Development of Novel CsCl-based Ultrafast Scintillators

In this work, we explore scintillation properties and timing performance of novel core valence luminescence crystals. These materials may be promising for the heterostructure concept in time-of-flight PET, for photon counting CT, or in high energy physics experiments due to their ultrafast 1-2 ns single-component decay times, relatively high light outputs compared to BaF
2
, and higher densities compared to fast plastic scintillators. Single crystals of Cs
3
MgCl
5
, Cs
2
MgCl
4
, and CsMgCl
3
are grown, and scintillation is observed in Cs
3
MgCl
5
and Cs
2
MgCl
4
for the first time. The effects of doping crystals with 5 mol% Zn are also investigated for all three compounds, and light output is found to increase significantly without negatively impacting decay time. As a result, an improved coincidence time resolution (CTR) can be expected for the Zn-doped crystals. The best CTR of 98 ps FWHM has been measured with CsMgCl
3
:Zn 5%.