Kenneth A. LaBel

Emerging optocoupler issues with energetic particle-induced transients and permanent radiation degradation

Radiation-induced permanent degradation and single event transient effects for optocouplers are discussed in this paper. These two effects are independent to the first order and will be addressed separately. Displacement damage-induced degradation of optocoupler current transfer ratio is reviewed. New data are presented that show the importance of application specific testing and that generalized quantification of optocoupler CTR degradation can lead to incorrect predictions of actual circuit performance in a radiation environment. Data are given for various circuit loading and drive current parameters. Previous work that introduces the idea that two mechanisms exist for inducing transients on the optocoupler output is discussed. New data are presented that extends the evidence of this dual mechanism hypothesis. In this work measurements show that single event transient cross sections and transient propagation varies with circuit filtering. Finally, we discuss utilization of the optocouplers in the space environment. New data are applied to two examples: one on permanent degradation and the other on single event transient rates in high bandwidth applications.

Performance of the high-energy single-event effects test Facility (SEETF) at Michigan State university's national Superconducting Cyclotron laboratory (NSCL)

The performance of Michigan State Universitys Single-Event Effects Test Facility (SEETF) during its inaugural runs is evaluated. Beam profiles and other diagnostics are presented, and prospects for future development and testing are discussed.

Single event test methodology and test results of commercial gigabit per second Fiber Channel hardware

This article presents a detailed description of the single event test methods used to evaluate two different component sets conforming to the Fiber Channel (FC) commercial high-speed serial bus standard. The devices tested perform the hierarchically low-level functions such as transmission coding and actual electrical or optical linking. Pertinent portions of the FC specification, and details of the test setup and methods are presented prior to description of the observed error types, correlation of error types to source circuitry, and radiation test results. The authors conclude that one of these COTS device sets may be suitable for space use with the use of additional circuit hardening, and that the other (also a COTS device set) is not suitable for space use. The test methods and descriptions of error types should prove useful in preparation for future FC component SEE testing.

The Living with a Star Program NASA's role in assuring performance in space and atmospheric environments

NASA has initiated the Living with a Star (LWS) Program to develop the scientific understanding to address the aspects of the Connected Sun-Earth system that affect life and society. A goal of the program is to bridge the gap between science, engineering, and user a~dication communities. This will enable future . . science, operational, and commercial objectives in space and atmospheric environments by improving engineering approaches to the accommodation andlor mitigation of the effects of solar variability on technological systems. A pre-formulation study determined the optimum combination of science missions, modeling, and technology infusion elements to accomplish this goal. The results of the study are described below.

In situ measurement of the particle linear energy transfer using the sensitive junctions of the device under test

We describe an approach for using charge collection measurement techniques to determine the LET of a particle that reaches the sensitive region with an unknown energy. The method requires that a calibration of the response of the sensitive region to particle LET be established. Then from this calibration, the unknown LET can be determined. We also give recommendation on how to use complex charge collection data to determine the distribution of particle LET reaching the sensitive region and how to correct the particle fluence for this distribution.

Radiation Effects on Emerging Technologies: Implications of Space Weather Risk Management

As NASA and its space partners endeavor to develop a network of satellites capable of supporting humankinds needs for advanced space weather prediction and understanding, one of the key challenges is to design a space system to operate in the natural space radiation environment. In this paper, we present a description of the natural space radiation environment, the effects of interest to electronic or photonic systems, and a sample of emerging technologies and their specific issues. We conclude with a discussion of operations in the space radiation hazard and considerations for risk management.