Multibeam Healing for Laser Micromachining in Manufacturing

DESCRIPTION (provided by applicant): There is considerable interest in new and innovative manufacturing methods for medical imaging technologies to enhance performance while reducing cost. The precision and low-force signature of lasers makes them very attractive alternatives to traditional machining methods for brittle materials, particularly scintillators such as lutetium oxyorthosilicate (LSO), gadolinium oxyorthosilciate (GSO), lutetium-yttrium oxyorthosilicate (LYSO), etc. used in high-resolution diagnostic imaging and nuclear medicine. However, material damage, especially micro-scale cracking, during laser machining is a frequently encountered problem that results in added costs, needless scrap, and reduced performance/reliability. These issues have prevented the tremendous commercial potential of laser machining from being fully utilized to manufacture large and finely pixelated scintillator arrays. The goal of the Phase I research was to demonstrate the feasibility of defect free laser machining of brittle scintillators using a novel multibeam approach. We are pleased to report that the Phase I research has not only clearly demonstrated the feasibility of our approach but has also led to a major discovery that has the potential to dramatically reduce the cost and duration of pixelation. Thus our Phase I effort has laid a firm foundation for achieving our ultimate goal of defect-free manufacturing of scintillator arrays using laser machining. With these exceptional results, the technique of laser pixelation and multibeam healing is now poised for exploitation in rapid and cost effective systems for micro-machining arrays of various sizes, shapes, and orientations in scintillators of critical importance to medical and non-medical applications. The proposedresearch is designed to address manufacturing issues through detailed simulation studies of the material's behavior during laser ablation, and by implementing a new laser beam delivery system based on experimental findings that confirm the simulation results. Developing such a system and a body of knowledge in scintillator micro-machining will allow fabricating large arrays of various scintillators at significantly reduced manufacturing cost, while greatly improving detector performance with reduced pixelsizes and inter-pixel gaps. Therefore, the proposed research has great commercial relevance, especially for modalities as PET where higher resolution and lower cost is critically important.