PhD Thesis Defense | Pablo Herrero Gómez
Development of sensors for individual barium ion identification in the context of the NEXT experiment
June 23, 11:00
Candidate: Pablo Herrero Gómez
Supervisors: Celia Rogero Blanco and Francesc Monrabal Capilla
This thesis encompasses the first steps in the development of a chemo-sensor for individual Barium dication detection to be implemented in the NEXT experiment. The sensor works by converting chemical properties of the ion into a detectable optical signal. Using fluorescent chemo-sensors may be a unique tool in the field of neutrino physics. The NEXT experiment searches for the neutrinoless double beta decay of Xe-136. In this reaction two electrons and the Ba++ dication are produced. Detecting the Ba ion in delayed coincidence with the two electrons would make the NEXT experiment background free. This required adapting fluorescence chemo-sensors to the ultra-dry environment of NEXT. The sensor is built by immobilising fluorescent molecules on an appropriate surface which preserves its photochemical properties. To this end, atomically-precise molecular deposition and characterization techniques were used. Additionally, a fluorescence microscope has been developed to meet these conditions and requirements.