BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:Towards fast dose calculations for novel radiotherapy treatments w ith generative adversarial networks DTSTART;VALUE=DATE-TIME:20211124T053500Z DTEND;VALUE=DATE-TIME:20211124T055000Z DTSTAMP;VALUE=DATE-TIME:20260810T203333Z UID:indico-contribution-1302-4344@events01.synchrotron.org.au DESCRIPTION:Speakers: Florian Mentzel ()\n**Introduction**\nExisting appro ximations used in clinical treatment planning are either not fast or not a ccurate enough for some novel irradiation techniques like microbeam radiat ion therapy (MRT)\, which relies on arrays of sub-mm synchrotron-generated \, polarized X-ray beams. We present studies using generative adversarial networks (GANs) to mimic full Monte Carlo simulations of radiation transpo rt to achieve a compromise of fast and accurate dose computation for varia ble phantoms and irradiation scenarios.\n\n**Materials & Methods**\nTo obt ain a generalised model for the dose prediction a conditional GAN using a 3D-UNet architecture is developed. As proof of concept\, we predict the si mulated dose depositions of a bone slab inside a water phantom with variab le rotation angles and thicknesses. Subsequently\, we demonstrate that our model is generalisable by applying it to a simplified head phantom simula tion.\nAll Monte Carlo simulations are performed with Geant4 using a phase space file obtained from a validated simulation at the Australian Synchro tron.\n\n**Results** \nThe trained model predicts for both the bone slab i nside the water phantom and the simple head phantom dose distributions wit h deviations of less than 1% of the maximum dose for over 94% of the simul ated voxels in the beam. Dose predictions near material interfaces are acc urate on a voxel-by-voxel basis with less than 5% deviation in most cases. Dose predictions can be produced in less than a second on a desktop PC co mpared to approximately 50 CPU hours needed for the corresponding Geant4 s imulation.\n\nhttps://events01.synchrotron.org.au/event/146/contributions/ 4344/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4344/ END:VEVENT BEGIN:VEVENT SUMMARY:Neutron and synchrotron characterisation techniques for hydrogen f uel cell materials DTSTART;VALUE=DATE-TIME:20211124T052000Z DTEND;VALUE=DATE-TIME:20211124T053500Z DTSTAMP;VALUE=DATE-TIME:20260810T203333Z UID:indico-contribution-1302-4341@events01.synchrotron.org.au DESCRIPTION:Speakers: Krystina Lamb (ANSTO)\nHydrogen fuel cells and other renewable energy technologies have specific materials and functional need s which can be more fully understood using neutron and synchrotron charact erisation techniques. In this presentation\, a materials which has applica tions in proton exchange membranes is studied with a variety to techniques to develop a comprehensive understanding of the functional-structural rel ationship. The materials used here is phosphotungstic acid (HPWA) stabilis ed in an ‘inert’ mesoporous silica host material. This aim of this res earch is to develop an understanding of the interaction between the HPWA a nd the silica and whether different structures or surface chemistries have advantageous or detrimental effects.\nTwo silica symmetries used were Ia3 ̅d (face centred cubic bi-continuous) and P6mm (2D hexagonal with cylind rical pores) which were vacuum impregnated with solutions of HPWA in a ran ge of concentrations. The resulting powder samples were then analysed usin g small angle x-ray scattering (SAXS)\, inductively coupled plasma emissio ns spectroscopy (ICP-OES)\, nitrogen gas adsorption/desorption\, near edge X-ray absorption fine structure (NEXAFS/X-ray absorption near edge struct ure/XANES) of the O and Si k-edges\, Fourier transform infra-red spectrosc opy (FTIR)\, Raman spectroscopy\, and then formed into a disk using polyet hylene as the binder for electrical impedance spectroscopy (EIS). \nThe in sights gained from this systematic study indicate that the surface chemist ry of the silica host has a significant effect on the performance\, uptake and interactions with the HPWA anions\, where lower concentrations of HPW A result in stronger host:HPWA interactions but lower conductivity\n\nhttp s://events01.synchrotron.org.au/event/146/contributions/4341/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4341/ END:VEVENT BEGIN:VEVENT SUMMARY:Magnetic Ordering in Superconducting Sandwiches DTSTART;VALUE=DATE-TIME:20211124T050500Z DTEND;VALUE=DATE-TIME:20211124T052000Z DTSTAMP;VALUE=DATE-TIME:20260810T203333Z UID:indico-contribution-1302-4339@events01.synchrotron.org.au DESCRIPTION:Speakers: Andrew Chan (The University of Auckland)\nOur cuprat e-manganite ‘superconducting sandwich’ multilayers exhibit a highly un usual magnetic-field induced insulating-to-superconducting transition (IST )\, contrary to the commonly held understanding that magnetic fields are d etrimental to superconductivity [1\, 2]. This new behaviour is a result of the specific magnetic and electronic properties of the manganite coupling with the high-Tc cuprate (YBa2Cu3O7-δ\, YBCO). Due to the specific manga nite composition\, Nd0.65(Ca0.7Sr0.3)0.35MnO3 (NCSMO)\, we hypothesize the behaviour to originate from CE-type antiferromagnetic ordering as well as charge and orbital ordering [3]. \n\nThe magnetic data presented here wil l focus on polarized neutron reflectometry (PNR) and elastic neutron scatt ering on a YBCO-NCSMO trilayer and superlattice. The model that best descr ibed the PNR data for the trilayer had antiparallel moments at the YBCO-NC SMO interfaces. In the superlattice\, the direction of moments at NCSMO in terfaces were found to alternate with film depth whose long-ranged orderin g was broken below 35 K in a 1 T applied field. The stability of the AFM o rder in the superlattice was further supported by a robustness of magnetic in-plane half-order elastic scattering peaks at 9 T. This evidences the i nterplay of magnetism and superconductivity that play a role in realizing the IST effect in our superconducting sandwiches.\n\nREFERENCES\n[1] B. Ma llett et al. Phys. Rev. B. 94\, 180503(R) (2016) \n[2] E. Perret et al. Co mms. Phys. 45\, 1-10 (2018) \n[3] Y. Tokura. Rep. Prog. Phys. 69\, 797-851 (2006).\n\nhttps://events01.synchrotron.org.au/event/146/contributions/43 39/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4339/ END:VEVENT BEGIN:VEVENT SUMMARY:Characterization of MOSFET sensors for dosimetry in alpha particle therapy DTSTART;VALUE=DATE-TIME:20211124T045000Z DTEND;VALUE=DATE-TIME:20211124T050500Z DTSTAMP;VALUE=DATE-TIME:20260810T203333Z UID:indico-contribution-1302-4338@events01.synchrotron.org.au DESCRIPTION:Speakers: Fang-Yi Su (Centre for Medical Radiation Physics\, University of Wollongong)\nAlpha particle therapy\, such as diffusing alph a-emitters radiation therapy (DaRT) and targeted alpha-particle therapy (T AT)\, exploits the short-range and high linear energy transfer (LET) of al pha particles to destroy cancer cells locally with minimal damage to surro unding healthy cells. Dosimetry for DaRT and TAT is challenging\, as their radiation sources produce mixed radiation fields of α particles\, β par ticles\, and γ rays. There is currently no dosimeter for real-time in viv o dosimetry of DaRT or TAT. Metal-oxide-semiconductor field-effect transis tors (MOSFETs) have features that are ideal for this scenario. Owing to th eir compactness\, MOSFETs can fit into fine-gauge needle applicators\, suc h as those used to carry the radioactive seeds into the tumour. This study characterized the response of MOSFETs designed at the Centre for Medical and Radiation Physics\, University of Wollongong. MOSFETs with three diffe rent gate oxide thicknesses (0.55 µm\, 0.68 µm\, and 1.0 µm) were irrad iated with a 5.5 MeV mono-energetic helium ion beam (He2+) using SIRIUS 6M V accelerator tandem at the Australian Nuclear Science and Technology Orga nization (ANSTO) and an Americium-241 (241Am) source. The sensitivity and dose-response linearity were assessed by analysing the spatially resolved median energy maps of each device and their corresponding voltage shift va lues. The results showed that the response of the MOSFET detectors was li near with alpha dose up to 25.68 Gy. Also\, it was found that a gate bias of between 15 V and 60 V would optimize the sensitivity of the detectors t o alpha particles with energy of 5.5 MeV.