Supervisors: Dr. Maurits van der Grinten (RAL/PPD) + Dr. Jim Dobson (Kings College London)
This joint studentship is directly related to the world-leading LUX-ZEPLIN (LZ) dark matter experiment (Phys. Rev. Lett. 131, 041002), currently taking data at the Sanford Underground Research Facility in South Dakota, USA, and the planned next generation XLZD experiment. The work will involve the study and mitigation of the leading background sources (Phys. Rev. D 108, 012010, Eur. Phys. J. C (2020) 80: 1044) originating from radon emanation in current and next generation dark matter detectors.
Central to this PhD will be the cold radon emanation facility CREF at RAL. This PPD facility has recently been commissioned and provides high sensitivity radon assay capabilities over a wide range of temperatures. After an initial year of coursework at KCL, you will be working on making the world's first temperature dependent radon emanation measurements to fully characterise key materials relevant to LZ and XLZD, working on sample treatments to optimise the performance/purity of the detector materials, and be closely involved in increasing the sensitivity of CREF further.
You will also join the LZ/XLZD collaborations and make leading contributions to both the Rn background analysis and physics searches. In the case of LZ, the student will develop a high-precision Rn-background model, using an improved flow-based Rn tagging algorithm that leverages ML-based inter-event correlation techniques (such as Long Short-Term Memory deep learning and Hidden Markov Models for Time Series analysis) to reduce the impact of this leading source of background. You will then perform an improved dark matter search using the full LZ dataset targeting a channel that benefits most from reduced-Rn backgrounds, such as the main WIMP search or various leptophilic DM models in the electron-recoil band. For XLZD, you will work towards combining measurements from CREF with their improved Rn-background model to evaluate the projected sensitivity of the detector and determine radio-purity requirements for construction.
There is also the potential for a long term attachment (LTA) to LZ at SURF, South Dakota to contribute to the operations of the experiment.
For more details, contact Maurits van der Grinten (maurits.van-der-grinten@stfc.ac.uk) or Jim Dobson (jim.dobson@kcl.ac.uk).
