skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: A high-current microwave ion source with permanent magnet and its beam emittance measurement

Abstract

The progress of a 2.45 GHz high-current microwave ion source with permanent magnet for T(d,n){sup 4}He reaction neutron generator is reported in this paper. At 600 W microwave power and 22 kV extraction voltage, 90 mA peak hydrogen ion beam is extracted from a single aperture of 6 mm diameter. The beam emittance is measured using a simplified pepper-pot method. The (x,x{sup '}) emittance and the (y,y{sup '}) emittance for 14 keV hydrogen ion beam are 55.3{pi} and 58.2{pi} mm mrad, respectively. The normalized emittances are 0.302{pi} and 0.317{pi} mm mrad, respectively.

Authors:
; ; ;  [1];  [2]
  1. School of Nuclear Science and technology, Lanzhou University, Lanzhou 730000 (China)
  2. Institute of Modern Physics, the Chinese Academy of Sciences, Lanzhou 730000 (China)
Publication Date:
OSTI Identifier:
21124035
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 79; Journal Issue: 7; Other Information: DOI: 10.1063/1.2954967; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; APERTURES; BEAM EMITTANCE; CURRENTS; ELECTRIC POTENTIAL; GHZ RANGE; HELIUM 4; HYDROGEN IONS; ION BEAMS; ION SOURCES; KEV RANGE; MICROWAVE RADIATION; NEUTRON GENERATORS; PERMANENT MAGNETS

