Single-pixel multimode detectors (30/50 μm) have the drawback to have a limited countrate (~10 MHz) due to their size. However, if we take this large single-pixel detector and split it into four smaller multipixel elements the overall countrate can be increased 16 times!
A multipixel element has a quarter of the detection area which reduces its inductance by a factor of four. Hence, this element can work four times fasters then the large single-pixel detector. Since there are four multipixel detectors present, the overall countrate is increased by on other factor of 4, yielding a factor of 16 increase in countrate.
Brilliant, isn’t it?