University of the Witwatersrand, Johannesburg
SCHONLAND RESEARCH INSTITUTE FOR NUCLEAR SCIENCES
THREE YEAR REPORT
1998-2000
Introduction…………………………………………………………………..….………………...3
Applied and Environmental Physics Research Programme……………………………………….5
Ion Implantation and Surface Studies Research Programme…………………………………….22
Nuclear Physics Research Programme…………………………………………………………..33
WITS-Northern Accelerator Research Centre…………………………………………………...37
Health Physics Service…………………………………………………………………………...90
Introduction
The Schonland Research Institute's mission is to pursue a vigorous programme of both pure and applied nuclear research for the African context, including overseas collaborations where appropriate, integrated with the training of our higher degree students.
This Report covers the first three years (1998-2000) of the implementation of the 1996 Umbrella Schonland proposals. In accordance with the Physics Department's plan, the Schonland Research Centre for Nuclear Sciences was restructured as a federation of four Research Programmes, each with its own Group Leader, sharing a common support infrastructure. In addition the University's Health Physics Service has its home at the Schonland. Some of the Groups are subdivided internally along the lines of individual research interests, as will become apparent in this Report.
The four recognized Research Entities are:
- Applied and Environmental Physics Research Programme (Prof. J.I.W. Watterson);
- Ion Implantation and Surface Studies Research Programme (Prof. T.E. Derry);
- Nuclear Physics Research Programme (Prof. V. Hnizdo then Dr. J.M. Carter);
- Wits Northern Accelerator Centre (Dr. S.H. Connell).
To these must be added the Health Physics Service (Prof. T.L. Nam).
Matters of common interest are overseen by the Schonland Co-ordinating Committee with a rotating (2-year) chairmanship, chosen from the Group Leaders. The Chairman for the first half of the period under review was Prof. Vladimir Hnizdo; since his resignation in the middle of 1999 to take up a post in America, Prof. Trevor Derry has been Chairman.
The current membership of the Schonland Co-ordinating Committee is:
Prof. T.E. Derry (chair), Dr. S.H. Connell (deputy chair), Prof. J.I.W. Watterson, Dr. J.M. Carter, Mr. A.H. Andeweg (Technical rep.), Mr. D.B. Rebuli (Postgraduate rep.), Prof. B.J. Cole (Head of Physics Dept.) and Prof. W.U. Reimold (Geology Dept.). Other representatives attend meetings from time to time.
/The…
The University's recognition of separate Research Entities under the Schonland umbrella has been very successful. Attention and effort have now been freed for the business of research and teaching, and several major projects have blossomed, as detailed in this triennial Report.
Notable has been the implementation under International Atomic Energy Agency auspices and funding, of an annual five-month Radiation Protection Course serving the whole of Africa, which necessitated major structural changes to the Schonland buildings to accommodate some twenty students plus equipment. The Tandem van de Graaff accelerator has been computerized and equipment donations received for the addition of Accelerator Mass Spectrometry. Further IAEA donations have established the Environmental Isotope Laboratory as a Regional Centre for southern and eastern Africa.
In early 2000 a motivation was submitted to the University Research Committee for the elevation of the Schonland to the status of a Research Institute, with the proviso that its federal structure be retained. A University Research Institute is regarded as carrying out an established research programme that has continuity and is independent of the presence of specific individual researchers. We felt sure that we fitted this description, and were encouraged by the Executive Director (Research), Prof. Barry Mendelow. Later last year, Institute status was conferred on us by the URC, underlining a productive track record of over 40 years, a vigorous organization, and a promising future.
Trevor Derry
March 2001.
Applied and Environmental Physics Research Programme
February 2001
J.I.W. Watterson, Research Programme Leader
and
B. Th. Verhagen, Honorary Research Fellow
Introduction
The philosophy of this group is to carry out intrinsically interesting research in physics in an academic way and apply it a developing country such as South Africa. It is a fact that much of the research, particularly in physics, conducted in most developing countries is not of direct relevance to that country. Whilst certainly of cultural importance, it does not contribute directly to the economic, environmental or social well-being of that particular country.
