One of biggest threat to the deployed aerospace and defense electronics systems is radiation. Long term exposure of astronauts to radiation is equally challenging. This force can occur naturally in space and at high altitudes on Earth, or can come in massive doses from the detonation of nuclear weapons. Deep-space and long-duration missions, where both crew members and spacecraft no longer benefit from the protection of Earth’s magnetic fields, are considered high risk for adverse radiation impacts. Aircraft flying at altitude, at about 30,000 feet and above, also are starting to experience radiation-induced effects. “There are 500 times more neutrons at 30,000 feet than there are on the ground,” points out Aitech’s Romaniuk.
Ionizing radiation can cause significant problems for electronic devices. Ensuring the reliable operation of microcircuits and software in outer space is an important scientific and economic objective. There are various measures used to protect electronic circuits from radiation, One is the shielding of electronics which is not only expensive, but it also can be heavy enough to adversely influence launch costs. There are other ways of dealing with space radiation, ranging from redundant subsystems, selective shielding, and upscreening commercial off-the-shelf (COTS) electronics for enhanced reliability.
Weight is a significant factor in designing aerospace technologies, and the shielding most commonly found in aerospace devices consists of putting an aluminum box around any sensitive technologies. This has been viewed as providing the best tradeoff between a shield’s weight and the protection it provides.
DARPA launched an SBIR in July 2022 to develop a new material system capable of more effective high energy gamma-ray shielding than traditional materials such a lead and concrete at comparable cost.
There are various operational environments where shielding is required to protect people and sensitive electronics
from ionizing radiation. These include space environments, areas with highly radioactive materials or areas near
intense nuclear reactions, such as fission and fusion sources. Although traditional radiation shielding materials have largely been suitable, developing a new material system that provides 10x more effective shielding compared to traditional materials, or that were 10x lighter or more compact than traditional materials while providing equivalent shielding would enable a range of missions where traditional shielding is inadequate.
Specifically, at 1 MeV to 100 MeV energy levels, a material that provides twice or greater the linear attenuation coefficient at comparable density to existing shielding materials is being sought.
This topic seeks innovation in novel materials for shielding gamma ray radiation at MeV to GeV energies, capable of withstanding high fluences, that can be produced inexpensively and in large quantities, and ideally with flexible form factors.
Phase I is a feasibility study that would demonstrate the scientific, technical, and commercial merit and feasibility of the concept resulting in a basic material system and credible material production flow. Activities could include
material modeling, basic material synthesis, fabrication experiments, and material system characterization. Key
materials characteristics and interfaces should be identified and quantified showing how attenuation goals could be
achieved in terms of necessary shielding and high-volume production cost. Challenges and risks in perfecting
shielding characteristics, and scaling the shielding material to required volumes for practical applications must be
identified and proposed mitigation strategies presented.
Phase II builds upon feasibility established in Phase I and ultimately produces and demonstrates a TRL 5 prototype
material meeting Section II b goals. The Phase II base period (year 1) will focus on overall material system
development and characterization and scalable process development. The Phase II increment period (year 2) will
refine material production processes, refine shielding performance and conduct initial practical demonstrations. The Phase II option period (year 3) will produce usable quantities of the optimized material system with demonstrated low-cost techniques, and support demonstrations meeting program goals.
Phase I goals, and plans to achieve program goals by the end of Ph 2. This should be a culmination of the Phase 1
effort, demonstrating a viable technical path supported by empirical and modeling data to achieving overall
program goals, with risks and mitigation strategies fully detailed.
PHASE III DUAL USE APPLICATIONS:
Successful development of the subject material system will be applied in demonstration of relevant DoD and
commercial applications, with commercialization strategies developed for each. Military electronics in space
environments would be one such example. For commercial applications, targeting applications where traditional
shielding poses challenges to effective implementation will be targeted. These may include irradiation facilities,
reactor applications, and high energy physics applications.