The NRL can provide gamma-only irradiations using multiple different irradiators:
The highest dose rate is achievable using a Co-60 underwater irradiator that provides gamma rays of 1173 keV and 1332 keV for in-situ irradiation of devices. Samples and experiments are irradiated in a 6"-diameter dry tube. Due to the design of the loading elevator, the usable diameter for an experimental setup in the 6"-diameter tube is ~ 4". The usable height is limited by the falloff in the flux profile and the dose rate, both of which can be found in the linked Co-60 irradiator page.
A benchtop irradiator is also available for low dose-rate testing.The space for sample irradiations is ~ 7.75" in length by 3.75" in diameter. The current dose rate in the sample irradiation can be seen on the linked benchtop irradiator page.
A spot irradiator makes use of a source collimator to enable in-situ radiation-damage testing of an electronic device while minimizing the dose received by other devices nearby on the test board.