Speaker
Description
Recently, Low Gain Avalanche Detectors (LGADs) has emerged as a technological
solution for precise timing measurements in the tens of ps range. They have led to a
range of developments in High Energy Physics and other applications. In space application, the timing of particles is one of the crucial observable that has a direct implication
on particle identification. However, to distinguish particles with similar mass an absolute timing resolution is required in the order of O (10 ps). In space the rate of
particles is not as high as HEP and power consumption is an issue, ultimately reducing
the number of channels. The typical size of silicon sensor for strip geometry in space
application is 100 µm pitch and 50-60 cm long resulting in a channel area of about 1 cm2
whereas, the typical LGAD channel size is O (1 mm2
). This work was motivated by
the requirement of a O (1 cm2
) sized LGAD detector. In this work, we investigated the
jitter of the sensor as a function of different sensor thickness and gain values. In addition, we measured some big area sensors using the transient current technique (TCT) to
study the signal shape and gain uniformity. We discuss the measurements performed
with pad sensors of dimensions 5 mm × 5 mm (with and without gain), and strip sensors with pitch 192 µm and 3.5 cm long stips. These pad sensors with gain layer, are
the biggest single channel LGADs ever fabricated in Fondazione Bruno Kessler (FBK)
with standard LGAD technology. After successful measurements with TCT, we discuss
the gain, gain uniformity, signal shape, signal propagation, and issues that need to be
addressed while making large-area sensors.
