Speaker
Description
Radiation detectors play a crucial role across a wide range of applications. Emerging technologies, such as photon-counting computed tomography and advanced single-photon emission computed tomography imaging, demand a combination of high energy resolution, fast scintillation kinetics, and high stopping power. Cerium-doped thallium lanthanum chloride (Tl$_2$LaCl$_5$:Ce, TLC) has recently been introduced as a promising scintillator candidate that combines these properties, making it an attractive material for next-generation radiation detection systems.
We investigate the energy resolution under various excitation energies and the achievable coincidence time resolution (CTR) of two identical crystals coupled to NUV-HD SiPMs. An energy resolution of 4.2% at 511 keV was measured, enabling a clear separation between full-energy deposition and the K-shell escape events. By selecting either 511 keV coincidence events or K-shell escape events, a CTR of 215 $\pm$ 4 ps and 232 $\pm$ 6 ps was obtained, respectively. These values are more than eight times better than expected based on literature values considering scintillation yield and kinetics.
Cramér–Rao lower-bound calculations of the achievable time resolution reveal a strong dependence on the scintillation rise time. The measured timing performance requires a scintillation rise time faster than $\tau_r$ = 2 ns when accounting for prompt Cherenkov photons, or faster than $\tau_r$ = 300 ps in the absence of such prompt photon contributions.
These findings indicate that the scintillation rise time of TLC may be substantially faster than previously reported (4-8 ns), highlighting the importance of early scintillation kinetics and Cherenkov light for timing performance. Combining energy resolution around 4%, competitive timing, and high stopping power, TLC could bridge the performance gap between dense scintillators such as LYSO:Ce and high-resolution materials such as LaBr$_3$.
| Track | FTMI |
|---|---|
| Presentation type | Oral |