Count rate nonlinearity in near infrared detectors: inverse persistence

The count rate non-linearity of near-infrared devices was first found in the HST NICMOS. In this report we present a physical model of the cause of this effect, show how it is related to persistence, and compare the predictions of the model to other observations of anomalous detector behavior. This model is able to explain not only the count rate non-linearity but also several other effects. Overall, the excellent agreement between this model and the observations gives us strong confidence that we understand the underlying cause of the count rate non-linearity. This understanding should allow us to develop methods to accurately calibrate and remove the effect from JWST observations.