Physics

Projects Topics

Topic

Supervisor

Abstract
Identification Of Impurity Transitions In Zinc Selenide Roger Lewis ZnSe is a candidate material for white light-emitting diodes. The spectrum of impurities in ZnSe is complex and not fully understood. The aim is to understand the spectrum of nominally pure ZnSe by examining specimens intentionally doped with specific impurities.
P And P2 Implanted Silicon Roger Lewis The semiconductor system of phosphorous in silicon has been suggested as the basis of a quantum computer. The aim of the project is to examine silicon implanted with both P and P2 ions to determine if optical methods might be used in the readout of the “qubits”.
Temperature Dependence Of The Resistivity Of Electronic Materials: the colossal magnetoresistance and colossal electroresistance nexus
 Roger Lewis The aim is to measure the electrical resistivity of materials over a wide temperature range, 10 K to 300 K, and account for the behaviour observed, in particular the occurrence of electroresistance. Samples may include metals; low-, intermediate- and high-temperature superconductors; semiconductors; oxides.

Suitable for summer scholarship, honours, PhD
THz IMAGING

 Roger Lewis To develop methods of using THz radiation, which lies between the optical and microwave regions of the electromagnetic spectrum, to produce images. Imaging of  materials of interest for applications in security, biology, and quality control.

Suitable for summer scholarship, honours, PhD
High efficiency terahertz emitters

 Roger Lewis To develop better sources of THz radiation under excitation by ultrashort laser pulses.

Suitable for: summer, honours, PhD
Investigation and interpretation of the response of thermoluminiscent dosimeters (TLD) for micro and nanodosimetry. Michael Lerch, Anatoly Rozenfeld, Yigal Horowitz,
Atara Horowitz
TLD detectors are major  dosimetry instrumentation for QA in radiotherapy and radiation protection.  Detailed investigation of glowcurve of the response of TLD detectors can be used for identification of charge trapping associated with  highly localized deposited energy on nanometre scale that is leading to possibility to use TLD detectors for nanodosimetry on DNA level.
 
During the project students will be learning theory of TLD and will develop mathematical models of the response of the TLD detectors to high LET radiation.
Developed model will be applied to analyse experimental data obtained on TLD detectors irradiated on different high LET radiation sources at accelerator in Columbia Uni USA and ANSTO heavy ion probe.
Experimental measurements will be carried at accelerator facility at Uni of Melbourne in January 2009.
Investigation of spectroscopy characteristics of Silicon Photomultipliers (SiPM ) and their application for Positron Emission Tomography(PET) Marco Petasecca, Anatoly Rozenfeld
PET is a powerful diagnostic tool for cancer and other disorders which is based on functional imaging. Quality of PET images depends heavily on radiation detectors and ability to measure in coincidence 511keV photons with a good timing resolution. CMRP is developing innovative approach to PET small animal scanner based on new readout electronics and SiPM detectors.
During the project students will investigate spectroscopic characteristics timing  resolution achievable with SiPM couple optically coupled with LGSO scintillators and will compare that with PIN Photodiodes and PM.
Students with an interest in microelectronics and good software skills will be involved in studding of DAQ system for these detectors and development DAQ software.
Investigation of MOSkin detectors for HDR brachytherapy and radiotherapy applications in IMRT Peter Metcalfe, Michael Lerch and  Anatoly Rozenfeld
In radiotherapy complications arise related to overdosing of skin during the cancer treatment, e.g. breast, head and neck treatment.  CMRP has developed a unique detector for skin dosimetry during radiotherapy treatment.
Investigation of different designs  of these detectors on medical LINAC and Ir-192 source with the aim to predict angular response and water equivalent depth  of  dose measurements is the aim of this project.
 