Jeffrey Sachs, Professor of International Trade at Harvard and Director for the Centre of International Development has made this point particularly well in an article in the Economist. He points out that most scientific research in developing countries is undertaken in areas that are of direct relevance only to developed economies. He presents a chart which shows the overwhelming dominance of the rich countries in publications (90% of the total) and patents (95% of the total). He points out also that rich countries benefit from the scientific talent of the poor countries and that many of the scientific and technological breakthroughs are made by poor-country scientists working on rich-country problems in rich-country laboratories. This could be further extended by observing that research in the laboratories and universities of the developing countries often uses scarce local human resources and equipment to contribute to the solution of problems mainly of relevance to rich country science and hence to the economies of the richer nations.
Two South African examples are those of computed tomography discovered by Cormack in South Africa in the 1960’s and radical heart surgery associated with the name of Chris Barnard. In spite of the fact that these originated in this country, today CT scanners are all manufactured in the United States or Europe and artificial heart valves are manufactured in the United States and sold throughout the world. The economic benefits of these world class advances have been negligible in the country of their origin.
The Applied Physics Research Group pursues lines of research established by us in the Schonland Institute over many years, applying the techniques of Physics to the understanding of problems of economic and social importance in the context of Africa. This programme has three main themes: the application of isotope measurements in the understanding of water and other environmental systems, the application of nuclear-based methods to mining and the understanding and measurement of radiation in the environment. All of these fields include elements of pure science and academic research as well as the development of direct economic and social benefits.
The application of isotope measurements in the understanding of geohydrology has been pursued at the Schonland, since its founding as the Nuclear Physics Research Unit in 1957, in the Environmental Isotope Research Group. Under the leadership of Prof B. Th Verhagen, the Environmental Isotopes Laboratory has been established as a foremost laboratory in Africa for the measurement of light isotopes.
The development of nuclear techniques in mining had its origin in the National Institute for Metallurgy’s Activation Analysis Research Group, which was later broadened to include the development of techniques for on-line measurement.
There are thus three main programmes in the Group: the Environmental Isotope Programme, lead by Prof. Verhagen, and the Applied Nuclear Physics Programme as well as the Programme on Radiation in the Environment, led overall by Prof. J.I.W. Watterson.
· Environmental Isotopes Programme
· Historical
The Group had its beginnings in the late 50's as the tritium laboratory, the initiative in the Department of Physics actually pre-dating the establishment of the Nuclear Physics Research Unit, which was to be renamed the Schonland Research Centre (SRC) in the mid-eighties and recently the Schonland Research Institute.
The initial aim was the development of methods to enrich environmental tritium. The practical applications of tritium to hydrological problems were developed in the late 60's. In the early seventies, the requirement of studying deep ground water with high residence times in the Kalahari prompted the development of radiocarbon analysis. A Water Research Commission contract to study ground water in the northern Cape and Sishen mine allowed for the expansion to stable isotope analysis which added mass spectrometry to the facility, re-named the Environmental Isotope Laboratory, in the mid-seventies.
Numerous studies, mainly of ground water systems but also of other environmental concerns followed, using the largely home-built low level counting facilities. During this period, the Environmental Isotope Group (EIG) became internationally acknowledged, generating many cooperative studies and research contracts. These were conducted with this and other universities, local and international research bodies, government agencies, and the private sector. The Group Leader spent several extended periods abroad being invited to participate in projects in this context.
By the mid-nineties, the Group became more actively engaged with the International Atomic Energy Agency (IAEA) in cooperative research programmes (CRP's) and a Regional Model Project for northern Africa, involving seven countries. The Group rendered expert services to this project in the course of which a similar endeavour for southern and eastern Africa was proposed. This new model project, which had its inception on 1 January 1999, is centered on the EIG as a regional facility responsible for training, scientific input and analytical services. To facilitate the latter, the EIG received an infusion of state of the art analytical equipment for a total of some R 2 million from the IAEA. With the re-structuring of the SRC in 1997, the EIG became part of the Applied and Environmental Physics Group (AEPG).
The EIG is at present largely self-supporting and is led by Prof B Th Verhagen, retired in 1997, at present Honorary Research Fellow. Active steps are being taken towards leadership succession for the EIG.
· Some past achievements
Research at the EIG has revolutionised the hydrology of the Kalahari and other arid and semi-arid environments. This work demonstrated that ground water renewal is an ongoing process in such environments and that resources are often not "fossil", or the remnants of earlier "pluvial" periods as believed previously.
