Negative Hydrogen Ion Beam Research Articles

The formation of a negative hydrogen ion beam by surface conversion of a positive ion beam on cesiated tungsten surfaces

Presented are measurements on the generation of negative hydrogen ion beams via the conversion of positive ion beams on low work function surfaces placed outside the positive ion source. The converter surfaces are positioned parallel to the beam axis and the positive ion beam is directed onto them by the increase of the beam divergence caused by beam retardation. Results include a negative hydrogen ion beam current of 15 mA at a current density of 6.2 mA/cm2. The converter work function is lowered by the deposition of a Cs monolayer. The Cs coverage could be maintained during the bombardment by the intense H+ beam through surface migration of the Cs from a reservoir.

Production of intense beams of polarized negative hydrogen ions by double charge exchange in alkali vapour

The intensity of the polarized negative hydrogen ion beam of the ETHZ atomic beam polarized ion source has been substantially improved by a new double charge exchange device. Increasing the diameter of the charge exchange canal to 1.4 cm results in a beam output of the source of 6 μA of polarized negative hydrogen ions. Further improvements of the charge exchanger are proposed and discussed. With an updated design of the atomic beam apparatus, beams of 0.5 mA polarized negative hydrogen ions may be obtained from such a source.

A 50-mA Negative Hydrogen-Ion Source

An ion source of the magnetron type, which produces a 50-mA negative hydrogen-ion beam of good quality for accelerator injection, has been developed. This source has been in use for over a year and has become the principal ion source for all modes of accelerator operation at Fermilab. Details of the design and operation of this source along with information regarding beam quality and reliability are presented.

Neutral Beam Injection for a Proton Storage Ring

The spallation neutron source at the Los Alamos Scientific Laboratory is to be upgraded with the addition of a high current Proton Storage Ring (PSR). This paper describes a novel charge changing injection technique that substantially simplifies the ring design. The method consists of converting the 800-MeV negative hydrogen (H-) ion beam from the linac to a 100% neutral hydrogen (Ho) beam having an acceptable emittance and drifting it directly onto the proton closed orbit in the ring. The neutralization is accomplished by electric field dissociation of the H- ions.

Tailoring of Specific Sizes of Cluster Ions for Producing Intense Negative Ion Beams

For the purpose of producing an intense beam of monoatomic negative hydrogen ions from a beam of accelerated positive hydrogen cluster ions, the mean specific size of the cluster ions of 103 atoms/charge for an acceleration voltage of 1 MV is necessary for efficient formation of the negative ions. A fundamental investigation on the tailoring of specific sizes has been carried out by using nitrogen cluster ions with a mean specific size of 105 atoms/charge. The nitrogen cluster ions were accelerated at a voltage of up to 20 kV before entering the divider which reduced their specific sizes by multiple ionization. The order of magnitude of the mean reduced specific size is 103–104 atoms/charge for the ionizing electron current up to 140 mA. These values were crosschecked by different experimental methods, examined theoretically and concluded to be resonable.

Mathematical simulation and experimental analysis of nonlinear interaction of positive and negative ion beams

Abstract The paper presents a theoretical analysis of collective interaction of beams of positive and negative ions of equal mass, based on the system of two one-dimensional, non-stationary Vlasov equations together with the equation for the electric field. The mathematical model is constructed for the nonlinear stage of the process and serves as a theoretical foundation for a detailed discussion of the mechanism of beam interaction. The experimental basis for this discussion is provided by experiments on interaction of beams of positive and negative hydrogen ions, which together constitute the synthesized plasma. A detailed comparison of the results of computations and experiments showed a satisfactory agreement between the data of both methods of investigation. The mechanism of beam interaction at the nonlinear stage of the process is considered.

The injector of the oxford electrostatic generator project

The vertical injector provided for the Oxford electrostatic generator project is described. Beams of negative hydrogen ions were accelerated to 10.2 MeV, of negative oxygen ions to 9.5 MeV and of alpha particles to 15.6 MeV, corresponding to terminal voltage of 9.7 MV. In operation coupled with the tandem, protons were accelerated to energies of 20 MeV, with currents of 200 nA.

Collisional Electron Detachment from Hydrogen Atoms and Negative Hydrogen Ions between 4 and 18 MeV

A beam of negative hydrogen ions accelerated by a cyclotron has been passed through various gases and the resulting charge states determined by magnetic analysis. Reduction of the data yields values of the cross sections for removing one or both electrons from the negative ion and the cross section for removing the electron from the hydrogen atom. Measurements were made on hydrogen gas at 4.2, 7.4, 9.8, 14.6, and 17.9 MeV; and on helium, nitrogen, oxygen, and argon gases at 14.6 MeV.

The production of intense negative helium and hydrogen ion beams

A description is given of the source and experimental arrangement used for the production and measurement of 830 μA of negative hydrogen ions and 1.1 μA of negative helium ions.

The extraction of a negative hydrogen ion beam from a duo-plasmatron source

The extraction of a negative hydrogen ion beam from a duo-plasmatron source

The acceleration and extraction of negative hydrogen ions in the C.U. cyclotron

A negative hydrogen ion beam of several microamperes has been obtained in the University of Colorado cyclotron. A one microampere external proton beam has been extracted by stripping the electrons off with a 50 mg/cm2 Al2O3 foil.

Negative Hydrogen and Deuterium Ion Beams

The charge state of a monoenergetic beam of hydrogen atomic and molecular ions traversing a hydrogen gas target has been measured as a function of the energy of the beam and the thickness of the gas target. The yield of negative ions from protons has a maximum of 1.5% at 13 kev. From diatomic and triatomic molecular ions the maximum yields were 3.0% and 4.5% at 26 and 39 kev, respectively. The experiments have also been performed with deuterium ions traversing the hydrogen gas target. The deuterium results are almost identical with those of hydrogen if the energy scale for the hydrogen data is multiplied by two.