An important development in the field of radiation oncology is the demonstration that ultra-fast dose rate (also known as FLASH) radiation therapy at the same delivered dose has fewer side effects than regular radiation therapy. This finding is under intense investigation globally and a race is underway to understand and subsequently implement this methodology in the clinic. Current proton and electron treatment modalities are capable of delivering FLASH treatment to patients, however, a quality assurance device is needed to translate FLASH-RT to the clinic. Besides dose, the FLASH-QA device also needs to measure dose rate information, which is critical for FLASH-RT. The goal of this project is to develop a FLASH-QA device to meet these unmet needs for FLASH-RT.