Field Ion Source Development for Neutron Generators

Journal Article · Sun Jan 01 04:00:00 EST 2012 · Nuclear Instruments and Methods in Physics Research, Section A

DOI:https://doi.org/10.1016/j.nima.2011.09.034· OSTI ID:1035885

Johnson, B Bargsten; Schwoebel, P R; Holland, C E; Resnick, P J; Hertz, K L; Chichester, D L

An ion source based on the principles of electrostatic field desorption is being developed to improve the performance of existing compact neutron generators. The ion source is an array of gated metal tips derived from field electron emitter array microfabrication technology. A comprehensive summary of development and experimental activities is presented. Many structural modifications to the arrays have been incorporated to achieve higher tip operating fields, while lowering fields at the gate electrode to prevent gate field electron emission which initiates electrical breakdown in the array. The latest focus of fabrication activities has been on rounding the gate electrode edge and surrounding the gate electrode with dielectric material. Array testing results have indicated a steady progression of increased array tip operating fields with each new design tested. The latest arrays have consistently achieved fields beyond those required for the onset of deuterium desorption ({approx}20 V/nm), and have demonstrated the desorption of deuterium at fields up to 36 V/nm. The number of ions desorbed from an array has been quantified, and field desorption of metal tip substrate material from array tips has been observed for the first time. Gas-phase field ionization studies with {approx}10,000 tip arrays have achieved deuterium ion currents of {approx}50 nA. Neutron production by field ionization has yielded {approx}10{sup 2} n/s from {approx}1 mm{sup 2} of array area using the deuterium-deuterium fusion reaction at 90 kV.

• Research Organization: Idaho National Laboratory (INL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC07-05ID14517
• OSTI ID: 1035885
• Report Number(s): INL/JOU-12-24978
• Journal Information: Nuclear Instruments and Methods in Physics Research, Section A, Journal Name: Nuclear Instruments and Methods in Physics Research, Section A Journal Issue: 1 Vol. 663; ISSN NIMAER; ISSN 0168-9002
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
DESIGN
DESORPTION
DEUTERIUM
DEUTERIUM IONS
DIELECTRIC MATERIALS
ELECTRICAL FAULTS
ELECTRODES
ELECTRON EMISSION
ELECTRONS
ELECTROSTATICS
FABRICATION
ION SOURCES
IONIZATION
MODIFICATIONS
NEUTRON GENERATORS
NEUTRONS
SUBSTRATES
TESTING
TRITIUM
deuterium
field desorption
field ionization
ion source
neutron generator
tritium