CMS Technical Design Report for the Phase 1 Upgrade of the Hadron Calorimeter

Abstract

This report describes the technical design and outlines the expected performance of the Phase 1 Upgrade of the CMS Hadron Calorimeters. The upgrade is designed to improve the performance of the calorimeters at high luminosity with large numbers of pileup events by increasing the depth-segmentation of the calorimeter and providing new capabilities for anomalous background rejection. The photodetectors of the CMS Barrel and Endcap Hadron Calorimeters, currently hybrid photodiodes (HPDs), will be replaced by silicon photomultiplier (SiPM) devices. The single-channel phototubes of the Forward Hadron Calorimeter will be replaced by multi-anode phototubes operated in a dual-anode configuration. The readout electronics for all three calorimeter systems will also be replaced. A new charge-integrating ADC, the QIE10, with an integrated TDC will be used along with a 4.8 Gbps data-link. The off-detector electronics will also be substantially upgraded to handle higher data volumes and improve the information sent to the calorimeter trigger system. The expected performance of these upgrades is discussed, including a detailed study of several Higgs and SUSY analyses. The planning for the implementation of this upgrade is presented, including construction, testing, and installation. AcknowledgmentsWe would like to thank the technical staff from the various institutions for the design, R&D and testing of the many components of this upgrade.We also wish to thank the LHCC for their oversight and crucial advice during the development of the HCAL Phase 1 upgrade project. We also acknowledge the warm support received from the CMS management team. The important feedback from following CMS internal reviewers greatly helped in the development of this technical design report: Finally, we dedicate this technical design report for the phase 1 upgrade of the HCAL subdetectors to the memory of our colleague

Cherenkov detector for beam quality measurement

“…The red (black) dashed lines show the collimator aperture for beam 1 (2). The solid lines show the average background rate in the BHM detectors.…”

“…The BHM can distinguish the low rate of machine induced background (MIB) from the vast flux of collision products. The electronics is based on the Phase 1 upgrade of the CMS Hadronic Calorimeter [2], with firmware and readout adapted to the beam monitoring requirements [3]. A BHM detector unit is composed of a quartz bar coupled to a fast photomultiplier tube (Hamamatsu R2059) at one end and painted with black paint at the opposite end, see Figure 1.…”

Search for Anomalous Trilinear Couplings of Electroweak Gauge Bosons Using Angular Variables at $\sqrt{s}$ = 13 TeV at CMS

“…The hadronic calorimeter (HCAL) is the part of the CMS detector that is designed to measure the energy of both charged and neutral hadrons [19,20]. It lies just outside the ECAL.…”

Silicon photomultipliers in particle and nuclear physics

“…SiPMs are also used to upgrade existing detectors, such as the hadronic barrel and endcap calorimeters of CMS [16]. For these two systems, the hybrid photodiodes (HPDs) used in the original detector are in the process of being replaced by SiPMs.…”

“…Two different sensor sizes Figure taken from [20] are used to match the varying number of fibers guiding the light from the scintillator layers. By choosing SiPMs with a short recovery time of less than 10 ns, which allows a pixel to fire more than once during the collection time of the scintillation light of ∼ 40 ns, the effective pixel count, and thus the dynamic range, is increase by a factor of approximately three [16]. This extends the range of a quasi-linear response of the SiPMs, as shown in Figure 4, while also resulting in a slight distortion of the pulse due to an accentuation of the late tail of the photon distribution where photon sensor saturation has abated.…”