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Date
2023Type
- Doctoral Thesis
ETH Bibliography
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Abstract
This thesis aims to push forward the development of diamond particle detectors that could be used in future high-energy experiments where radiation tolerance without cooling is required. The detectors are made with polycrystalline chemical vapor deposition (pCVD) diamonds as the sensor material. This work had two major objectives: The development of a fabrication process that could be scaled up to mass-produce diamond planar pixel detectors and the understanding and modeling of the signal characteristics from 3D diamond detectors.
For the first objective, a fabrication process with yields of up to 99.7 % of the pixels was achieved. All the problems that led to defective pixels were identified and could be solved before scaling up the fabrication process. As for the second objective, it was determined that hexagonal cells collect more charge than cells with rectangular or square shapes for unirradiated detectors.
As for irradiated detectors up to a fluence of 3.5×1015 p/cm2 800 MeV/c protons, efficiencies above 99.6 % were achieved for a threshold similar to the ones available in state-of-the-art readout chips in pixel detectors (i.e. ∼ 1500 e) when the cells had a side length of 50 µm. For the irradiated devices with cells of 50 µm and the unirradiated devices with cells of 100 µm, it was found that charge collection efficiencies above 50 % were achieved.
A simulation framework based on the finite element method was used to estimate the capacitance of the measured devices. For most of the devices, the estimated capacitance was within 5 % of the measured capacitance during the test beams. Only one of the simulations underestimated the measured capacitance by 39 %. The reason for this disagreement is unknown.
Extending the simulation framework to model, based on first principles, the movement of the ionized charges inside the diamond, it was possible to reproduce the measure data within 6 % for 3D square cells with a strip readout. The findings support the model proposed by S. Lagomarsino et al., which is based on two mean free paths for the charge carriers that accounts for the movement of the charge carriers parallel to the grain boundaries and perpendicular to the grain boundaries. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000604983Publication status
publishedExternal links
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Publisher
ETH ZurichOrganisational unit
03904 - Wallny, Rainer / Wallny, Rainer
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ETH Bibliography
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