\n\nhttps://events01.synchrotron. org.au/event/146/contributions/4338/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4338/ END:VEVENT BEGIN:VEVENT SUMMARY:Good vibrations: phonons in topological thermoelectrics DTSTART;VALUE=DATE-TIME:20211124T043000Z DTEND;VALUE=DATE-TIME:20211124T045000Z DTSTAMP;VALUE=DATE-TIME:20260810T203333Z UID:indico-contribution-1302-4397@events01.synchrotron.org.au DESCRIPTION:Speakers: David David Cortie ()\nThermoelectric materials harn ess a temperature gradient to produce a voltage via the Seebeck effect\, p roviding a way to harvest and recycle heat. Recently a new generation of t hermoelectrics has been developed that offer unprecedented performance by leveraging topological physics. The key to their functionality is their r obust high electronic conductivity in tandem with their low thermal conduc tivity. The latter can be engineered by controlling the lattice vibrations or “phonons”. Here I will discuss recent neutron spectroscopy experim ents at the Australian Centre for Neutron Scattering\, ANSTO\, which offer unique insights into the differences between “good” optical and “ba d” acoustic phonon vibrations in thermoelectrics. I will show how these experiments are complemented by large-scale molecular dynamic simulations on the GADI supercomputer within the National Computing Infrastructure. Ti me permitting\, I will also briefly demonstrate how we use the Centre for Accelerator Science and neutron reflectometry to enable surface-engineerin g in these novel crystals for microelectronic applications.\n \n\nReferenc es:\nN. Islam\, D. L. Cortie et\, Acta Materialia 215\, 117026 (2021)\nW. Zhao\, Cortie\, Wang et al\, Physical Review B 104 (8)\, 085153 (2021)\nD. L et al. Cortie Applied Physics Letters 116 (19)\, 192410 (2020)\n\nhttps: //events01.synchrotron.org.au/event/146/contributions/4397/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4397/ END:VEVENT BEGIN:VEVENT SUMMARY:Verification of L-alanine single-crystallinity for anisotropic syn chrotron terahertz measurements DTSTART;VALUE=DATE-TIME:20211125T030500Z DTEND;VALUE=DATE-TIME:20211125T032000Z DTSTAMP;VALUE=DATE-TIME:20260810T203333Z UID:indico-contribution-1302-4343@events01.synchrotron.org.au DESCRIPTION:Speakers: Jackson Allen (UOW)\nOne way to probe the molecular interactions of a material is by using terahertz (THz) spectroscopy\, whic h has been used to study L-alanine in detail [1]. However\, isotropic THz spectroscopy has limitations in identifying the origin of vibrational mode s since the direction of the associated dipole moment is random in an isot ropic THz measurement. Therefore\, there is a benefit to performing anisot ropic (polarised) THz measurements. This work represents the first anisotr opic measurements performed on L-alanine\, the simplest chiral amino acid\ , and one of the earliest amino acids fundamental to early life on Earth [ 2].\n\nAn appropriate sample for anisotropic measurements must be highly s ingle-crystalline. This presentation describes a method to prepare and tes t a sample for anisotropic THz measurements. Samples have been grown at th e University of Wollongong\, and sample verification has been done at ACNS ’s Taipan triple-axis spectrometer. Using Taipan\, a narrow mosaic sprea d of ~0.8° was determined\, and single\, well-fitted Gaussian peaks were observed in both sample rotation and Q-space scans\, suggesting high singl e-crystallinity in our L-alanine samples. Additionally\, the Taipan measur ements were able to verify the orientation of the L-alanine single crystal s with respect to their crystallographic axes. \n\nAnisotropic THz measure ments were taken on the THz – Far Infrared beamline at the Australian Sy nchrotron using a wire-grid polariser. Distinct absorption bands were obse rved for different crystal orientations\, further confirming single-crysta llinity\, and identifying the dipole moment directions for the observed mo des. We thus demonstrate a method of performing anisotropic THz measuremen ts.\n\n\n[1] T. J. Sanders et al.\, J. Chem. Phys.\, 154\, 244311 (2021) \ n[2] V. Kubyshkin and N. Budisa\, Int. J. Mol. Sci.