MoTiC: Development of a Prototype of a Monolithic Particle Tracking Detector with Timing
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Author
Date
2023Type
- Doctoral Thesis
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Abstract
Depleted Monolithic Active Pixel Sensors (DMAPS) are a promising technology for
particle tracking detectors in future particle physics experiments. CMOS processes that
are tolerant of the high voltages required for full depletion have become available in
recent years. This allows for charge collection by drift, which has made DMAPS strong
candidates for future pixel detectors.
The combination of measurements of spatial coordinates with time of arrival measure-
ments promises capabilities to disentangle tracks originating from multiple interaction
vertices. In this thesis, a new DMAPS prototype called MoTiC (Monolithic Timing Chip)
and the data acquisition system for its operation are presented. There are two chips:
MoTiC A incorporates 5120 and MoTiC B 3840 square pixels of 50 µm pitch. While
MoTiC A features several different preamplifiers, the sensor geometries are varied in
MoTiC B. Groups of 4 pixels share a time-to-digital converter (TDC), consisting of a
digital part with coarse resolution and an analog part for interpolation. The chips were
designed and fabricated in a modified 110 nm CMOS process.
The performance of the chips was evaluated in laboratory measurements and beam
tests with an electron beam at DESY. While the TDC has a resolution of below 10 ps
in standalone test structures, the TDC in the pixel array was demonstrated to have
a resolution of better than 50 ps, measured with calibration signals. The best spatial
resolution achieved at an incident angle of 8◦ with samples of 200 µm thickness was
4.8 ± 0.5 µm, while the spatial resolution at vertical incidence was measured to be
6.3 ± 0.4 µm. Hit efficiencies above 99.8 % were achieved with most preamplifiers and
sensor geometries. The time resolution of the TDC in the beam was demonstrated to be
about 1.2 ns, relying only on the digital part of the TDC. When also using the analog
part of the TDC, the time resolution with actual particle hits is expected to be on the
order of some hundred picoseconds. Within the thesis, an improved version of MoTiC
was developed, eliminating several design flaws in the first version. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000648047Publication status
publishedExternal links
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Publisher
ETH ZurichSubject
Detectors; MAPS; TimingOrganisational unit
03904 - Wallny, Rainer / Wallny, Rainer
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ETH Bibliography
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