The nature of light-absorbing particles in the atmosphere represent one of largest uncertainties in climate models. Soot (black carbon) absorbs light across the visible spectrum, and quantifying its presence in the atmosphere is important both for air quality as well as climate impact. Photoacoustic spectroscopy (PAS) is a well-established method for sensitive and selective detection of trace gases as well as for the measurement of aerosol particles. In particular, PAS systems often serve as standards for black carbon measurements, with minimum detectable concentrations down to 0.1-1 ug/m3. However, these instruments are relatively large and high cost, with limited applicability for widespread use in ambient or environmental monitoring and model validation; quartz-enhanced photoacoustic spectroscopy (QEPAS) uses mass-produced quartz tuning forks with a resonant frequency of 32 kHz to detect acoustic waves using miniature fork-microphone configuration.
In this project, the candidate will develop further the QEPAS sensor designed by the collaborative effort of the Cambridge team, by understanding in greater detail the fundamental absorption and transduction processes inherent to QEPAS systems. The goal is to have a working instrument that can produce carbon black measurements with improved sensitivity one order of magnitude below the current 40 ug/m3 level. Immediate improvements in sensitivity of a factor of 5 can be obtained in gas phase using a resonant tube. Further improvements could be achieved by using custom tuning forks (with a small penalty to cost) which could operate at lower frequencies and thus benefit from higher amplification gains. Depending on how the instrument is configured, we may also be able to relate the particle or agglomerate size to the signal phase.
Applicants should have (or expect to obtain by the start date) at least a good 2.1 degree in an Engineering or related subject.
The Aerosols Science CDT studentships are fully-funded (fees and maintenance) for eligible UK students. EU and international students will be considered for partial funding (home-level fees and maintenance).
Further details about eligibility and funding can be found at: https://epsrc.ukri.org/skills/students/help/eligibility/ https://www.postgraduate.study.cam.ac.uk/finance/fees
To apply for this studentship please complete the online application form which can be found on the following website; https://www.aerosol-cdt.ac.uk/2021-projects/
Please note that any offer of funding will be conditional on securing a place on the course. Candidates will need to apply separately for admission through the University’s Graduate Admissions application portal; https://www.postgraduate.study.cam.ac.uk/courses/directory/egegpdars The final deadline for PhD applications is 30 June 2021, although it is advisable to apply earlier than this.
The University actively supports equality, diversity and inclusion and encourages applications from all sections of society.