Cesium Iodide doped with Sodium CsI(Na) is a widely used material nowadays. High light output (85% of that of NaI(TI)), emission in the blue spectral region (in coincidence with the maximum sensitivity range of the most popular PMT with bialkali photocatodes), and substantially lower hygroscopicity in comparison with that of NaI(TI) makes this material a good alternative for NaI(TI) in many standard applications. The temperature dependence of light output has its maximum at 80°C. This makes it possible to use CsI(Na) the scintillation material at elevated temperatures. The decay time of CsI(Na) depends on the dopant concentration and varies in the range of 500 - 700 ns.
Properties:
Density [g/cm3] | 4.51 |
Melting point [K] | 894 |
Thermal expansion coefficient [K-1] | 49 x 10-6 |
Cleavage plane | none |
Hardness (Mho) | 2 |
Hygroscopic | yes |
Wavelength of emission maximum [nm] | 420 |
Lower wavelength cutoff [nm] | 300 |
Refractive index at emission maximum | 1.84 |
Primary decay time [µs] | 0.63 |
Afterglow (after 6ms) [%] | 0.5 - 5.0 |
Light yield [photons/MeVγ] | 38-44x103 |
Photoelectron yield [% of NaI(Tl)] (y rays) | 85 |
