Conveners
Scintillation Mechanisms: session 1
- Richard Williams (Wake Forest University)
Scintillation Mechanisms: session 2
- Andrey Vasiliev (Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, )
Non proportionality (NP) of scintillation response is usually used as an explanation of intrinsic resolution change, nevertheless there are no direct links between definitions of these scintillation parameters. At [1] the wide spread between LY and energy resolution (ER) was pointed for the same scintillator (NaI:Tl). The literature data are between 5 and 12% resolution that is out of the LY...
Many mixed crystal scintillators have been investigated during last years. It appears that tuning the composition of a mixed crystal allows to increase the scintillation yield, decrease the afterglow, and improve the energy resolution.
Some properties of mixed crystal scintillators exhibit a non-linear concentration dependence, which differs from the linear Vegard's law. We interpret these...
Tungstates are widely used as scintillator materials in security, medicine and particle physics devices (e.g., CaWO$_4$, CdWO$_4$, PbWO$_4$). Their emission is represented by a broad band in the visible spectral region, which is usually ascribed to the radiative decay of self-trapped excitons (STEs) localized at oxyanion complexes. Due to the large energy of optical phonons and strong...
The performance of new and improved materials for gamma ray scintillator detectors is dependent on multiple factors such as quantum efficiency, energy transport etc. In halide scintillator materials the energy transport is often impacted by both intrinsic hole and electron traps such as Vk centers and their associated self-trapped excitons (STE) as well as traps associated with defects and...
The Sr co-doped LaBr3:Ce3+ scintillator is an almost ideal scintillator regarding energy resolution and speed. However, its relatively low density limits application in various fields. To develop scintillators with density higher than 8 g/cm3 one has to abandon the research field of the halides, and instead explore oxides containing high Z-cations like Hf, Ta, W, Tl, Pb, or Bi. The question...
We report excitation-induced picosecond absorption over an extended spectral range from 320 nm to 2700 nm in LaBr$_{3}$, LaBr$_{3}$:Ce(4%) and LaBr$_{3}$:Ce(20%). Preliminary identification of a V$_{k}$ band near 3.6 eV, self-trapped exciton (STE) hole transition near the same energy, and STE bound-electron transitions spanning 0.46 eV to 1.1 eV have been made. Comparison to recent...
New requirements for timing of scintillator-based radiation detectors for future high energy physics experiments and medical imaging applications necessitate demand for novel tools to study the non-equilibrium carrier dynamics in scintillators on picosecond time scale. In this report, we summarize our current results on the application of free carrier absorption to study the carrier dynamics...
Recent progress in various fields of scintillator applications has created a high demand for fast scintillators. In particular, the Time-Of-Flight Positron Emission Tomography (TOF-PET) technique requires coincidence time resolutions (CTRs) better than 100 ps FWHM in order to improve the image signal to noise ratio offering shorter scanning times, lower patient doses and better image quality....
The radius of initial (femtosecond-scale) energy deposition around the local trajectory of a high-energy electron in a scintillator has been characterized as roughly 3 nm by several researchers, e.g. [1]. The resulting strong radial gradients of carrier density drive diffusion which can both dilute and separate carrier populations. This significantly influences the rate terms for capture,...
Lead molybdate (PbMoO4) crystal is isotructural to lead tungstate but it features a lower light yield. On the contrary, it is a promising candidate as scintillator for high energy physics and the neutrinoless double β decay experiment, due to the inevitable occurrence of the 100Mo isotope. PbMoO4 crystals were also suggested to find application in cryogenic dark matter experiments. Point...
The recent measurement of non-proportionality of each of the decay components in CsI:Tl (fast, slow, and tail) [1] found opposite slopes of the fast and tail proportionality curves above about 10 keV. This suggests that combining both components could improve resolution by more than just the statistics of the additional photons. Indeed, Moszynski et al had shown this in studies of...
ZnO crystals and nanoparticles have promising scintillation properties an subnanosecond scintillator. There is huge number of publications concerning laser excitation of ZnO. Nevertheless, it is still not clear how the properties of ZnO scintillation are connected with the physics of process in this crystal, which significantly differs from traditional inorganic scintillators being mostly...
