# VCI2022 - The 16th Vienna Conference on Instrumentation

Feb 21 – 25, 2022
Vienna University of Technology
Europe/Vienna timezone

## The LHCb VELO Upgrade I

Feb 22, 2022, 4:25 PM
20m
Vienna University of Technology

#### Vienna University of Technology

Gusshausstraße 27-29, 1040 Wien
Live Presentation Semiconductor Detectors

### Speaker

Paula Collins (CERN)

### Description

LHCb physics achievements to date include the world's most precise measurements of the CKM phase $\gamma$ and the rare decay $B^0_s \rightarrow \mu^+ \mu^-$, the discovery of $C\!P$ violation in charm, and intriguing hints of lepton-university violation. These accomplishments have been possible thanks to the enormous data samples collected and the high performance of the sub detectors, in particular the silicon vertex detector (VELO). The experiment is being upgraded to run at higher luminosity, which requires 40 MHz readout for the entire detector and newer technologies for most of the sub detectors.

The VELO upgrade modules are composed of hybrid pixel detectors and electronics circuits mounted onto a cooling substrate, which is composed of thin silicon plates with embedded micro-channels that allow the circulation of liquid CO$_2$. This cooling substrate gives excellent thermal efficiency, no mismatch to the front-end electronics, and optimises physics performance due to the low and very uniform material distribution. The detectors are located in vacuum, separated from the beam by a thin Al foil. The foil was manufactured through a novel milling process and thinned further by chemical etching. The VELO modules are currently beeing assembled into the two halves before final installation into LHCb. The design, production, installation and commissioning of the VELO upgrade system will be presented together with test results.

Primary experiment LHCb