Students will be involved in design of the phantom with a rectal balloon and measurements of dose on the surface of the surface of the balloon in a water and Perspex phantoms. Experimental data will be compared with planning system using Treatment planning software PINNACLE .
Students with excellent computer skills will be involved in Monte Carlo simulations of MOSkin detector. This work will be in collaboration with USA based collaborators at Wisconsin University. 
The Morphology And Origin Of The Lagoon, Trifid And W28 Supernova Bill Zealey The Lagoon, Trifid and W28 SNR are one of the best examples of supernova triggered star formation. Photometry, astrometry and multi wavelength imagery will be assembled using internet resources. The distance to key features in the region will be derived and a model developed for the region's evolution.
A Maxillary Phantom For Ct Scanners Bill Zealey CT Scanners are becoming increasingly used for dental/maxillary imaging. Radiation sensitive tissue lies in the area subjected to X-rays. Students will design and construct a head phantom using materials with similar attenuation to bone, brain and muscle. GAFChromic film and MOSFET dosimeters will be used to measure radiation doses to the base of the brain and soft palate.
Catchment Areas On Mars Bill Zealey Detailed altimetry and mapping data is available for the Martian surface. It is likely that Mars has experienced periods within the past 500 Myrs when liquid water could have existed on its surface. This project will identify and map possible catchment areas and their drainage channels. Estimates of flow will be made from bed profiles.
Investigation Of Screening Properties In Spintronics Systems Chao Zhang Spin-dependent transport phenomena are of great importance to both condensed matter physics and device applications. In InGaAs- based two-dimensional systems, there is a spontaneous spin splitting which is mainly induced by the Rashba effect (with an SU(2) symmetry). This coupling can be tuned with an applied gate voltage. The dielectric function of spintronics systems exhibits many important features such as two-colour plasmon excitation and negative screening effect. The project will study the screening properties of spintronics systems using the analytical results we recently derived.
Spin Josephson Devices Chao Zhang A spintronic system of particular interest in fundamental sciences and in device applications is a ferromagnetic/nonmagnetic/ferromagnetic (FNF) junction. Since a polarised spin state has a well-defined amplitude and phase, there is a straightforward analogy between the relevant quantities in an FNF junction for spin transport and a superconducting/insulator/superconductor (SIS) junction for charge transport. The project will calculate the spin tunnelling current and its dependence on the applied bias.
A Spectroscopic Method For Determining The Concentration Of Phosphorus Introduced Into Silicon By Neutron Transmutation And To Find Spectral Line Widths As A Function Of This Concentration Rodney Vickers and P. Fisher Doping of silicon is important in the electronics industry. This is done effectively by neutron transmutation of silicon into phosphorus. The phosphorus concentration is assessed from the resistivity of the material. However, the starting material contains other impurities which affect the resistivity. The spectra of the impurities, obtained at liquid helium temperature, permit their concentrations to be determined. The objective of the project is to measure the absorption strengths and linewidths of the spectral lines of phosphorus as a function of neutron fluence and correlate these with the concentration of phosphorus supposedly produced by the fluence.
Transport And Magnetic Critical Current In Mgb2 Superconductor J. Horvat Critical current density (Jc) of MgB2 superconductor is usually measured by magnetic method. However it is the transport Jc that matters in practical applications of MgB2 and there is a discrepancy between the values and character of Jc obtained by these two methods. The project will examine why this discrepancy occurs.
Critical Current Density And Resistivity Of Mgb2 Superconductor J. Horvat Studies on thin MgB2 films suggest a correlation between their critical current density (Jc) and resistivity in the normal state. This correlation occurs because of inherent agglomeration of MgB2 crystals as the thin film is grown. The project will study if the same correlation occurs for MgB2 in the form of pellets and wires. This will point the main factors limiting Jc in MgB2 and establish if there are differences in agglomeration between thin film and bulk form of MgB2.
New Concept For Occurrence Of Superconductivity: Lowering Of Effective Mass Of Holes By Creation Of Cooper Pairs J. Horvat The BCS theory of superconductivity is based on creation of Cooper pairs, whereby the potential energy of charge carriers decreases. However this theory cannot explain superconductivity at temperatures higher than 40K and many other observations. A new theory has been developed that is based on the decrease of the effective mass of charge carriers as they form Cooper pairs, resulting in a decrease of their kinetic energy. This theory can explain high-temperature superconductivity and all other experimental observations, but it still needs to be verified experimentally. This project is aimed at exploring potential experiments that would verify the new theory.
Spectroscopic Quantification Of Radiation Damage In Biological Materials George Takacs Develop infrared and Raman spectroscopic techniques for the detection of radiation damage in tissue samples.
Modelling The Performance Of Solid Oxide Fuel Cells George Takacs Develop mathematical models of solid oxide fuel cells in order to compare the performance of different cells.
A search for non-linear optical effects in LED’s subjected to high current pulses. David Martin

Some red and near infrared light emitting diodes, subjected to fast (10 ns) high intensity (up to 100 A) current pulses can be made to lase.

The optical spectrum consists, typically, of a comb of closely spaced cavity modes.

Non-linear optical effects would generate sum and difference frequencies in the blue and THz regions of the electromagnetic spectrum, respectively. Although expected at these high light intensities, blue light output has not yet been observed.

