Speaker
Dr
Marco Povoli
(SINTEF MINALAB)
Description
The recent revival of space exploration implies an increased interest in space travels that are associated with many challenges and risks, mostly related to the ever-changing adverse space weather. Radiation of any types can be detrimental to both astronauts and the equipment on-board. The capability of monitoring radiation levels reliably in space is therefore becoming a critical aspect for space missions. Many existing radiation monitoring systems are bulky and require operation at high voltages and powers, for example, the Tissue Equivalent Proportional Counter (TEPC). Other systems are often fabricated using off-the-shelf components, including Si diodes for radiation detection, but lack the necessary radiation tolerance to ensure sensor survival throughout the entire mission. The 3D silicon sensor technology provides unique solutions to the limitations of the existing technologies for radiation monitoring in space. This new technology was introduced to mitigate the effects of radiation damage in High Energy Physics Experiments. Through state-of-the-art micro-machining, 3D technology decouples the inter-electrode spacing from the thickness of the silicon sensor. Columnar electrodes are etched through the silicon bulk, allowing for inter-electrode spacing that is independent of the bulk thickness. The reduction in electrode spacing results in ultra-low operating voltage (<10 V), fast sensor response (< 1ns), and increased radiation hardness. Design, fabrication, and testing of a novel 3D silicon sensors tailored to space applications and manufactured at SINTEF MiNaLab are here reported. Electrical characterisation shows excellent fabrication yield. The functional characterisation of the sensors was carried out at SINTEF with a laboratory grade radioactive source (241Am, alpha) and with protons of energies in the range 70 to 202 MeV at the TIFPA proton therapy centre in Trento, Italy. The results of the functional characterisation are very satisfactory and allowed to identify the best sensor implementation amongst the ones tested. A brief analysis of the findings and recommendations for the use of 3D sensors in future space activities will also be discussed. A further development plan will be presented, aiming at a portable, real-time on-line micro-dosimeter for space applications realised in collaboration with the Centre for Medical Radiation Physics at the University of Wollongong, Australia.
