CMS Bulletin

UPGRADES

The three post-LS1 Phase 1 Upgrade projects (the L1-Trigger, Pixel Tracker, and HCAL) are all making excellent progress and are transitioning from the prototype to the execution phase. Meanwhile plans are developing for Phase 2, a major Upgrade programme targeting the third long shutdown, LS3. News on Phase 1 is included under the respective projects; we only provide a brief summary here.

Phase 1
The plan for the L1 Trigger relies on the installation during the present shutdown of optical splitting for the Trigger input signals. This will allow the new Trigger system to be brought online and fully commissioned during beam operation in 2015, while CMS relies on the existing legacy Trigger for physics. Once fully commissioned the experiment can switch over to the new Trigger, which will provide greatly improved performance at high event pile-up, by 2016. System tests of the splitter system, and of the new architecture of the calorimeter trigger were very successful, and the work in LS1 is on-track. Prototype boards for the new trigger are either under study, or in production, with full system test planned for the first half of next year. There has been good progress on developing new algorithms, but more work is needed on algorithms and software to be ready for physics in 2016. Help wanted and welcome! The success of this project will make a major impact on our physics in Run 2.

Prototype components and modules for the Pixel detector have been tested and validated. The final version of the readout chip is being submitted to foundry, and the production sensors for BPIX are ordered, and pre-production FPIX sensors are under test. A full CO₂ cooling system has been commissioned at the Tracker Integration Facility and installation of the pipework and cooling systems at P5 are planned for 2014.

The R&D programme to develop silicon photo-multipliers for HCAL has been very successful, with sensors from two vendors meeting specification for photo-electron efficiency, dynamic range, radiation tolerance and neutron insensitivity. The new micro-TCA back-end electronics is in production for HF, which is the first detector to receive the upgrade. The prototype new readout chip (QIE10) performs very well for both charge measurement and timing. This is the first version of the QIE with an integrated TDC.

Phase 2
The overall scope for the Phase 2 upgrade was further developed, following the June Upgrade Week held at DESY. The performance longevity of the existing (or Phase 1) detectors is a driving concern in defining the scope and has been extensively studied. It is clear that the entire tracking system and the endcap calorimeters must be replaced. In addition, the very high pile-up anticipated beyond LS3 will require a further upgrade to the Trigger, with incorporation of tracking into all physics objects and major increase in the Trigger bandwidth. A description of the full upgrade scope, along with an initial cost estimate was documented and presented to the CERN Resource Review Board (document ref. CERN-RRB-2013-124). The emphasis is now on simulation studies to motivate the upgrades, on R&D to develop the technologies and on conceptual design of the detector upgrades. The goal is to submit a Technical Proposal covering the whole Phase 2 programme by September 2014, and to prepare TDRs for the individual detectors by 2016/’17.

An ECFA workshop on HL-LHC was held in October. This was the first time that all experiments and the accelerator and theory communities presented and discussed plans for the high-luminosity phase. Working groups (on physics areas, tracking, calorimeters, machine-experiment interface etc) met several times ahead of the workshop, and presented summaries at the meeting. The final report is available online. The workshop was a great success, discussions are underway to continue and extend this approach.

The studies presented at the ECFA workshop used DELPHES to demonstrate the physics potential at HL-LHC. To fully develop the CMS plan for Phase 2 Monte Carlo simulation of the detector is needed. This is a critical juncture in establishing Phase 2, and development of the simulation and reconstruction code for the new detector is key. The goal is to produce a CMSSW release early in 2014 and to embark on a Monte Carlo and analysis campaign in the spring. This is a great place and time to forge the future of CMS – and to gain experience for the beam conditions we will be facing. Join the effort!