Mr. Oliver Hetherington Profile

Oliver Hetherington

at Open Univ

SPIE Involvement:

Author

Publications (14)

Proceedings Article | 27 August 2024 Presentation + Paper

SMILE soft x-ray imager (SXI) CCD370 proton irradiation results

S. Parsons, D. Hall, O. Hetherington, T. Buggey, T. Arnold, M. W. Hubbard, A. Holland

Proceedings Volume 13103, 131030E (2024) https://doi.org/10.1117/12.3016657

KEYWORDS: Charge-coupled devices, X-rays, Temperature metrology, X-ray imaging, Solar processes, Silicon, X-ray fluorescence spectroscopy, Solar energy, Signal detection, Sensors

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Proceedings Article | 21 August 2024 Poster + Paper

Evaluating UV detector enhancement technologies for the next generation of space telescopes: the path to CASTOR

Jesper Skottfelt, Chiaki Crews, Ben Dryer, David Hall, Oliver Hetherington, Michael W. Hubbard, Douglas Jordan, David Morris

Proceedings Volume 13093, 130933W (2024) https://doi.org/10.1117/12.3018390

KEYWORDS: Ultraviolet radiation, Ultraviolet detectors, Sensors, Space telescopes, Imaging spectroscopy, Quantum efficiency, CMOS sensors, Stars, Silicon

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SPIE Journal Paper | 10 August 2024 Open Access

Impact of particle passage and focusing from micro-pore optics for radiation damage estimates

Michael W. Hubbard, Thomas Buggey, David Hall, Charly Feldman, Jonathan Keelan, Oliver Hetherington, Steven Parsons, Timothy Arnold, Andrew Holland

JATIS, Vol. 10, Issue 03, 034003, (August 2024) https://doi.org/10.1117/12.10.1117/1.JATIS.10.3.034003

KEYWORDS: Particles, Simulations, Charge-coupled devices, Equipment, Eye, X-ray optics, Monte Carlo methods, Space operations, X-rays, Image sensors

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SPIE Journal Paper | 14 October 2023 Open Access

Electro-optical characterization of a CMOS image sensor optimized for soft x-ray astronomy

Charles Townsend-Rose, Thomas Buggey, James Ivory, Konstantin Stefanov, Lawrence Jones, Oliver Hetherington, Andrew Holland, Thibaut Prod’homme

JATIS, Vol. 9, Issue 04, 046001, (October 2023) https://doi.org/10.1117/12.10.1117/1.JATIS.9.4.046001

KEYWORDS: Dark current, CMOS sensors, Quantum efficiency, Image sensors, Electrooptics, X-ray astronomy, X-rays, Quantum reading, Photons, Manganese

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Proceedings Article | 5 October 2023 Presentation + Paper

Characterization, quantum efficiency, and radiation hardness of a CMOS image sensor optimized for soft x-ray astronomy

Charles Townsend-Rose, Thomas Buggey, James Ivory, Konstantin Stefanov, Lawrence Jones, Oliver Hetherington, Andrew Holland

Proceedings Volume 12678, 126780I (2023) https://doi.org/10.1117/12.2674828

KEYWORDS: Dark current, Quantum efficiency, CMOS sensors, Image sensors, X-rays, Ionizing radiation, Electro optics, X-ray astronomy, Ion irradiation

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SPIE Journal Paper | 26 July 2023 Open Access

Impact of impurities in shielding material on simulations of instrument background in space

Michael W. J. Hubbard, David Hall, Oliver Hetherington, Timothy Arnold, Andrew Holland

JATIS, Vol. 9, Issue 03, 034004, (July 2023) https://doi.org/10.1117/12.10.1117/1.JATIS.9.3.034004

KEYWORDS: Beryllium, Simulations, Molybdenum, Equipment, Fluorescence, Particles, Aluminum, Iron, Space operations, Sensors

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Proceedings Article | 29 August 2022 Presentation + Paper

