australian institute of physics 2019 wa student conference · the published ligo binary black hole...
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Australian Institute of Physics2019 WA Student Conference
14th November 201908:45 – 16:45
University of Western Australia
Bayliss Building
Conference Organiser:Tobias Hain
Justin FreemanDagmawi TadesseKavi ChapagainNicolas Okeeffe
Alireza Aghajamali
Thanks to the Australian Institute of Physics
Special thanks to our local industry sponsors and donors
www.measurement.net.au+61 (8) 9414 7800
Measurement Innovation is a wholly Australian owned business specialising in the supply andhire of electronic test and measurement equipment since 1991. Measurement Innovation sells
the entire Keysight Test and Measurement product range in Western Australia and theNorthern Territory. Its rental division Measurement Rentals offers an increasing range of testequipment for hire across Australia. The company offers a range of other products, provides
training and consultancy, and continues to strive for engineering excellence and customerservice.
We thank Stu Midgeley for his donation
Thanks to participating local Perth Universities
Conference Program
08:45 – 09:00 Registration and Coffee
09:00 – 09:10 Welcome and Houskeeping
Session 1, Chair: TBA
09:10 – 09:23 B. Dix-Matthews Coherent optical doppler orbitography (UWA)
09:23 – 09:36 C. Chatterjee Using deep learning to localize gravitational wave sources(UWA)
09:36 – 09:49 S. Balaksrishnan Calcium hydride destabilised by alumina for concentrated solarpower applications (Curtin)
09:49 – 10:02 A. Nugaliyadde Quantum computing for artificial intelligence (Murdoch)
10:02 – 10:15 K. Williamson Thermochemical energy storage utilising metal carbonates(Curtin)
10:15 – 10:28 J. J. Buzolic Can ionic liquids spontaneously exfoliate hexagonal boron ni-tride? (UWA)
10:28 – 11:00 Morning Tea
Session 2, Chair: TBA
11:00 – 11:13 L. Scarlett Electrons scattering on molecular hydrogen: vibrational close-coupling calculations (Curtin)
11:13 – 11:26 J. Chauhan Understanding the properties of X-ray binary jets using SKAprecursors (Curtin)
11:26 – 11:39 H. Satari Passive imaging of ambient seismic noise for advanced gravi-tational wave detectors (UWA)
11:39 – 11:52 J. Kendrick Comparison of the dose to eye lens during radiotherapy of noseusing VMAT, electrons, and brachytherapy (UWA)
11:52 – 12:05 S. Boublil Teaching the Einsteinian physics paradigm (UWA)
12:05 – 12:18 B. Rusanov Investigating cone-beam computed tomography dose calcula-tion accuracy: A comparative study on competing HU calibra-tion techniques (UWA)
12:18 – 12:31 E. Matwiejew Simulation of open quantum networks (UWA)
12:31 – 13:30 Lunch
Session 3, Chair: TBA
13:30 – 13:43 A. Azadi Neutral Solute transport in biological filters, the story of kid-ney filtration (Murdoch)
13:43 – 13:56 A. Williamson Detecting Cosmic Rays using the Murchison Widefield Array(Curtin)
13:56 – 14:09 B. Wright Comprehensive investigation into the stability of Varian andElekta kv and MV imaging systems during arc delivery (UWA)
14:09 – 14:22 J. Tian Are fast radio bursts associated with short gamma-ray bursts?(Curtin)
14:22 – 14:35 C. Arrow A novel approach for tumour margin assessment based on low-coherence interferometry (UWA)
14:35 – 14:48 R. D’Alonzo Optimising protocols for the safe and efficacious delivery ofradiation therapy to preclinical models of medulloblastoma(UWA)
14:48 – 15:20 Afternoon Tea
Session 4, Chair: TBA
15:20 – 15:33 S. Prabu Space surveillance using the Murchison Widefield Array(Curtin)
15:33 – 15:46 O. Ahmed Catalytic de-halogenation of halogen-containing solid wastesby transition metal oxides (Murdoch)
15:46 – 15:59 F. H. Zuluaga Corrections to the stability of accretion by black holes in Ein-stein’s Quantum Gravity (UWA)
15:59 – 16:12 D. D’Mello Spatial mode correction for coherent free-space optical links(UWA)
16:12 – 16:25 P. E. Atkinson Atomic clocks and King plots
16:25 – 16:45 Best Talk Award ceremony and Closing
16:55 – Drinks
18:00 AGM dinner
Abstracts
09:10 – 09:23 B. Dix-Matthews
Coherent optical doppler orbitography
B. Dix-Matthews1,2,3∗, S. Schediwy1,2,3, S. Driver3, M. Tobar2,3
1 Department of Physics, University of Western Australia, Perth, Australia.2 ARC Centre of Excellence for Engineered Quantum Systems, University of Western
Australia, Perth, Australia.3 International Centre for Radio Astronomy Research, University of Western Australia, Perth,
Australia.
Doppler orbitography uses the Doppler shift in a transmitted signal to determine the orbitalparameters of artificial satellites including range-rate (or inline velocity). We describe a techniquefor atmospheric-limited optical Doppler orbitography measurements based on a system that iscapable of suppressing atmospheric phase noise imprinted on the transmitted optical signals.We demonstrate the performance of this system over a 2.2 km horizontal link with a simulatedsatellite Doppler shift at the far end. A horizontal link of this length has been estimated tocomprise around half the total integrated atmospheric turbulence as a vertical link to space.We obtained an estimated range rate precision of 9.0 nm.s?1 at one second of integration, and0.70 nm.s-1 when integrated over a five-minute low earth orbit transit. This represents fourorders-of-magnitude improvement over traditional microwave techniques in terms of range-rateprecision.
The performance of this system is a promising proof of concept for optical Doppler orbitog-raphy. The next steps are to extend this system to a more realistic vertical link with a movingremote terminal. This will more accurately reflect the Doppler shifts and environmental chal-lenges associated with performing this technique to artificial satellites in low earth orbit.
09:23 – 09:36 C. Chatterjee
Using deep learning to localize gravitational wave sources
C. Chatterjee1,∗, L. Wen1, K. Vinsen2, M. Kovalam1, A. Datta3
1 Department of Physics, The University of Western Australia.2 International Centre for Radio Astronomy Research, The University of Western Australia.3 Department of Computer Science and Software Engineering, The University of Western
Australia.
