YBa<sub>3</sub>B<sub>9</sub>O<sub>18</sub>:  A Promising Scintillation Crystal

Single crystals of the newly discovered borate YBa<sub>3</sub>B<sub>9</sub>O<sub>18</sub> with dimensions up to 13 × 8 × 4 mm<sup>3</sup> were successfully grown by the Czochralski pulling method. X-ray excited luminescence measurements of the YBa<sub>3</sub>B<sub>9</sub>O<sub>18</sub> showed a broad emission band in the wavelength range from 350 to 500 nm with a peak center at 400 nm. The light yield is about 6−7 times larger than that of PbWO<sub>4</sub> measured at nearly the same conditions. The results show that borate can also exhibit attracting scintillation properties. A narrow temperature range for growth and drastic anisotropy of the growth rates are the main difficulties in growing large crystals. The crystal growth and properties of denser isostructural REBa<sub>3</sub>B<sub>9</sub>O<sub>18</sub> series (RE = Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb) deserve further investigation.