Few problems in fundamental physics are as clearly motivated or as important as discovering the nature of the elusive dark matter that accounts for most of the mass of the universe. Direct detection experiments located deep underground are searching for the rare interactions of these well-motivated, relic particles in very sensitive detectors. Liquid xenon (LXe) technology has led these searches for over a decade. Recently, the top international collaborations in the field have come together in the XLZD consortium to build the definitive experiment: one able to discover or rule out electroweak-scale particle dark matter in the accessible parameter space remaining above the very challenging neutrino background. Exciting opportunities exist also in neutrino physics, including establishing the existence of neutrinoless double-beta decay; this is another paradigm-shifting discovery which may be accessible to such an experiment, which could explain the matter-antimatter asymmetry in the universe. This proposed 'rare event observatory' will deploy a LXe detector with up to 80 tonnes of 'active' mass in an ultra-low-background experiment to address these and other questions, at least two of which could entail Nobel-Prize worthy discoveries. This Pre-Construction project prepares the UK contribution to the XLZD experiment and builds the case to bring this ambitious international experiment to the UK. STFC is developing a major new underground laboratory at the Boulby mine, and XLZD would be the centrepiece of the new state-of-the-art facility. A future construction project must be carefully prepared, and this development work is delivered through this Pre-Construction project. The proposed UK contribution to XLZD includes major experimental hardware systems, especially those most naturally suited to the host nation; these will be designed and prepared in this phase. In addition, we will deliver with key industrial partners bold programmes for clean manufacture underground, for engineering and skills development, and for environmental sustainability. These programmes relate to challenges that must be addressed, but which we deliberately develop into opportunities: to provide return to UK industry and wider economic impact, to develop capabilities that support future STFC and UKRI projects, and to be a pathfinder in how Big Science moves towards Net Zero.

It is well-established that there exists a mysterious, non-luminous mass component in our Universe. In 1933, Fritz Zwicky determined that galaxies rotating in the Coma Cluster were moving much faster than expected from the gravitational pull of the visible matter; this was the first piece of evidence to point towards an additional non-visible, mass component in our Universe. Zwicky measured approximately 10 times more mass than the total mass of the visible matter. Since then, there has been a flurry of astrophysical and cosmological evidence to support this argument, which indicates that the visible matter in our Universe, which is accounted for in our Standard Model of particle physics, only makes up 5% of the total energy density of the Universe. The evidence suggests that up to 25% of the Universe is comprised of this mysterious, "dark matter", however it is yet to be experimentally detected. The nature of dark matter is therefore one of the biggest mysteries in modern-day particle physics; its discovery is critical in understanding the origin of the universe, as well as unlocking the door to a new era on particle physics. As such, there is growing excitement within the astroparticle physics community to find dark matter, with many experiments currently searching for direct evidence of a dark matter particle interaction. So far, there has been no experimental evidence of dark matter. However, experiments are continuing to push the boundaries to rule out a variety of dark matter candidates. One class of dark matter candidates that has yet to be searched for is "light" dark matter, which is predicted to have a smaller mass than most current experiments are typically designed to search for. As a Future Leader Fellow, I have designed a comprehensive and exciting research programme that will search for this experimentally-unexplored light dark matter, using a combination of both the largest dark matter experiment under construction to date, DarkSide-20k (DS20k), and one of the smallest, QUEST-DMC. These experiments search for evidence of a dark matter particle scattering from a target atom, using liquid noble gases as their target media. Since DarkSide-20k and QUEST-DMC use different target media, they have the potential to explore different dark matter models and mass ranges, and therefore between the two experiments, there is the very real possibility of a dark matter discovery. The programme will use sophisticated data analysis techniques combined with cutting-edge quantum sensor technology to unlock the potential of both experiments, striving to achieve world-leading sensitivity to a range of light dark matter candidates. The impact of this programme is significant: if light dark matter is not discovered in this search, a large fraction of light dark matter candidates will have been ruled out, which is knowledgeable and important insight for next-generation dark matter detectors. In addition to the scientific impact, the development of enhanced quantum sensor technology required for this programme will have substantial implications on future detector designs for dark matter and other low-energy physics searches, and serves to benefit the wider community outside of astroparticle physics who require leading-edge quantum sensors.

