Design, performance, and calibration of CMS hadron-barrel calorimeter wedges

Extensive measurements have been made with pions, electrons and muons on four production wedges of the compact muon solenoid (CMS) hadron barrel (HB) calorimeter in the H2 beam line at CERN with particle momenta varying from 20 to 300 GeV/c. The time structure of the events was measured with the full chain of preproduction front-end electronics running at 34 MHz. Moving-wire radioactive source data were also collected for all scintillator layers in the HB. The energy dependent time slewing effect was measured and tuned for optimal performance.     

Simulations for CMS hadron endcap calorimeter upgrade at HL-LHC

The upgrade of the present endcap calorimeters is foreseen to prepare the CMS experiment for the High Luminosity LHC. Integrated doses at the location of the front layers of the hadron endcap calorimeter are expected to reach 20 Mrad. Studies of radiation fields are presented in this report. At the same time, the effects of pileup will become more severe, making the identification of jet objects more challenging. We estimated the effects of different transverse segmentations of back hadron calorimeter (BH) for CMS upgrade.     

Underground horizontal ionization-neutron calorimeter-pairmeter

The necessity, prospects, and possibility of development of an underground multipurpose device for detecting high-energy penetrating particles (muons) are described. The use of lead as an absorber and plastic scintillators with gadolinium allow the simultaneous use of the device as an ionization-neutron calorimeter and a pairmeter for detecting nuclear and electromagnetic cascades from penetrating particles and separating ones from the others. The presented results of calculations of the pairmeter characteristics using the GEANT program show the possibility of estimating the muon energy from 100 GeV to 200 TeV with an accuracy of 40% for a version with 150 layers (2 cm lead + 1 cm plastic each).     

Electromagnetic secondaries and punch-through effects in the CMS ME1/1

The aim of this work is to estimate the shower leakage from the CMS Endcap Hadron calorimeter (HE) due to electromagnetic secondaries and punch-through in the region of the ME1/1 Forward Muon Station. Two configurations are considered: with and without the CMS Endcap Electromagnetic calorimeter (EE). The experimental data have been taken during the combined beam test of CMS subdetectors (HE, ME, RPC, DT) at the CERN H2 beam facility in 2004. Serial CSC chambers (ready for installation in CMS) fully equipped with readout electronics have been exposed. Simulation of a beam test setup has been performed using the GEANT4-based simulation software package OSCAR. The text was submitted by the authors in English.     

Influence of magnetic field on scintillators brightening in hadron calorimeters of endcap parts of Compact Muon Solenoid plant of Large Hadron Collider

The influence of magnetic field on brightening of scintillators of endcap hadron calorimeters of the Compact Muon Solenoid (CMS) plant of the Large Hadron Collider (LHC) has been investigated. Experimental studies were performed with cosmic ray muons in real configuration of the CMS plant with magnetic field (B = 3.8 T) turned on and off. It was shown that the magnetic field increases the brightening of scintillators by 8.4%.     

Performance studies of prototype II for the CASTOR forward calorimeter at the CMS experiment

We present results of the performance of the second prototype of the CASTOR quartz–tungsten sampling calorimeter, to be installed in the very forward region of the CMS experiment at the LHC. The energy linearity and resolution, as well as the spatial resolution of the prototype to electromagnetic and hadronic showers are studied with E=20–200 GeV electrons, E=20–350 GeV pions, and E=50, 150 GeV muons from beam tests carried out at CERN/SPS in 2004. The responses of the calorimeter using two different types of photodetectors (avalanche photodiodes APDs, and photomultiplier tubes PMTs) are compared.     

The neutron field and radiation shielding efficiency measurement and the luminosity monitoring using the HF RADMON system of the CMS setup

The HF RADMON system monitors radiation environment in the region of the forward calorimeter of the CMS setup. Measurements of neutron fluxes at energies of 7, 8, and 13 GeV are carried out; estimates of the radiation shielding efficiency are obtained. Modernization of the system for operating under high luminosity conditions is completed and its capabilities to be used as an additional luminometer are confirmed.     

Jet energy measurements in CMS

The expected performance of CMS for jet energy measurements is discussed. The use of the different calibration methods allows one to restore the linearity of the CMS calorimeter relative to jets and to improve the jet energy resolution. The text was submitted by the author in English.     

CALICE silicon-tungsten electromagnetic calorimeter

A highly granular electromagnetic calorimeter prototype based on tungsten absorber and sampling units equipped with silicon pads as sensitive devices for signal collection is under construction. The full prototype will have in total 30 layers and be read out by about 10000 Si cells of 1 × 1 cm². A first module consisting of 14 layers and depth of 7.2X ₀ at normal incidence, having in total 3024 channels of 1 cm², was tested recently with e ⁻ beam. We describe the prototype and discuss some preliminary testbeam results on its performance with respect to position resolution, response inhomogeneity and transverse containment.      

The design of a module of a new electromagnetic calorimeter for COMPASS II

A new-generation high-granularity Shashlyk EM calorimeter read out by micropixel avalanche photodiodes with thermostabilization based on the Peltier element is designed and constructed.     

The CMS electromagnetic calorimeter

An overview of the design of the CMS electromagnetic calorimeter is presented. Some of the technical challenges are described together with the current state of their development.     

