Advanced Nuclear Science and Technology Techniques (ANSTT3) Workshop

13 Sep 2021, 08:30 → 15 Sep 2021, 20:00 Africa/Johannesburg

Online (Zoom)

                                     Participants at the ANSTT meeting in 2019

 

The ANSTT3 will be a a two and half day virtual workshop (13-15 September) focusing on Metrology, Neutrons, Environmental Measurements and Networking.  The shortened ANSTT will however make provision for the inclusion of four round table discussions aimed at providing updates on our inter-Africa and international collaborations from previous meetings. This follows on from the ANSTT series of meetings held in 2018 and 2019.

Collaborations both UK-Africa and inter-Africa will again be at the forefront of the workshop, including Memoranda of Understanding.

A preliminary timetable is under preparation.

The workshop will be organised by the University of Brighton and iThemba LABS.

Topics to be discussed include:

• Metrology and applications
• Environmental measurements
• Neutron physics and applications
• Collaborations, UK-Africa, inter-Africa

There will be ample opportunity for informal discussions.

We plan to return to our workshop in a more normal format in March 2022 as vaccination programmes are rolled-out throughout the world. 

For enquiries or further information, contact the Event Coordinator: Michelle van der Ventel-Bark on anstt2020@tlabs.ac.za

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                                                                                                               Participants 2018

Monday, 13 September

09:45 → 10:00 Welcome

10:00 → 10:30 Metrology and Applications

Convener: Alison Bruce (University of Brighton)

10:00 F-18 activity mesurements at NMISA

F-18 is an important radionuclide in PET imaging and is produced at iThemba LABS. Therefore, iThemba LABS and other producers and users of F-18 require traceability from a metrology institute. At NMISA the absolute activity of F-18 was determined through a primary measurement using 4πβ-γ liquid scintillation coincidence counting. Conventional beta-efficiency extrapolation was employed. Subsequently, a factor for the NMISA ionization chamber was determined and used during a SIRTI comparison. A non-extrapolation method based on a detection efficiency analysis was also employed to analyse the data, using an adaptation of the double-phototube coincidence efficiency for a threshold above the second monopeak. Results and uncertainty budgets for the two methods are presented and discussed. Dissemination of F-18 traceability to iThemba LABS is also presented.

Speakers: Milton van Rooy (NMISA) , Mr Martin van Staden (NMISA) , Mrs Joline Lubbe (NMISA) , Dr Bruce Simpson (NMISA)

MvRooy ANSTT3 13 Sept 2021.pdf

MvRooy ANSTT3.mp4

11:00 → 11:15 Break

11:15 → 12:00 Presentations 1

Convener: Pete Jones (iThemba LABS)

11:15 Development of a digital data acquisition system for neutron metrology

Fast neutron fields are found in a wide variety of contexts, for example at accelerator and medical radiation facilities, around nuclear power plants, in airplanes in flight and space stations. These fields often vary widely with respect to both energy and intensity which complicates measurements of energy dependent fluence. Bonner sphere systems remain widely in use, although systems based on scintillator detectors offer distinct advantages including improved energy resolution on the fast neutron energy range (above 1 MeV). Since scintillators are typically sensitive to all types of radiation, including gamma rays, it is necessary to select neutron-only events, and pulse shape discrimination capabilities of selected scintillators is typically used for this purpose. Digital pulse processing electronics offer several distinct advantages over analogue systems, including being more cost effective and compact, but most importantly the flexibility of analyzing raw pulses in list mode.

Within the neutron metrology and spectrometry community digital pulse processing systems are being developed for a variety of purposes. New digital data acquisition systems need to be benchmarked against the current metrology standards, typically based on analogue systems. We present a comparison between the IRSN fast neutron metrology analogue acquisition system to an off-the-shelf CAEN desktop digitizer. Measurements were made using a BC-501A scintillator detector at IRSN AMANDE accelerator based facility. Uncertainty budgets for measurements of neutron energy dependent fluence distributions are compared for the analogue and digital acquisition systems. The broader aim of this project is to further the development of a digital data acquisition system for fast neutron metrology using advanced scintillator technology for use in neutron fields where time-of-flight may or may not be available.

Speaker: Ms Chloé Sole (UCT )

ANSTT3_DDAQ_Chloé_final.pdf

11:30 Investigation of limit of detection using standard radioactive sources with a LaBr3(Ce) detector

Investigation of limit of detection using standard radioactive sources with a LaBr3(Ce) detector
F. van Niekerk1, S.R. Johnson2, P. Jones3
1Department of Physics, University of Stellenbosch.
2Department of Physics, University of Cape Town.
3Department of Subatomic Physics, iThemba LABS.