Citation Formats

Yao Zeen, Tan Xinjian, Du Hongxin, Luo Ben, and Liu Zhanwen. A high-current microwave ion source with permanent magnet and its beam emittance measurement. United States: N. p., 2008. Web. doi:10.1063/1.2954967.
Yao Zeen, Tan Xinjian, Du Hongxin, Luo Ben, & Liu Zhanwen. A high-current microwave ion source with permanent magnet and its beam emittance measurement. United States. doi:10.1063/1.2954967.
Yao Zeen, Tan Xinjian, Du Hongxin, Luo Ben, and Liu Zhanwen. 2008. "A high-current microwave ion source with permanent magnet and its beam emittance measurement". United States. doi:10.1063/1.2954967.
@article{osti_21124035,
title = {A high-current microwave ion source with permanent magnet and its beam emittance measurement},
author = {Yao Zeen and Tan Xinjian and Du Hongxin and Luo Ben and Liu Zhanwen},
abstractNote = {The progress of a 2.45 GHz high-current microwave ion source with permanent magnet for T(d,n){sup 4}He reaction neutron generator is reported in this paper. At 600 W microwave power and 22 kV extraction voltage, 90 mA peak hydrogen ion beam is extracted from a single aperture of 6 mm diameter. The beam emittance is measured using a simplified pepper-pot method. The (x,x{sup '}) emittance and the (y,y{sup '}) emittance for 14 keV hydrogen ion beam are 55.3{pi} and 58.2{pi} mm mrad, respectively. The normalized emittances are 0.302{pi} and 0.317{pi} mm mrad, respectively.},
doi = {10.1063/1.2954967},
journal = {Review of Scientific Instruments},
number = 7,
volume = 79,
place = {United States},
year = 2008,
month = 7
}
  • An all-permanent-magnet (APM) microwave hydrogen ion source was developed to reduce the size and to simplify structure of a conventional solenoid coil microwave ion source developed for reliability improvement of high current proton linac application systems. The difficulty in developing the APM source was sensitive dependence of the source performance on axial magnetic field in the microwave discharge chamber. It was difficult to produce high current proton beam stably without precise tuning of the magnetic field using solenoid coils. We lowered the sensitivity using multicusp magnetic fields for plasma confinement at the discharge chamber sidewall of the source. This enabledmore » stable high current proton beam production with the APM microwave ion source with no tuning coil. The water cooling and the power supply for the coils are not necessary for the APM source, which leads to better reliability and system simplification. The outer diameter of the APM source was around 300 mm, which was 20% lower than the coil source. The APM source produced a maximum hydrogen ion beam current of 65 mA (high current density of 330 mA/cm{sup 2}, proton ratio of 87%, and beam energy of 30 keV) with a 5 mm diameter extraction aperture, pulse width of 400 {mu}s, and 20 Hz repetition rate at 1.3 kW microwave power. This performance is almost the same as the best performances of the conventional coil sources. The extracted ion beams were focused with electrostatic five-grid lens to match beam to acceptance of radio-frequency quadrupole linacs. The maximum focused beam current through the orifice (5 mm radius) and the lens was 36 mA and the 90% focused beam half-width was 1-2 mm.« less
  • A permanent-magnet microwave ion source has been built for use in a high-yield, compact neutron generator. The source has been designed to produce up to 100 mA of deuterium and tritium ions. The electron-cyclotron resonance condition is met at a microwave frequency of 2.45 GHz and a magnetic field strength of 87.5 mT. The source operates at a low hydrogen gas pressure of about 0.15 Pa. Hydrogen beams with a current density of 40 mA/cm{sup 2} have been extracted at a microwave power of 450 W. The dependence of the extracted proton beam fraction on wall materials and operating parametersmore » was measured and found to vary from 45% for steel to 95% for boron nitride as a wall liner material.« less
  • We present recent work on the development of a microwave ion source that will be used in a high-yield compact neutron generator for active interrogation applications. The sealed tube generator will be capable of producing high neutron yields, 5x10{sup 11} n/s for D-T and {approx}1x10{sup 10} n/s for D-D reactions, while remaining transportable. We constructed a microwave ion source (2.45 GHz) with permanent magnets to provide the magnetic field strength of 87.5 mT necessary for satisfying the electron cyclotron resonance (ECR) condition. Microwave ion sources can produce high extracted beam currents at the low gas pressures required for sealed tubemore » operation and at lower power levels than previously used RF-driven ion sources. A 100 mA deuterium/tritium beam will be extracted through a large slit (60x6 mm{sup 2}) to spread the beam power over a larger target area. This paper describes the design of the permanent-magnet microwave ion source and discusses the impact of the magnetic field design on the source performance. The required equivalent proton beam current density of 40 mA/cm{sup 2} was extracted at a moderate microwave power of 400 W with an optimized magnetic field.« less
  • A 2.45 GHz microwave ion source together with a beam transport system has been developed at VECC to study the problems related with the injection of high current beam into a compact cyclotron. This paper presents the results of beam profile measurement of high current proton beam at different degrees of space charge neutralisation with the introduction of neon gas in the beam line using a fine leak valve. The beam profiles have been measured at different pressures in the beam line by capturing the residual gas fluorescence using a CCD camera. It has been found that with space chargemore » compensation at the present current level (∼5 mA at 75 keV), it is possible to reduce the beam spot size by ∼34%. We have measured the variation of beam profile as a function of the current in the solenoid magnet under the neutralised condition and used these data to estimate the rms emittance of the beam. Simulations performed using equivalent Kapchinsky-Vladimirsky beam envelope equations with space charge neutralization factor are also presented to interpret the experimental results.« less
  • A 2.45 GHz high-current microwave ion source with permanent magnet was developed at Peking University. The source body is about 10 cm in diameter and 10 cm in height, and its weight is less than 5 kg. It can operate in both pulse and continuous wave (cw) modes. In pulse mode, more than 100 mA hydrogen ion current was extracted from a 5 mm ion extraction aperture, when the microwave power is 500 W and the extraction voltage is 45 kV, which corresponds to a beam density of 500 mA/cm{sup 2}. In cw mode, up to 60 mA of hydrogenmore » ion current can be extracted, and the beam density is 300 mA/cm{sup 2} at the same conditions. The proton ratio is about 80% and the normalized root-mean-square emittance is less than 0.1{pi} mm mrad in both modes.« less