Electronics Damage Testing
The NRL offers two types of electronics damage testing: neutron displacement damage testing, and total ionizing dose (TID) testing.
Neutron Displacement Damage Testing:
Multiple vertical dry tubes and a beam port are available at the NRL for displacement damage testing with neutrons. Two of the vertical dry tubes are 2.5 inch tubes located in the core, and either a 7 inch or 10 inch vertical dry tube can be positioned against the east face of the core for testing. Experiments can be designed using these tubes such that guidelines published in ASTM F1190 and E1854, MIL-STD-750 TM 1017, and ESCC 22900 are met, and these experiments can be for 1 MeV silicon-equivalent neutron fluences up to ≈1x1017 n/cm2 for the in-core tubes and up to about 1x1016 n/cm2 for the ex-core tubes. For testing requiring a higher neutron-to-gamma ratio, an experiment rig utilizing a 2 inch-thick bismuth plate is being designed for use in the 10 inch tube. Neutron dosimetry is performed by spectrum unfolding using induced activity in metal foils, and this dosimetry can be performed specific to the test article's location on the experimenter's test fixture.
Total Ionizing Dose (TID) Testing:
Gamma-rays from cobalt, cesium, and scandium sources may be used to evaluate electronic devices for effects caused by ionizing radiation. The cobalt and cesium sources are in fixed-geometry irradiators, but use of the scandium sources can be customized to the requirements of the experiment. The scandium sources are created by activating scandium metal using the reactor, and the sources are used in a "spot source" testing facility that can make use of an adjustable-position collimator to provide dose to the test article while minimizing dose to other ICs mounted on the evaluation board. The collimator reduces dose 1.5 inch away from the test article to less than 20% of the test article exposure.
Available dose rates in the irradiators range from less than 10 mrad(Si)/s to 8 rad(Si)/s. The lower dose rates fall in the range for Enhanced Low Dose Rate Sensitivity (ELDRS) testing, as published in MIL-STD-750 TM 1019, ESCC 22900, and ASTM F1892 guidelines. Dosimetry is performed using nanoDOTS™ placed at the test article's location inside the test fixture.
NRL can provide additional guidance and support in designing and developing radiation test fixtures and circuits, and radiation test plans. Previous customers have developed and used various dry tubes and gamma irradiators for evaluating devices from cryogenic temperatures up to 150 °C.