Nathan Ahmad

University of Technology Malaysia

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Martin J. Cryan

University of Bristol

Sara Núñez‐Sánchez

Galicia Sur Biomedical Foundation

Jamie Stokes

University College London

Neil A. Fox

University of Bristol

Neciah Dorh

Philips (United Kingdom)

M. Missous

University of Manchester

N. Khalid

Commissariat à l'Énergie Atomique et aux Énergies Alternatives

J. R. Pugh

University of Bristol

Ian Bickerton

University of Bristol

N. I. M. Nor

Universiti Malaysia Perlis

Cooperative Institutions

University of Bristol

University of Technology Malaysia

University College London

Quaid-i-Azam University

COMSATS University Islamabad

Universiti Malaysia Perlis

International Islamic University, Islamabad

Cabot (United States)

Abdus Salam Centre for Physics

Pakistan Institute of Nuclear Science and Technology

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高周波応用のための新しいInGaAs/InAlAs/InP pHEMTの小信号モデリング【Powered by NICT】

IEEE Conference Proceedings (2016)

Ong Jing Xian Nathan Ahmad Isa M. Mohamad Isa Siti S. Mat Mujahid Muhammad

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Two dimensional array of MPPC and CsI(Tl) for radiation monitoring prototype

IOP Conference Series Materials Science and Engineering (2021)

A A Jasni Y-S Yap I. H. Hashim Nathan Ahmad Nur Hazwani Binti Ramlee

Abstract An effcient radiation and position monitoring system is useful for preliminary security inspection and radiation emergency preparedness and response. A high sensitivity and effective monitoring system is needed for these applications. In this study, two position-sensitive prototypes were proposed by using of 8 Multi Pixel Photon Counters (MPPC) and coupled to the cesium iodide with Thallium (CsI(Tl)) scintillator. This inorganic scintillator was chosen for its output wavelength compatibility with MPPC, slightly hygroscopic, high photon transmission, and input energy. For both prototypes, eight MPPCs with di_erent con_gurations were used to obtain active areas of 2.0 × 2.4 cm 2 and 2.5 × 4.5cm 2 , respectively. The prototype has been tested with radioactive (Tl-204 and Co-60). The intensity received by each MPPC’s readout will be recorded using Extended Analogue SiPM Integrated ReadOut Chip (EASIROC) module. Our test showed that both prototypes were sensitive to both beta and gamma sources and were able to reliably determine the sources’ positions. It was shown that the first prototype had greater resolution and performance than the second prototype. This studies may help to improve radiation detection system which is suitable for homeland security, medical field and scanning system.

Silicon Photomultiplier

10.1088/1757-899x/1106/1/012028

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Enhanced broadband optical absorption from nanostructured nickel thin-films for solar energy applications

Nathan Ahmad Jamie Stokes Neil A. Fox Mianzhen Teng Martin J. Cryan

This paper presents results obtained from Finite Difference Time Domain (FDTD) and Transfer Matrix Method (TMM) modelling of nickel thin-films. It is shown that by adding a periodic grating to the surface of the nickel we can dramatically increase its optical absorption over the 300 nm-1000 nm spectral range at normal incidence. The main aim of this work is to maximise the optical absorption of a thin nickel film as part of a solar-thermal energy conversion device.

Transfer-matrix method (optics)

10.1109/icton.2012.6253726

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Solar Thermal Characterisation of Micro and Nano-Patterned Solar Absorbers

Hanyu Cen Nathan Ahmad Sara Núñez‐Sánchez Alex Reip P.J. Dobson

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Ultra-thin metal films for enhanced solar absorption

Nano Energy (2012)

Nathan Ahmad Jamie Stokes Neil A. Fox Mianzhen Teng Martin J. Cryan

10.1016/j.nanoen.2012.08.004

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Citations (49)

Effects of Tin Doping on the Physical Properties of Thermally Deposited Sb2S3 Thin Films

Current Nanoscience (2013)

Nasir Ali Waqar Adil Syed Imran Murtaza Shahzad Hussain Nathan Ahmad

Tin doped antimony sulfide thin films have been grown on glass substrates at room temperature by vacuum thermal evaporation method. The doping was carried out during the growth by two source method with the aim to investigate its effects on electrical, structural and optical properties of 1, 2 and 3 wt.% Sn-doped Sb2S3 thin films. Using transmission spectra in the range of 200-1800 nm, the absorption coefficient of the deposited films in the fundamental absorption edge has been analyzed to identify the possible optical transition in these films, where the energy band gap corresponding to the optical transition is calculated. Hot point probe method has been used to study the conductivity type and photoconductivity values of the thin films in the wavelength range 380-1100 nm of the incident photons. Effects of doping on external quantum efficiency (EQE) are also investigated. Keywords: Tin antimony sulfide, thin film, electrical and structural properties.

Absorption edge

Photoconductivity

Lead sulfide

10.2174/15734137113090990005

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Solar absorbers using 1D and 2D periodic nanostructured nickel films

Journal of Optics (2014)

Nathan Ahmad Jamie Stokes Martin J. Cryan

This paper presents results obtained from finite difference time domain and transfer matrix method modelling of nickel thin films. It is shown that by adding a periodic 1D grating to the surface of the nickel its optical absorption over the 300 nm–1000 nm spectral range can be dramatically increased. 2D gratings show excellent polarization independence making them ideally suited to high temperature solar thermal applications.

10.1088/2040-8978/16/12/125003

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1D Nickel Gratings as Solar Absorbers

Nathan Ahmad Sara Núñez‐Sánchez Martin J. Cryan

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Deep-groove nickel gratings for solar thermal absorbers

Journal of Optics (2016)

Nathan Ahmad Sara Núñez‐Sánchez J. R. Pugh Martin J. Cryan

This paper presents measured and modelled optical absorptance and reflectance for deep-groove nickel nano-gratings in the 450–950 nm wavelength range. The structures have been fabricated using focused ion beam etching and characterised using Fourier spectroscopy and the field distributions on the gratings have been studied using finite difference time domain modelling. Realistic grating structures have been modelled based on focused ion beam cross sections and these results are in good agreement between measured and modelled results. The roles of surface plasmon polaritons and slot modes are highlighted in the strong broadband absorbance that can be achieved with these structures.

Groove (engineering)

Absorptance

10.1088/2040-8978/18/10/105901

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1D Nickel Gratings as Solar Absorbers: META’15, The 6th International Conference on Metamaterials, Photonic Crystals and Plasmonics; New York, USA

Nathan Ahmad Sara Núñez‐Sánchez Martin J. Cryan

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