Rutherford International Fellowship Programme: Second Cohort of Fellowships Awarded

Following a call for proposals in 2016, the second cohort of RIFP Fellows have been appointed and are starting the next stage of their careers at STFC and the Diamond Light Source. 12 Fellows will spend 2 years working on their chosen projects and benefiting from the available STFC and Diamond facilities and expertise.

The range of projects is very broad, and includes: development of THz methods and new chamber coatings for particle accelerators; development of time-resolved x-ray methods for biological studies; neutron and muon studies of novel transition metal oxides, surfactants relevant to personal care products and archaeological objects; tests of fundamental particle physics through exploring the top quark and detector development for ATLAS at CERN; signal propagation studies for advanced satellite communication; studies of wave propagation in the Earth’s magnetosphere; and studies of the origin and evolution of interstellar dust.

A news story on some of the Fellows who have recently started is available online.

The individual projects are listed here.

Fellow Department name Project title Brief summary of project
Shyamal Mondal ASTeC Particle beam manipulation with high-field THz pulses

A new generation of high-energy particle accelerators is essential in meeting the scientific challenges of the 21st century. Advanced concepts such as Free Electron Lasers will allow unprecedented access to some of shortest physical processes in the physical world occurring on femtosecond (10-15 s) timescales.

Conventional accelerator technology – based on radio-frequency manipulation of particles – is limited to acceleration gradients of less than 100MV/m, requiring the need for multi-km scale facilities in high-energy particle physics experiments. Such technology also requires complex equipment and control measures to enable femtosecond resolution in temporal measurement and control of particle bunches.

Terahertz radiation presents the potential means to overcome these challenges, enabling acceleration gradients several orders of magnitude higher than at radio frequencies. Furthermore, terahertz accelerators have the possibility to be inherently synchronised to femtosecond precision, with multiple critical systems driven by a single-pulsed laser system.

This project will deliver a terahertz-driven deflecting structure for femtosecond accelerator diagnostics. This will involve optimisation of an appropriate high field-strength terahertz source and optical engineering design to enable the necessary terahertz/particle interaction. This system will be experimentally validated on a working particle-accelerator, demonstrating the viability of the terahertz as a means to manipulate and control high-energy particle beams.

Yuchen Yang ASTeC Innovation of NEG Coating Deposition for Next Generation Accelerators

To develop high-brightness, diffraction-limited storage rings-based light sources by focusing the beam, it requires beam chambers in millimetre diameter in order to gain good control of beam position and shape. When the vacuum conductance is much reduced in such narrow chambers, it is difficult to reach the ultrahigh vacuum (UHV) that is necessary for accelerators. Non-evaporative getter (NEG) thin films deposited on the inner surface of the chamber would transform the vacuum chamber from an outgassing source into a pump, as well as supress electron multipacting and electron cloud due to its low secondary electron yield (SEY). The extensive use of NEG-based pumping systems for large vacuum systems was pioneered by the European Organization for Nuclear Research (CERN). SAES-Getters have made NEG technology commercially available. NEG has contributed to the achievement of UHV in storage rings for particle physics research and synchrotron radiation production, and are now widely accepted by the accelerator community.

Our project will focus on the optimisation and innovation of NEG coating deposition in various narrow chamber geometries, as well as their underlying plasma dynamics, providing solutions for Future Circular Collider (FCC) which its design has commenced with a support of EuroCirCol EU H2020 programme.

Sepideh Aliasghari ASTeC Superconductinrga diof requency (SRFc) avityp reparationa nd deposition

Superconducting coatings for superconducting radio frequency cavities is an intensively developing field that should ultimately lead to acceleration gradients better than those obtained by bulk Nb RF cavities. The use of copper as main cavity structure primarily is due to lowering the cost of the cavity since high purity niobium cost around 40 times more than copper. Another important aspect is the copper thermal conductivity with respect to that of niobium that can be crucial in promptly transmitting the heat generated in local hot spots to the liquid helium bath. There have been extensive studies in PVD deposition which have shown that the film structure and hence superconducting properties of the films are strongly dependent on deposition temperature, charged particles energy and density that concurrently bombard the surface during film growth as well as substrate lattice parameters. In comparison there has been very little systematic study on the effect of substrate preparation process to provide optimum interface quality that produce highly adherent films to reduce thermal contact resistance. We propose to examine/determine the effect of each step in cleaning/preparation process on the surface in terms of surface chemistry as well as surface microstructure, morphology and residual impurities which have consequential effect on substrate /film interface adhesion. As well as niobium thin film, the study will examine other superconducting thin film such NbTiN, Nb3Ge and MgB2.