The project will continue to examine the spectrum for blue output using a newly developed pulse generator which is expected to generate current pulses of up to 500 A.
Magneto-optical imaging in superconductors and other magnetic media Alexey Pan This project enables “seeing” magnetic properties of different superconducting and magnetic materials down to microscopic scale at low temperatures. It will develop skills in image analysis and quantification, as well as optical lithography. Visualization and intelligent control of magnetic domain walls in the active magneto-optical media can also provide non-contact means to manipulate magnetic quanta as well as biological and medical micro-specimens.
Fabrication and analysis of thin films and multilayered hybrid structures Alexey Pan The main aim of this project is to develop and understand new multilayered superconducting hybrid film systems and junctions, consisting of various superconductor/magnetic combinations. These new hybrid combinations are expected not only to enhance current-carrying abilities of superconductors for power applications, but also to enable the exploitation of known and novel tuneable quantum phenomena for electronic applications.
Superconducting coated conductors: flexible superconducting thin film wires Alexey Pan The focus of this project is development, understanding and optimisation of flexible coated conductors produced by a pulsed laser deposition technique, in order to enhance the current-carrying ability of high-temperature superconducting coatings (including multi-layered coatings) for long-length applications in electrical industry. To achieve desirable electromagnetic properties governed by the nano-structures of the coatings, a well-balanced combination of global and local electromagnetic measurements with advanced structural characterisations will be employed.
Magnetically induced "over-critical" currents in superconducting wires and tapes Alexey Pan This project will focus on understanding of magnetically induced current redistribution in superconducting MgB2 wires or/and high YBaCuO coated conductors based on the "long-range" magnetic interaction between magnetic environment and superconductors. This interaction is predicted to push up the current-carrying ability of the superconductors for different power applications. Apart from a new technology development, the significance of the project is in the fundamental understanding of magnetic interactions of this kind.
Nano/micro-dosimetry: superconducting thin films against cancer Alexey Pan and Anatoly Rosenfeld A new interdisciplinary project aims to develop new field of research combining the strength in areas of superconductivity, thin film and multilayer fabrication, nano-technology, as well as medical and radiation physics. The aim of this challenging project is to measure the spatial distribution of ionisations in biological tissues and other matters, controlling the radiation by sensitive superconducting thin film detectors.
Study of vortex dynamics in superconductors Alexey Pan The project aim is to study, clarify, and understand issues related to the behaviour of flux quanta (vortices): their dynamics, pinning, and depinning mechanisms in high temperature superconducting YBCO thin films or/and other superconductors. The knowledge and understanding in this area is not only a challenging versatile problem of the condensed matter physics, but also an important task for the majority of superconducting applications.
Current-carrying ability and mechanisms of its limitations in MgB2 superconductors Alexey Pan The main goal is to locally visualise and quantify the streamlines of the supercurrents flowing in MgB2 superconductor and to identify structural and fundamental bottlenecks limiting the global current-carrying ability of this promising superconductor. Its zero-resistance (zero energy loss) offers a unique natural phenomenon that is used for enhancing performance of motors, generators, transformers, as well as medical and scientific instrumentation.
Development of superconducting mulifilamentary leads with ultra-low thermal conductivity for cryoelectronic applications Alexey Pan The project aim is to develop novel technologies for new superconducting current leads, carrying large channels of digital information with minor attenuation and ultra-low thermal conductivity for high-sensitivity, low-noise superconductive cryogenic electronics. Effective elimination of heat generation and its transfer to the cryogenic electronics can make it price competitive, significantly outperforming the conventional semiconductor-based systems.
Dose Painting Peter Metcalfe PET-CT Scan images are becoming increasingly used for  imaging in Radiation Therapy Treatment Planning. The student will analyse the impact of using different PET intensity levels on the dose coverage "dose painting" that can be achieved using intensity modulated radiation therapy beams.
Back Projecting Fluence Maps Peter Metcalfe Checking intensity modulation radiation therapy treatment plans using fluence maps obtained by an electronic portal imaging device during IMRT beam delivery with the EPID in dose collection position. The student project will involve “back projecting” fluence maps to calculate the dose in a virtual phantom at isocentre and comparing this dose to the radiotherapy treatment planning predicted dose.
Characterisation of a novel diamond detector for radiation protection Susanna Guatelli study on the diamond tissue-equivalence by means of dedicated Geant4 simulations, in radiation fields of interest for medical physics and space science.
Last reviewed: 15 October, 2009