Glass and Quartz Microscintillators for CMOS-Compatible Multispecies Radiation Detection

Abstract

This paper reports on a small-scale radiation detector that is sensitive to alpha, beta, gamma, and neutron radiation using scintillators doped with boron nanoparticles utilizing CMOS fabrication techniques. Two types of microscintillators have been fabricated and tested: One relies on sintered glass frit doped with boron nanoparticles, and the other uses quartz with boron diffused into the substrate. Radiation impinging on the scintillation matrix produces varying optical pulses of varying intensities depending on the type of radiation particle. The optical pulses are differentiated by on-chip pulse height spectroscopy and recorded on a microcontroller. The pulse height circuitry has been fabricated with both discrete circuits and designed into a single integrated circuit package. The quartz substrates have shown to be more transparent to the wavelength of the created optical pulses, which results in a higher count rate when compared to the tested glass scintillator. The quartz scintillator also shows better absorption of radiation particles, resulting in better detection efficiencies than the glass. The quartz also has been tested with varying doping levels and has the ability to detect neutrons. Source differentiation between 137Cs and 60Co has also been demonstrated.