  We present the development of a single-photon detector and the connected
read-out electronics. This `hybrid' detector is based on a vacuum tube,
transmission photocathode, microchannel plate and a pixelated CMOS read-out
anode encapsulating the analog and digital-front end electronics. This assembly
will be capable of detecting up to $10^9$ photons per second with simultaneous
measurement of position and time.
  The pixelated read-out anode used is based on the Timepix4 ASIC
($65~\mathrm{nm}$ CMOS technology) designed in the framework of the Medipix4
collaboration. This ASIC is an array of $512\times448$ pixels distributed on a
$55~\mathrm{\mu m}$ square pitch, with a sensitive area of $\sim
7~\mathrm{cm}^2$. It features $50$-$70~\mathrm{e^{-}}$ equivalent noise charge,
a maximum rate of $2.5~\mathrm{Ghits/s}$, and allows to time-stamp the
leading-edge time and to measure the Time-over-Threshold (ToT) for each pixel.
The pixel-cluster position combined with its ToT information will allow to
reach $5$-$10~\mathrm{\mu m}$ position resolution. This information can also be
used to correct for the leading-edge time-walk achieving a timing resolution of
the order of $10~\mathrm{ps}$.
  The detector will be highly compact thanks to the encapsulated front-end
electronics allowing local data processing and digitization. An FPGA-based data
acquisition board, placed far from the detector, will receive the detector hits
using $16$ electro-optical links operated at $10.24~\mathrm{Gbps}$. The data
acquisition board will decode the information and store the relevant data in a
server for offline analysis.
  These performance will allow significant advances in particle physics, life
sciences, quantum optics or other emerging fields where the detection of single
photons with excellent timing and position resolutions are simultaneously
required.
