Speaker
Description
We present development of the Charged & Neutral Particle Tissue Equivalent Proportional Counter (CNP-TEPC) instrument that is aimed at measuring charged particle and neutron dose rates in real time in the low Earth orbit (LEO). The CNP-TEPC consists of a central TEPC and a plastic scintillator guard detector, which enables both an accurate radiation dose measurement and a particle identification, since the tissue-equivalent composition of the central detector simulates radiation interactions with soft tissues while the types of the detected particles can be identified via a coincidence between the central and the guard detector events. The central TEPC simulates 2 µm thick soft tissue, allowing precise measurement of the lineal energy distribution of incident radiation within the range of 0.1 to 1,000 keV/µm. The guard detector is built into a hemisphere using an 8 mm thick plastic scintillator. The signals from each detector are processed by the data acquisition module, which measures the arrival time and pulse height of each detection event. The module employs an analog-to-digital converter and a Field-Programmable Gate Array for the TEPC, an ASIC chip for an array of silicon photomultipliers which are optically coupled to the scintillator. The 1st generation of the CNP-TEPC instrument was developed as the payload for the NEUtron DOSimetry & Exploration (NEUDOSE) CubeSat, which was deployed into the LEO in 2023. Following this, the 2nd generation is currently under development with a major upgrade in digital pulse processing. Comprehensive performance measurements are carried out to characterize its response to fast neutrons using the 238PuBe and 7Li(p,n) neutron sources at the McMaster accelerator laboratory. The new instrument will be deployed on an external platform of the International Space Station in 2027 for a mission lasting up to 16 weeks.
