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

This study investigates the effects of space environmental radiation on the performance of In
_0.53
Ga
_0.47
As Quadrant Photodiodes (QPDs) and assesses their suitability for the Laser Interferometer Space Antenna (LISA) mission. QPDs of 1.0 mm, 1.5 mm, and 2.0 mm diameter were irradiated with 20 and 60 MeV protons, 0.5 and 1 MeV electrons, and Co
₆₀
gamma rays. An exposure corresponding to a Displacement Damage Equivalent Fluence (DDEF) of 1.0×10
⁺¹²
p/cm² for 20 and 60 MeV protons and a total ionising dose of 237 krad were applied, exceeding the radiation requirements for the LISA mission by a factor of approximately five. 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 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.