Speaker
Description
SrI2(Eu) is a promising scintillator having high brightness, 3% energy resolution at 662 keV, and no self-activity. The elpasolite Cs26LiYCl6(Ce) (CLYC) has also shown great promise for dual-gamma-neutron detection. However, high production costs have slowed their adoption into mainstream detection technologies. Costs related to precursors may be mitigated through continuing improvements, but features inherent to the Bridgman technique limit achieving high throughput. Interactions with the ampoule wall can create defects, and resulting stresses become aggravated by thermal gradients along the boule length. Therefore, growth rates are limited to less than 1 millimeter per hour. With edge-defined film-fed growth (EFG), crystal solidification proceeds from a free surface, which removes the possibility of defect formation at the ampoule wall. The lower density of surface defects in EFG-grown material allows the crystal to sustain higher levels of stress without cracking. SrI2 crystals have been grown by EFG at rates 10 times faster than the Bridgman-grown crystals. EFG also allows for near-net shape growth of cuboids, which reduces material loss to machining. We will share our latest results of EFG growth of SrI2(Eu) and CLYC cylinders and cuboids. We shall discuss considerations for seeding, material compatibility, die design, and overall equipment design. In addition, we will complement our discussion with 3D conjugate thermal models of the apparatus.