Deep Learning algorithms, in particular neural networks have been steadily gaining popular-ity among the gravitational wave community for the last few years. The reliability and accuracyof Deep Learning approaches in gravitational wave detection, parameter estimation and glitchclassification have already been proved and verified by several groups in recent years. In thispaper, we report on the construction of a deep Artificial Neural Network (ANN) to localize sim-ulated gravitational wave signals in the sky with high accuracy. We have modelled the sky as asphere and have considered cases where the sphere is divided into 18, 50, 128, 1024, 2048 and4096 sectors. The sky direction of the gravitational wave source is estimated by classifying thesignal into one of these sectors based on it’s right ascension and declination values for each ofthese cases. In order to do this, we have injected simulated binary black hole gravitational wavesignals of component masses sampled uniformly between 30-80 solar masses into Gaussian noiseand used the whitened strain values to obtain the input features for training our ANN. We inputfeatures such as the delays in arrival times, phase differences and amplitude ratios at each of thethree detectors Hanford, Livingston and Virgo, from the raw time-domain strain values as wellas from analytical versions of these signals, obtained through Hilbert transformation. We showthat our model is able to classify gravitational wave samples, not used in the training process,into their correct sectors with very high accuracy (> 90%) for coarse angular resolution using18, 50 and 128 sectors. We also test our localization on test samples with injection parameters ofthe published LIGO binary black hole merger events GW150914, GW170818 and GW170823 for1024, 2048 and 4096 sectors and compare the result with that from BAYESTAR and ParameterEstimation (PE). In addition, we report that the time taken by our model to localize one GWsignal is around 0.018 secs on 14 Intel Xeon CPU cores.
References[1] B. P. Abbott, R. Abbott, T. D. Abbott, M. R. Abernathy, F. Acernese, K. Ackley, C. Adams,T. Adams, P. Addesso, R. X. Adhikari, et al. Phys. Rev. Lett., 116:131103, Mar 2016.
[2] Daniel George, Hongyu Shen, and E. A. Huerta. “Classification and unsupervised clusteringof ligo data with deep transfer learning”. Phys. Rev. D, 97:101501, May 2018.
[3] Timothy D. Gebhard, Niki Kilbertus, Ian Harry, and Bernhard Schlkopf. “Convolutionalneural networks: a magic bullet for gravitational-wave detection?” 2019.
09:36 – 09:49 S. Balaksrishnan
Calcium hydride destabilised by alumina for concentratedsolar power applications
S. Balaksrishnan1,∗, M. V. Sofianos1, M. Paskevicius1, M. R. Rowles2, C. E. Buckley1
1 Fuels and Energy Technology Institute, Curtin University, GPO Box U1987, Perth, WA 6845,Australia.
2 John de Laeter Centre, Curtin University, GPO Box U1987, Perth, WA, 6845, Australia.
Calcium hydride (CaH2) destabilised with aluminium oxide (Al2O3) at a 1:1 molar ratiowas investigated as a high temperature thermal battery for concentrated solar power plants(CSP)[1]. The thermodynamic suitability of this system was initially theoretically predicted.
(a) In situ X-ray diffraction data and
(b) Temperature programmeddesorption measurements of
CaH2/Al2O3 system.
The predicted enthalpy and entropy of this systemduring hydrogen release was ∆H = 103kJ/mol H2
and ∆S = 160J/K − mol H2 respectively.Temperature programmed desorption measurementsshowed that the addition of Al2O3 destabilisedCaH2 by reducing the decomposition tempera-ture to ∼600 ◦C in comparison to ∼1100 ◦Cfor pure CaH2at 1 bar H2 pressure [2]. Theexperimental enthalpy and entropy of this sys-tem were determined by pressure compositionisotherm measurements between 635 and 655 ◦C.The enthalpy was measured to be ∆H =161.9kJ/mol H2 and entropy ∆S = 178.2J/K −mol H2. The mismatch between the theoreti-cal and experimental values is due to the dif-ferent reaction pathways observed between the-oretical predictions and experimental measure-ments. The system exhibited a degrading per-formance during cycling at 635 ◦C, which wasfound to be due to the presence of excessAl2O3, as confirmed by X-ray diffraction andthe sintering effects shown by scanning elec-tron microscopy. The hydrogen cycling capac-ity was significantly improved by reducing the ini-tial amount of Al2O3 to a 2:1 molar ratio ofCaH2 to Al2O3, deeming this system a promis-ing and cost-effective thermal battery for CSPplants.
References[1] Manickam K, Mistry P, Walker G, Grant D, Buckley CE, Humphries TD, et al. Futureperspectives of thermal energy storage with metal hydrides. International Journal of HydrogenEnergy. 2019;44(15):7738-45.
[2] Ronnebro EC, Whyatt G, Powell M, Westman M, Zheng FR, Fang ZZ. Metal hydrides forhigh-temperature power generation. Energies. 2015;8(8):8406-30.
09:49 – 10:02 A. Nugaliyadde
Quantum computing for artificial intelligence
A. Nugaliyadde1,∗
1 College of Science, Health, Engineering and Education, Murdoch University, Perth, WesternAustralia.
The recent news of achieving Quantum Supremacy from the Google Sycamore structure hasattracted the computing computers to understand and learn how to adapt to Quantum Comput-ing (QC) [1]. This shows that QC is capable of doing fast calculation compared to the fastestsupercomputer. Although, this calculation is a simple calculation this is step towards achievinghigh calculations. Machine learning has gained attention recently due to its achievements [2]. Asubcategory of machine learning, deep learning has created a spark in the Artificial Intelligenceby achieving ground breaking results [3]. In order to achieve ground breaking results in deeplearning, they require finding the optimal weights. The search of finding an optimal set of weightsin machine learning or deep learning requires a large number of calculations. Furthermore, thiscalculation does not always achieve the optimal weight value. Machine learning and deep learningmodels rely on finding the optimal weights. The optimal weight is calculated, and found throughmany number of iterations. Without optimal weights machine learning and deep learning modelswould fail. These multi-dimensional calculations require high performance computers. However,QC which uses qubits require only one qubit to represent 2 states [4]. Therefore, calculations canbe done faster, with less number of qubits. Grover’s algorithm can be stated as one algorithmwhich is capable of finding an optimal weight values [5]. Following Grover?s algorithm shows thepossibility of achieving complex calculations and finding an optimal weights to achieve the bestresults from the machine learning/ deep learning models.
References[1] F. Arute, K. Arya, R. Babbush, D. Bacon, J. C. Bardin, R. Barends, et al., ”Quantumsupremacy using a programmable superconducting processor,” Nature, vol. 574, pp. 505–510,2019.
[2] D. Michie, D. J. Spiegelhalter, and C. Taylor, ”Machine learning,” Neural and StatisticalClassification, vol. 13, 1994.
