Successful Construction of CPPF system for CMS Experiment


The Concentration, Pre-Processing and Fan-out (CPPF) system for the CMS Level 1 (L1) Trigger Phase I Upgrade has been successfully developed and constructed by scientists of the Institute of High Energy Physics (IHEP). This announcement was made in the CMS Trigger Monthly meeting on June 20th, 2017, at CERN, Geneva, during the CMS Week, the quarterly meeting for the CMS experiment at the Large Hadron Collider.

The CPPF system including hardware, firmware and software proved with data analysis results to be in stable operation after a month of testing running as a part of the full system with cosmic ray and LHC beam collisions representing a completion of full CMS L1 Trigger Phase I Upgrade.

In view of the limitations of the CMS detector system with a LHC running at an energy of 14 TeV and luminosity of 2x1034cm-2s-1, CMS scientists decided to upgrade the detector system to improve its performance. For the trigger and data acquisition system, a new MTCA architecture was  introduced, as well a 10 Gbps high-speed data interconnection and processing, to reduce pile-up and to enhance the event selection and data recording capabilities for the whole experiment.

After the technical discussions by IHEP trigger team leader Prof. Liu Zhen’an and IHEP CMS team leader Prof. Chen Guoming, with CMS trigger Management and experts in 2013, IHEP team obtained the chance to design and construct the CPPF system, with design experiences in the PANDA and BELLE II experiments and xTCA-for-Physics standard development. The system was expected to have a capability greater than 614 Gbps of throughput for trigger preprocessing with concentration and fan-out. After three years’ work, the IHEP team completed the design, prototyping, validation, and mass production, and FPGA firmware, Butler and SWATCH software development.

On March 18, 2017, a complete CPPF system, integrated in a MTCA chassis, was added into the L1 trigger upgrade system. On April 29, the CMS software integration was completed, after which the data taking with cosmic ray and beam collision began. The success of this project in a short period of time provided a chance for the Chinese researchers both to contribute in the CMS experiment, and to learn from the outstanding experts in this international collaboration.

Contact Information

Prof. Liu Zhen'an

Experimental Physics Division