Among the myriad of toxics that contribute to water toxicity, heavy metals derived from mining have a huge impact in our environment even at very low doses. In parallel, mines play a pivotal role in the industrial/technical development of our societies. Usually, mining acid drainages or polluted waters are accompanied by critical raw elements (CRE). Today passive disperse alkaline. Dispersed Alkaline Substrate (DAS) reactors is one of the technologies (TRL-9) that blocks the scape of these toxic elements from mines. For instance, heavy metals and valuable metals (CRE) are concentrated at different levels of DAS reactors during operation. So, envisioning a technology able to develop a circular economy for mining water by coupling its remediation to the recovery of valuable resources concentrated in DAS is highly appealing from environmental end economic point of views. SELFAQUASENS project brings key academic and non-academic actors within and beyond EU to develop a modular self-sensing filter and membrane technology able to: (I) remediate heavy metals and salinity pollutions in mining water, (II) couple the remediation to the recovery of CRE and (II) sense the concentration of specific elements or groups of elements during the process. SELFAQUASENS joints varied interdisciplinary and intersectoral expertise in an International research and training network formed by 5 universities, 2 large scale research facilities, 2 research centers and 2 SMEs. As a result, the R&I system of Europe will be strengthened by an ambitious exchange and training program that covers all the research disciplines, sectors and international actors needed to achieve the objectives of the action. The project will have significant impacts in the short to long terms into the EU society, economy and environment by: (I) pursuing the mission for toxic-free rivers and oceans, creating new sources of CRE for the EU economy, and improving the health and quality of the EU citizens.

Space telescopes for astronomy and Earth observation revolutionise our understanding of the universe and the planet we live on. The mirrors that collect the light from the astronomical object (e.g. stars, planets, nebulae) or the Earth, and direct it to the detector, are arguably the most important parts of the telescope, as without them the light cannot be studied. However, mirrors for space telescopes need to be lightweight, that is, to have a low mass, due the size of the rockets that launch them; designed specifically for the given science goal (bespoke); and to be fixed within the telescope without distorting the reflecting surface. All these challenges make mirrors for space telescopes one of the most challenging, and therefore expensive, parts to make! The goal of my research is to increase the use of additive manufacture (AM), also known as 3D printing, within space telescopes, but particularly for low mass mirrors. AM is a new method of manufacture that builds a part layer-by-layer from a digital design file. The primary benefit of AM is in the freedom of design offered by the layer-by-layer approach, which cannot be achieved by using today's manufacturing methods: mill, drill, lathe, casting, or forging. AM can print specialised low mass structures for the given science goal, combine multiple parts into one (mirror + mount), and it is a method of manufacture that is ideal for bespoke, one-off designs, like telescope mirrors. In Years 1 to 4 of my Future Leaders Fellowship (FLF), I investigated three key topics: 1) with more design freedom, how do you choose the correct low mass structure for your mirror; 2) AM is not a perfect method of manufacture, therefore, how can you reprogram the 3D printer to get the best print for your mirror; and 3) how do AM printed parts behave in a space environment and how can we encourage the use of AM in space telescopes. Building upon Years 1 to 4, my FLF renewal aims to break, or lower, some of the barriers limiting AM use in space telescopes today. The focus of the renewal is to progress AM mirrors through the Technology Readiness Levels (TRLs); these levels represent how mature a technology is. TRL 1 is an idea and TRL 9 is technology that has been successfully flown on a space mission. The FLF renewal seeks to increase AM mirrors to TRL 6, which is where the technology is demonstrated within a relevant environment, in this case, applying vibrations and shocks equivalent to those felt by a rocket during launch, and applying heat to mimic the day-night cycle of an orbit around the Earth. To complement 'demonstration within a relevant environment', AM samples and prototype AM mirrors will be studied to understand how microscopic defects in manufacture can affect how well the mirror reflects light, and how these defects can be measured in terms of size and location. A secondary focus of the renewal is to understand what holds an engineer back from designing with AM. Given the benefits of AM in hardware for astronomy, why is it not used more widely? Part of the answer lies in the perception that AM is just not ready yet, which I hope to solve by increasing the TRL. However, a part of the answer also lies within the experience that an engineer has and the existing procedures followed within an engineering team. The renewal seeks to understand what holds an engineer back and how engineers can be supported to include AM within their manufacturing toolkit. Supporting engineers and raising the TRL is a research challenge and requires multiple disciplines (e.g. optics, materials science, metrology, manufacture, and social science) coming together to learn the answers. My research vision is to see AM mirrors within future space telescopes, which then have enabled new discoveries within the fields of astronomy and Earth Science.

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