Speaker
Description
With the High-Luminosity Large Hadron Collider (HL-LHC) the number of events per bunch crossing increases. To cope with these high rates in the pixel trackers, per-pixel time measurements are required, which implies the need for fast sensors. The Inverted Low-Gain Avalanche Detector (iLGAD) is one of the options that is being investigated. This presentation will show the results of an inverse Low-Gain Avalanche Detector (iLGAD) with a pitch of 55 μm, a thickness of 250 μm and a large-area (2 cm2), bump bonded to a Timepix4 ASIC. Timepix4 has 195 ps time binning on each pixel and therefore an ideal ASIC to test the sensor. The sensor is characterised with laser and radio-active source measurement in the lab and during beam test at the CERN SPS North Area H8 beamline, where the timepix4 telescope was used. The telescope consists of four 100 µm thick sensors for temporal resolution and four 300 µm thick sensors for spatial resolution. Downstream of the telescope there are two MCPs used as time reference, giving a temporal resolution of 12 ps. The iLGAD is placed in the centre of the telescope as DUT, where the telescope has a pointing resolution of 2.3 ± 0.1 μm.
The iLGAD shows an almost uniform gain of around 4 and an efficiency of 99.6±0.1%. Without any corrections the obtained time resolution is about 750 ps. After timewalk and clock corrections the time resolution becomes 358 ps. To understand the details of the time resolution also grazing angle measurements are done, which allow to measure the time-resolution as function of depth of the charge deposition in the sensor. This provides more insight for the perpendicular time resolution.
| Workshop topics | Detector systems |
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