Professor Simon Doyle

Biography

Academic History 2017 – Present: Reader in Experimental Astrophysics, School of Physics and Astronomy Cardiff University

2015 – 2017: Senior Lecturer, School of Physics and Astronomy Cardiff University

2012 – 2015: Lecturer, School of Physics and Astronomy Cardiff University

2008 – 2012 Postdoctoral Research Associate (PDRA), School of Physics and Astronomy Cardiff University

2004 – 2008 PhD Physics, School of Physics and Astronomy Cardiff University

Education History

2013 – 2014: Modules 1 and 2 of Postgraduate Certificate in Teaching and Learning (PCULT), Cardiff University

2004 – 2008 – PhD student in experimental astrophysics

1999 – 2003: MPhys Astrophysics School of Physics and Astronomy Cardiff University

Teaching and PhD supervision Experience

2012 – Present: PhD Supervisor (6 students to date, three current, three graduated)

2017 – Present: Deputy Module Organiser and primary assessor – MPhys student project module

2013 – Present: Module Organiser – Electromagnetic Radiation Detection

2012 – Present: PhD Co-supervisor (4 students to date)

2012 – Present: Postgraduate lectures

2012 – Present 1st and 2nd year undergraduate tutor (21 students to date)

2013 – Present: BSc project supervisor (8 students to date)

2014 – Present: MPhys project supervisor (4 students to date)

2015 – 2017: Deputy Module Organiser – Astronomy Instrumentation

2013 – 2017: Placement student academic supervisor (4 students)

2012 – 2017: Deputy Module Organiser – Practical Physics

2012 – 2013: Deputy Module Organiser – Electromagnetic Radiation Detection

2008 – 2012: Assistance with BSc and MPhys project students (6 students)

Research funding

STFC 2019 – Present STFC Industrial Partnership Scheme (IPS) “Rapid Airport Security Screening Using Superconducting Technology PI

STFC 2019 – Present SO-UK Phase A PI

STFC 2019 – Present A programme of technology, astrophysics and cosmology in Cardiff – Detector program PI

EPSRC (QUANTIC Hub, Glasgow), Titanium Nitride Kinetic Inductance Detectors for Terahertz Imaging - 2, Cardiff PI 2018-Present

EPSRC (QUANTIC Hub, Glasgow), Titanium Nitride Kinetic Inductance Detectors for Terahertz Imaging, Cardiff PI 2017-2018

RCUK Newton Fund (administered by STFC: “MUSCAT- a new technology large format camera for the Large Millimeter Telescope”. Cardiff PI 2015 - Present

STFC Industrial Partnership Scheme (IPS). “A commercial THz imaging system using Lumped Element Kinetic Inductance Detectors”. PI 2015 - 2018

STFC Consolidated grant: PI on the detectors theme (theme 10) 2016 - 2019

STFC Consolidated grant: PI on the detectors theme (theme 11) 2015 - 2016

SPACEKIDS - EC REA FP7-Space: Senior scientist and work package leader on this grant. 2012 - 2015

STFC Impact Acceleration Account: Co-I on this grant. 2012

School of Physics and Astronomy administrative roles

PCUTL mentor 2015- present

PDRA and Academic staff Mentor 2015 - present

AIG Cleanroom users group representative 2016 - present

Board of Studies member 2012 – Present

Exam Board member 2012 – Present

Postgraduate Admissions Tutor 2014 – Present

Postgraduate progression panel 2016 - present

PhD student interview and selection panel 2012 - present

Membership of external working groups and panels

NIKA Editorial Board 2013 – present

Institute of Physics Low Temperature Group 2012 – 2016

Science organising committee, Science Foundation Ireland MKIDs group. 2016 - Present

Technical advisor to Science Foundation Ireland MKIDs group. 2016 – Present

STFC Detector advisory committee 2018

Roles in external assessment

PhD external examiner, University of Grenoble Alps, France, 2019

STFC Consolidated grant reviewer 2016, 2018

Journal of low temperature physics publication referee 2019, 2016 and 2012

PhD external examiner, Royal Holloway, University of London, 2013

Invited talks and lectures

Seminar talk, Maynooth, March 2015

FISICA workshop, Maynooth, January 2015

Low Temperature Detectors conference, Grenoble 2015 (Invited September 2014)