[3] Y. LeCun, Y. Bengio, and G. Hinton, ”Deep learning,” Nature, vol. 521, pp. 436–444, 2015.
[4] A. Trabesinger, ”Quantum computing: towards reality,” Nature, vol. 543, pp. S1–S1, 2017.
[5] P. G. Kwiat, J. Mitchell, P. Schwindt, and A. White, ”Grover’s search algorithm: an opticalapproach,” Journal of Modern Optics, vol. 47, pp. 257–266, 2000.
10:02 – 10:15 K. Williamson
Thermochemical energy storage utilising metal carbonates
K. Williamson1,∗, K. T. Møller1, C. Buckley1, M. Paskevicius1
1 1Department of Imaging and Applied Physics, Fuels and Energy Technology Institute, CurtinUniversity, GPO Box U1987, Perth 6845, WA, Australia.
* kyran [email protected]
Energy Storage is of the utmost importance to balance supply and demand in a renew-able energy future [1]. High-temperature energy storage is important to improve efficiency inapplications such as Concentrated Solar Power [2]. Metal carbonates have great potential asthermochemical energy storage materials through the endo- and exothermic release and uptakeof CO2 with low cost and high energy density [3]. However, the major challenge is the loss ofCO2 capacity, which drastically decreases over multiple cycles [4].
Recently, it was established that raw dolomite, CaMg(CO3)2, performed significantly betterthan laboratory synthesized dolomite due to the positive effect of chemically inert impuritiespresent in the sample [3]. However, its relatively low operational temperature (550◦C) leavesroom for improvement. Thus, both CaCO3 and a reactive carbonate composition of BaCO3-BaSiO3 have been investigated, which have operational temperatures at 900 and 850◦C, respec-tively. Preliminary results suggest that a suitable additive enhances the cyclic stability andreaction kinetics, see Figure. This presentation will give an overview of present research and anoutline of future perspectives.
Showing the decreasing CO2 capacity of CaCO3 (black squares) with increasing cycling.
References[1] Sweetnam, T.; Spataru, C. Chapter 23 - Energy Storage Worldwide. In Storing Energy;Letcher, T. M., Ed.; Elsevier: Oxford, 2016; pp 501–508.
[2] CSP Projects Around the World - SolarPACES https://www.solarpaces.org/csp-technologies/csp-projects-around-the-world/ (accessed Oct 23, 2019).
[3] Humphries, T. D.; Mller, K. T.; Rickard, W. D. A.; Sofianos, M. V.; Liu, S.; Buckley, C.E.; Paskevicius, M. Dolomite: A Low Cost Thermochemical Energy Storage Material. J. Mater.Chem. A 2019, 7 (3), 1206–1215.
[4] Grasa, G. S.; Abanades, J. C. CO2 Capture Capacity of CaO in Long Series of Carbona-tion/Calcination Cycles. Ind. Eng. Chem. Res. 2006, 45 (26), 8846–8851.
10:15 – 10:28 J. J. Buzolic
Can ionic liquids spontaneously exfoliate hexagonal boronnitride?
J. J. Buzolic1,∗
1 School of Molecular Sciences, University of Western Australia.
The demand for high quality two-dimensional nanosheets is increasing, due to the highlyuseful properties of the monolayer form of materials such as graphite and hexagonal boron nitride.As current production methods of nanosheets are either not scalable to mass production levelsor result in low-quality products rife with defects, research into production methods involvingspontaneous exfoliation that are scalable and require no input of external energy is vital for thefuture manufacturing of electronic devices. In my honours thesis, I show evidence indicatingthe spontaneous exfoliation of few layer hexagonal boron nitride nanosheets from exposure ofbulk hexagonal boron nitride to specific ionic liquids. Evidence of partially exfoliated layerswhich are pinned to the bulk of the nanosheet was found for certain ionic liquid mixtures, and aproposed exfoliation mechanism was produced (see Figure). Evidence that few-layer hexagonalboron nitride nanosheets can be exfoliated using certain ionic liquids, in combination with theinput of external energy from established liquid phase exfoliation methods, was also collected.
Spontaneous exfoliation of graphene using ionic liquids, composed of an imidazolium cationand with a surface tension that matches the surface energy of graphene, has previously beenfound [1]. The structure of hexagonal boron nitride is similar to graphene; the notable differenceis the addition of ionic bonding. The reported surface energy of hexagonal boron nitride is lowerthan graphene, which means the ionic liquids selected for the study of the spontaneous exfoli-ation of hexagonal boron nitride will have lower surface tensions than the ionic liquids selectedfor graphene. The nanosheets produced from spontaneous exfoliation will be thermodynamicallystable, as the interfacial energy of the material and the liquid mixture will be minimised andtherefore will not be energetically favourable for the nanosheets to restack.
Proposed exfoliation mechanism of h BN exposed to EMI TFSI and EMI TFMS (v/v 1:1)
References[1] A. Elbourne, B. McLean, K. Votchovsky, G. G. Warr, R. Atkin, J. Phys. Chem. Lett. 2016,7, 3118.
11:00 – 11:13 L. H. Scarlett
Electrons scattering on molecular hydrogen: vibrationalclose-coupling calculations
L. H. Scarlett1,∗, J. S. Savage1, M. C. Zammit2, D. V. Fursa1, I. Bray1
1 Department of Physics, Curtin University, Australia.2 Theoretical Division, Los Alamos National Laboratory, USA.
Molecular hydrogen is present in a range of vibrationally-excited states in fusion, astrophys-ical, and industrial plasmas. Vibrationally-resolved collision data for electron-H2 collisions arerequired for modelling the properties and dynamics, and controlling the conditions of many low-temperature plasmas [1]. Measurements of excitations in H2 are typically limited to scatteringon the ground vibrational state, and it is dificult to experimentally determine fully vibrationally-resolved cross sections due to the overlapping vibrational levels of various electronic states.Hence, there is significant demand for accurate theoretical calculations to produce recommendedcross sections.
Recently, the convergent close-coupling (CCC) method has been utilised in the fixed-nuclei(FN) and adiabatic-nuclei (AN) approximations to produce accurate sets of cross sections forelectrons scattering on all vibrational levels of the ground electronic state of H2 [2,3]. The FNand AN approximations rely on the Born-Oppenheimer approximation to decouple the electronicand nuclear degrees of freedom, a method which is valid only at sufficiently high incident en-ergies. At low incident energies, a more accurate treatment of the coupling between electronicand vibrational states is required. This talk will give an overview of the application of the CCCmethod to molecular scattering, and the current progress towards performing vibrational close-coupling calculations of electron-H2 scattering cross sections.