\, 20\, 5507 (2019)\n\n https://events01.synchrotron.org.au/event/146/contributions/4343/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4343/ END:VEVENT BEGIN:VEVENT SUMMARY:Wavefield Characterisation of MHz XFEL Pulse Trains DTSTART;VALUE=DATE-TIME:20211125T025000Z DTEND;VALUE=DATE-TIME:20211125T030500Z DTSTAMP;VALUE=DATE-TIME:20260810T203333Z UID:indico-contribution-1302-4340@events01.synchrotron.org.au DESCRIPTION:Speakers: Trey Guest (La Trobe University\, European XFEL)\nX- ray Free Electron Laser (XFEL) light sources present new opportunities in the imaging of single particles and biomolecules. The interpretation and a nalysis of XFEL imaging data depends critically on a fundamental understan ding of the characteristics of the inherently stochastic XFEL pulses deliv ered to the instrument. Exploiting the unique MHz repetition rate of the E uropean XFEL to image single particles requires an improved understanding of both the inter- and intra-train fluctuations in pulse structure and bea m pointing\, which are frequently implicated in the loss of information in XFEL single particle imaging (SPI) and other classes of coherent diffract ion experiment. Failure to account for fluctuations of the electron bunch phase-space and/or trajectory within a pulse train can result in deviation s of the recorded wavefront and intensity statistics from theoretical beha viour and lead to conflation of the structure of the source and sample in single particle reconstruction.\n\nContrary to expectations\, X-ray optica l data collected at the SPB-SFX instrument of the European XFEL demonstrat es a sensitivity of inter- and intra-train variations in beam pointing to beam delivery parameters\, including the order of a pulse within a train. This data is presented in comparison to a partially coherent wave optical simulation of the SPB-SFX instrument\, through which photon diagnostics ha ve been designed and developed\, with the goal of improving the stability and subsequent imaging quality of the user-end photon beam. We describe th ese preliminary results within the scope of developing a novel phase-retri eval method applicable to the study of MHz repetition rate XFEL sources\, using nearfield speckle-tracking measurements.\n\nhttps://events01.synchro tron.org.au/event/146/contributions/4340/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4340/ END:VEVENT BEGIN:VEVENT SUMMARY:Scattering or spectroscopy? Both! DTSTART;VALUE=DATE-TIME:20211125T023000Z DTEND;VALUE=DATE-TIME:20211125T025000Z DTSTAMP;VALUE=DATE-TIME:20260810T203333Z UID:indico-contribution-1302-4394@events01.synchrotron.org.au DESCRIPTION:Speakers: Chris McNeill (Monash University)\nIn this presentat ion I will discuss the development of resonant tender X-ray diffraction to study the molecular packing of semiconducting polymers. Semiconducting po lymers are being developed for application in a wide range of optoelectron ic devices including solar cells\, LED and transistors. Being polymeric ma terials they offer advantages over traditional semiconductors including ea se of processing and mechanical flexibility. Most semiconducting polymers are semicrystalline\, with the way in which polymer chains pack strongly a ffecting their optoelectronic performance. Unlike small molecule crystals whose structure can be directly solved using crystallographic methods\, se miconducting polymers are more disordered meaning that there are not enoug h diffraction peaks available. To squeeze more information from the diffra ction peaks that are present\, we have turned to resonant diffraction: By varying the X-ray energy across an elemental absorption edge\, the variati ons in diffraction intensity that are observed can provide additional info rmation. Also known as anomalous diffraction this technique has been appli ed in other fields including protein crystallography. As many semiconducti ng polymers utilise sulfur as heteroatoms\, we have studied resonant diffr action effects at the sulfur K-edge in the tender X-ray regime. Furthermor e we have adopted a spectroscopic approach exploiting anisotropic near-edg e X-ray absorption features at the sulfur K-edge that produce highly aniso tropic resonant diffraction effects. This marrying of spectroscopy and sca ttering enables us not only to infer information about the position of the resonant atoms within the unit cell\, but also to deduce the orientation of molecular bonds and orbitals within the unit cell.\n\nhttps://events01. synchrotron.org.au/event/146/contributions/4394/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4394/ END:VEVENT END:VCALENDAR