  Micro-channel plate (MCP)-based photodetectors are capable of picosecond
level time resolution and sub-mm level position resolution, which makes them a
perfect candidate for the next generation large area photodetectors. The
large-area picosecond photodetector (LAPPD) collaboration is developing new
techniques for making large-area photodetectors based on new MCP fabrication
and functionalization methods. A small single tube processing system (SmSTPS)
was constructed at Argonne National Laboratory (ANL) for developing scalable,
cost-effective, glass-body, 6 cm x 6 cm, picosecond photodetectors based on
MCPs functionalized by Atomic Layer Deposition (ALD). Recently, a number of
fully processed and hermitically sealed prototypes made of MCPs with 20 micron
pores have been fabricated. This is a significant milestone for the LAPPD
project. These prototypes were characterized with a pulsed laser test facility.
Without optimization, the prototypes have shown excellent results: The time
resolution is ~57 ps for single photoelectron mode and ~15 ps for
multi-photoelectron mode; the best position resolution is < 0.8 mm for large
pulses. In this paper, the tube processing system, the detector assembly,
experimental setup, data analysis and the key performance will be presented.
