Ultra-Fast, Radiation Hard Scintillators for High Energy Physics

Scintillators with very fast decay (< 10 ns) are needed to handle the very high event rate in future high energy physics (HEP) experiments. They are also expected to be extremely radiation hard without the necessity of replacement, to withstand high absorbed doses of the order of hundred Mrads. The progress in the detection technology can be maintained and leveraged only if new materials are developed. The problem is addressed through development of an ultra-fast, ultra-dense, and radiation-hard scintillator for new generation of calorimeters. Yb doped Lu2O3 was identified in Phase I as the most promising composition from a few novel materials. The fast scintillation is achieved through a unique Charge Transfer (CT) luminescence. The material is manufactured using a scalable ceramic process. During Phase-II we optimized the manufacturing process to fabricate transparent, high-quality samples of Lu2O3:Yb. We also initiated a scale up process producing large samples as large as 2.5 cm cubes. The scaled-up samples showed good transparency and their light yields was consistent with the smaller samples manufactured during Phase-I. Radiation hardness and material properties were evaluated at Caltech. We found that these samples survived gamma doses up to 50 MRad. The plan for Phase-IIA entails significant expansion in the scale up of the material to 2x2x15 cm3 sizes, as required by the application. This ambitious endeavor will encompass several specific efforts, namely: (1) Collaborating closely with our vendors to procure optimized starting materials, ensuring good manufacturability and superior quality of ceramics. (2) Enhancing the optical integrity of the samples through meticulous optimization of the manufacturing processes, thus elevating their overall quality. (3) Fabricating large samples in the form of bars (4) Rigorously assessing the material properties and its resilience to radiation exposure. In addition to high energy physics applications, ultra-fast and radiation hard materials would be attractive for high count rate applications such as nuclear fuel monitoring, dosimetry, detectors for measuring radiation in the event of a nuclear blast, energy resolved high energy radiography, or medical applications such as Positron-Emission-Tomography. The proposed material can deliver performance that surpasses the benchmark materials at potentially lower cost.