Abstract

We have developed a model predicting the equilibrium caesium coverage work function of the cathode (in eV) and the expected H- beam current (in arb. units) of the ISIS Penning ion source. The model is based on semi-empirical expressions for the cathode work function, negative ion surface ionization yield, and caesium adsorption and desorption rates. We compare the model predictions to experimental data with 760 μs discharge and 250 μs beam pulses. It is concluded that the ISIS Penning ion source operates near the optimum cathode work function in a wide range of caesium pressures and cathode temperatures. The model implies that long pulse operation of the source requires elevated Cs oven temperature and improved cathode cooling.

Details

Title
Caesium Balance of the ISIS H Penning Ion Source
Author
Tarvainen, O 1 ; Faircloth, D 1 ; Lawrie, S 1 ; Sarmento, T 1 ; Abel, R 1 ; Macgregor, J 1 ; Cahill, C 1 ; Stanley, T 1 ; Whitehead, M 1 ; Wood, T 1 

 STFC ISIS Pulsed Spallation Neutron and Muon Facility, Rutherford Appleton Laboratory , Harwell, OX11 0QX UK 
First page
012031
Publication year
2022
Publication date
Apr 2022
Publisher
IOP Publishing
ISSN
17426588
e-ISSN
17426596
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2655155555
Copyright
Published under licence by IOP Publishing Ltd. This work is published under http://creativecommons.org/licenses/by/3.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.