One of the most rewarding of these studies has been producing a conceptual model for the aquifer feeding the northern wellfield of Jwaneng diamond mine in SE Botswana. This has led to an understanding of previously puzzling aspects of the well field's performance; to estimates of recharge, later confirmed by water balance studies and to information on the potential vulnerability of the system to pollution with changing land use.
The Group has been invited by governments and the private sector to participate in numerous major ground water development projects with considerable success in contributing to conceptual and numerical modelling and thus to the overall resource assessment. The Group contributed to a number of studies by other Departments within this university, notably Geology, Archaeology and Botany as well as at other universities. The Group leader made a major contribution to a wide ranging set of isotope hydrology investigations in the arid zone in developing countries undertaken by the Federal Geoscience Institute, Hanover, FRG.
The final report on a Water Research Commission project and subsequent publication (Verhagen et al. 1999) showed for the time that estimates of ground water recharge in several studies based on isotope "snapshot" data could be corroborated by independent methods which required sometimes many years of observations.
The Group's work on ground water pollution using a wide spectrum of environmental isotopic tracers has been ground-breaking. In various studies using stable isotopes of water and of nitrogen, sources of pollution could unequivocally be established. The Group discovered the distinct isotopic signal on Gauteng mains water as a means of tracing such water in the environment; discovered artificial tritium in landfill leachate as a means of tracing such leachate in the environment; produced the concept of incipient pollution - at concentrations which may not yet be chemically evident but can be identified by their isotopic association.
Using stable isotopes and tritium the Group developed an approach to urban hydrology almost unique to South Africa: using the numerous private boreholes as sampling points for pin-pointing leakages. In the process, interesting small-scale features of ground water recharge were discovered.
Since 1999, the Group has been engaged in contributing isotope and other data to seven research projects in as many southern and eastern African countries under the umbrella IAEA Regional Model Project on Sustainable Water Resources. It drives the South African investigation under this project and contributes scientifically to the others. It has contributed to three Cooperative Research Projects, as well as some larger and smaller investigations in cooperation with the private sector.
· Aims and nature of the EIG
The aims of the EIG are the application of both radioactive and stable isotopes of mainly the light elements (H,C,N,O,S) to the study of processes in the environment. The fields of mostly interdisciplinary research have been hydrology, archaeology, geology, and the life sciences.
· The staff of the Group at present consists of
Prof B Th Verhagen, Leader
Mr M J Butler, Research Officer
Mr O H T Malinga, Mass Spectrometer Technician
M. J. Mabitsela, Technician
· The analytical facilities of the EIG consist of:
1. State-of-the-art GEO20-20 isotope ratio mass spectrometer (IRMS), with automated preparation systems and part of the upgrading package financed by the IAEA under the regional project
2. two 25 year old isotope VG602 IRMS which are amongst the very few of these instruments world-wide still being kept operational
3. two state-of-the-art Packard low level liquid scintillation spectrometers, the first purchased with EIG funds, supplemented by the University three years ago; the second was commissioned two weeks ago and is part of the upgrading package financed by the IAEA under the regional model project.
4. various vacuum lines for sample preparation, electrolysis system and handling and general laboratory facilities.
· Summary of activities during 1998-2000
Activities: 1998
B Th Verhagen travels on expert missions to Uganda and Ethiopia to assist counterparts in IAEA projects to complete their final reports (January). Further investigation with Dr C J Barnes of Australia of the Lake Beseka problem in Ethiopia (January/February)
B Th Verhagen presents invited paper at ICARID international conference in Mumbai, India (February).
The EIG hosts a planning meeting on the project Sustainable Water Resources in Johannesburg attended by representatives of the IAEA and seven southern and eastern African countries. The EIG obtains unanimous support for being appointed Regional Centre for this project (March).
B Th Verhagen presents paper at the International Conference on the Role of a National Geological Survey in Sustainable Development, Gaborone, Botswana (May)
B Th Verhagen presents paper at Geocongress, Pretoria (July)
B Th Verhagen initiates Taaibosch Fault project, South Africa's contribution to the regional model project Sustainable Groundwater Resources (October)