Ashley Hughes Diamond Development of pump-probe circular dichroism at B23

Time resolved spectroscopy is a vital tool in the understanding of how systems change in reaction to stimuli. This is especially true in the case of biological systems such as proteins. The understanding of the kinetics of a reaction to stimuli can give vital information on the mechanism of action which can then lead to a better understanding of diseases, or how drugs work, or the folding mechanism of a protein system. The installation and commissioning of a ns laser in combination with B23 circular dichroism (CD) beamline’s highly collimated beam would lead to world leading time-resolved CD being available to the user community allowing fast (0.5 ms) kinetics on a range of biological systems. These can include for example: caged ligand systems (such as pharmaceticals), photoactive proteins (understanding these is important for increasing crop yields and optigenetics) and T-Jump experiments, capable of determining fast protein folding and unfolding rates. The development of these capabilities alongside a novel low volume (<25 μl) closed loop capillary sample delivery system which negates the mal effects of UV damage on sensitive samples would greatly increase the experimental possibilities of the beamline and take advantage of the unique attributes of the facilities in place.

Jhuma Sannigrahi ISIS Neutron scattering and μSR studies on transition metal based oxides: An experimental

Transition metal oxides, that straddle the subtle boundary between covalent, ionic and metallic bonding, show copious physical phenomena, such as high-Tc superconductivity in layered cuprates, colossal magnetoresistance in perovskite manganites, half-metallicity, low dimensional magnetism, coexistence of magnetism and ferroelectricity — termed multiferroicity, spin-liquid ground state and many more. Reaching that regime of understanding experimentally, where ground state magnetic structures, magnetic excitations, spin fluctuations of transition metal oxides can be investigated in detail, is the central focus of this proposal. Hence, we will carry out neutron and μSR experiments on different polycrystalline and single crystalline samples of transition metal oxides. X-ray synchrotron study will also be performed as per requirement to investigate the crystal structure. One of the aims of these investigations will be to discover new multiferroics and low dimensional magnets and also to explore the nature of ground state and magnetoelectric coupling that will provide the model systems needed to test the validity of various theoretical models. Another key focus is to explore the exotic physics behind spin ice/spin liquid behaviour observed in frustrated pyrochlores. The present proposal will also open a new route to study the interplay of Coulomb interactions, spin-orbit coupling, and the band topology in pyrochlore irridates.

Yao Chen ISIS Exploration of the aggregate structure for oligomeric surfactant by neutron scattering

Surfactants have been widely used in cosmetics, detergents and pharmaceutical industries. These applications are always related to surfactant-lipid interactions. The interaction plays an important role in a vast field, including the activity and delivery of drugs, the regulation of cellular processes and the food digestion. The lipid-surfactant interaction helps to predict the skin irritation power of surfactant because human skin is mainly composed of lipids and proteins. The interaction of conventional single chain surfactant with lipid has been well studied to promote its practical use. However, with the growing customer requirement, novel surfactants with higher cleaning efficiency and lower dosage are needed. Oligomeric surfactant, with three or more hydrophobic tails, should be taken into consideration due to its outstanding self-assembly properties. Therefore, the interaction of oligomeric surfactant with lipid should be considered first before practical use. In this proposal, with the help of SANS at ISIS, the most powerful approach to study the precious structures of surfactant aggregates, the precious aggregate structure of the oligomeric surfactants can be detected. We seek to know how different surfactant aggregates interact with lipid and the results will lead some new applications for oligomeric surfactants.

Anna Fedrigo ISIS Advanced neutron techniques in archaeometallurgy

The application of neutron diffraction and imaging techniques have long demonstrated their potential in the characterisation of dense materials in engineering and material science. In this project they will be used as non-destructive analytical tools for the study of metallic artefacts of archaeometric interest—objects for which, metallography, until recent years at least, has been seen as the method of choice. Moreover, while metallography provides punctual information, neutrons can probe non-destructively macroscopic and ‘representative’ areas; the use of non-invasive methods is highly relevant for cultural heritage objects, due to their uniqueness and immaterial value.

As the development and advancement of societies have been intimately tied to their ability to produce and manipulate materials, the applications of neutron-based techniques to archaeometallurgy studies can be invaluable in improving our knowledge on the technological evolution of ancient civilisations, and in helping with the conservation of museum objects.

Neutron techniques are a very useful, but, at present under-used approach. This project may hopefully encourage further studies and applications to metal artefacts and therefore may substantially contribute to a general expansion of the techniques and methods utilised by Institutions and Museums to understand, investigate, and preserve our Cultural Heritage.

Jacob Linacre PPD Direct and indirect searches for new physics in events with top quarks using LHC proton-proton collisions at the CMS detector

The standard model (SM) of particle physics is known to be only an incomplete and approximate description of the Universe. The top quark is the heaviest elementary particle in the SM, a fact that may be connected to the existence of new physics beyond the SM – particularly in the Higgs mechanism of electrokweak symmetry breaking, which is responsible for the existence of elementary particle mass. We look for signs of new physics beyond the SM predictions in events with top quarks using LHC proton-proton collisions at the CMS detector. A direct search for top quark partners is performed, where we seek to identify events with properties consistent with new heavy, vector-like quarks. This search is complemented by an indirect but model-independent search for new physics interacting with top quarks, by looking for deviations from SM predictions in precision measurements of top quark properties. In order to enable these and similar searches to continue at the future High Luminosity LHC, we study the performance of the upgraded track trigger for events with top quarks, including optimisation of reconstruction algorithms and working points.