International Symposium of Space Terahertz Technology - Moscow 2014

Superconducting Devices & Applications, National Physics Laboratories, 2013

Low Temperature Detectors Summer School, Toulon, France, May 2012

Workshop on Microwave spectral polarimetry – Paris 2012

National Astronomy Meeting, Glasgow (not attended due to travel disruption)

Other conference talks, group talks and session chairs

SPACEKIDS concluding presentation to the European Commission, Noordwijk 2016

SPACEKIDs workshop, Noordwijk, 2016

SPACEKIDs workshop, Cardiff 2014

FIRI workshop, London 2013

Public lecture, Cardiff 2013

Low Temperature Detector Conference, Pasadena 2013

Group talk, Jena 2013

Second Keck Institute for Space Studies TiN development workshop, Pasadena 2012

Micro-resonator workshop, Grenoble 2011

First Keck Institute for Space Studies TiN development workshop, Pasadena 2011

SPIE conference, San Diego 2010

Infrared Millimeter and Terahertz Waves (IRMMW-THz), Rome 2010

Session Chair Low Temperature Detectors Conference, Stanford 2009

SPIE conference, Marseille 2008

Superconducting Resonators workshop, Utrecht 2007

Low Temperature Detector Conference, Paris 2007

International Symposium of Space Terahertz Technology Conference, Gothenburg 2007

Ultra low noise detectors workshop, Cambridge 2007

Superconducting Resonators workshop, Pasadena 2006

Publications

Teaching

2020 - Present: Deputy Module Organiser and primary assessor – PX1150 Year 1 Experimental Physics

2017 – Present: Deputy Module Organiser and primary assessor – PX4310 MPhys student project module

2013 – Present: Module Organiser – PX3144 Electromagnetic Radiation Detection

2012 – Present 1st and 2nd year undergraduate tutor

2013 – Present: PX3315 BSc project supervisor

2014 – Present: PX4310 MPhys project supervisor

2015 – 2017: PX4125 Deputy Module Organiser – Astronomy Instrumentation

2013 – 2017: Placement student academic supervisor

2012 – 2017: Deputy Module Organiser – PX2133  Practical Physics

2012 – 2013: Deputy Module Organiser – PX3144 Electromagnetic Radiation Detection

My research focuses on the area of detector and instrument development for millimetre, sub-millimetre and Terahertz imaging for astronomy and commercial applications. Detecting light at the long wavelengths is challenging as most room temperature objects radiate at these wavelengths and that the photon energy is too low to make use of conventional semiconductor based systems such as Charged Coupled Devices (CCDs). Performing sensitive imaging at these long wavelengths therefore requires working at cryogenic temperatures typically below 1K (-272°C) and using novel detector technologies that make use of superconducting material properties to convert light into a measurable output. I lead a group of researchers and technical staff that continues to develop instrumentation and detector arrays based on Kinetic Inductance Detectors as well as new compact continuous sub-Kelvin cryogenic coolers.

Kinetic Inductance Detectors

One of the significant outputs of my research has been the invention and development of the Lumped Element Kinetic Inductance Detector (LEKID). This is a variant of the Microwave Kinetic Inductance Detector (MKID) that has properties to enable direct coupling to light (like in a CCD pixel) and convenient coupling to microstrip structures. The LEKID is a superconducting, high quality factor microwave resonator consisting of a planar capacitor-inductor circuit. The inductor has two components – a fixed geometrical inductance Lg and a kinetic inductance Lk resulting in a resonant frequency F0=1/[(Lg+Lk)C]^0.5 (typically 0.5-3 GHz). The absorption of a photon with energy greater than the superconducting band gap (hν > 2Δ typically around 90GHz for aluminium based devices) splits paired electrons in the superconducting inductive section modifying F0 though an increase in Lk. This response to absorbed optical power is sensed by measuring the shift in the amplitude and phase of a fixed microwave tone propagated along a microwave feed line to which a LEKID is coupled. This is demonstrated in figure 1.

