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Gallium nitride (GaN)-based blue-emitting diodes (CREE Model C430-DH85) were irradiated at room temperature with protons in the energy range 2 to 115 MeV at fluences varying from 1 10 11 to 1 10 15 cm 2 . Light output degradation curves were obtained for each energy and the damage constant ( ) associated with these curves was determined according to the theory of Rose and Barnes. For proton energies less than 10 MeV, varies inversely with the proton energy ( ). At higher energies, is consistently above the 1 relationship. The change in nature of the energy dependence is attributed to nuclear interactions. Nonionizing energy loss calculations for the case of protons on GaN are presented. Good agreement between theory and experiment is obtained.Index Terms-Blue LEDs, energy dependence, gallium nitride, light emission degradation, non-ionizing energy loss (NIEL), optoelectronics, proton, quantum-well light-emitting diodes, radiation damage.

In 2012, Defence Research and Development Canada, in partnership with a number of other Canadian and International organizations, led a series of three field trials designed to simulate a Radiological Dispersal Device (RDD). These trials, known as the Full-Scale RDD (FSRDD) Field Trials, involved the explosive dispersal of a short-lived radioactive tracer ((140)La, t1/2 = 40.293 h). The FSRDD Field Trials required a significant effort in their planning, preparation, and execution to ensure that they were carried out in a safe, efficient manner and that the scientific goals of the trials were met. The discussion presented here details the planning and execution of the trials, outlines the relevant radiation safety aspects, provides a summary of the source term and atmospheric conditions for the three dispersal events, and provides an overview of the measurements that were made to track the plumes and deposition patterns.