Instrumentation

Supervisors: Gavin Dalton

This project will look at aspects of the development of calibration and alignment strategy for the focal plane structure of the MOSAIC spectroscopic instrument for the 39m ELT. The MOSAIC focal plane will host 275 robotic positioners, each with an optical relay and compensation optics to mitigate the effects of atmospheric dispersion, which focus the ELT beam onto groups of optical fibres. A first build of the prototype focal plane will commence in early 2025. The MOSAIC science team are now also obtaining prototypical observations with WEAVE at the 4.2m William Herschel Telescope that will be used to explore the data processing stages needed to ensure MOSAIC’s full potential, and there are further opportunities to work on analysis of high redshift galaxy spectra that will combine spectra from WEAVE with near-infrared spectra from the Euclid satellite mission. Within the scope of these works there are multiple opportunities to study aspects of instrumentation and the links from instrument design through advanced data processing and astrophysical analyses.

Supervisors: Boon Kok-Tan, Dimitra Rigopoulou

The millimetre (mm) and sub-mm wavelength regime is crucial for advancing our understanding of the universe. Approximately half of the energy generated by star formation and black hole accretion throughout cosmic history has been absorbed by dust and re-radiated as thermal radiation in the mm/sub-mm and far-infrared bands. Consequently, sub-mm astronomy plays a pivotal role in addressing key questions about planet formation, star formation, galaxy evolution, and large-scale structure formation as part of our broader multi-wavelength observational efforts.

Astronomical observations in the mm/sub-mm range, including the first direct detection of black hole, have only been made possible by the remarkable capabilities of near quantum noise limited Superconductor-Insulator-Superconductor (SIS) heterodyne receivers. These receivers are routinely used on observatories such as the Event Horizon Telescope (EHT), the Atacama Large Millimetre/Submillimetre Array (ALMA), and far-infrared space observatories, enabling high spectral and spatial resolution observations of faint celestial objects. However, significant limitations remain in the use of SIS receivers for upcoming ground-based and space-borne astronomical observations.

Currently, most major mm/sub-mm heterodyne facilities around the world are equipped with only a single-pixel receiver per telescope. Increasing the number of pixels at the focal plane would allow for much faster mapping of extended astronomical objects, making it possible to undertake large observational projects that were previously unfeasible. In short, increasing pixel count is akin to building multiple telescopes, but at a fraction of the cost and effort.

This programme encompasses two complementary scientific aims: the first focuses on developing advanced quantum detectors, while the second centres on an observational project.

On the instrumentation side, we have already built experimental systems to test SIS mixers across the frequency range from 160 GHz to 950 GHz. In this project, we aim to develop a medium-sized 25-pixel heterodyne array with advanced capabilities to split incoming astronomical signals into two orthogonal polarisation states and two distinct sidebands; the latter effectively doubling the observational bandwidth. This design is equivalent to a 100-pixel heterodyne array by traditional standards, but with additional polarisation capabilities – a feat that has not yet been demonstrated. If successfully implemented, this would result in the most powerful heterodyne array ever built. Our ultimate goal is to push this technology into the hundreds-of-pixels range in preparation for the ALMA 2040 upgrade and AtLAST, the largest-ever single-dish sub-mm telescope, which is under consideration for construction in the 2030s.

We are seeking a student to join this exciting venture. Key tasks include: 1) developing the 25-pixel dual-polarisation sideband-separating array receiver, 2) upgrading the existing experimental setup to test the array receiver’s performance, and 3) potentially commissioning the demonstrator array receiver at the James Clerk Maxwell Telescope (JCMT) in Hawai’i.

Observationally, the student will be expected to work on a Galaxy Evolution project focusing on the properties of the ISM (gas and dust) in infrared (IR) luminous galaxies. The project will specifically explore the link between the molecular gas and dust content of IR luminous galaxies.  ALMA has made significant progress by providing a census of the cold molecular gas and dust continuum emission in these galaxies. However, little is known about their properties.  For this purpose, we will use the unparalleled capabilities of JWST to probe the emission from PAHs (Polycyclic Aromatic Hydrocarbons) which are a key diagnostic of the ISM as they regulate its thermal and chemical balance. The project will involve reduction and analysis of spectroscopic data from large millimetre and submillimetre observatories, in particular NOEMA and ALMA as well as spectroscopic observations with JWST MIRI and NIRSpec.

