MIRA: A Low-Noise ASIC With 35-μm Pixel Pitch for the Readout of Microchannel Plates

Spectroscopic observations in the far and extreme ultraviolet (FUV/EUV) spectral regions are of great interest in various scientific fields, such as solar physics, interstellar medium physics, and planetary exospheres studies. In this work we present MIRA (MIcrochannel plate Readout ASIC), an Application Specific Integrated Circuit (ASIC) to be coupled with a microchannel plate (MCP) as photons counting detector for future UV spectrometers working in the 55-200 nm spectral range. The first prototype of MIRA features an MCP 2D anode readout with a compact pixel size (35 × 35 μm 2 ) for a total of 32 × 32 pixels in a 2 × 2 mm 2 ASIC area. MIRA, designed in 65-nm CMOS process, features two selectable analog processing times (130 or 260 ns), a count rate per pixel of 100 kcps and an Equivalent Noise Charge ENC = 20 e - , smaller than most photon counting ASICs, to allow operations with lower MCP gains, to extend MCP lifetime for long missions in space. A charge sharing correction logic is implemented inside each pixel to grant a spatial resolution of 35 μm, even in the case of charge sharing. In the paper, the ASIC design is described and the results of its experimental characterization, also in a preliminary test with a MCP, are presented.