8th International symposium on Negative Ions, Beams and Sources - NIBS'22

Session

Oral session 9

5 Oct 2022, 14:10

Auditorium (Orto Botanico)

5. Caesium Balance of the ISIS H$^-$ Penning Ion Source in Long Pulse Operation

Olli Antero TARVAINEN (STFC Rutherford Appleton Laboratory)

05/10/2022, 14:10

1. Fundamental processes and modelling

Oral

We have developed a semi-empirical model predicting the equilibrium caesium coverage (in monolayers) and the resulting work function of the ISIS Penning ion source cathode (in eV) in long pulse operation. We use the caesium balance model to predict the temporal structure of the extracted H$^-$ beam current pulses and compare the model predictions to experimental data with 60 mA, 2 ms beam...

48. Plasma Electrode Materials for Cs-free Negative hydrogen ion Sources

Mamiko SASAO (Office of R&D Promotion, Doshisha University)

05/10/2022, 14:40

1. Fundamental processes and modelling

Oral

Cesium additives are currently used in negative hydrogen(H-/D-) ion sources, which are key components in nuclear fusion plasma heating systems and high energy proton accelerators. Here, a thin cesium layer on a Molybdenum plasma electrode (or plasma grid), PE, lowers the surface work function, and results in high H-/D- production rates. However, in future systems, alternative ion source...

86. The effect of oxygen impurities on a caesium-covered Mo(001) surface: insights from Molecular Dynamics simulations for negative ion sources.

MARIA RUTIGLIANO (CNR-ISTP (Istituto per la Scienza e Tecnologia dei Plasmi))

05/10/2022, 15:10

1. Fundamental processes and modelling

Oral

Caesium-covered molybdenum surfaces are considered for negative ion production [1] [2]. Surface chemical-physics can help to understand the surface process influencing and determining device performances.
Molecular Dynamics simulations based on ab initio calculations in the framework of DFT( Density Functional Theory) have been used to simulate the interactions occurring at the gas-surface...

37. Rotational and vibrational temperatures of Hydrogen nonequilibrium plasmas from Fulcher band emission spectra

Domenico BRUNO (ISTP - CNR)

05/10/2022, 15:40

1. Fundamental processes and modelling

Oral

A roto-vibrational specific corona model is discussed for the simulation of the Fulcher spectrum in low pressure Hydrogen discharges. The model takes into account the processes of electron-impact excitation, spontaneous emission and predissociation and allows to simulate the molecular Fulcher spectrum in the [600:640] nm range.
The model is applied to the analysis of emission spectra...

27. Development and Commissioning of a Hydrogen Ion Source for the CERN ALPHA Experiment

Mark Andrew JOHNSON (Science and Technology Facilities Council - ASTeC)

05/10/2022, 16:10

1. Fundamental processes and modelling

Short oral

The CERN ALPHA experiment makes precision measurements of antihydrogen atoms held in a superconducting magnetic minimum trap. Recent studies of the antihydrogen spectrum have provided unique tests of fundamental physics, and to improve on these studies ALPHA is now proposing upgrades to directly compare hydrogen and antihydrogen within their existing atom trap. One route towards producing...