Further measurements of the scintillation properties of lead carbonate

Measurements are presented on the scintillation properties of lead carbonate (PbCO₃), a recently discovered, heavy inorganic scintillator. The light output of the natural crystal cerussite was measured during ⁶⁰Co irradiation at 23°C. After an exposure of >2.5×10⁶ rad, the light output increased by 25% and no visible crystal coloring occurred, suggesting that PbCO ₃ is useful in high-radiation fields. The emission spectrum was adequately described by the sum of four Gaussian peaks whose position and width did not change during the irradiation. The scintillation light output is temperature dependent, increasing with decreasing temperature from 680 photons/MeV at +30°C to 3200 photons/MeV at -40°C to 11900 photons/MeV at -120°C. The scintillation decay lifetime was measured with the delayed coincidence method between 30°C, and -140°C and fit to the sum of four exponentials. At 30°C the four components are 20% at 3.9 ns, 44% at 24 ns, 26% at 186 ns, and 11% at 1.40 μs. At -40°C, the four components are 24% at 37 ns, 45% at 107 ns, 18% at 359 ns, and 12% at 1.07 μs. At -120°C, the four components are 0.3% at 1.8 ns, 3.5% at 3.8 ns, 40% at 539 ns, and 56% at 2.71 μs. From 30°C to -140°C, the initial flux remains constant at about 45 photons/ns/MeV