Animal studies show that external-beam radiotherapy reduces normal tissue toxicities when delivered at ultra-high dose rates (>40 Gy/s), a condition referred to as FLASH. The dependence of the FLASH effect on peak dose rate and beam time structure is under intense investigation. An enormous range of peak dose rates has been proposed, leading to research interest in a range of novel detector technologies that are not generally used in clinical dosimetry. We will concentrate on a specific, feasible configuration while still accommodating the full range of detectors under consideration.