# Silicon Technologies for the CLIC Vertex Detector

## TL;DR

This paper reviews the R&D efforts for developing a high-precision, low-material-budget vertex detector for the CLIC collider, focusing on sensor and ASIC innovations tested through prototypes and simulations.

## Contribution

It introduces novel sensor and ASIC designs, including prototypes and hybridization techniques, evaluated through beam tests and simulations for the CLIC vertex detector.

## Key findings

- Prototype sensors and ASICs meet resolution and timing requirements.
- Hybridization techniques show promise for sensor-ASIC interconnection.
- Simulation results align with experimental data, guiding future improvements.

## Abstract

CLIC is a proposed linear e+e- collider designed to provide particle collisions at center-of-mass energies of up to 3 TeV. Precise measurements of the properties of the top quark and the Higgs boson, as well as searches for Beyond the Standard Model physics require a highly performant CLIC detector. In particular the vertex detector must provide a single point resolution of only a few micrometers while not exceeding the envisaged material budget of around 0.2% X0 per layer. Beam-beam interactions and beamstrahlung processes impose an additional requirement on the timestamping capabilities of the vertex detector of about 10 ns. These goals can only be met by using novel techniques in the sensor and ASIC design as well as in the detector construction. The R\&D program for the CLIC vertex detector explores various technologies in order to meet these demands. The feasibility of planar sensors with a thickness of 50-150 um, including different active edge designs, are evaluated using Timepix3 ASICs. First prototypes of the CLICpix readout ASIC, implemented in 65 nm CMOS technology and with a pixel size of 25x25 um^2, have been produced and tested in particle beams. An updated version of the ASIC with a larger pixel matrix and improved precision of the time-over-threshold and time-of-arrival measurements has been submitted. Different hybridization concepts have been developed for the interconnection between the sensor and readout ASIC, ranging from small-pitch bump bonding of planar sensors to capacitive coupling of active HV-CMOS sensors. Detector simulations based on Geant4 and TCAD are compared with experimental results to assess and optimize the performance of the various designs. This contribution gives an overview of the R&D program undertaken for the CLIC vertex detector and presents performance measurements of the prototype detectors currently under investigation.