National Physical Laboratory

Srinath Rajagopal

Current interests

Srinath Rajagopal

Srinath Rajagopal is the lead scientist responsible for the provision and development of traceable ultrasound pressure standards and its dissemination to the end user as part of National Measurement System. He is currently leading work on photoacoustic methods for generating broadband (0 – 100 MHz) and high amplitude (up to 10 MPa) planar ultrasound fields with an aim to improve/enhance calibration range of medical hydrophones. He has co-developed new calorimetric and solid-state pyroelectric techniques to measure ultrasonic output power and acoustic characterization of tissue-like materials at elevated frequencies relevant to medical imaging. He is also pursuing a PhD (part-time) with Biomedical Ultrasound Group of University College London.


Srinath received his BEng in Biomedical Engineering from Visvesvaraya Technological University, Belgaum, India, in 2002, and MRes at the Bioengineering Department from the University of Strathclyde, Glasgow, UK, in 2004. He started as a Research Physicist at Precision Acoustics Ltd, Dorchester. Whilst at Precision Acoustics he was responsible for their calibration service, software development for automating test and measurements, providing support in production and testing of hydrophones and auditing of internal processes to ISO 9001: 2000 quality standards. He joined NPL in 2007 and has since been active in the Medical Ultrasound Group.


Srinath represents the UK on the International Electrotechnical Commission TC87/WG8 Ultrasonics – Field Measurements.

Selected publications

  • The practicalities of obtaining and using hydrophone calibration data to derive pressure waveforms
    A.M. Hurrell; S. Rajagopal
    IEEE Trans Ultrason Ferroelectr Freq Control, 64 (1), pp 126–140 (2017)
  • A comparison between heterodyne and homodyne interferometry to realise the SI unit of acoustic pressure in water
    T. Koukoulas; S. Robinson; S. Rajagopal and B. Zeqiri
    Metrologia, 53, pp 891–898 (2016)
  • Reference characterisation of sound speed and attenuation of the IEC agar-based tissue-mimicking material up to a frequency of 60 MHz
    S. Rajagopal; N. Sadhoo; B. Zeqiri
    Ultrasound in Med. & Biol., 41 (1), pp 317–333 (2015)
  • The buoyancy method - a potential new primary ultrasound power standard
    S. Rajagopal and A. Shaw
    Metrologia, 49 (3), p- 327–339 (2012)
  • A random phased array device for delivery of high intensity focused ultrasound
    J.W. Hand, A. Shaw, N. Sadhoo, S. Rajagopal, R.J. Dickinson and L.R. Gavrilo
    Physics in Medicine and Biology, 54 (19), pp 5675–5693 (2009)

Contact details

Tel: 020 8943 6696

Last Updated: 8 Aug 2017
Created: 27 Mar 2012


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