RD53

RD53 RD53 is a family of prototype hybrid pixel readout integrated circuits developed for high-luminosity upgrades of collider detectors. It was conceived to meet the requirements of experiments at the CERN Large Hadron Collider upgrade era and integrates lessons from prior projects at DESY, INFN, and Brookhaven National Laboratory. The design targets high radiation tolerance, fast timing, and fine spatial resolution for use in ATLAS, CMS, and other silicon tracking systems.

Background and development

The project emerged from the community efforts to address challenges identified during preparatory work for the High-Luminosity Large Hadron Collider upgrade and drew on technologies from the FE-I4 and CMS Phase-1 Upgrade initiatives. Key institutions coordinated under the umbrella of pixel R&D programs at CERN and partner laboratories including DESY, INFN, Brookhaven National Laboratory, University of California, Santa Cruz, and KEK. The collaboration responded to requirements set by the ATLAS Experiment and the CMS Experiment for increased hit rates, improved granularity, and survival to intense ionizing and non-ionizing radiation. Prototyping, tape-outs, and iterative revisions involved semiconductor foundries experienced with advanced nodes used for high-energy physics, following roadmaps similar to those used in the RD50 and RD53A precursor activities.

Design and specifications

The architecture uses a 65 nm CMOS process selected for density, speed, and radiation tolerance; the layout and analog front-end derive from techniques validated in the FE-I4 and Medipix programs. The chip comprises a matrix of pixel cells with in-pixel amplification, discrimination, and time-over-threshold measurement, supporting sparse readout and triggering schemes compatible with the ATLAS Insertable B-Layer and CMS Tracker Upgrade electronics. Interfaces include high-speed serial links compatible with the GBT optical link standard and custom serializer/deserializer blocks used in Versatile Link applications. Power distribution and thermal management build upon methods developed at CERN cooling trials and module prototyping campaigns at INFN Laboratori Nazionali di Frascati.

Performance and testing

Laboratory characterization used setups common to silicon pixel validation such as source tests, laser scans, and charge injection benches developed at DESY and CERN. Beam tests were conducted at facilities including the CERN SPS, DESY Test Beam Facility, and Fermilab Test Beam Facility to measure spatial resolution, efficiency, timing jitter, and cluster size in configurations emulating ATLAS and CMS geometries. Radiation hardness was evaluated with proton and neutron irradiations at sites like KIT, TRIUMF, and Los Alamos National Laboratory following protocols from the RD50 community. Measurements demonstrated tolerance to fluences and total ionizing doses consistent with HL-LHC projections, while firmware and DAQ integration leveraged frameworks from the ALICE and LHCb readout ecosystems.

Applications and deployments

Primary applications target inner tracking layers and vertex detectors in the ATLAS Experiment and CMS Experiment upgrades for the HL-LHC, where high hit rates and radiation levels demand advanced pixel readout. Additional deployments include test modules in beamline studies and integration in prototype telescope arrays at DESY and CERN for detector commissioning. The modular design permits adaptation for experiments beyond LHC, such as future collider concepts explored at the International Linear Collider and detector R&D at KEK, as well as use in synchrotron light-source imaging projects at facilities like Diamond Light Source and ESRF for high-rate photon counting.

Collaboration and funding

The effort was coordinated by a consortium of national labs and university groups including CERN, DESY, INFN, Brookhaven National Laboratory, University of Bonn, University of Glasgow, and others, often organized through pixel detector working groups associated with the CERN detector R&D program. Funding and in-kind contributions came from national science agencies such as the European Commission framework programs, the U.S. Department of Energy, the Deutsche Forschungsgemeinschaft, and national ministries supporting INFN and partner institutions. Collaborative governance followed models used in multi-institution projects like the ATLAS Pixel Upgrade and the CMS Phase-2 Upgrade with technical boards, review panels, and joint testbeam campaigns.

Category:Pixel detectors Category:CERN experiments