Systematic studies of small scintillators for new sampling calorimeter

A new sampling calorimeter using very thin scintillators and the multi-pixel photon counter (MPPC) has been proposed to produce better position resolution for the international linear collider (ILC) experiment. As part of this R&D study, small plastic scintillators of different sizes, thickness and wrapping reflectors are systematically studied. The scintillation light due to beta rays from a collimated ⁹⁰Sr source are collected from the scintillator by wavelength-shifting (WLS) fiber and converted into electrical signals at the PMT. The wrapped scintillator that gives the best light yield is determined by comparing the measured pulse height of each 10 × 40 × 2 mm strip scintillator covered with 3M reflective mirror film, teflon, white paint, black tape, gold, aluminum and white paint+teflon. The pulse height dependence on position, length and thickness of the 3M reflective mirror film and teflon wrapped scintillators are measured. Results show that the 3M radiant mirror film-wrapped scintillator has the greatest light yield with an average of 9.2 photoelectrons. It is observed that light yield slightly increases with scintillator length, but increases to about 100% when WLS fiber diameter is increased from 1.0 mm to 1.6 mm. The position dependence measurement along the strip scintillator showed the uniformity of light transmission from the sensor to the PMT. A dip across the strip is observed which is 40% of the maximum pulse height. The block type scintillator pulse height, on the other hand, is found to be almost proportional to scintillator thickness.      

Performance studies for the prototype III of CASTOR — forward calorimeter at the CMS experiment

We present preliminary results of the performance of prototype III of the CASTOR quartz-tungsten sampling calorimeter, to be installed in the very forward region of the CMS experiment at the LHC. The energy linearity and resolution, as well as the spatial resolution of the prototype to electromagnetic and hadronic showers are studied with E= 10−200 GeV electrons, E= 20−350 GeV pions, and E= 50, 150 GeV muons in beam tests carried out at CERN/SPS in 2007.     

Electromagnetic calorimetry and e/γ performance in CMS

The European Physical Journal C - The electromagnetic calorimeter of the CMS experiment at LHC will consist of about 76000 Lead Tungstate crystals. Its main purpose is the very precise energy...     

Role of hot electron transport in scintillators: A theoretical study

Despite recent intensive study on scintillators, several fundamental questions on scintillator properties are still unknown. In this work, we use ab‐initio calculations to determine the energy dependent group velocity of the hot electrons from the electronic structures of several typical scintillators. Based on the calculated group velocities and optical phonon frequencies, a Monte‐Carlo simulation of hot electron transport in scintillators is carried out to calculate the thermalization time and diffusion range in selected scintillators. Our simulations provide physical insights on a recent trend of improved proportionality and light yield from mixed halide scintillators. (© 2016 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)     

Measurement of space resolution of endcap hadronic calorimeter CMS using beam testing of CMS HCAL prototype in 2003

Results of measurement of space resolution of the hadronic endcap calorimeter (HE) CMS based on data obtained at testing HE prototype on a pion beam at CERN in 2003 are presented. Polar angle resolution as a function of polar angle and pion energy are determined. Coefficients for transition from the shower center to particle coordinates are calculated.     

Design, performance, and calibration of?the?CMS?hadron-outer?calorimeter

The Outer Hadron Calorimeter (HCAL HO) of the CMS detector is designed to measure the energy that is not contained by the barrel (HCAL HB) and electromagnetic (ECAL EB) calorimeters. Due to space limitation the barrel calorimeters do not contain completely the hadronic shower and an outer calorimeter (HO) was designed, constructed and inserted in the muon system of CMS to measure the energy leakage. Testing and calibration of the HO was carried out in a 300 GeV/c test beam that improved the linearity and resolution. HO will provide a net improvement in missing E _T measurements at LHC energies. Information from HO will also be used for the muon trigger in CMS. Deceased. Now at University of Pennsylvania, Philadelphia, PA, USA. At Niğde University, Niğde, Turkey. At Marmara University, Istanbul, Turkey. At Kafkas University, Kars, Turkey. At Süleyman Demirel University, Isparta, Turkey. At Mersin University, Mersin, Turkey. At Izmir Yüksek Teknoloji Enstitüsü, Izmir, Turkey.     

Search for anomalous and exotic cosmic rays phenomena in the CMS experiment on the CASTOR calorimeter at the large hadron collider

The creation of the CASTOR forward calorimeter in the compact muon spectrometer (CMS) experiment at the Large Hadron Collider (LHC), CERN enabled us to perform experiments at energies corresponding to those of cosmic rays but at much greater intensities, the most important factor in studying rare and anomalous phenomena.     

Transmission electron microscopy of heteroepitaxial layer structures

The characterization of heterostructural layers by transmission electron microscopy using cleaved wedge specimens proves to be a fast analysis method. Examples are given for GaAlAs/GaAs and strained GaInAs/GaAs layer systems. It is demonstrated that the (200) dark-field contrast of GaInAs/GaAs layers reverses at an In concentration of x ≈ 0.47. Experimental high-resolution electron images of the edges of cleaved 90° wedges compare very well with computer-simulated images. Characteristic image features in GaAs and AlAs are explained by non-linear beam interactions and are shown to be sensitive to electron beam misalignment. These investigations are important to make a more precise assessment of interfaces possible.     

Numerical investigation of flow over two sweepback wedges at M = 4 and 6

Results of numerical simulation are discussed: simulation was carried out for a configuration of two wedges with sweepback leading edges placed on a pre-compression ramp in a way that skewed surfaces of the wedges deflect the compressed flows in the opposite directions. It was demonstrated that this configuration produces a flow with irregular interaction in the plane of symmetry for shock waves produced by sweepback wedges. The shock waves formed by the skew wedges induce 3D boundary layer separations along sweepback leading edges of the wedges. Flows in the separation zones are directed toward the plane of symmetry of this configuration; they interact and produce in the central part a “swollen” zone of separation flow with a typical S-shaped profile of velocity. Simulation data was obtained for the free stream flow with Mach number M = 4 and 6 and based upon Navier—Stokes equations and k-ωSST turbulence model using FLUENT computation code. Inviscid flow described by Euler equations was considered as well.