Keywords: LaBr3(Ce) detector; Background radiation; Gamma radiation

Abstract

Ambient background radiation has been measured using a LaBr3(Ce) detector. This background gamma-radiation is mainly a result of construction materials (such as concrete) and air. Radionuclides that form part of the background have been identified after an energy calibration of the detector was performed using 22Na, 60Co and 152Eu radiation sources. These same sources have been measured at increasing distances from the detector. The study focussed mainly on the determination of the detection limits of each radiation source taking into account the presence of background radiation. Therefore, the change in the intensity measured for each source as a function of increasing distance from the detector has been emphasised. This application is in relation to the solid angle between the points of the radiation source and the active detector volume. Further studies and application of all data available will focus on the relevant factors in order to calculate the limit of detection for a specific activity for each radiation source.

This study forms part of a broader research project that entails the design, building and commissioning of a prototype mobile gamma-ray detection system equipped with a LaBr3(Ce) detector. The successful development of such a detector system will enable in situ measurements of radiation in various robust terrestrial environments with improved sensitivity and spectral resolution.

Speaker: Mr Ferdie van Niekerk

SAIP 2021 Presentation slides updated.pdf

11:45 A new Instrumental Neutron Activation Analysis facility at UCT

Instrumental Neutron Activation Analysis (INAA) is one of the most sensitive techniques to non-destructively determine the isotopic composition of a sample. The sensitivity of the technique is determined by the isotope of interest, intensity of the neutron source and neutron energy spectrum. In the case of thermal neutron irradiation with a nuclear reactor the minimum detection limits tend towards the level of ppb. We are in the process of implementing a new INAA facility within the Metrological and Applied Sciences University Research Unit (MeASURe) in the Department of Physics, University of Cape Town. The n-lab currently offers two neutron sources, a D-T sealed tube neutron generator (STNG) and radioisotopic 241Am/9Be source. The STNG produces mono-energetic neutrons of around 14 MeV, with an intensity of 10E8 neutrons per second, and the 220 GBq AmBe source produces neutrons with a broad energy spectrum, ranging from thermal to 11 MeV.

The first experimental phase will determine the limits of detection for a range of isotopes with the existing experimental set-up. This will be supplemented with simulation driven designs for neutron moderators, multipliers and reflectors in order to lower these limits.

Speaker: Sizwe Mhlongo (University of Zululand)

Sizwe-ANSTT_oral_presentation_v1.pdf

12:00 → 12:30 Metrology and Applications

12:00 The Significance of a Protocol in X-ray Radiography: Influential Parameters

Background Information and Aims: X-ray imaging is one of the classical human health diagnostic procedures. The aim of this work was to explore and analyze the X-ray exposure parameters and their significance in a given protocol in relation to image quality.
Materials and Methods: Exposures were delivered on meaty cow ribs, which served as a human equivalent phantom with tissue heterogeneities. Six different protocols corresponding to the foot, wrist, ankle, forearm, chest, and hand were used in exposing the phantom with a Shimadzu RAD speed MC unit. The resultant images were analyzed with Image J software for relative intensities so as to index image quality per protocol.
Results and Discussions: There were variations in the relative intensities read at selected image pixels protocol by protocol. This showed that the relative intensities can be used to make predictions of image quality and associated dose.
Conclusions: It is crucial to use the appropriate protocol for any given X-ray imaging procedure to minimize the dose delivered to tissue without compromising image quality. Relative intensity and thus optical density can be used as a measure of image quality and radiation dose by protocol.

Speaker: Dr Nhlakanipho Mdziniso (University of Eswatini, Department of Physics)

Presentation.pdf

14:00 → 14:30 Metrology and Applications

Convener: Alison Bruce (University of Brighton)

14:00 The central role of metrology in applied nuclear physics research

The art and act of measurement lie at the very heart of the enterprise of Science. Measurement mediates between the complexity of the real universe in which we live and the idealised order of physical theory. Careful observation of nature thus plays a powerful role in the creation of all scientific knowledge, and the subsequent development of technologies. Unambiguous understanding of the quality of data from experiment, whether from the detectors located within the caverns of the Large Hadron Collider at CERN, or from a handheld radiation counter, is critical for the effective use of the data. I will argue why radiation metrology is a critical component of all applied nuclear physics research and make the case for measurement to be placed at the forefront of our laboratory-based teaching programmes.