References[1] A. Larricchiuta, et al., Plasma Sources Sci. Technol. 15 (2006) S62.
[2] M. C. Zammit et al., Phys. Rev. A 95 (2017) 02270
[3] J. K. Tapley et al., J. Phys. B 51 (2018) 144007
11:13 – 11:26 J. Chauhan
Understanding the properties of X-ray binary jets usingSKA precursors
J. Chauhan1,∗, J. Miller-Jones1, G. Anderson1
1 Curtin Institute of Radio Astronomy (CIRA)/ICRAR.
Accretion is the process by which matter is pulled from a less massive star and accumulatedonto a more massive object under the influence of a strong gravitational field. Instead of fallingdirectly onto the compact object, the accreted matter forms a disc around the compact objectdue to its initial angular momentum. Most objects in the Universe, from newly-forming starsand stellar corpses such as white dwarfs (WDs), neutron stars (NSs) and stellar-mass black holes(BHs) through to the supermassive BHs at the centres of galaxies, grow in mass via the process ofaccretion. X-ray binaries (XRBs) are a special class of binary stars where a black hole or a neutronstar is accreting matter from a donor star. XRBs typically show frequent outbursts when theirbrightness increases by many orders of magnitude across the entire electromagnetic spectrum.During the outbursts, the highly energetic ionized matter is also ejected along the axis of thedisc at close to the speed of light, known as jets. These relativistic jets are bright in radio waves.XRBs provide us with an opportunity to study the connection between inflow and outflow arounda black hole as they evolve on humanly observable timescales. Until recently, the lack of sensitivelow-frequency radio instruments has prevented detailed studies of XRB radio jets below 1 GHz,limiting our knowledge of that regime. Low-frequency radio observations can provide insights intoopen questions such as the underlying physical process connecting the accretion inflow with theoutflow. We are observing XRB jets with next-generation radio telescopes, including precursorfacilities to the Square Kilometre Array (SKA), such as the Murchison Widefield Array (MWA),to learn more about their physical properties.
11:26 – 11:39 H. Satari
Passive imaging of ambient seismic noise for advancedgravitational wave detectors
H. Satari1,∗, L. Ju1, E. Saygin2, C. Zhao1, D. Blair1
1 School of Physics, University of Western Australia.2 CSIRO, Deep Earth Imaging Future Science Platform.
Low frequency seismic noise is one of the main limits that affect the sensitivity of GravitationalWave (GW) detection. Ground seismic motion is about 12 orders of magnitude larger than thecurrent differential test mass displacement due to a GW signal created by huge celestial bodies.Seismic noise contaminates the output of a laser interferometer either via mechanical coupling ofvibrations to key optical components, or via direct Newtonian interactions between seismic den-sity fluctuations and the test masses. Either way, seismic motion limits the performance of GWdetectors below 20 Hz for advanced detectors and below 7 Hz for future generation observatories.We analyse data of a simple array of broadband seismometers deployed in the Gingin High Opti-cal Power Test Facility (HOPTF) located at Western Australia, and study low frequency ambientseismic noise dominantly caused by ocean waves. The acquired data will be processed and anal-ysed for the purpose of dominant surface seismic displacement pattern recognition. This will helpin the vibration isolation and control required to improve GW detection sensitivity between 0.1to 10 Hz. We will measure dispersion of surface waves via cross correlation and transfer functionanalysis and create seismic velocity models through the inversion of these measurements. Theresults will provide locational information as well as the spectral and spatial profile of dominantseismic sources. One example of such analysis is provided in Figure, which shows considerablesimilarity between cross correlation time lags computed between a pair of seismometers and swelldirection measured by two nearby buoy stations. Our goal is to develop techniques to establisha ‘seismic weathervane’ for real time seismic noise characterisation.
Cross correlation time lags VS Buoys’ swell direction
References[1] Driggers, J. (2015). Noise Cancellation for Gravitational Wave Detectors. PhD thesis, Cali-fornia Institute of Technology.
[2] Beker, M. G. (2013). Low-Frequency sensitivity of Next Generation Gravitational Wave De-tectors. PhD thesis, VU University Amsterdam.
[3] Snieder R, Slob E. and Wapenaar, K. (2010). Lagrangian Green?s function extraction, withapplications to potential fields, diffusion, and acoustic waves. New J. Phys. 12:063013.
11:39 – 11:52 J. Kendrick
Comparison of the dose to eye lens during radiotherapy ofnose using VMAT, electrons, and brachytherapy
J. Kendrick1,∗
1 School of Physics, University of Western Australia.
Radiotherapy is a commonly used treatment method for skin cancer patients. As with othertypes of cancer treatment, the primary objective is to localise damage to the tumour whilstlimiting as much as possible the exposure to healthy tissue. Critical anatomical structures inthe vicinity of the tumour are always at risk of radiation damage. A significant component ofcancer treatment, therefore, involves attempting to minimise the radiation exposure to thesesensitive biological locales. The human eye represents one such critical organ of particular im-port in radiotherapy treatments. Radiation exposure exceeding certain thresholds to the ocularregion can have a myriad of detrimental effects on the patient, ranging from cataract formationto severe Dry Eye Syndrome (DES) [1]. Such dramatic side effects associated with irradiation ofthe ocular region underscores the importance of having an understanding of which radiotherapytreatment modalities are likely to minimise these in the clinical setting. This project aims toundertake such an analysis. A comprehensive comparison will be made between three commonradiotherapy methods utilised for treatment of skin cancer on the nose, namely; Brachytherapy,Volumetric Modulated Arc Therapy (VMAT) and Electron beam therapy. The dose distributionsfor each will be calculated, and exposure to critical structures of the ocular region ascertained.Radiochromic film will be used to calculate 3D dose distributions in the ocular region, focussingprimarily on the lens dose, allowing a systematic evaluation of each treatment modality?s abilityto minimise dose to the ocular region. The constructed 3D dose distributions will be comparedto the Treatment Planning System (TPS) generated dose distributions. In particular, the ElektaXiO and the VARIAN EclispeTM TPS dose calculations will be compared to the 3D reconstructeddose distributions for accuracy comparison.
References[1] Stewart FA, Akleyev AV, Hauer-Jensen M, Hendry JH, Kleiman NJ, Macvittie TJ, et al.ICRP PUBLICATION 118: ICRP Statement on Tissue Reactions and Early and Late Effects ofRadiation in Normal Tissues and Organs ? Threshold Doses for Tissue Reactions in a RadiationProtection Context. Annals of the ICRP. 2012;41(1-2):1-322.
