Student’s Spotlight – Arun Haridas Choolakkal
Arun Haridas Choolakkal, a final-year PhD student at the Thin Film Physics division of Linköping University, is set to defend his thesis in December 2024.
His research is a significant contribution to the filed of solid-state neutron detectors, driven by the need for alternative to 3He neutron detectors. Arun’s PhD project centres on the development of boron carbide-based detectors as a viable alternative for neutron detection in large scale neutron facilities. These advanced detectors are being developed for the next generation neutron imaging applications.
Technical approach
The innovative aspect of Arun’s research involves the integration of neutron converter material into Si sensor-chips. This process requires the conformal deposition of boron carbide thin film, leveraging the high neutron absorption cross-section of 10B isotope for thermal neutrons. The challenge lies in depositing these materials within intricate structures patterned on Si chips, ensuring uniformity and effectiveness. To achieve this, Arun employs chemical vapor deposition technique to synthesize conformal boron carbide thin films. His approach includes developing strategies to enhance the conformality of these films, ensuring they meet the stringent requirement of neutron detectors.
Collaborative efforts
Arun’s project is part of an international collaboration that encompasses various critical aspect of neutron detector development. This includes Si wafer processing and patterning, simulation studies, and the development of passivation layer. Additionally, the project involves irradiation tests at neutron facilities to validate the performance of the prototype neutron sensors. His specific contribution focuses on the development and integration of the neutron converter layer, a crucial component that enhances the efficiency and effectiveness of the detectors. This collaborative effort highlights the interdisciplinary nature of the research and collective drive to address the global 3He shortage.
New possibilities
‘‘The beauty of science lies in its ability to uncover unexpected horizons.’’ The strategies developed for achieving conformal boron carbide depositions have found applications beyond just trench or via deposition. An unexpected turn in Arun’s PhD research occurred when he tested the conformal boron carbide process on random oriented carbon nanotubes within a membrane structure. These methods, initially developed for neutron detectors, beautifully transformed to also serve in the deposition of a potential protective coatings on carbon nanotubes. The insights gained from conformal boron carbide deposition further propelled Arun’s project towards the innovative idea of synthesizing tubular graphitic boron carbide on carbon nanotubes. This approach presents a viable route for B-doped graphitic nanomaterials, which hold promises for the next generation electronic applications.