Speaker: Andy Buffler (UCT)

Buffler for ANSTT3 Sept 2021.pdf

14:30 → 15:15 Round Table: Metrology and Applications

15:15 → 16:00 Round Table: Neutron Physics and Applications

Tuesday, 14 September

10:00 → 11:00 Environmental Measurements

Convener: Pete Jones (iThemba LABS)

10:00 Compton Camera Imaging for Environmental Purposes

On 11th March 2011 the Fukushima Daiichi nuclear power plant suffered major damage after being hit by a magnitude 9 earthquake and subsequent tsunami. This resulted in a major radionuclide release to the environment. In response to this, remediation of the surrounding agricultural land commenced.

Part of the scientific focus is on understanding the dynamics of 137Cs, in terms of plant uptake and retention in soils. Accurate quantification of activities for sources whose distributions vary spatially and temporally is required.

At the University of Liverpool, UK we have characterised the near-field response of our Compton camera Gamma-Ray Imager (GRI) system to enable accurate estimation of 137Cs activity and its location.

The ability to precisely determine activity and distribution at small scales (sub-cm resolution in a sub-metre phase space) is considered to have applications beyond studying the dynamics of radiocaesium in environmental media.

At present, activity can be reliably estimated from the event rate for point-like sources, and a method to derive activity for distributed sources from the reconstructed Compton images is in development.

The characterisation and validation study of the system performance will be presented.

Speaker: Dr Helen Boston (University of Liverpool)

ANSTT3 2021 HCBoston.pdf

10:30 Assessment of Radiological hazards for Latrite Mining Field in Ilorin South LGA, North-central Nigeria

Assessment of activity concentrations of 40K, 238U, 232Th and gamma dose rate (DR) was carried out over a latrite mining field using a well calibrated Super-Spec (RS-125) gamma spectrometer, along Ajese-Ipko road, Ilorin-south, Kwara state, Nigeria. The results of the radioactivity measurements were used to assess the radiological hazards associated with the latrite mining field and it’s suitability as building material. Fifty (50) measurements of the activity concentration of the radionuclides were obtained at about 1 meter above the topsoil to cover a large area. For each of these 50 sample points, measurements were taken four (4) times for better accuracy. The mean activity concentrations of 238U and 232Th are higher than their corresponding global average of 32.00 Bqkg-1 and 30.00 Bqkg-1 respectively provided by UNSCEAR. This is a cause for worry as significant enhancement in the concentration of 238U and 232Th will increase the level of the background radiation and possibly render the soil unfit for use in building and construction purposes. The results of the radiological impact parameters (RIP) such as the mean values of the indoor radiation dose rate (Din). indoor Annual Effective Dose (EADindoor) and Annual Gonadal Equivalent Dose (AGED) are above the recommended limits provided by UNSCEAR. Since other hazard parameters are close or could possibly be approximated to the permissible limit, this implies that the lateritic soil from this mine field may not be too suitable for building and construction purposes (either as raw material or finished product).

Speakers: Dr Mojisola Usikalu (Covenant University) , Mr Muyiwa Orosun (University of Ilorin)

11:00 → 11:15 Break

11:15 → 12:30 Presentations 2

Convener: Alison Bruce (University of Brighton)

ANSTT3 Bezuidenhout.pdf

11:15 The investigation of natural radionuclides as tracers for monitoring sediment processes

In situ and sampling measurements of naturally occurring radionuclides were investigated in terrestrial sediment in various environments. These environments include beaches, wetlands, river basins, and deserts that are within Southern Africa. The distribution patterns of the natural radionuclides were extracted and characteristics were compared and investigated. These characteristics were used to develop a method that can radio fingerprint types of sediment. The fingerprinting can then be used as a tracer to track sediment movement in aquatic systems when artificial disturbances, like dredging, occur.

Speaker: Jacques Bezuidenhout

ANSTT3 Bezuidenhout.pdf

11:45 Soil-to-plant transfer factors and radiological risk assessment (Monte Carlo simulation) of selected mining sites in Nigeria.

