Commissioning and operation of the new Phase I CMS pixel detector (#2213)
1 Cornell University, Department of Physics, Ithaca, New York, United States of America
The Phase I upgrade of the CMS pixel detector is built out of four barrel layers (BPIX) and three forward disks in each endcap (FPIX). It comprises a total of 124M pixel channels, in 1,856 modules and it is designed to withstand instantaneous luminosities of up to 2 x 10^34 cm-2 s-1. Different parts of the detector have been assembled over the last year and later brought to CERN for installation inside the CMS tracker. At various stages during the assembly, tests have been performed to ensure that the readout and power electronics, and the cooling system meet the design specifications. After tests of the individual components, system tests have been performed before the installation inside CMS. In addition to reviewing these tests, we also present results from the final commissioning of the detector in-situ using the central CMS DAQ system, and results from the initial operation of the detector first with cosmic rays and then with pp collisions.
Keywords: cms, phase-1 pixel, pixel
Prototyping of larger structures for the Phase-II upgrade of the pixel detector of the ATLAS experiment (#2917)
D. Alvarez Feito1
1 CERN, EP, Geneva, Switzerland
For the high luminosity era of the Large Hadron Collider (HL-LHC) it is forseen to replace the current inner tracker of the ATLAS experiment with a new detector to cope with the occuring increase in occupancy, bandwidth and radiation damage. It will consist of an inner pixel and outer strip detector aiming to provide tracking coverage up to |η|<4. The layout of the pixel detector is foreseen to consist of five layers of pixel silicon sensor modules in the central region and several ring-shaped layers in the forward region. It results in up to 14 m² of silicon depending on the selected layout. Beside the challenge of radiation hardness and high-rate capable silicon sensors and readout electronics many system aspects have to be considered for a fully functional detector. Both stable and low mass mechanical structures and services are important. Within the collaboration a large effort is started to prototype larger detector structures for both the central and forward region of the detector. The aspect of system integration is tested with prototype components. In the paper the latest evaluation of mechanical and thermo-mechanical prototypes and fully electrical prototypes is presented. Important qualification steps of the system design are discussed.
Submitted by Susanne Kuehn for ATLAS InnerTracker speakers committee
Keywords: silicon, pixel detector, tracking, hep
The Mu3e scintillating fiber tracker (#4062)
1 PSI, Paul Scherrer Institute, Villigen, Aargau, Switzerland
The Mu3e experiment searches for the mu -> eee (mu=muon, e=electron/positron) decay and it aims at reaching an ultimate sensitivity of 10-16 on the branching fraction (B) of the mu -> eee decay, four orders of magnitude better than the current limit B(mu -> eee)<10-12. The experiment will be hosted at the Paul Scherrer Institute (Villigen, Switzerland) which delivers the most intense low momentum continuous muon beam in the world (up to few x 108 mu/s).
Keywords: Scintillating fibers; Silicon photomultipliers; Tracker; High energy physics; Charged lepton flavour violation search;
SciFi - The New Scintillating Fibre Tracker for LHCb (#2008)
C. Joram1, A. Comerma2
1 CERN, EP Department, Geneva 23, Switzerland
The LHCb detector will be upgraded during the Long Shutdown 2 (LS2) of the LHC in order to cope with higher instantaneous luminosities and to read out the data at 40MHz using a trigger-less read-out system. The current LHCb main tracking system, composed of an inner and outer tracking detector, will not be able to stand the increased particle multiplicities and will be replaced by a single homogenous detector based on scintillating fibres.
The new Scintillating Fibre (SciFi) Tracker covers a total detector area of 340 m2 and will provide a spatial resolution for charged particles better than 100 μm in the bending direction of the LHCb spectrometer. The detector will be built from individual modules (0.5 m × 4.8 m), each comprising 8 fibre mats with a length of 2.4 m as active detector material. The fibre mats consist of 6 layers of densely packed blue emitting scintillating fibres with a diameter of 250 μm. The scintillation light is recorded with arrays of state-of-the-art multi-channel silicon photomultipliers (SiPMs). A custom ASIC will be used to digitize the SiPM signals. Subsequent digital electronics performs clustering and data-compression before the data is sent via optical links to the DAQ system. To reduce the thermal noise of the SiPM in particular after being exposed to a neutron fluence of up to 1012 neq /cm2, expected for the lifetime of the detector, the SiPMs arrays are mounted 3D-printed titanium cold-bars placed in so called cold-boxes and cooled down by to -40oC.
