  The Compact High Energy Camera (CHEC) is a camera design for the Small-Sized
Telescopes (SSTs; 4 m diameter mirror) of the Cherenkov Telescope Array (CTA).
The SSTs are focused on very-high-energy $\gamma$-ray detection via atmospheric
Cherenkov light detection over a very large area. This implies many individual
units and hence cost-effective implementation. CHEC relies on dual-mirror
optics to reduce the plate-scale and make use of 6 $\times$ 6 mm$^2$ pixels,
leading to a low-cost ($\sim$150 kEuro), compact (0.5 m $\times$ 0.5 m), and
light ($\sim$45 kg) camera with 2048 pixels providing a camera FoV of $\sim$9
degrees. The electronics are based on custom TARGET (TeV array readout with
GSa/s sampling and event trigger) ASICs and FPGAs sampling incoming signals at
a gigasample per second, with flexible camera-level triggering within a single
backplane FPGA. CHEC is designed to observe in the $\gamma$-ray energy range of
1$-$300 TeV, and at impact distances up to $\sim$500 m. To accommodate this and
provide full flexibility for later data analysis, full waveforms with 96
samples for all 2048 pixels can be read out at rates up to $\sim$900 Hz. The
first prototype, CHEC-M, based on multi-anode photomultipliers (MAPMs) as
photosensors, was commissioned and characterised in the laboratory and during
two measurement campaigns on a telescope structure at the Paris Observatory in
Meudon. In this paper, the results and conclusions from the laboratory and
on-site testing of CHEC-M are presented. They have provided essential input on
the system design and on operational and data analysis procedures for a camera
of this type. A second full-camera prototype based on Silicon photomultipliers
(SiPMs), addressing the drawbacks of CHEC-M identified during the first
prototype phase, has already been built and is currently being commissioned and
tested in the laboratory.
