Radiation Tolerance of Low-Noise Photoreceivers for the LISA Space Mission

This study investigates the effects of space environmental radiation on the performance of In0.53Ga0.47As quadrant photodiodes (QPDs) and assesses their suitability for the laser interferometer space antenna (LISA) mission. QPDs of 1.0-, 1.5-, and 2.0-mm diameter were irradiated with 20- and 60-MeV protons, 0.5- and 1-MeV electrons, and Co60 gamma rays. An exposure corresponding to a displacement damage equivalent fluence (DDEF) of <inline-formula> <tex-math notation="LaTeX">$1.0\times 10+ 12 $ </tex-math></inline-formula>p/cm2 for 20- and 60-MeV protons and a total ionizing dose (TID) of 237 krad were applied, exceeding the radiation requirements for the LISA mission by a factor of approximately 5. Experiments were conducted to measure changes in QPD dark current, capacitance, and responsivity. The QPDs were integrated with a low-noise dc-coupled transimpedance amplifier (TIA) to form the quadrant photoreceiver (QPR). QPR noise and performance in an interferometric system like LISA were also performed. Although radiation impacted their dark current and responsivity, almost all QPDs met LISA’s validation criteria and did not demonstrate any critical failure. These findings suggest that the tested QPDs are promising candidates for LISA and other space-based missions.