The research status and challenge of space radiation physics and application

Space radiation physics and application include the theory and the key technologies of studying radiation effects in spacecraft electronics systems and improving the on-orbit survival probability of spacecrafts. It is an interdisciplinary science involving nuclear science and astronautics electronics. The research work mainly covers simulation of radiation environment, interaction between radiation and materials, radiation hardening, as well as radiation measurement and diagnosis. In recent years, new challenges and problems to the research of space radiation physics have arisen along with the rapid development in microelectronics and space technology. Radiation effects, including single event effects, total ionizing dose effects, displacement damage, charging and discharging effects, are one kind of main threats for space applications. The study of space radiation physics and application plays a fundamental role in maintaining the robustness against radiation of the spacecraft electronics systems. Countries like America and Russia have devoted a lot in this field, now they have a whole set of facilities, guidelines and principles to guarantee the fabrication, evaluation, and utilization of the radiation-hardened electronic devices and systems. However, there are still some problems left unsolved. Furthermore, as the fast development of the electronics, new problems emerge quickly. Space radiation environments mainly include the Van Allen trapped belt, Solar cosmic rays, galactic particles. The fluence of the related protons, electrons, and heavy ions are strongly dependent on solar activity and geomagnetic activity. The distribution of particle fluence is highly no uniform. Spacecraft working in different orbits may face diverse radiation environments. To describe the radiation environments, series of models have been developed for describing the distribution of trapped protons and electrons. Although continued being modified, the errors between predicted values and measured ones are still quite large. It is essential to keep working on this area and increase the accuracy. To measure the parameters like categories, fluence, energy and flux of the radiation environments, many types of detectors have been developed. Along with the emergence of new types of material, it is always meaningful to keep improving the performance and efficiency of detectors. Exploring the underlying mechanisms of radiation effects is extremely important for carrying out the research on radiation hardening by design. In the past 50 years, more and more work has been devoted to studying the physical mechanisms and gained valuable results. However, we still do not get the clear whole physical pictures of some well-known effects. Meanwhile, more and more electronic devices with new material and new structures bring new challenge to the mechanism study. To make sure that an electronic system is robust enough to radiation environments, it is necessary to quantify the radiation vulnerability of every electronic device in the system. Through circuit or system simulation, the radiation vulnerability of the whole system can be estimated. At present, it is still difficult to perform this kind of simulation accurately. This paper discusses the present status and developments tendency in simulating the space radiation environment, developing laboratory simulation equipments, measuring radiation field, researching radiation effects and mechanism, estimating and testing radiation effects, hardening electronics devices, etc. Furthermore, the key and basic problems in this field were discussed. The corresponding advices of space radiation physics and application were proposed.