The Czech Republic and JINR. Long-Term Fruitful

physicists have designed completely original new MAPD with high sensitivity and high
dynamic range for calorimetry.
The silicon-based multipixel avalanche photo diodes (left)
and MAPD test facility at Charles University (right)
The basic task during the develpoment of MAPD is the test and measurement of the
local characteristics to provide the feedback to the designers and the factory about
performance and quality of the modifications introduced in the new design version.
This work was systematically done in the past years in collaboration of JINR and
Charles University groups led by Dr. Z.Krumstein and Prof. R.Leitner, respectively. Special
setup using focused pulsed laser beam with the beam spot of a few µm was operated at
Charles University to study MAPD local characteristics and zone variation. In these
measurements the laser beam power was well tunable by adjusting driving pulse amplitude,
and the spot position on the MAPD was adjusted by moving laser over detector.
Several types of scans were performed: long linear scans over the whole matrix (1x1
mm) in both directions and fine scans over a single detection cell (30x30 µm) in both
directions. During the scans the parameters like the sensitivity, gain, recovery time and others
were measured, providing an important feedback to the MAPD designers. One of the results is
presented in the figure below. The scan shows uniform response over the whole MAPD 3N
type matrix.
The results of test scan of whole MAPD 3N type matrix
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