JPL has over twenty missions concurrently in development at any one time, each with its own requirements based on the mission objectives and environment at the target destination. The radiation environment drives many of these requirements and may vary from a very low dose level, barely able to affect any mission (such as a high altitude or low earth orbit mission), to the harshest radiation environments able to end a mission in a matter of days (such as the radiation belts around Jupiter, which is 10000 times worse than low earth orbit).
For the mission requirements to be met, the spacecraft and its payload must be able to endure its respective environment. The radiation environment causes many deleterious effects on a spacecraft, any of which may prematurely end a mission. These effects can manifest in gradual degradation of an object, such as the darkening of a lens or a reduction in power from a solar cell, or these effects can manifest as a sudden interruption or failure in functionality, such as an electrical discharge event or processor malfunction that halts or damages a spacecraft.
The Radiation Effects Group maintains in-house facilities and partnerships with outside entities that support total ionizing dose testing with radioactive isotopes, single event effects testing with picosecond laser and single event effects testing at heavy ion accelerator facilities around the world. The Group also manages the operation of the Dynamitron, providing 3 MeV electrons for characterization studies of the impact of internal charging in electronics and materials in a space environment.
Single Event Effects Picosecond Laser Lab
A single event effect (SEE) occurs when a single energetic particle is capable of creating an observable effect in an integrated circuit (IC). In space, SEEs are caused by the liberation of electron-hole pairs from direct ionization (always the dominant process for heavy ions) or indirect ionization, where protons or neutrons produce an energetic recoil particle which generates the electron-hole pairs. Typically, costly cyclotrons are used to reproduce the space-particle environment to measure the susceptibility of microelectronic devices to SEE. A pulse of focused laser beam can be utilized to simulate SEE (the absorption of a picosecond pulsed photon will generate electron-hole pairs on the same time frame as ionizing particles) with the advantage of being able to localize the sensitive region of an IC with significant cost savings relative to broad beam testing.
More information about the picosecond laser lab can be found in Pulsed Laser System to Simulate the Effects of Cosmic Rays in Semiconductor Devices
- In some cases, in-house pulsed laser can be used in lieu of a cyclotron facility for SEE testing at a fraction of the cost
- Fully calibrated Spectra-Physics Ti:Sapphire mode-locked Tsunami laser
- 2.5ps pulses with a waist size of 1.0 micron
- Can be used on many device types
- Applicable for SEE (SEL, SEU, SET, SEFI) analysis and screening
- Computer-controlled X-Y stage can be used to correlate SEE susceptibility to laser position
- Tunable laser wavelength and energy (typically 1 to 500pJ per pulse).