ions at an energy of 50 keV.
RESUMEN
A tuner is an important element of a superconducting radio frequency (SCRF) cavity, which is used to tune the cavity at resonance frequency. The measurement and control of the pulsed detuning phenomenon is very challenging and can be measured in the superconducting state of the cavity at a high voltage gradient. This paper describes an innovative method and unique approach for the measurement of dynamic changes in resonance frequency of the SCRF cavity even at room temperature. For this purpose, a 1.3 GHz nine-cell prototype dressed cavity with RRCAT's designed X-link tuning device is used. A test setup for measurements of dynamic changes in resonance frequency of the RF cavity has been designed and developed. The cavity response for piezo-excitation at various pulse widths has been determined. In order to simulate the Lorentz force detuning (LFD) effect, the source frequency has been modulated similar to the superconducting scenario in the SCRF cavity. To compensate the simulated detuning, a fast tuner is operated with half sinusoidal pulses at various combinations of pulse width and time advance to find out an optimum waveform. This optimized waveform will be used with a fast tuning control system to control LFD under actual operation conditions of the SCRF cavity.
RESUMEN
A multicusp-free external antenna based radio frequency (RF) negative hydrogen (H-) ion source was developed to produce 16 mA of H- ion current at -50 kVDC accelerating voltage operated with a pulse width of 2 ms at 2 Hz repetition rate. A pulsed RF igniter system is devised for generating the initial electron and ion pairs required to generate the main plasma in the pulsed mode. This pulsed RF igniter reliably starts ignition with a hydrogen gas flow rate in the range of 18-50 standard cubic centimeter per minute (SCCM). This system eliminates the need of igniter in continuous operation although it is operated in low power mode. This source operating at a low average power and without any moving parts can be expected to have a superior lifetime. This paper describes the development and operational characteristics of the pulsed RF ignited H- ion source.
RESUMEN
A cold cathode arc discharge filament based multicusp H- ion source (HNIS) has been developed using an innovative low power igniter system working in a glow discharge regime to achieve a longer lifetime of the filament. This HNIS is cesium-free and its experimental prototype generates a maximum H- ion beam (HNIB) current of 12 mA at 50 keV beam energy in pulse mode with a peak arc power of 27 kW using the triode extraction system. This article presents the results of initial commissioning of the HNIS and steering magnetic field used to separate out the co-extracted electrons from HNIB, verified through experiments and 3-D ion beam simulations.