Monthly Archives: April 2017

Radiobiology and Dosimetry experiments

During the last weekend in March and the first weekend in April, research teams from iThemba LABS and the University of Wollongong in Australia, SCK-CEN in Belgium, and MSc students from UWC and CPUT jointly completed several Radiobiology and Dosimetry experiments using the SSC and the clinical proton beam. The main goal was to investigate out-of-field radiation dose and DNA damage in pediatric proton therapy, acute response of cancer cells, variation of relative biological effectiveness (RBE) and rise of linear energy transfer (LET) along the spread-out-Bragg peak and to conduct micro-dosimetric survey of neutron contamination in the treatment room. The results will help us to improve secondary cancer risk estimations in pediatric proton therapy and to develop biology motivated proton treatment planning.

Experimental team from SCK-CEN, University of Wollongong, UWC, CPUT and part of the participating staff of iTL

State-of-the-art detectors at iThemba LABS

The Department of Subatomic physics completed the installation and started commissioning of its latest measurement instrument “Facility for Low Spin Structure Studies of Exotic States and Nuclei”. The facility comprises of 8 LaBr3 scintillation detectors and electronics and was funded through a NRF NEP grant and iThemba LABS. The state-of-the-art detectors will be used to study sub-nanosecond lifetimes in nuclear states, and will be combined with other instruments in the laboratory. Current measurements are underway measuring radioisotopes produced at the lab, and environmental samples.

Left to right: Dr Pete Jones, Mr Lumkile Msebi (iThemba/UWC), Mr Abraham Avaa (iThemba/WITS), Ms Bashir Munirat (US), Mr Vetle Ingeberg (iThemba/Oslo), Dr Faiçal Azaiez, Dr Rudolph Nchodu

Student Matters (03/04/2017)

Sipokazi Panya panya an MSc (Physics) UNISA student, based at iThemba LABS (MRD) under the supervision of Prof M Maaza, Prof B M Mothudi, and Dr A H Galmed, visited the National Institute of Laser Enhanced Sciences (NILES), Cairo University, Egypt. During her stay (24 February to 24 March 2017) she performed her experiments with Laser-Induced Breakdown Spectroscopy (LIBS). Her research topic title is “Laser-Induced Breakdown Spectroscopy (LIBS) on Geological Samples: Compositional Differentiation and Relative Hardness Quantification”.

Sipokazi Panya (Panya, second from the right, back row) at the National Institute of Laser Enhanced Sciences (NILES), Cairo University, Egypt

IAEA Coordinated Research Project

The neutron physics group of iThemba LABS is currently participating in an IAEA (International Atomic Energy Agency) Coordinated Research Project (CRP) that was approved on October 30th, 2012. The title of the CRP is “Testing and Improving the IAEA International Dosimetry Library for Fission and Fusion (IRDFF)”. The main aim of this CRP is to improve, test and validate the International Reactor Dosimetry and Fusion File (IRDFF) with proper decay data and documentation (more information is available at https://www-nds.iaea.org/IRDFF/).

3rd Research Coordination Meeting Group, 20-24 March 2017, IAEA Headquarters, Vienna, Austria

At the first Research Coordination Meeting (RCM) in July 2013, it was agreed that the contribution from iThemba LABS will be to measure neutron activation cross sections in the energy range 40 to 200 MeV. In addition, the measurements at iThemba LABS must include 90 MeV and 140 MeV neutron energies, in order to compare with the results from the University of Kyoto, conducted at the Research Center for Nuclear Physics (RCNP) cyclotron facility of Osaka University. During the third CRM, (20-24 March 2017, Zina Ndlovu gave a presentation on the “Cross-section measurements for neutron-induced reactions in Co, Au, Bi and Tm at neutron energy of 90 and 140 MeV”. For more information, visit https://www-nds.iaea.org/IRDFFtest/RCM3/index.htm.

New data on nuclear molecular state in Oxygen-16

The best candidate for a molecular state configuration in 16O was investigated using the K600 spectrometer and the CAKE silicon detector array. This state is interpreted by various models as a good candidate for a dilute cluster of 4 alpha-particles. Even though the new data provides a much clearer picture of a very elusive state, the landscape in the excitation energy just above the 4-alpha break-up threshold appears more intricate than thought before.  K.C.W Li presented the findings at the International Nuclear Physics Conference in Adelaide (Australia) and published a high impact factor publication in Physical Review C Rapid Communications.

The 14-Carbon puzzle

The nucleus 14-Carbon presents a long standing mystery for nuclear physics. Some of its properties cannot be explained even with the most sophisticated models which may be due to new underlying physics. Complicating things further is the difficulty in measuring 14-Carbon in the laboratory and only recently technology has advanced enough to attempt the measurement. The first three months of this year PhD student Christiaan Brits spent at the Florida State University where 14-Carbon beams can be accelerated. During this time he prepared the software and experimental setup consisting of 4 different types of detectors. These efforts culminated in a three week experimental run and, although it is too early to speculate on the results, the collected data are expected to solve the 14-Carbon puzzle.