This project is ideal for a student who enjoys engaging with theoretical work on quantum sensors, superconducting electromagnetism, and cutting-edge astrophysical developments, while also being enthusiastic about coding, lab-based experiments, and data analysis. Our state-of-the-art cryogenic detector laboratory provides excellent facilities, and the student will be supported by a technician, postdocs, and supervisors, with access to commercial and custom software for research purposes.

Further Readings: 

• https://iopscience.iop.org/article/10.1088/1361-6668/acca51/pdf
• https://ora.ox.ac.uk/objects/uuid:d19a2b82-b5b9-416f-b098-ea4bd4d96ed6/files/smg74qn32h
• https://ui.adsabs.harvard.edu/abs/2022MNRAS.512.2371H/abstract
• https://arxiv.org/pdf/2202.10576.pdf 

Note: A similar project with slightly different focus can be found on the ALP post-graduate page:
https://www.physics.ox.ac.uk/study/postgraduates/dphil-atomic-and-laser-physics/dphil-projects

Supervisors: Boon Kok-Tan, Dimitra Rigopoulou

The development of superconducting parametric amplifiers (SPAs) has garnered significant attention from the astronomical, quantum computing, and dark matter search communities. SPAs offer quantum-limited sensitivity across a broad bandwidth, coupled with ultra-low heat dissipation, making their performance superior to the state-of-the-art cryogenic low-noise amplifiers currently used in these fields. While many prospective innovations remain to be explored, SPAs certainly have the potential to revolutionise many ultra-sensitive instrumentations, particularly in astronomy and quantum computing, operating from microwave to terahertz wavelengths.

SPAs can significantly enhance the sensitivity of heterodyne receivers and enable the development of large astronomical arrays, potentially thousands of pixels while most current sub-mm telescope equipped with only a few pixels. Their large bandwidth, high power handling, and quantum-limited noise performance will have a profound impact on quantum computing architecture, improving the fidelity needed to process hundreds of qubits. This, in turn, could accelerate progress towards practical quantum computing and boost the speed of axion dark matter searches.

This programme comprises two complementary research areas: the development of quantum amplifiers and an observational project.

On the instrumentation side, the student will begin by studying the theoretical foundations and learning to use commercial electromagnetism software, along with in-house codes, to design the amplifiers. They will also have the opportunity to participate in device fabrication using state-of-the-art clean room facilities, either at Oxford or with collaborators at Paris Observatories, CalTech/JPL, and IRAM etc. Additionally, the student will gain hands-on experience with sub-Kelvin cryogenics and novel experimental techniques to measure the performance of the amplifiers, specifically investigating sensitivity and gain across the microwave and millimetre ranges. Ultimately, the student will integrate the amplifier into existing astronomical receivers, quantum computing architectures (in collaboration with Condensed Matter Physics), and the UK Dark Matter Search experiment, assessing their impact on overall system performance.

Observationally, the student will be expected to work on a Galaxy Evolution project focusing on the properties of the ISM (gas and dust) in infrared (IR) luminous galaxies. The project will specifically explore the link between the molecular gas and dust content of IR luminous galaxies.  ALMA has made significant progress by providing a census of the cold molecular gas and dust continuum emission in these galaxies. However, little is known about their properties.  For this purpose, we will use the unparalleled capabilities of JWST to probe the emission from PAHs (Polycyclic Aromatic Hydrocarbons) which are a key diagnostic of the ISM as they regulate its thermal and chemical balance. The project will involve reduction and analysis of spectroscopic data from large millimetre and submillimetre observatories, in particular NOEMA and ALMA as well as spectroscopic observations with JWST MIRI and NIRSpec.

This project is ideal for a student who enjoys delving into the theoretical aspects of quantum sensors and superconducting electromagnetism, as well as cutting-edge developments in astrophysics. They should also be comfortable with coding, lab-based experimental work, and data analysis. The Superconducting Quantum Detector Group at Oxford offers a well-equipped laboratory with all the necessary instruments to design and test quantum devices. The student will receive support from an experienced technician and collaborate with post-docs, other DPhil students, and experts in electronics, mechanics, and photo-fabrication. Access to both commercial and proprietary software will be provided to facilitate their research.