A CMOS image sensor for soft x-ray astronomy

Konstantin Stefanov, Charles Townsend-Rose, Thomas Buggey, James Ivory, Oliver Hetherington, Andrew Holland, Julian Heymes, Jérôme Pratlong, Georgios Tsiolis, David Morris, Kyriaki Minoglou, Thibaut Prod'homme, Matthew Soman

Proceedings Volume 12191, 121910N (2022) https://doi.org/10.1117/12.2630733

KEYWORDS: Sensors, X-rays, CMOS sensors, X-ray imaging, X-ray astronomy, Silicon, Photodiodes

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SPIE Journal Paper | 26 May 2022

Developing the active trap model for charge-coupled device charge transfer optimization in large-scale space missions

Thomas W. Buggey, Matthew Soman, David Hall, Nathan Bush, Steven Parsons, Oliver Hetherington, Andrew Holland

JATIS, Vol. 8, Issue 02, 028003, (May 2022) https://doi.org/10.1117/12.10.1117/1.JATIS.8.2.028003

KEYWORDS: Charge-coupled devices, Instrument modeling, Optimization (mathematics), X-rays, Electrodes, Space operations, Temperature metrology, Sensors, Data modeling, Performance modeling

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SPIE Journal Paper | 27 July 2021 Open Access

Enhanced simulations on the Athena/Wide Field Imager instrumental background

Tanja Eraerds, Valeria Antonelli, Chris Davis, David Hall, Oliver Hetherington, Andrew Holland, Michael Hubbard, Norbert Meidinger, Eric Miller, Silvano Molendi, Emanuele Perinati, Daniel Pietschner, Arne Rau

JATIS, Vol. 7, Issue 03, 034001, (July 2021) https://doi.org/10.1117/12.10.1117/1.JATIS.7.3.034001

KEYWORDS: Particles, Molybdenum, Sensors, Aluminum, Device simulation, Imaging systems, Electrons, Physics, Luminescence, Monte Carlo methods

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Proceedings Article | 13 December 2020 Poster + Paper

Enhanced simulations on the Athena/WFI instrumental background

Tanja Eraerds, Valeria Antonelli, Chris Davis, David Hall, Oliver Hetherington, Andrew Holland, Jonathan Keelan, Norbert Meidinger, Eric Miller, Silvano Molendi, Emanuele Perinati, Daniel Pietschner, Arne Rau

Proceedings Volume 11444, 114443Y (2020) https://doi.org/10.1117/12.2560932

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Proceedings Article | 13 December 2020 Presentation + Paper

Developing the active trap model for CCD charge transfer optimisation in large-scale space missions

T. Buggey, M. Soman, D. Hall, S. Parsons, N. Bush, O. Hetherington, G. Randall, M. Leese, A. Holland

Proceedings Volume 11454, 114541F (2020) https://doi.org/10.1117/12.2561399

KEYWORDS: Charge-coupled devices, Solar radiation models, Space operations, Data modeling, Magnetosphere, Fourier transforms, Testing and analysis, Solar processes, Performance modeling, Data acquisition

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Proceedings Article | 13 December 2020 Presentation + Paper

Processing x-ray data on board the SMILE SXI

George Randall, Steven Parsons, David Hall, Thomas Buggey, Oliver Hetherington, Mark Leese, Andrew Holland, Dean Yeoman, Matthew Soman

Proceedings Volume 11454, 114540T (2020) https://doi.org/10.1117/12.2560339

KEYWORDS: X-rays, Solar processes, Imaging systems, X-ray imaging, Space operations, Data modeling, Magnetosphere, Ultraviolet radiation, Plasma, Ions

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Proceedings Article | 13 December 2020 Presentation + Paper

Radiation damage testing status of the CCDs for the SMILE SXI

Steven Parsons, David Hall, Andrew Holland, Peter Verhoeve, Steven Sembay, George Randall, Oliver Hetherington, Dean Yeoman, Thomas Buggey, Matthew Soman

Proceedings Volume 11454, 114540Q (2020) https://doi.org/10.1117/12.2560337

KEYWORDS: Radiation effects, Charge-coupled devices, Cryogenics, Solar processes, Magnetosphere, X-rays, Space operations, Satellite imaging, Satellites, X-ray imaging

