Neutron Damage to Commercial GaAsP LED Devices

On-line measurement of the degradation of a small set of commercial LED devices bombarded with a 15 MeV median energy neutron beam has been obtained. During irradiation the light output of an LED was recorded via a fiber optic link to an external area free of radiation where a photodiode detector viewed the fiber optic signal. All data were recorded on DVMs, on chart recorders and on magnetic tape with an on-line computer. The data for each LED can be described by one primary damage function and the amount of damage is rather strongly dependent on the amount of phosphorous in the GaAsP LEDs studied. The neutron energy distribution and intensity are well known from previous dosimetry measurements. Radiographic data determined that a homogeneous spatial distribution of neutron flux is used. The neutron beam was uniform over the dimension of the samples and 2 × 1010 neutrons/cm2/sec are easy to obtain.