Fabrication Description CMS Endcap
Introduction
The Carnegie Mellon University (CMU) High-Energy Physics (HEP) Group with John Alison, Valentina Dutta, and Manfred Paulini studying elementary particle physics currently as members of the CMS Collaboration. The CMS detector is a large multi-purpose experiment operating at the Large Hadron Collider (LHC) at CERN, the European particle physics laboratory near Geneva, Switzerland. Research with the CMS experiment explores the fundamental constituents of matter and has received high priority within the U.S. particle physics program as supported by the Office of High Energy Physics at the U.S. Department of Energy’s (DOE) Office of Science, which is sponsoring this research. CMU physicists have participated in the CMS experiment since 1994 and the CMS experiment is expected to continue operating at the LHC with participation from CMU faculty for the next 20 years.
In the high-luminosity phase of the LHC physics program, the accelerator is foreseen to provide an integrated luminosity of about 3000 fb−1 over 10 years of operation starting in 2030. As outlined in the Technical Proposal for the Phase-II upgrade of the CMS detector, several upgrades are planned to address the aging of the present detector elements. One such element of the Phase-II upgrade is the replacement of the current electromagnetic and hadronic endcap calorimeters with a High Granularity Calorimeter (HGC) that has electromagnetic and hadronic sections with excellent transverse and longitudinal segmentation. The scope of the CMU work within the US-CMS collaboration is the construction of all parts for the hadronic section of the endcap calorimeter (CE-H). This work includes the design and construction of the active detectors in the CE-H, which will be integrated into two large scale devices (endcaps) whose total cost is greater than $5M . The endcaps will be used for the duration of the HL-LHC program, currently expected to run until 2041.
Module Assembly at CMU
Carnegie Mellon University has been chosen by the US-CMS upgrade project as one of three U.S. Module Assembly Center for the CMS Phase-II Endcap Calorimeter Upgrade together with UC Santa Barbara (UCSB) and Texas Tech University (TTU). There are in addition three international assembly sites in China, India, and Taiwan working on the module assemble for the electromagnetic portion of the endcap calorimeter.
The standard modules are the basic building blocks for the hadronic section of the endcap calorimeter. A module consists of a base plate, a sheet of kapton gold-plated on one side, a silicon sensor, and a printed circuit board (PCB). Using a robotic device called a gantry, these components are taped and epoxied together to form a solid stack and the electrical connections between the PCB and the silicon sensor are accomplished by wire bonding. The activities at the CMU Standard Module Assembly Site consist of the assembly of about 5000 full-hexagon 192-channel modules, testing during the assembly process, quality control (QC) at the end of production, and shipping of the modules, in ESD-safe foam and boxes, to the cassette production site.