How to pronounce“submultiple”in English

When Tiffany and Kenneth questioned him about safety, Taylor spoke convincingly if bafflingly about time doses and distance intensities of inverse square lawsand roentgen submultiples. He explained the different types of radiation alpha, beta, gamma, x-ray, and how they dictated the amount and kindof shielding necessary. With his new phone-- newfound knowledge Taylor insisted, he could master the furtive energy that seeped from his rocks and metals and other collectibles.