A Southern African positron beam

• Published in: Applied surface science Vol. 116; pp. 53 - 58
• Main Authors: Britton, D.T., Härting, M., Teemane, M.R.B., Mills, S., Nortier, F.M., Van der Walt, T.N.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01-05-1997; Elsevier Science
• Subjects: Charged-particle beams; Electromagnetism; electron and ion optics; Electron and positron beams; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Physics; Instrumentation; Positron sources; Sodium 22; Positron beams
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/S0169-4332(96)00974-9

The first stage of a state of the art positron beam, being constructed at the University of Cape Town, is currently being brought into operation. This is the first positron beam on the African continent, as well as being the first positron beam dedicated to solid and surface studies in the southern hemisphere. The project also contains a high proportion of local development, including the encapsulated
22Na positron source developed by our collaboration. Novel features in the design include a purely magnetic in-line deflector, working in the solenoidal guiding field, to eliminate unmoderated positrons and block the direct line of sight to the source. A combined magnetic projector and single pole probe forming lens is being implemented in the second phase of construction to achieve a spot size of ∼ 10 μm without remoderation.