Weimin Song PPD Development of Silicon Strip Sensor test platform for the upgrade of the ATLAS experiment at CERN

The project is to work within the particle physics department at STFC-RAL to develop a software test platform that will allow PPD to run repeatable production tests of silicon detector modules, used in the upgrade of the ATLAS inner detector at CERN. The modules have demanding electrical and mechanical requirements in terms of signal efficiency and noise performance, as well as High and Low Voltage powering and cooling. Testing these modules in various ways (given through a variable software platform) optimises both the production flow and the product itself for later operation. Delivering a framework that allows PPD to run repeatable tests on objects in a simplistic and fast manner, whilst delivering accurate and repeatable results will allow me to apply my software skills in support of the future production of the tracker as well as enhancing the hardware of the future tracker by early stage understanding of characteristics. Developing an understanding of the achievable performance, I will also test CMOS active sensor candidates to compare their performance to the baseline module build envisaged for the ATLAS inner detector upgrade.

Charilaos Kourogiorgas RAL Space Advanced Radio Propagation Modeling for High Throughput Satellite Communication Systems In this project, the effects of the propagation of the transmitted signals through the atmosphere are modelled for satellite communication links using data from RAL Space, in order to evaluate the performance of the High Throughput Satellite Systems. The demand of high data rates for satellite communication services requires the signal transmission at higher frequency bands (20/30 GHz, 40/50 GHz or even 75/115 GHz). However, atmospheric phenomena (rain, clouds, turbulence, atmospheric gases) degrade the link performance. The compensation of signal attenuation due to the atmosphere requires the use of Fade Mitigation Techniques which depend on the spatio-temporal variations of the atmospheric losses. In this project, models able to predict the statistics and the variability of the channel will be developed. To obtain accurate models, the extensive data set of attenuation measurements and concurrent meteorological data from RAL space will be used. The measurements have been conducted from multiple ground stations with ITALASAT F1 at 20, 40 and 50 GHz and with the ALPHASAT at 20 and 40 GHz. In order to obtain the spatial variations also a large-scale and study the effects at different climatological areas, measurements from Heriot-Watt University and National Technical University of Athens will be also employed.
Tieyan Wang RAL Space The role of Kinetic Alfvén wave (KAW) turbulence in the Earth’s magnetosphere

The plasma which constitutes a major part of the solar wind and the Earth’s magnetosphere is generally in a fluctuating/turbulent state. The associated waves play a key role in transferring plasma mass, momentum and energy between regions. Turbulence at kinetic scales is often considered to possess kinetic Alfvén wave signatures, which carry parallel electric field fluctuations, and thus often lead to plasma heating and energization. Due to the lack of plasma measurements at high sampling rates, previously, observational knowledge of kinetic-scale fluctuations in the Earth’s magnetosphere has been limited. This proposal aims to understand the role of kinetic Alfvén turbulence in the Earth’s magnetosphere by answering questions on how it affects the electron/ion motion; how it dissipates the energy, and how it relates to other key physical process (plasma heating, magnetic reconnection).

These scientific objectives will be completed through the combination of data analysis based on multi-spacecraft observations (from Cluster, MMS and Swarm) of wave, field and particle distributions, with existing theoretical and simulation results. Powerful multi-point data analysis methods guarantee the accurate estimation of wave mode, electric current and field topology. We focus on the cusp, magnetopause, and magnetosheath, but will analyse other regions where relevant.

Olivia Jones UKATC The death of stars and the origin of dust in galaxies

The origin and evolution of dust impacts upon all areas of astronomy, from cosmology to planet formation. Dust profoundly affects the spectral appearance of galaxies and the many processes that determine the physical, chemical, and thermal state of their interstellar medium (ISM). I will characterize the physics and chemistry of dust production in stellar ejecta and supernova remnants, constraining the cosmic evolution of dust from the high-redshift early universe to the present-day. This will be done empirically, through observations with revolutionary new telescopes such as the James Webb Space Telescope (JWST). The unprecedented sensitivity and resolution provided by JWST in infrared wavelengths will enable the discovery and characterization of individual dust-producing stars in distant galaxies, ranging from metal-poor dwarf galaxies to solar-metallicity spirals and ellipticals. These observations will be directly compared to predictions from dust-evolution models that are representative of the high-redshift universe. In doing so I will directly explore how galaxies have evolved from the early universe to our own Milky Way.

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