Speaker
Description
To withstand the much higher radiation levels resulting from a tenfold rise in integrated luminosity at the High-Luminosity LHC, the CMS experiment will upgrade its existing endcap calorimeters (CE) with the new High Granularity Calorimeter (HGCAL). This detector will enable particle-flow calorimetry through its exceptionally fine transverse and longitudinal segmentation for both readout and triggering, providing over six million readout channels. The electromagnetic compartment and the high-radiation zones of the hadronic section will employ silicon pad sensors, collectively covering a surface area of 620 square meters. The system is designed to endure particle fluences up to 1.5e16 neq/cm2 and radiation doses reaching 1.5 MGy.
The sensors are fabricated on 8-inch p-type silicon wafers with active thicknesses of 300 µm, 200 µm (both float zone), and 120 µm (epitaxial). They are diced into hexagonal geometries to optimize wafer area utilization and facilitate efficient tiling. To study radiation-induced bulk damage as well as inter-cell effects on the wafer-scale sensors, full sensors – from prototypes to production rounds – were irradiated with neutrons at the Rhode Island Nuclear Science Center (RINSC) up to fluence levels of 1.4E16 neq/cm².
This talk focusses on the electrical characterization (IV+CV) of production sensors of all three thicknesses exposed to 2E15 neq/cm2. The study investigates for the first time the isothermal annealing behaviour at 60°C after annealing durations ranging from 10 to 5000 minutes. Hamburg model parameters extracted from the full-sensor data will be compared to single-diode results. The post-irradiation behaviour of sensors with hot regions in the pre-irradiation IV measurements as well as epitaxial sensors with stacking faults in individual cells are investigated.
| Type of presentation (in-person/online) | in-person presentation |
|---|---|
| Type of presentation (I. scientific results or II. project proposal) | I. Presentation on scientific results |
