Report/Guide

Rajagopal, S; Fury, C; Zeqiri, B (2015) Primary calibration of 1 mm membrane hydrophones for BIPM/CIPM key comparison CCAUV.U-K4 - final description of NPL results. NPL Report. AC 15

Rajagopal, S; Zeqiri, B; Cox, B* (2015) A scoping study of the potential of photoacoustics to support primary standard calibration of medical ultrasonic hydrophones up to 100 MHz. NPL Report. AC 14

Rajagopal, S; Zeqiri, B (2013) Recommendations on the requirements of measurement infrastructure for elastography metrology. NPL Report. AC 8

Article

Koruk, H; Rajagopal, S (2024) A comprehensive review on viscoelastic parameters used for engineering materials including soft materials and the relationships between different damping parameters. Sensors, 24 (18). 6137

Zeqiri, B; Baker, C; Pounder, A; Serno, D; Rajagopal, S (2023) Large-area pyroelectric-based differential detector for medical Ultrasound Computed Tomography. IEEE Sensors Journal, 23 (16). pp. 18276-18291.

Hacker, L; Ivory, A M; Joseph, J; Grohl, J; Zeqiri, B; Rajagopal, S; Bohndiek, S E (2023) A Stable Phantom Material for Optical and Acoustic Imaging. Journal of Visualized Experiments, 196. e65475

Rajagopal, S; Allen, T; Berendt, M; Lin, D; Alam, S; Richardson, D J; Cox, B T (2023) The effect of source backing materials and excitation pulse durations on laser-generated ultrasound waveforms. The Journal of the Acoustical Society of America, 153 (5). pp. 2649-2658.

Rajagopal, S; de Melo Baesso, R; Miloro, P; Zeqiri, B (2023) Dissemination of the acoustic pascal: the role and experiences of a National Metrology Institute. IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 70 (2). pp. 101-111.

Rajagopal, S; Robinson, S P; Ablitt, J; Miloro, P; Wang, L; Zeqiri, B; Hurrell, A (2023) On the importance of consistent insonation conditions during hydrophone calibration and use. IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 70 (2). pp. 120-127.

Rajagopal, S; Cox, B T (2021) Modelling laser ultrasound waveforms: The effect of varying pulse duration and material properties. The Journal of the Acoustical Society of America, 149 (3). pp. 2040-2054. ISSN 0001-4966

Rajagopal, S; Sainsbury, T; Treeby, B E; Cox, B T (2018) Laser generated ultrasound sources using carbon-polymer nanocomposites for high frequency metrology. The Journal of the Acoustical Society of America, 144 (2). pp. 584-597. ISSN 0001-4966

Hurrell, A M*; Rajagopal, S (2017) The practicalities of obtaining and using hydrophone calibration data to derive pressure waveforms. IEEE Trans. Ultrason. Feroelectr. Freq. Control, 64 (1). pp. 126-140.

Rajagopal, S; Fury, C R; Zeqiri, B; Brandt, M*; Wilkens, V*; Koch, C*; Matsuda, Y*; Yoshioka, M*; Ping, Y*; Yan, Z*; Wenping, B*; Felix, R P*; Oliveira, E G*; Uchida, T*; Horiuchi, R*; Xing, G Z* (2016) Report on BIPM/CIPM key comparison CCAUV.U-K4: Absolute calibration of medical hydrophones in the frequency range 0.5 MHz to 20 MHZ. Final report. Metrologia, 53 (1A). 09004.

Koukoulas, T; Robinson, S P; Rajagopal, S; Zeqiri, B (2016) A comparison between heterodyne and homodyne interferometry to relise the SI unit of acoustic pressure in water. Metrologia, 53 (2). pp. 891-898.

Rajagopal, S; Sadhoo, N; Zeqiri, B (2015) Reference characterisation of sound speed and attenuation of the IEC agar-based tissue-mimicking material up to a frequency of 60 MHz. Ultrasound Med. Biol., 41 (1). pp. 317-333.

Kenwright, D A*; Sadhoo, N; Rajagopal, S; Anderson, T*; Moran, C M*; Hadoke, P W*; Gray, G A*; Zeqiri, B; Hoskins, P R* (2014) Acoustic assessment of Konjac-Carrageenan tissue-mimicking material at 5-60 MHz. Ultrasound Med. Biol., 40 (12). pp. 2895-2902.

Rajagopal, S; Zeqiri, B; Gélat, P N (2014) Calibration of miniature medical ultrasonic hydrophones for frequencies in the range 100 to 500 kHz using an ultrasonically absorbing waveguide. IEEE Trans. Ultrason. Feroelectr. Freq. Control, 61 (5). pp. 765-778.

Koukoulas, T; Rajagopal, S; Robinson, S P; Moss, B*; Zeqiri, B; Theobald, P D (2013) Primary ultrasonic interferometer photodiode characterisation using frequency-modulated laser wavefront radiation. Metrologia, 50 (6). pp. 572-579.

Zeqiri, B; Zcarbonauhar, G*; Rajagopal, S; Pounder, A* (2012) Systematic evaluation of a secondary method for measuring diagonostic-level medical ultrasound transducers output power based on a large-area pyroelectric sensor. Metrologia, 49 (3). pp. 368-381.

Rajagopal, S; Shaw, A (2012) The buoyancy method - a potential new primary ultrasound power standard. Metrologia, 49 (3). pp. 327-339.

Conference or Workshop Item

Shah, A; Ivory, A M; Rajagopal, S; Zeqiri, B (2019) Comparison of techniques to characterise the point spread function of an acoustic-resolution photoacoustic microscope. In: 2019 IEEE International Ultrasonic Symposium (IUS), 6-9 October 2019, Glasgow, UK.

Ivory, A M; Shah, A; Rajagopal, S; Zeqiri, B (2019) Development and investigation of the acoustic properties of tissue-mimicking materials for photoacoustic imaging techniques. In: 2019 IEEE International Ultrasonic Symposium (IUS), 6-9 October 2019, Glasgow, UK.

Rajagopal, S; Treeby, B E; Cox, B T (2018) Effect of Backing on Carbon-Polymer Nanocomposite Sources for Laser Generation of Broadband Ultrasound Pulses. In: 2018 IEEE International Ultrasonics Symposium, 22-25 October 2018, Kobe, Japan.

Sinden, D; Rajagopal, S; Chaggares, N C; Pang, G; Ivanytskyy, O (2017) Reducing uncertainties for spatial averaging at high frequencies. In: 2017 IEEE International Ultrasonics Symposium (IUS), 6-9 September 2017, Washington DC, USA.