Conveners
H– sources for accelerators: Oral session O3
- Dan Faircloth (STFC)
- Jacques lettry (CERN)
The U.S. Spallation Neutron Source (SNS) is a state-of-the-art neutron scattering facility delivering the world’s most intense pulsed neutron beams to a wide array of instruments which are used to conduct investigations in many fields of science and engineering. Neutrons are produced by spallation of liquid Hg by bombardment of short (~1s), intense (~40A) pulses of protons delivered at 60 Hz...
The Spallation Neutron Source (SNS) accelerator system includes a 65-keV H- injector, a 2.5-MeV RFQ, a 1-GeV linac series, and an accumulator ring. The H- injector consists of an RF-driven, Cs-enhanced H- ion source and a compact, two-lens electrostatic LEBT. SNS routinely operates at 1.4 MW average beam power for three run cycles per year. In the recent two run cycles (FY20A and FY20B), due...
Global models of plasma discharges are a standard tool in plasma fluid simulations incorporating complicated chemistry. These models use global balances of energy and conservation of species number in order to estimate volume averaged number densities and temperatures of plasma components. Simple semi-analytic estimates of species density profiles valid in a wide range of parameters are used...
A Large Volume Surface Plasma Source with a converter for the Los Alamos linear accelerator was developed. A large gas-discharge chamber with a multipole magnetic wall and 2 heated cathodes can support a discharge generating a plasma. A cooled converter with a diameter of 5 cm and a potential of up to -300 V emits negative ions, accelerates them and focuses in an emission aperture with a...
The Los Alamos Neutron Science Center (LANSCE) H- ion source (LHIS) has provided stable output for decades of LANL mission needs. While operationally well understood, the internal relationship between the LHIS plasma, cesium distribution (the catalyst for producing H- ions), and produced H- beam remains a mystery, only explored indirectly with models.
We will develop fast, accurate, and...
We report on the progress in modeling performance of the H-ion source at LANSCE. We have developed a numerical model describing key physics processes from the first principles. The model accurately describes degradation of tungsten filaments and predicts their life time as well as the change in the performance. The model has been benchmarked against experimental data and shows good agreement...