11:52 – 12:05 S. Boublil
Teaching the Einsteinian physics paradigm
S. Boublil1,∗, J. Li1, D. Blair1
1 The University of Western Australia, School of Physics, Perth, Australia.
Integrating Einsteinian physics into primary, middle and high school curriculum has becomea challenge and researchers in physics education are determined to find ways to do it. It iswell accepted among researchers that in order to better understand today’s science and tech-nology, students need to be presented with our best understanding of nature and the universe[1-3]. The incredibly rapid technological development of recent years from digital technology toquantum physics makes the process of transferring knowledge to the younger generation evenmore difficult. Einsteinian physics is the basis for understanding modern physics. Einstein’s newparadigm developed over a hundred years ago continue to provide us with a solid theory in ex-plaining physical events. Einstein new paradigm is to become a starting point for developing andintegrating new disciplinary content into an existing curriculum. This process involves choos-ing proper disciplinary knowledge to be transferred, searching ways of didactically transposingthis knowledge to teachers and students and provide effective applications of this knowledgein teaching practices (What to teach, when to teach it in the learning progression and how toteach it). The Einstein-First project as its name implies deals exactly with this educationalprocess of developing effective ways of teaching both students and future teachers alike. Thenecessity of teaching Einsteinian physics has already been established, but still many questionsremain: What training do teachers need in order to integrate new concepts into their practiceand orchestrate them in a way that is consistent with existing content knowledge (from Galileoto Newton)? Are the existing approaches and models in teaching Einsteinian physics suitable forteachers and students in schools? Will these approaches and models properly introduce them tothe Einsteinian physics paradigm?
In order to investigate these questions, my research will use the methodology of didactic en-gineering and the collaborative model. This method will help me to establish a list of elementsthat will be studied in developing a curriculum and develop lesson plans for teaching Einsteinianphysics at year 7, 8, 9, 10 in Australia.
References[1] E. K. Henriksen, B. Bungum, C. Angell, C. W. Tellefsen, T. Frgt, and M. V. Be, Relativity,quantum physics and philosophy in the upper secondary curriculum: challenges, opportunitiesand proposed approaches Phys. Educ. 49, 678 (2014).
[2] T. Kaur, D. Blair, J. Moschilla, W. Stannard, and M. Zadnik, Teaching einsteinian physicsat schools: Part 1, models and analogies for relativity Phys. Educ. 52, aa83e4 (2017).
[3] D. Blair, K. Henriksen, and M. Ellen Hendry, Why don?t we teach Einstein’s theories inschool?[internet](2016).
12:05 – 12:18 B. Rusanov
Investigating cone-beam computed tomography dosecalculation accuracy: A comparative study on competing
HU calibration techniques
B. Rusanov1,∗, G. Mukwada1, M. Ebert1
1 School of Physics, University of Western Australia.
* brani [email protected]
Modern radiotherapy treatment modalities rely heavily on accurate patient images takenimmediately prior to irradiation to reduce setup error and confirm prescribed target volumes.Researchers have begun experimenting with LINAC mounted CBCTs to develop alternate usessuch as “dose of the day” verifications, and adaptive radiotherapy (ART). These studies aremotivated by the inadequacy of treatment protocols to account for inter-fractional changes inpatient anatomy. During the course of treatment patients may lose weight, their anatomy mayshift, and tumours may progress or regress. The initial treatment plan used to delineate planningtarget volumes (PTV) on day one may become invalid if severe anatomical changes occur at oraround the PTV site. The use of wider margins may compensate for these changes, but beammisalignment may still persist leading to negative outcomes such as cancerous tissue underdosage,excessive healthy tissue necrosis and increased risk to organs at risk, latent adverse effects,and increased possibility of tumour recurrence. Extending the role of CBCTs to verify doseparameters pre-treatment, and if necessary, re-optimize PTVs via ART techniques for bettertumour conformity and sparing of healthy tissue will increase the overall efficacy of RT treatmentsand patient outcomes.
The main challenge to developing such protocols is poor CBCT image quality. CBCTs areprone to artefacts and suffer from increased scatter. Consequently, CBCTs are unreliable forperforming dose calculations, visually assessing anatomy, and confidently re-optimizing PTVs.This research aims to investigate and compare various HU-to-ED calibration methods, as wellas explore image quality improvement techniques proposed in the literature to enable accurateCBCT image dose calculations. Thereby opening the possibility of introducing an ART protocolinto the radiotherapy workflow. Both phantom and real patient CBCT images will be analysedat various anatomical regions to ensure results are consistent with real-world clinical conditions.
12:18 – 12:31 E. Matwiejew
Simulation of open quantum networks
E. Matwiejew1,∗, J. Wang1
1 School of Physics, University of Western Australia.
With the increasing significance of quantum effects in emerging sensing, transport and in-formation technologies, it is important to have readily accessible simulation tools with whichto guide research and design. QSW MPI is a software package developed for the modeling ofquantum stochastic walks, a generalization of the classical random walk and continuous-timequantum walk. This model allows for the study of a wide range of Markovian open quantumsystems subject to a varying degree of incoherent scattering. Scalable to massively parallel com-puters, QSW MPI makes possible the simulation of many thousands of basis states, and extendsthe standard quantum stochastic walk model to the study of non-Hermitian absorption andemission processes, which are of particular significance to excitonic energy transport in molecu-lar systems.
13:30 – 13:43 A. Azadi
Neutral Solute transport in biological filters, the story ofkidney filtration
A. Azadi1,∗, B. Gardiner1
1 College of Science, Health, Engineering and Education, Murdoch University.
The mechanism of filtration is not a new concept. Ranging from simple sieving in your kitchenstraining spaghetti to the most complicated separation plants in oil refinery or water treatment.Here, we are focusing on an important biological example of filtration, particularly that found inthe kidney. Our kidneys are vital for separating waste products from our blood. A key structureseparating the blood from the nephron tubules is the glomerulus [1]. It is within the glomerulusthat filtration occurs. How this filter works as a filter, to separate solute by size or charge, isstill not well understood. Further, like all filters, how the glomerulus avoids clogging or foulingis also unknown. Answering these sorts is the aim of this project. Here, specifically we are doingcomputational study of the case of transport of neutral solutes across the glomerulus membraneto elucidate the factors governing filtering, maintenance and clogging.
Example computational predictions of solute concentrations.