Further Readings: 

• https://www.nature.com/articles/nphys2356, http://science.sciencemag.org/content/350/6258/307
• https://ui.adsabs.harvard.edu/abs/2022MNRAS.512.2371H/abstract
• https://arxiv.org/pdf/2202.10576.pdf 

Supervisors: Mike Jones, Angela Taylor

The Experimental Radio Cosmology Group is engaged in a several high-profile projects in instrumentation for radio and microwave background projects. These include:

Simons Observatory (SO), a multi-national project to measure the polarization of the Cosmic Microwave Background (CMB) using a collection of millimetre-wave bolometric telescopes in Atacama, Chile. In Oxford we are desiging the digital readout for the KIDS detector arrays and will be invovled in the commissioning, operation and data anlaysis of the SO:UK instruments.

The C-Band All-Sky Survey (C-BASS) and the European Low-Frequency Survey (ELFS), which are measuring the Galactic foregrounds that contaminate CMB polarization observations. We are involved in all aspects of the instrument design and data analysis.

The Square Kilometre Array the world's biggest radio astronomy project, for which we are designing cryogenic receivers. 

These projects require a broad range of skills in design, testing and implementation of advanced instrumentation, and also offer the opportunity to become involved in the data analysis and science exploitation of these projects. There are several different DPhil projects possible in this overall area depending on the interests and aptitudes of the student, and these can involve more than one project (for example, SO and ELFS).

Supervisors: Matthias Tecza, Niranjan Thatte

One of the E-ELT's highest scientific priorities is to characterise exo-planets and to take images of Earth-like planets.  For this purpose the E-ELT will be equiped with a dedicated planetary camera and spectrograph, called PCS, to be commissioned in the 2030s. The overriding factor in directly imaging exo-planets is the contrast ratio between the faint planet and the bright star it orbits.

In Oxford we are leading the R&D effort to establish which spectrograph design offers the best performance. Using a bench mounted spectrograph we will measure the achievable contrast ratio of an image-slicer based and a lenslet-array based spectrograph.

We are looking for motivated D.Phil student who has a keen interest in state-of-the-art instrumentation. She/he will be involved in the design and set-up of the experiment, including opto-mechanical design, and data acquisition using CCD detectors.  The student will also reduce, process, and analyse the data collected to determine and optimise the achievable contrast, including applying and/or developing novel algorithms to exploit the advantages of image-slicer or lenslet-array based spectrographs.

Supervisors: Matthias Tecza, Fraser Clarke

This project is a unique and rare opportunity for a hands-on instrumentation DPhil focused on upgrading the Philip Wetton Observatory here in Oxford, by designing and constructing a scientific instrument to exploit the parameter space offered by this small telescope. This would involve a full lifecycle of an astronomical instrument project, from concept, through the design and construction phase to commissioning, something that is impossible with modern instrument projects for large telescopes due to their long timescales. As part of a small team you would be involved in all aspects of an astronomical instrumentation project: from optical and mechanical design; assembly, integration and test; and data acquisition, reduction, and analysis software. You would gain a detailed know-how of instrumentation techniques at visible and near-infrared wavelengths and first-hand knowledge of how instruments imprint their signature on the gathered data, which is crucial to a deeper understanding of observational data from space and ground-based observatories.

Supervisors: Andrew Siemion, Alex Pollak, Joe Bright

Breakthrough Listen, headquartered in the Department of Physics since 2023, is humanity’s most comprehensive search for technosignatures (indicators of technology as a proxy for extraterrestrial intelligence). The Listen team employs cutting-edge digital hardware at telescopes across the world and in space, developing new algorithms and approaches to ingest and process enormous streams of data.

With instruments such as the Vera C. Rubin Observatory soon starting their surveys of the sky, and pathfinders and precursors to the Square Kilometre Array telescope already producing outstanding science, the time is ripe to harness the tools of modern astronomy to expand technosignature searches into their next phase.

One SKA pathfinder, the Allen Telescope Array, was recently upgraded to support streaming digital signal processing as part of a collaboration with NVIDIA. Using NVIDIA Holoscan, a cutting-edge GPU-accelerated digital signal processing pipeline, SETI Institute and NVIDIA researchers, in collaboration with the Listen team, demonstrated real-time machine learning processing for the detection of fast radio bursts. 

The incoming student will be expected to build on the prototype system to deploy a full technosignature and transient detection pipeline at the ATA, and from there to expand deployment to other facilities with existing SETI Institute and Listen backend processing instruments. Real time processing will enable data to be analysed at the native frequency and time resolution delivered from the telescope (impossible in archival data because of time and frequency averaging used to make data volumes manageable). Streaming processing will enable subsets of data on interesting signals to be archived, as well as triggering other facilities to undertake real-time follow-up. 

The student will be expected to have a background in high performance computing, digital signal processing, and / or GPU programming.