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By their very nature, KIDs are naturally multiplexed in the frequency domain and have demonstrated multiplexing ratios of order 1000 detectors/readout channel over readout bandwidths of 2GHz [1]. Furthermore, KID devices only require a single cryogenic amplifier and a pair of coaxial lines to readout each channel leading to a dramatic reduction in the complexity of cryogenic readout electronics and overall focal plane cost compared to rival technologies such as Transition Edge Sensors (TES). KID based focal planes have also demonstrated photon noise limited performance on ground-based mm-wave instruments such as NIKA-2 [2] where the group at Cardiff collaborated on the detector and optical filtering development.

Compact and continuous sub-Kelvin cooling platforms

Our group has been working in collaboration with Chase Cryogenics to develop compact and continuous cooling platforms based upon sorption and dilution refrigerator technology. This work has been proven in the MUSCAT instrument where continuous operation at 130mK under an optical load has been achieved continuously in a self-contained system. The principle is that a pair of standard sorption coolers are run sequentially to provide pre-cooling to a miniature dilution refrigerator unit [3]. The miniature dilution unit runs in a similar way to a standard dilution refrigerator but circulation of the Helium-3 is created through a convective effect. Such a system does not require large volumes of costly Helium-3 nor does it require a bulky room temperature gas handling system. The unit is fully automated and has been proven to maintain its base temperature for months at a time. The entire system is pre-cooled with a commercially available Pulse Tube Cooler (PTC) meaning that no liquid cryogens are required, and the entire system can be controlled remotely.

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MUSCAT – Full Instrument Development

The experience developed in cryogenics and detector design and fabrication has enabled our group to build an end-to-end cryogenic astronomical camera operating at 300GHz (1mm). The Mexico UK Sub-millimetre Camera for Astronomy (MUSCAT) was developed as part of a knowledge exchange program between the UK and Mexico resulting in a full camera being built for installation at the Large Millimeter Telescope (LMT) in Mexico in early 2021. The camera’s focal plane was designed to be simple and cost effected and can be replicated and adapted by our Mexican partners in future configurations. Using the compact and simple cryogenic sub-Kelvin coolers developed by the group means that MUSCAT can be retrofitted with new focal plane technologies and filtering at the site with minimal effort. Ths makes MUSCAT a versatile instrument platform. The Camera is now fully commissioned in the lab and has demonstrated photon noise limited performance meaning the system has reached the fundamental limits in terms of sensitivity. More details about this project can be found here.

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Imaging systems for industry

Our group has also worked with a commercial partner Sequestim to produce passive security imaging for airport passenger and goods vehicle screening using the technology developed for astronomy. Many materials including clothing and truck tarpaulins are transparent to millimetre and sub-millimetre light meaning we can detect hidden objects beneath these materials. Importantly, the combination of simplified cryogenics and large format arrays of sensitive detectors makes this approach commercially viable. Another important benefit of this approach is that it is purely passive. Unlike rival systems, our camera does not need to irradiate the object to be screened meaning it is safe for humans and can work at ranges of up to 20 meters. The versatility of such a system means that is can screen people and vehicles on the move, drastically improving security screening times. Further information about Sequestim can be found here.

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Supervision

Current Students

• Amber Hornsby, PhD student - Cardiff (2016- Present) - Development of Multichroic Polarisation Sensitive Focal Planes for observations of the Cosmic Microwave Background.
• Gethin Robson, PhD student - Cardiff (2020 - Present) - Development of Superconducting Detectors and Filtering Structures for the Next Generation of sub-mm Astronomical Instruments.

Past Students

• Josie Parrianen, PhD student - Cardiff (2014-2018) - Studies of the Limits of Single Photon Detection in Lumped Element Kinetic Inductance Detectors.
• Pete Barry, PhD student - Cardiff (2010-2014) - The Development of SuperSpec; A Fully Integrated On-Chip Spectrometer for Far-Infrared Astronomy.