References[1] Alpern RJeoc, Moe OWeoc, Caplan MJeoc. Seldin and Giebisch’s the kidney: physiology &pathophysiology. Fifth;Fifth; ed. Amsterdam: Elsevier/AP; 2013.
13:43 – 13:56 A. Williamson
Detecting Cosmic Rays using the Murchison WidefieldArray
A. Williamson1,∗, C. W. James1, S. J. Tingay1
1 International Centre for Radio Astronomy Research, Curtin University, Bentley, WA 6102,Australia.
Cosmic rays are the most extreme particles in the Universe and are detectable on Earth. Theradio emission produced by cosmic rays when they interact with the Earth?s atmosphere is anexcellent tracer of their properties. The low Radio Frequency Interference environment of theMurchison Widefield Array (MWA) makes this instrument ideal for detecting and measuring thisradio emission and therefore the study of high energy cosmic rays. From the radio information,the characteristics of the particle such as energy, incident direction, and species have to be re-constructed, aided by the use of air shower simulations. However, the pulses produced by theseair showers occur on timescales of the order of 15 ns and the standard output time resolutionof the MWA is 100 microseconds. In this talk, I present the status of cosmic ray detection atthe MWA and, in particular, the development of an algorithm to access higher time resolution.I will describe the computational performance of this algorithm and the efficiency at which itreconstructs this higher time resolution. I will also report on the deployment of a prototypeparticle detector at the Murchison Radio Observatory and the plans for future experiments withthe MWA.
13:56 – 14:09 B. Wright
Comprehensive investigation into the stability of Varianand Elekta kv and MV imaging systems during arc
delivery
B. Wright 1,∗, P. Rowshanfarzad1, M. Ebert1, G. Mubashar2, G. Mukwada3, M. Barnes4
1 Department of Physics, University of Western Australia.2 School of Computer Science & Software Engineering, University of Western Australia.
3 Department of Radiation Oncology, Sir Charles Gairdner Hospital, Perth.4 Department of Radiation Oncology, Calvary Mater Newcastle Hospital, Newcastle, and
University of Newcastle.
Introduction:
The quantification of geometric errors associated with radiotherapy are an important part of anyquality assurance procedure, with IGRT used as a method in order to reduce the impact of thiserror. The study compares two different image processing techniques in terms of accuracy andprecision, with the better performing algorithm used to determine the stability of the kV andMV imaging systems during arc delivery, and thus quantifies the accuracy of the IGRT systemsused.
Methods:
A comparison was done between the Optical Flow algorithm and the Hough Transform by com-paring pairs of images taken with the kV imaging panel moved laterally. Phantoms were attachedto the kV Source and MV source, with a Winston-Lutz phantom also used. The positions ofball-bearings in the corners of the phantoms was then used to determine the source sag and panelsag in each plane.
Results:
The Optical Flow algorithm was found to perform better than the Hough Transform. Data wastaken from an Elekta Axesse, a Varian Trilogy, and a Varian TrueBeam. It was found that theTrueBeam was the most stable and accurate linear accelerator and the Trilogy the least. Therewas a noticeable error with the kV data from the TrueBeam linear accelerator when the sourcewas covered, with this error removed when it was uncovered. The kV data was found to beinconsistent when comparing a clockwise and counter-clockwise rotation.
Conclusion:
A quantitative assessment of the stability of the kV and MV imaging systems is important to con-duct in order to determine the accuracy of any machine used in radiotherapy. Information aboutthe kV source position during rotation can be used to increase the image quality of kVCBCTreconstruction, and difference in movement due to rotation direction should be investigated fur-ther in order to determine the cause.
14:09 – 14:22 J. Tian
Are fast radio bursts associated with short gamma-raybursts?
J. Tian1,∗
1 Curtin Institute of Radio Astronomy, Curtin University.
Short gamma-ray bursts (GRBs) are believed to originate from binary neutron star (BNS)mergers. As such compact binaries are plausible gravitational wave emitters, this scenario wasrecently confirmed by the simultaneous detection of GRB 170817A and gravitational wave eventGW170817. Although there have been many efforts to search for electromagnetic counterpartsof short GRBs and/or GW events, only a few of them have radio detections. Considering BNSmergers have been predicted to produce radio emission through several possible mechanisms, thislack of detection may be caused by the incapability of instruments of performing rapid follow-upobservations of short GRBs, especially for the prompt radio emission. The missing capacityin sensitivity, frequency coverage and response time can be addressed by the Murchison Wide-field Array (MWA) triggering mode. In my PhD project I will use the MWA to observe Fermiand Swift detected short GRBs. Thanks to the electronic steering of the MWA and VOEventbased automatic trigger system, the MWA has the potential to capture the earliest prompt radioemission from short GRBs at MHz frequencies for the first time. There are several types of post-merger remnants whose life-times depend on the progenitor masses and the equation-of-state ofnuclear matter. Follow-up observations with the MWA will help constrain post-merger remnantmodels. Another interesting phenomenon, fast radio bursts (FRBs), have been proposed to begenerated by BNS mergers. If we can associate them with short GRBs in observation, it willprovide decisive evidence for their origin.
14:22 – 14:35 C. Arrow
A novel approach for tumour margin assessment based onlow-coherence interferometry
C. Arrow1,2,∗, Q. Fang1,2, B.F. Kennedy1,2
1 BRITElab, Harry Perkins Institute of Medical Research, Perth, Western Australia.2 School of Physics, The University of Western Australia, Perth, Western Australia.
The complete removal of tumour is the goal of breast conserving surgery, but is not oftenachieved. As such the re-excision rate for breast conserving surgery is ∼30% [[?] [1]. Surgeonsoften manually palpate tissue to distinguish between tumour and healthy tissue. This is lim-ited by the spatial resolution of the fingers, and the lack of objectivity and repeatability amongand between surgeons. A previously proposed method of delineation, dubbed optical palpation,utilises a spectral domain optical coherence tomography system, consisting in part of a broad-band near infrared light source and spectrometer detector, together with a calibrated compliantsilicone layer to provide a surface stress map, or palpogram, contrasting between tumour and tis-sue in-vivo [2]. In this study, we propose a significantly cheaper method, utilising low-coherenceinterferometry. Our proposed method uses a cheaper light source, with poorer axial resolution,and replaces the expensive spectrometer with a single detector. Detected intensity is calibratedagainst deformation of the silicone layer, and from the known mechanical properties of the layer,provides an estimate of surface stress. . We explore the feasibility of such a method, providingproof-of-concept, by taking images on tissue-mimicking phantoms, and show preliminary resultsfor in-situ breast tumour.
