Irradiation Shield 1.375" diameter- The shields are not suitable for 360 degree irradiation (typical of a Cs source), and they are limited for use in units that produce energies less than 350kVp (X-Ray). The fixtures are to be used with fixed beam X-ray sources projecting vertically and do not protect the exit side of the irradiated specimen. A shield designed for use with a Cs source typically requires 4 times the lead thickness. These shields are ¼" (6.35mm) lead, and the attenuation factor depends on the kVp energy they are used with. Attempts to use our shields with a Cs source will result in inadequate shielding and overexposure to protected areas of an animal. The shields are regularly used in the Orthovoltage energy range and provide about a 100X attenuation.