Radiation Induced Transient Effects in HgCdTe IR Focal Plane Arrays J.C. Pickel a , R.A. Reed *b , P.W. Marshall c , A. Wacynski d , E. Polidan d , S. Johnson d , R. McMurray e , M. McKelvey e , K. Ennico e , R. Johnson e , and G. Gee f a PR&T, Inc., Fallbrook, CA 92028 b NASA Goddard Space Flight Center, Code 561, Greenbelt, MD, USA 20771 c NASA Consultant, Brookneal, VA 24528 d Global Science and Technology, NASA Goddard Space Flight Center, Greenbelt, MD 20771 e NASA Ames Research Center, Moffett Field, CA 94035-1000 f SGT, Inc, NASA/GSFC, Code561, Greenbelt, MD 20771 ABSTRACT The operability requirements of NASA’s James Webb Space Telescope (JWST) impose specific challenges on radiation effects mitigation and analysis. For example, the NIRSpec Instrument has the following requirements: • The percentage of pixels defined as operable for target acquisition shall not be less than 97% (TBR) (goal 99%) of the total number of pixels… An inoperable pixel is: o A dead pixel: a pixel with no radiometric response o A noisy pixel: a pixel with a total noise greater than 21 e-, per Fowler 8 exposure • The percentage of pixels defined as operable for science observations shall not be less than 92% (TBR) (goal 98%) of the total number of pixels… An inoperable pixel is: o A dead/low-DQE pixel: a pixel deviating by > 30% from the DQE mean value o A noisy pixel: a pixel with a total noise greater than 12 e- (goal 9e-) With these performance requirements and operation in space, the radiation environment from galactic cosmic rays (GCR), energetic solar particles, and activation of spacecraft materials can contribute significantly to the number of inoperable pixels. The two most important issues to date are radiation-induced transient effects and hot pixels. This paper focuses on the methods used to assess the impact of ionizing radiation induced transients on the HgCdTe SCA selected by JWST. Hot pixel effects in these detectors has been previously presented [1]. Both effects are currently under investigation. Keywords: Infrared focal plane arrays, radiation effects, IR, imager 1. INTRODUCTION The James Webb Space Telescope (JWST) will use mega-pixel class infrared (IR) detector arrays in the near infrared (NIR) instruments, including the Near-Infrared Camera (NIRCAM), Near-Infrared Spectrometer (NIRSpec) and Fine Guidance Sensor (FGS). The focal plane array will consist of multiple sensor chip assemblies (SCA). The JWST SCAs must be able to survive the ionizing particle radiation environment (background cosmic rays and solar particle events) for its Lagrange-point (L2) orbit and ten year mission lifetime goal,, These test and analysis results for the tested SCAs were published in [1]. In addition, the SCAs must have adequate performance in the presence of the continuous ionizing particle environment from cosmic ray background levels to allow the science mission to be accomplished, and that is the focus of this paper. To help determine their suitability for JWST and understand the performance limitations imposed by the space radiation environment, a comprehensive radiation test and analysis program is underway to assess candidate SCA technologies. * Currently at Vanderbilt University, robert.a.reed@vanderbilt.edu XXX-XXX-XXXX