To conduct real-time monitoring of the particle radiation environment in the orbit of the Tiangong space station, the installation of an energy particle detector operating on the outside of Wentian laboratory cabin module is proposed. Monitoring the energy, flux, and direction of high-energy protons, electrons, heavy ions, and neutrons in orbital space, as well as the LET spectrum and radiation dose rate generated by them, provides an important basis for studying the mechanism of the space environment that causes harm to space stations and astronauts. It also provides the necessary space environment parameters for the scientific experiment instruments on the space station. During its ground development process, the detector was verified by various calibration methods such as standard radioactive sources, equivalent signal generators, and particle accelerators. The results show that the detector can realize discrimination of particle ingredients (electrons, protons, heavy ions, and neutrons). Meanwhile, the measurement indexes can also realize target requirements, namely, from lower limit of 20 keV for medium-energy electrons and protons to heavy ion GeV, 0.025 eV~100 MeV for neutrons, and 0.233~17,475 keV/μm for the LET spectrum and 0.1~1000 mGy/day for the dose rate produced. The measurement precisions of all indexes are better than approximately 16%.
Particle radiation on the Moon is influenced by a combination of galactic cosmic rays, high-energy solar particles, and secondary particles interacting on the lunar surface. When China’s Chang’e-7 lander lands at the Moon’s South Pole, it will encounter this complex radiation environment. Therefore, a payload detection technology was developed to comprehensively measure the energy spectrum, direction, and radiation effects of medium- and high-energy charged particles on the lunar surface. During the ground development phase, the payload performance was tested against the design specifications. The verification results indicate that the energy measurement ranges are 30 keV to 300 MeV for protons, 30 keV to 12 MeV for electrons, and 8 to 400 MeV/n for heavy ions. The energy resolution is 10.81% for 200 keV electrons of the system facing the lunar surface; the dose rate measurement sensitivity is 7.48 µrad(Si)/h; and the LET spectrum measurement range extends from 0.001 to 37.014 MeV/(mg/cm2). These comprehensive measurements are instrumental in establishing a lunar surface particle radiation model, enhancing the understanding of the lunar radiation environment, and supporting human lunar activities.
Based on orbit detection data acquired by a positive channel Metal Oxide Semiconductor (PMOS) dose detectors on FY4-A (GEO), BD3-M15 (MEO), and YH1-01A (LEO) between November 2018 and November 2022, investigations reveal variations in total dose and the mechanism of radiation dose increase within the geostationary earth orbit (GEO), medium earth orbit (MEO), and low earth orbit (LEO) during the transition from the 24th to the 25th solar cycles. It provides the radiation dose parameters for the study of the space environment from different altitude orbits, and also provides an important basis for studying the solar minimum activity and dose generation The data indicate directional disparities in radiation doses among the orbital regions, with the hierarchy being FY4-A > YH1-01A > BD3-M15. Furthermore, the results show that the total doses of FY4-A and BD3-M15 were higher than that of YH1-01A by two orders of magnitude, with BD3-M15 > FY4-A > YH1-01A. The monthly radiation dose rates of FY4-A in GEO and BD3-M15 in MEO exhibited positive correlation with their corresponding APs during the solar minimum. Notably, for FY4-A, the monthly radiation dose rate during geomagnetic disturbed periods exceeded that of the dose rate during geomagnetic quiet periods by one order of magnitude. This analysis revealed the substantial impact of geomagnetic storms and space environment disturbances on radiation doses detected by MEO and GEO orbital satellites. These perturbations, attributable to medium- and small-scale high-energy electron storms induced by reproducible coronal holes, emerged as key driving factors of the increase in radiation doses in MEO and GEO environments.
1 January 2023 in Chinese Journal of Space Science
This article introduces the design and development of a space environment monitoring unit embedded in the versatile experimental assembly for electronic components outside the China space station’s Wentian laboratory cabin module. A newly designed comprehensive detection system is being used for the first time in this kind of detector. The sensor head of the instrument includes a silicon telescope (composed of two silicon semiconductors) for measuring the LET spectrum and radiation dose rate, a typical chip for monitoring a single-event upset, and a CR-39 plastic nuclear track detector for detecting heavy ion tracks. The two silicon sensors stacked up and down are used for measuring the LET spectrum, which ranges from 0.001 to 100 MeV·cm2/mg. A sensor charge allocation method is adopted to divide the detection range into four cascaded levels, each achieving different detection ranges separately and then concatenated together, while traditional detection methods need multiple sets of probes to achieve the same dynamic range. At the same time, using the two sensors mentioned above, the silicon absorption dose rate under two different shielding thicknesses can be obtained through calculation, ranging from 10−5 to 10−1 rad (Si)/h. Multiple calibration methods are applied on the ground. The preliminary in-orbit detection results are provided and compared with the simulation results obtained using the existing space environment model, and we analyze and discuss their differences.
With advancements in space exploration, the extreme conditions of space—such as ionizing radiation, temperature gradients, and micrometeoroid impacts—pose significant challenges to the operational stability and longevity of space-based detection systems. Therefore, the development of detectors with enhanced resilience and reliability has become imperative. Recent advancements in synthetic diamond detectors fabricated through chemical vapor deposition (CVD) have demonstrated high radiation tolerance, favorable thermal stability, and reliable radiation-detection performance. These attributes position diamond detectors as promising candidates for space radiation monitoring applications. This study systematically analyzed the physical properties, fabrication methodologies, radiation detection principles, and prospective applications of diamond detectors within the context of space environments, highlighting their advantages in comparison to conventional detection technologies.