One of the major route through which human are exposed to ionizing radiation is via food chain, which is consequent of soil-to-plant transfer of radionuclides. This work reported the activity concentrations of 40K, 238U and 232Th in samples of water, soil and guinea-corn collected from Beryllium and Gold mining sites in Kwara, Nigeria. In-situ measurements at approximately 1 m in the air was carried out using a well-calibrated portable Gamma Spectrometer (Super-Spec RS-125), while the collected samples were analyzed using a ‘3 x 3’ inch lead-shielded NaI (Tl) detector. The measured activities in the soil from both mines are lower than the in-situ measurements. This was attributed to the contribution from other terrestrial materials on-site. The estimated mean transfer factors (TFs) for 40K, 238U and 232Th are 0.21, 0.17 and 0.31, and 0.46, 0.19 and 0.28 respectively for the Beryllium and Gold mining sites. While the TFs for 238U and 232Th exceeds the mean value of 0.0062 and 0.0021 for 238U and 232Th respectively, the TFs for 40K are well below the 0.74 for grains provided by IAEA. The radiation impact assessment using the Monte Carlo simulations reveals values that were generally within the limits recommended by UNSCEAR.
Keywords: Cancer, Radioactivity, Gamma Spectroscopy, Risk Assessment, Monte Carlo

Speaker: Muyiwa Michael Orosun (Department of Physics, Covenant University, Ota, Ogun State, Nigeria)

14:30 → 15:15 Round Table: Environmental Measurements

15:15 → 16:00 Round Table: Future Collaborations and Networking

Wednesday, 15 September

10:00 → 10:45 Environmental Measurements

Convener: Alison Bruce (University of Brighton)

10:00 Application of nuclear interactions for material analysis: A case study of determination of metal contaminants from industrial effluents in North-West Nigeria using NAA technique

Neutron Activation Analysis (NAA), a non-destructive nuclear analytical technique that meets the criteria of experimental simplicity, analytical accuracy and flexibility has been applied to investigate the metal contents of industrial effluents collected at several sites in North-Western part of Nigeria. Ten elements (Cr, Co, Ca, Na, Eu, Hf, Th, Dy, Sb and Cs) were determined from 10 samples from the leather, textile and petrochemical industries. The enrichment factors were determined by comparison of the elemental concentration with that of a typical soil from an uninhabited, uncultivated, non-industrial area within the same locality of the survey. The analytical result shows that some of the industrial effluents have high elevated concentration for chromium, calcium, cobalt, sodium, antimony, and dysprosium. The most distinct being chromium from the tanneries due to the chemical processing stage of leather products involving tanning with chrome. Certified reference material was used during the analyses as quality control to assure the analytical quality of the results. The successful application of this nuclear analytical technique during this study confirms its suitability to environmental studies and the applicability of the k0-NAA method in the Nigeria Research Reactor-1 (NIRR-1) laboratories.

Speaker: Dr Michael Adeleye (Bingham University)

ANSTT3 Presentation - Michael Adeleye.pdf

10:30 Environmental Assessment Impact of Agbara Industrial Estate: A Review

This review gives insights into the levels of naturally occurring radionuclides (NOR), radioactive particles of air dust, heavy metals, environmental pollution and related hazards at Agbara industrial Estate, Agbara, Ogun State, Nigeria. Due to many industries located in Agbara industrial estates, there is much discharge of gaseous effluent, waste disposal. Industrial air dust harbours several pollutants, including heavy metals. The varying particle-size distribution of this dust and its large surface area makes it easier for the deposition and transport of heavy metals. The most used equipment for determination of radionuclide concentration is gamma-ray spectrometry with NaI (Tl) detector. Also, there are various methods used for the sampling of environmental pollution in dust and for heavy-metal determination which include: Andersen sampler filter and atomic absorption spectroscopy (AAS), inductively coupled plasma-mass spectrometry (ICP-MS), among others, respectively. Studies have shown that the pollutants in industrial areas are mainly derived from industrial activities but not a predominant source of pollution. Risk-assessment studies have shown that metals in urban dust could cause such problems as human pulmonary toxicity and reduction of invertebrate populations. The risk levels seem to be higher in children than adults, as some studies have shown. It is therefore important that scattered studies on heavy metals, pollution and radioactivity levels in a particular location should always incorporate risk assessment as one of the main issues and are put together in other to know what has been done and to detect research gaps.

Keywords: Radionuclides; heavy metals; pollution; industrial activities; risk assessment; toxicity; human health

Speaker: Akinwumi Akinpelu (Department of Physics, Covenant University, Ota, Ogun State, Nigeria)

10:45 → 11:30 Reportback: Metrology & Neutrons Round Table

Metrology feedback.pdf

Neutronphysics_13Sept2021.pdf

11:30 → 12:30 Reportback: Environmental & Networking Round Table

Collaboration_14Sept2021.pdf

Environment_14Sept2021.pdf

12:30 → 12:40 Closing and Final Remarks