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The joint European Space Agency and Chinese Academy of Sciences Solar wind Magnetosphere Ionosphere Link Explorer mission (SMILE) aims to develop a global scale understanding of the interaction between the solar weather and the Earth’s magnetosphere-ionosphere. The soft X-ray imager (SXI) is one of the instruments on board and will observe photons emitted in the 200 eV to 2000 eV energy range from the solar wind charge exchange process using two large 4510 x 4510 pixel CCD370s as a focal plane. The CCD370s take their design and qualification heritage from similar sensors being used in the PLATO mission, with specific modifications to optimize their performance in this soft X-ray energy range. SMILE will orbit Earth in a highly elliptical orbit and will pass through the radiation belts every 52 hours. The trapped and solar protons present will gradually damage the CCDs throughout the 3-year mission and degrade their performance. To understand the impact the damage has on the devices a series of proton radiation campaigns are being undertaken. These campaigns are being performed with flight-like SMILE CCDs, and functionally similar PLATO devices, with follow-up characterization across from -130 to -85 °C. The most recent irradiation campaign has been completed using a PLATO CCD280 kept below -85 °C for irradiation and characterization, and the results show that the measured parallel charge transfer inefficiency varies with temperature between 1x10^-4 and 4x10^-4 in unbinned full-frame readout mode. The effect of temperature annealing up to -85 °C on the parallel charge transfer inefficiency has also been assessed and shows that no temperature-dependent annealing of the radiation-induced damage has been observed. A similar behavior is expected to be seen in the SMILE devices, albeit with an anticipated improvement by a factor 3-4 due to the modifications made to the design. Thus, results indicate the SMILE CCD370s will meet the performance requirements of the SMILE SXI instrument.

Proceedings Article | 12 July 2018 Paper

Predicting the particle-induced background for future x-ray astronomy missions: the importance of experimental validation for GEANT4 simulations

David Hall, Jonathan Keelan, Chris Davis, Oliver Hetherington, Mark Leese, Andrew Holland

Proceedings Volume 10709, 1070937 (2018) https://doi.org/10.1117/12.2500298

KEYWORDS: Sensors, Electrons, Photons, Particles, Device simulation, Aluminum, Luminescence, X-rays, X-ray astronomy, Magnetism

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Particle-induced background, or “instrument background”, produced from the interaction of background photons and charged particles with a detector, either as primaries or through the generation of secondary photons or particles, is one of the major sources of background for the focal plane sensors in X-ray astronomy missions. In previous studies for the European Space Agency (ESA) X-ray Multi Mirror (XMM-Newton) mission, the dominant source of background was found to be caused by the knock-on electrons generated as high-energy protons pass through the shielding materials surrounding the detector. From XMM-Newton, the contribution of Compton and other photon-generated background was small in comparison to the knock-on electron component. However, for the Wide Field Imager (WFI) on board the ESA Advanced Telescope for High-ENergy Astrophysics (ATHENA) mission Athena, which houses much thicker silicon in the depleted p-channel field effect transistor (DEPFET) active pixel sensors of the focal plane when compared to the Charge Coupled Devices (CCDs) used in the XMM-Newton EPIC MOS cameras, this photon component may no longer be expected to have such a minimal impact and therefore both the photon and proton-induced components must be considered in more detail. In order to minimise the background, studies have been conducted on the use of a graded-Z shield in addition to an aluminium proton shield (employed for radiation damage minimization). For thin detectors, a low-Z component alone may suffice, reducing the fluorescence components of the background. However, with thicker detectors a high-Z component may give added benefit through the combination of the high-Z component to reduce the photon-induced effects and a low-Z component to reduce the fluorescence components from the shielding’s inner-surfaces, thus creating an “aluminium sandwich”. In all cases, careful optimization of the shielding configuration is required to balance each component of background specific to the design of the instrument involved. The optimization of any shielding relies heavily upon a validated and verified simulation toolkit. Here we present the latest progress on our ongoing validation and verification studies of the GEANT4 simulations used for such an optimization process through a series of experimental test campaigns.

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