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 microchannel plate readout ASIC (MIRA), an application-specific integrated circuit (ASIC) to be coupled with a microchannel plate (MCP) as photons counting detectors for future UV spectrometers working in the 55–200-nm spectral range. The first prototype of MIRA features an MCP 2-D anode readout with a compact pixel size (
$35\times 35$

$\mu $
m2) for a total of
$32\times 32$
pixels in a
$2\times 2$
mm2 ASIC area. MIRA, designed in a 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 (CSCL) is implemented inside each pixel to grant a spatial resolution of 35
$\mu $
m, even in the case of charge sharing. In this article, the ASIC design is described and the results of its experimental characterization, also in a preliminary test with an MCP, are presented.