(a) Palpogram (b) photograph, tissue mimicking phantom
References[1] H. Ballal, D. B. Taylor, A. G. Bourke, B. Latham, and C. M. Saunders, “Predictors of re-excision in wire-guided wide local excision for early breast cancer: a western australian multi-centre experience”, ANZ Journal of Surgery 85, 540?545 (2015).
[2] W. M. Allen, P. Wijesinghe, B. F. Dessauvagie, B. Latham, C. M. Saunders, and B. F.Kennedy, “Optical palpation for the visualization of tumor in human breast tissue”, Journal ofBiophotonics 12 (2018).
14:35 – 14:48 R. D’Alonzo
Optimising protocols for the safe and efficacious delivery ofradiation therapy to preclinical models of medulloblastoma
R. D’Alonzo1,∗, M. Ebert2, R. Endersby3, P. Rowshanfarzad1
1 School of Physics and Astrophysics, University of Western Australia, Perth, Australia.2 Department of Radiation Oncology, Sir Charles Gairdner Hospital, Perth, Australia.
3 Telethon Kids Institute, Perth, Australia.
Medulloblastoma is the most common childhood brain cancer, with 70% of cases occurringin children under 10 years of age [1,2]. Current treatment involves a combination of surgery,chemotherapy and radiation therapy (RT) [1]. Current RT techniques can cause a lifetime ofside effects, such as neurological and neuroendocrine damage [1]. Improved RT methods areneeded. Preclinical research using mice can be used to optimise new RT techniques that reduceside effects to enhance patient outcomes. Small animal irradiation devices treat with low energyx-ray beams in order to mimic human treatments in mice. The objective of this project wasto develop a methodology for performing craniospinal irradiation (CSI) with the X-RAD 225Cxwith SmART-Plan software on preclinical mouse models of medulloblastoma (D-425) that mim-ics the clinical treatment of medulloblastoma. Cone beam CT images taken of mice were used tocreate a treatment plan to deliver 2 Gy to the whole brain and spinal cord of live mice. Treat-ment plans using multiple fields and different sized collimators were developed that delivered auniform dose to the brain and spine. A curved mouse bed with 4.5 cm diameter was found to bethe optimal method to position the animal for uniform spinal cord irradiation. A treatment planwas developed that delivered 2 Gy to 99% of the brain, and 2 Gy to 95% of the spinal cord. Thetreatment plan was successful in whole brain irradiation, however given the complexity of thespinal cord further investigation is needed. Future experiments will evaluate potential impactsof CSI treatment long-term, and its efficacy in the control of medulloblastoma in mice. Further-more, the evaluation of novel therapies that combine radiation and chemo- or immunotherapy inmice have the potential to identify new approaches for children with brain cancer.
References[1] Gottardo N G, Gajjar A. Current Therapy for Medulloblastoma. Curr Treat Options Neurol,2006; 8: pg. 319-334.
[2] American Society of Clinical Oncology, Medulloblastoma ? Childhood, American Society ofClinical Oncology, 2018; accessed 23rd January 2018, available from:https://www.cancer.net/cancer-types/medulloblastoma-childhood
15:20 – 15:33 S. Prabu
Space surveillance using the Murchison Widefield Array
S. Prabu1,∗
1 ICRAR, Curtin University, Bentley, WA 6102, Australia.
Space is an integral part of our current civilization. It enables us to have long distancecommunications as well as remote sensing capabilities. Humanity has always pushed boundariesto increase the potential of our space borne instruments ever since the beginning of the space race.However, this environment is becoming more and more hostile for future space missions as timegoes by due to the rapidly increasing human-made objects orbiting Earth. These objects in LowEarth Orbit (LEO) have velocities about 7.8 km/s and at such velocities even a pebble sizedpiece of debris can cause havoc to operating satellites or future space missions. The numberof human-made objects orbiting Earth increased drastically when Iridium-33 satellite collidedwith Kosmos-2251 satellite in 2009. They have further increased in the last decade, due to theanti-satellite testing done by China, India, Russia and United States. If these objects are leftunchecked then they can lead to a cascade of collisions, called the Kessler Effect, which rendersthe entire orbit useless for future missions. Due to the exponential growth of debris in orbit,un-conventional detection methods have to be employed along with existing radars in order tohave a better knowledge of LEO. In this project, I aim to investigate, if using MWA for SpaceSurveillance adds value to the existing SSA architecture.
The main goal of this work is to understand the feasibility and limitations of the novel con-cept of using radio interferometers such as the Murchison Widefield Array for SSA. The goal willbe archived by utilising w-stacking interferometer imaging and source finding techniques primar-ily developed for wide-field radio astronomy purposes. The work will also answer the concernsraised by IAU about interference cause by constellations of satellites in LEO. The developedwork would also help complement the coherent detection techniques developed for MWA, forconverting MWA into a valuable SSA asset in the South-Eastern hemisphere.
Dynamic Spectrum for the ISS as detected by the MWA.
15:33 – 15:46 O. Ahmed
Catalytic de-halogenation of halogen-containing solidwastes by transition metal oxides
O. Ahmed1,2,∗, M. Altarawneh3, Z. -T. Jiang1
1 Surface Analysis and Materials Engineering Research Group, Chemistry and Physics, SHEE,Murdoch University, Murdoch, WA 6150, Australia.
2 Department of Physics, College of Education, Al- Iraqia University, Baghdad, Iraq.3 United Arab Emirates University, Department of Chemical and Petroleum Engineering,
Sheikh Khalifa bin Zayed Street, Al-Ain 15551, United Arab Emirates.
Catalytic co-pyrolysis of halogenated compounds with electric arc furnace dust (EAFD) con-stitutes an effective disposal strategy regarding energy recovery and environmental safeguard.However, despite many detailed experimental investigations over the last few years; the specificunderlying mechanism of the reactions between the halogen laden materials with EAFD remainlargely poorly understood. In this contribution, systematic theoretical thermo-kinetic investiga-tions were performed using the accurate density functional theory calculations to understand,on a precise atomic scale, the reaction mechanisms of major products from thermal decomposi-tion of polyvinyl chloride (PVC) and brominated flame retardants (BFRs) with nanostructures(clusters and surfaces) of hematite (α-Fe2O3), zincite (ZnO) and magnetite (Fe3O4).
