Langmuir probe diagnostics of plasma in high current electron cyclotron resonance proton ion source

Abstract

A high current Electron Cyclotron Resonance (ECR) proton ion source has been developed for low energy high intensity proton accelerator at Bhabha Atomic Research Centre. Langmuir probe diagnostics of the plasma generated in this proton ion source is performed using Langmuir probe. The diagnostics of plasma in the ion source is important as it determines beam parameters of the ion source, i.e., beam current, emittance, and available species. The plasma parameter measurement in the ion source is performed in continuously working and pulsed mode using hydrogen as plasma generation gas. The measurement is performed in the ECR zone for operating pressure and microwave power range of 10(-4)-10(-3) mbar and 400-1000 W. An automated Langmuir probe diagnostics unit with data acquisition system is developed to measure these parameters. The diagnostics studies indicate that the plasma density and plasma electron temperature measured are in the range 5.6 × 10(10) cm(-3) to 3.8 × 10(11) cm(-3) and 4-14 eV, respectively. Using this plasma, ion beam current of tens of mA is extracted. The variations of plasma parameters with microwave power, gas pressure, and radial location of the probe have been studied.

Emittance and proton fraction measurement in High current electron cyclotron resonance proton ion source

“…This may be due to the fact that the measured value of electron temperature does not change much with the increase of microwave power (400-1000 W) for residual pressure of 2 Â 10 À 5 mbar (corresponds to 2.5 Â 10 À 3 mbar in the plasma chamber) as reported in Ref. [2]. Fig.…”

“…The total beam current increases with the increase in gas pressure to a maximum of 17 mA. The proton fraction decreases with increasing gas pressure because as the gas pressure increases, the electron temperature decreases [2] and the recombination processes play a dominant role that lowers the proton fraction [24,25].…”

“…The ion beam is extracted by biasing the extraction electrodes when the plasma is stabilized. The studies on plasma characterization, beam extraction and stable operation of the ion source have been reported earlier [2,3]. In this paper we report the measurement of two crucial beam parameters i.e.…”

“…A high current Electron Cyclotron resonance (ECR) proton ion source has been designed and developed for Low Energy High Intensity Proton Accelerator (LEHIPA) at Bhabha Atomic Research Centre (BARC) [1][2][3]. LEHIPA consists of H þ ion source at 50 keV to be accelerated to 3 MeV by Radio Frequency Quadrupole (RFQ) and to 20 MeV by an Alvarez type DTL.…”

Beam acceleration through proton radio frequency quadrupole accelerator in BARC

“…Gas Pressure (10 electrodes when the plasma is stabilized. The studies on plasma characterization, beam extraction and stable operation of the ion source have been reported earlier [6,7]. The emittance was measured using two slit emittance meter and proton fraction was measured using a magnetic mass analyzer.…”