https://dspace.library.uu.nl/bitstream/handle/1874/24262/blasse_84_the%20luminescence%20of%20some%20oxidic%20bismuth.pdf;sequence=1

The luminescence of some oxidic bismuth and lead compounds

This chapter starts with a theoretical description of energy transfer in solids. First we consider single-step energy transfer and later multistep energy migration. The importance of separating the migration process and the trapping process is stressed. Experimental methods are also reviewed. Finally a large number of materials is treated. First those with strongly temperature-dependent energy migration are considered (tungstates, vanadates, Ce3+, Pb3+). Second, compounds with weak or no temperature dependence of the energy migration are reviewed (compounds of the transition metal and trivalent lanthanide ions and hexavalent uranium). It turns out that energy migration in nearly all of these systems is only qualitatively, and not quantitatively understood. Suggestions to improve this situation are given. These relate also to the influence of dimensionality on energy migration.

Energy transfer in concentrated systems

New heavy scintillators are being discovered with increasing frequency. In recent years NaI(Tl) (with its high light output and energy resolution) has been joined by BGO (with its high stopping power), BaF{sub 2} (with its excellent timing resolution), and CeF{sub 3} (with its speed and short Moliere radius). More than 10 potentially useful scintillators have been under development in the past five years, such as PbSO{sub 4} and Lu{sub 2}SiO{sub 5}(Ce). We tabulate the characteristics of these and other scintillators, including wavelength, luminous efficiency, decay time, and initial intensity. We describe a search strategy and the prospects for finding the ``ideal`` heavy scintillator, which would combine the light output of NaI(Tl) and CsI(Tl), the stopping power of BGO, and the speed of BaF{sub 2} and ZnO(Ga).

/pdf/experimental-efforts-and-results-in-finding-new-heavy-1w2a5tz9gi.pdf

Experimental Efforts and Results in Finding New Heavy Scintillators

The luminescence of Pb2+ in alkaline earth sulfates

The authors report on the scintillation properties of lead sulfate (PbSO/sub 4/), a scintillator that shows promise as a high-energy photon detector. Its physical properties are well suited for gamma detection, as it has a density of 6.4 gm/cm/sup 3/ and a 1/e attenuation length for 511 keV photons of 1.2 cm, is not affected by air or moisture, and is cut and polished easily. In 99.998% pure PbSO/sub 4/ crystals at room temperature excited by 511 keV annihilation photons, the fluorescence decay lifetime contains significant fast components having 1.8 ns (5%) and 19 ns (36%) decay times, but with longer components having 95 ns (36%) and 425 ns (23%) decay times. The peak emission wavelength is 335 nm, which is transmitted by borosilicate glass windowed photomultiplier tubes. The total scintillation light output increases with decreasing temperature from 3200 photons/MeV at +45 degrees C to 4900 photons/MeV at room temperature (+25 infinity C) and 68500 photons/MeV at -145 degrees C. In an imperfect, 3-mm cube of a naturally occurring mineral form of PbSO/sub 4/, (anglesite) at room temperature, a 511 keV photopeak is seen with a total light output of 60% that of BGO. >

/pdf/scintillation-properties-of-lead-sulfate-h2gmww336x.pdf

G. Blasse

Papers

Energy transfer phenomena in lead sulphate