The detailed kinetic analysis indicates that the dissociative adsorption of hydrogen halidesmolecules, the major halogen fragments from thermal degradation of halogen laden materials,over those metal oxide structures affords oxyhalides structures via modest activation barriers.Transformation of oxyhalides into metal halides occurs through two subsequent steps, furtherdissociative adsorption of hydrogen halides over the same structures followed by the release ofH2O molecule. In the course of the interaction of halogenated alkanes and alkenes with theselected metal oxide structures, the opening channel in the dissociative addition route requireslower activation barriers in reference to the direct HCl/Br elimination pathways. However,sizable activation barriers are encountered in the subsequent β C-H bond elimination step. Theobtained accessible reaction barriers for reactions of halogenated alkanes and alkenes with thetitle metal oxides demonstrate that the latter serve as active catalysts in producing clean olefinsstreams from halogenated alkanes.
15:46 – 15:59 F. H. Zuluaga
Corrections to the stability of accretion by black holes inEinstein’s Quantum Gravity
F. H. Zuluaga1,2,∗, L. A. Sanchez1
1 Universidad Nacional de Colombia – Sede Medellin.2 School of Physics, University of Western Australia.
From Stephen Hawking’s work on the emission of radiation in the vicinity of the black holeevent horizon due to the coupling of quantum fields with the space-time geometry of classicalgeneral relativity, it is clear that any theory of Quantum gravitation should have as a prioritythe correct description of quantum black holes.
In quantum gravity, the mathematical description of the interaction of the quantized gravi-tational field with the other quantum fields whose existence is known, and its phenomenologicalconsequences, is treated.
In asymptotic security, the program of the implementation of a quantum theory of gravita-tion within the approximation of the average effective action, is known as “Einstein’s quantumgravity” [1]. Within this program the analysis of the problem of the existence or not of thesingularity associated with black holes, the final state of the evaporation by Hawking radiation[3], the microscopic origin of the entropy of black holes and the problem of loss of information,quantum corrections to metrics that describe the geometry of different types of black holes [2],quantum corrections to spherically symmetric accretion by a black hole of Schwarzschild [3],among others.
In this talk I will present studies in the Einstein quantum gravity scenario: (1) the analysisof quantum corrections to spherically symmetric accretion through black holes [3], towards holesdistinct and more general black than Schwarzschild’s, that is, Schwarzschild- (Anti) of Sitter and(2) study of quantum corrections to accretion stability stationary against linear perturbations.
References[1] M. Reuter and F. Saueressig, New. J. Phys. 14, 055022 (2012).
[2] C. Gonzlez and B. Koch, Int. J. Mod. Phys. A 31, 1650141 (2016).
[3] R. Yang, Phys. Rev. D 92, 084011 (2015).
15:59 – 16:12 D. D’Mello
Spatial mode correction for coherent free-space opticallinks
D. D’Mello1,2,∗
1 School of Physics, The University of Western Australia.2 International Center for Radio Astronomy Research.
The transfer of high-precision optical frequency signals over free-space links, especially fromground to satellites, holds great promise for advances in fields from coherent optical commu-nications to General Relativity and fundamental physics tests. The performance of free-spacecoherent optical links is limited by atmospheric turbulence, which induces phase-noise, beam-wander and higher-order scintillation effects in an optical frequency signal propagating throughfree-space. For applications such as frequency distribution for clocks, the phase noise and beam-wander effects are more significant that the intensity fluctuations caused by scintillation.
Tip-tilt control corrects for beam-wander effects by varying the pointing of a beam using afeedback loop and a fast-steering mirror. We demonstrated that the implementation of tip-tiltcontrol for spatial mode correction, in addition to existing phase-stabilisation [1], increases thereliability and availability of free-space coherent links over a 150 m length. The spatial modecorrection introduces high frequency noise but does not effect the capabilities of the phase sta-bilisation system. Tip-tilt control suppresses intensity fluctuations in the received light coupledfrom free space into fiber at low frequencies (below 50 Hz) over a 150 m link, and will be criticalfor free-space links > 600m. These results are expected to be very transferable to links of longerdistances.
Laser1550 nm
Free-SpaceLink
Phase TM Opt . Term. Opt . Term. Phase RMTo end user
System Architecture, consisting of phase-stabilisation transmitter and receiver terminals, andspatial-mode stabilisation optical terminals
References[1] D. R. Gozzard, S. W. Schediwy, B. Stone, M. Messineo, and M. Tobar, ?Stabilized Free-SpaceOptical Frequency Transfer,?Physical Review Applied, 2018.
16:12 – 16:25 P. E. Atkinson
Atomic clocks and King plots
P. E. Atkinson1,∗, J. S. Schelfhout1, J. J. McFerran1
1 ARC Centre of Excellence for Engineered Quantum Systems, Department of Physics,University of Western Australia, 6009 Crawley, Australia.
* [email protected], [email protected]
King plots are a means of extracting nuclear parameters from isotopic frequency shifts inatoms. Recent proposals suggest that King plot nonlinearities may be indicative of phenomenabeyond the standard model of elementary particles [1,2]. We construct a King plot from the(6s2) 1S0 − (6s6p) 3P1 (intercombination) and (6s2) 1S0 − (6s6p) 3P0 (clock) transitions in ytter-bium. To do so, we have carried out sub-Doppler fluorescence spectroscopy on an atomic beamwith frequency comb measurements to determine all the hyperfine separations and isotope shiftsfor the 1S0 − 3P1 line in Yb [3]. Clock transition frequencies are known for three of the Ybisotopes, which is used to generate a King plot, but with only two data points. We can increasethe data by measuring the clock-line isotope shifts for a number of Yb isotopes and thus explorethe degree of linearity of the King plot. The clock line in bosonic (i.e. even numbered) isotopesis strictly forbidden, but the pathway can be opened with a so called quenching magnetic field.We have made recent changes to the experiment to enable detection of the bosonic clock-linesignals.
Experimental set up for 1S0 − 3P1 line detection and frequency measurements in Yb (Source:[3]). AOM, acousto-optic modulator; CNTR, frequency counter; CE, cat’s eye reflector; DAQ,
data acquisition for spectra; E, electric field polarization; f-comb, frequency comb (in thenear-IR); fR, repetition frequency; L, lens; LF, loop filter; LPF, long-wavelength pass filter; M,mirror; MOD, modulation; PMT, photo-multiplier tube; RFA, radio frequency amplifier; VCO,
voltage controlled oscillator.
References[1] J. C. Berengut et al., Phys. Rev. Lett. 120, 091801 (2018).
[2] C. Frugiuele, E. Fuchs, G. Perez, and M. Schlaffer, Phys. Rev. D 96, 015011 (2017).
[3] P. E. Atkinson, J. S. Schelfhout and J. J. McFerran, Phys. Rev. A, 100, 042505, (2019).