Single Event Effects


Single Event Effects (SEEs) are caused by a single, energetic particle, and can take on many forms. Single Event Upsets (SEUs) are soft errors, and non-destructive. They normally appear as transient pulses in logic or support circuitry, or as bitflips in memory cells or registers. Several types of hard errors, potentially destructive, can appear: Single Event Latchup (SEL) results in a high operating current, above device specifications, and must be cleared by a power reset. Other hard errors include Burnout of power MOSFETS, Gate Rupture, frozen bits, and noise in CCDs.

In the space environment, spacecraft designers have to be concerned with two main causes of Single Event Effects (SEEs): cosmic rays and high energy protons. For cosmic rays, SEEs are typically caused by its heavy ion component. These heavy ions cause a direct ionization SEE, i.e., if an ion particle transversing a device deposits sufficient charge an event such as a memory bit flip or transient may occur. Cosmic rays may be galactic or solar in origin.

Protons, usually trapped in the earth's radiation belts or from solar flares, may cause direct ionization SEEs in very sensitive devices. However, a proton may more typically cause a nuclear reation near a sensitive device area, and thus, create an indirect ionization effect potentially causing an SEE.

As spacecraft become driven more and more to reduce parameters such as power, weight, volume, and cost, while requiring increased functionality, emerging commercial technologies - often vulnerable to SEEs - have come to the forefront. These technologies include high speed and low power CMOS and fiber optics. Types of integrated circuits (ICs) that utilize these technologies range from complex microprocessors to dense SRAMs. All mission-critical devices must be tested for SEE - one Latchup or Gate Rupture in a critical system can destroy a mission!

The SEECA (Single Event Effects Criticality Analysis) discusses SEEs and device selection & utilization, and the Draft Single Event Effects Specification defines and clarifies types of SEEs.

We perform Single Event Effect (SEE) testing on just about anything in the realm of electronics & photonics (DRAM, FIFO, microprocessors, ADCs, fiber optics,...). A list of the devices we've tested, the test reports, and a planned testing schedule are all available. If you have a candidate device for testing, please contact Ken LaBel for more information.


A few useful links:
Schedule for upcoming (and recent) SEE test trips
List of devices which we've tested
SEE test reports & related papers
EEE Links - deals with parts, packaging, and processes
NASA/GSFC's Assurance Technologies Division
RADATA Data Base, compiled by NASA/JPL
REDEX Data Base, compiled by Naval Research Lab (NRL)
SEE test facilities we frequent:
Brookhaven National Laboratory SEUTF (heavy ion)
Lawrence Berkeley Labs 88" Cyclotron (heavy ion)
Texas A & M University Cyclotron (heavy ion)
Paul Scherrer Institute (heavy ion) (OK, so I only wish we could test here...)
University of California at Davis Crocker Nuclear Lab (proton)
Indiana University Cyclotron (proton)

If you know of any other relevant links or documents, please let me know! Martha O'Bryan

Return to Radiation Effects & Analysis Home Page
Curator: Martha O'Bryan
Last Revised November 15, 2000
A service of the Radiation Effects and Analysis Group, Kenneth A. LaBel, Group Leader