The production of fibre mats and modules is in full swing: fibre mats are being produced in four production centers and assembled to 5 m long modules at two sites. In parallel the readout electronics is finalized and its series production is prepared. The detector installation is foreseen to start end of 2019.
The talk will give an overview of the detector concept and will present the experience from the series production complemented by most recent test-beam and laboratory results.
Keywords: Scintillating Fibre Tracker, SciFi, SiPM, Tracking
Precision Timing Detectors using Cadmium-Telluride Sensors (#3189)
A. Bornheim1, C. Pena1, A. Mangu1, J. Mao1, M. Spiropulu1, S. Xie1, Z. Zhang1
1 Caltech, Pasadena, California, United States of America
Precision timing detectors for high energy physics experiments with temporal resolutions of a few 10 ps are of pivotal importance to master the challenges posed by the highest energy particle accelerators. Calorimetric timing measurements have been a focus of recent research, enabled by exploiting the temporal coherence of electromagnetic showers. Scintillating crystals with high light yield as well as silicon sensors are viable sensitive materials for sampling calorimeters. Silicon sensors have very high effciency for charged particles. However, their sensitivity to photons, which comprise a large fraction of the electromagnetic shower, is limited. A large fraction of the energy in an electromagnetic shower is carried by photons. To enhance the efficiency of detecting photons, materials with higher atomic numbers than silicon are preferable. In this paper we present test beam measurements with a Cadmium-Telluride sensor as the active element of a secondary emission calorimeter with focus on the timing performance of the detector. A Schottky type Cadmium-Telluride sensor with an active area of 1 cm2 and a thickness of 1 mm is used in an arrangement with tungsten and lead absorbers. Measurements are performed with electron beams in the energy range from 2 GeV to 200 GeV. A timing resolution of 20 ps is achieved under the best conditions.
Keywords: precision timing, cadmium-telluride, photon detectors
CMS central beam pipe instrumentation with Fiber Bragg Grating sensors: two years of data taking (#4180)
F. Fienga1, 2, Z. Szillasi5, N. Beni3, 5, A. Gaddi3, M. Consales4, A. Cusano4, A. Irace1, C. Schaefer3, W. Zeuner3, A. Ball3, S. Buontempo2, 3, G. Breglio1
1 University of Napoli Federico II, Napoli, Italy
On behalf of CMS Collaboration
This work describes the innovative applications to the monitoring in harsh environment, represented by the Compact Muon Solenoid (CMS) detector at the Large Hadron Collider (LHC), of the Fibre Bragg Grating (FBG) technology, which, although invented almost 40 years ago, is currently undergoing an explosion in variant manufac- turing technologies and applications. The environment inside a large particle physics experiment like the CMS poses several challenges of monitoring spatially varying quantities in an aggressive environ- ment, with high radiation, high magnetic field, tight electromagnetic compatibility (EMC) requirements, where particle detection priorities require monitoring sensors to have very low mass and associated service volume as well as excellent EMC compliance, conditions that can be very well satisfied by FBG sensors inscribed on optical fibres. The particular application described here is the monitoring of strain and temperature variation along the beryllium central beam pipe, a vacuum chamber which carries the counter-rotating proton beams in the Large Hadron Collider (LHC) to collisions within the CMS experiment. The mechanical complexity of the structure will be described and the temperature and strain measurements data recorded during the 2015 and 2016 LHC operations will be discussed. This FBG sensors system allows the monitoring of any deformation induced on the CMS central beam pipe during the detector motion in the maintenance periods and magnetic field induced deformation during operation phases. Moreover, the temperature FBG sensors represent a very elegant solution for monitoring the thermal behaviour of beam pipes throughout the various operational phases of accelerators. This technique has the potential for greatly simplifying the detailed monitoring of beam pipes in accelerators.
Keywords: Beam Pipe, Fibre Bragg Grating, High Energy Physics, Monitoring System, Strain, Temperature