High-density glass with tuned scintillation/Cherenkov response to improve hadron energy resolution in nuclear physics experiments

Achieving high-quality science at nuclear physics facilities requires the measurement of particle energy with excellent calorimeter energy resolution. Particles that produce electromagnetic showers can be detected with high precision. However, there is a need to improve the energy resolution of hadron calorimetry. This Phase I/II project addresses this need through the development of high-density scintillating glass for calorimeters based on dual readout, one of the most promising methods to achieve better performance for hadronic calorimeters, which consists of the simultaneous measurement of signals produced by Scintillation light (S) and Cherenkov light (C) in the same detector. This method is particularly effective in homogenous calorimeters. Phase I established the fabrication techniques for lab scale production (5-10 blocks) of high-density scintillating glass (CSGlass) with favorable C/S signal ratio, reproducible optical properties and dimensions up to ~10 radiation lengths. Initial measurements with R&D prototypes along with simulations indicate that CSGlass produces measurable Cherenkov and Scintillation light of sufficient intensity that can be separated for physics. The glass samples have excellent optical properties and radiation resistance (no damage up to 1000 Gy electromagnetic and 1015 n/cm2 hadron irradiation, the highest doses tested to date). The present samples have densities up to 5.4 g/cm3, X0=2.2-2.8 cm, and a Moliere radius of 2-3 cm. The feasibility for scaling up the size was demonstrated with the production of 2 x 2 x 40 cm3 blocks. Phase II will establish that the new CSGlass developed in Phase I coupled to state-of-the-art light sensors can meet the experimental specifications at GeV scale. Detailed studies of the performance of the high-density CSGlass will be performed using particle beams. The main objective is to show that signals can be separated into Scintillation and Cherenkov components that are measured simultaneously, e.g., through discrimination by timing and/or waveform. Production capability for larger numbers of uniform CSGlass will be developed to meet the need of large-volume nuclear physics electromagnetic calorimeters. A second objective of Phase II is to demonstrate the production of different CSGlass shapes. The Phase II program is aligned to make CSGlass blocks available to meet the needs of key nuclear physics experiments, e.g., the large-volume calorimeters for the Electron-Ion Collider (EIC), JLab, or future LHC upgrades, that require high performance scintillator material in large quantities on specific schedules. Other CSGlass benefits include reduced time and complexity of manufacturing, resulting in an estimated 80% cost reduction, and increased flexibility in shape and size for the final detector. The ability to manufacture novel high-density CSGlass will prove useful not only for hadronic calorimeters but also for homeland security applications where such scintillators would significantly reduce the false alarm rate in passive nuclear detection systems and allow for a large range of deployment. Fast response time and radiation hard glasses will find use in the scintillator market for security applications as active material for radiation portal monitors, in particular, at ports where cargo screening with large throughput is required.