Evaluates and demonstrates the use of chemical actinometer-dyed microspheres to directly measure the dose-distribution within a UV reactor, as an alternate approach to modeling and biodosimetric techniques. Also uses chemical actinometry as an alternate to conventional sensors to measure local intensity. Research partner: NYSERDA. Completed in 2007. Published as "Validation of large-scale, monochromatic UV disinfection systems for drinking water using dyed microspheres," in Water Research, 42(3), February 2007. This article can be downloaded from the Foundation Website.