Study of the anode self-trigger ability of the ME1/1 CMS Endcap Cathode Strip Chamber

The influence of the high background rates on the Cathode Strip Chamber (CSC) anode trigger ability has been studied. The investigation has been made with a P3 prototype of the CSC of ME1/1 Endcap muon station of the CMS experiment (CERN). The work has been done at the Gamma Irradiation Facility (GIF, CERN). P3 has been installed at the SPS X5c muon beam line in a background field of ¹³⁷Cs source. The CSC timing resolution and the track registration efficiency as a function of gamma rate are presented. The text was submitted by the authors in English.     

Calculation of the electric field at the edge of the operation region of the Cathode Strip Chambers of the CMS ME1/1 station

Distortion of the electric field near the edge of the operation region of the Cathode Strip Chamber (CSC) of the first Muon Endcap Station (ME1/1) of the Compact Muon Solenoid (CMS) is studied. The distortions of the shape and the magnitude of the electric field that arise from the presence of the insulating frame, which supports the anode wire array, are investigated. The electric field calculation is done with the aid of the boundary elements method. The text was submitted by the authors in English.     

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.     

The spatial resolution of the CMS ME1/1 muon station cathode strip chambers with CRAFT08 data

The spatial resolution of the outer part of the ME1/1 muon station has been studied with CRAFT08 (Cosmic Rays At Four Tesla-2008) data at the CMS detector (CERN). The ME1/1 Cathode Strip Chamber (CSC) layer spatial resolution as a function of the CMS solenoid magnetic field is presented. The influence of the strip width and anode wire tilt on the spatial resolution has been studied. Finally, the spatial resolution for the ME1/1 6-layer CSC was calculated and the ME1/1 outer part spatial resolution was estimated.     

Cathode strip chamber for CMS ME1/1 endcap muon station

Seventy-six serial ME1/1 cathode strip chambers have been produced in Dubna. These chambers are the coordinate detectors of the first muon station of the CMS detector at CERN. This paper describes the design of the chamber, its main mechanical parameters, and the results of the cosmic ray test. The text was submitted by the authors in English.     

Understanding the performance of CMS calorimeter

The performance of the CMS hadron calorimeter is studied using test beam facilities at CERN. Two wedges of brass-scintillator calorimeter are exposed to negative and positive beams with momenta between 3 and 300 GeV/c. Light produced in the scintillators are collected using wavelength shifting fibres and read out using hybrid photodiodes. Each of the wedges has 17 layers of scintillators. In one of these wedges signal from all 17 layers are grouped together while in the other each layer is read out separately. The response, energy resolution, longitudinal and lateral shower profiles are measured. on behalf of the CMS Collaboration     

ME1/1 cathode strip chambers for CMS experiment

The ME1/1 cathode strip chambers are the part of the CMS endcap muon system. They were designed and produced in Dubna. The chambers have been installed in the detector and commissioning has been completed. This paper describes chamber readout electronics and presents the results of the tests with cosmicray muons. The article is published in the original.     

全尺寸CMS RE1/2阻抗板探测器样器束流测试结果

介绍了CMS RE1/2 全尺寸阻抗板探测器的束流测试结果.探测器气体室的阻抗板表面采用不需要淋油的特殊光洁处理,外支撑框架采用铝质蜂窝板,以保证足够的强度以及整个RPC所占空间尽量小.在GIF的束流测试结果表明该样品在高辐射本底下能够达到满探测效率.时间分辨率以及噪声水平都符合CMS实验的要求.     

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.     

Beam Test Results of the First Full-Scale Prototype of CMS RE1/2 Resistive Plate Chamber

We reported the muon beam test results of the first full–scale prototype of CMS RE1/2 Resistive Plate Chamber (RPC).The bakelite surface is treated using a special technology without oil to make it smooth enough.The full scale RE1/2 RPC with honeycomb supporting frame is strong and thin enough to be fitted to the limited space of CMS design for the inner forward RPC.The muon beam test was performed at CERN Gamma Irradiation Facility (GIF).The detection efficiency of this full scale RPC prototype is>95% even at very high irradiation background.the time resolution (less than 1.2 ns) and spatial resolution are satisfactory for the muon trigger device in future CMS experiments.The noise rate is also calculated and discussed.     

The Test Beam on BEPC and Physics Works on It

This paper reports the design and construction of the primary beam of the test beam on BEPC,as well as the acquirement of the positive-charged secondary beam,and the various particles,e⁺,π⁺,μ⁺,p,in the secondary beam have been measured with TOF method and threshold Cherenkov counter.The radiation damage studies of SDC calorimeter modules using the test beam have also been briefly described.     

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.     

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.     

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.     

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.     

Design, performance, and calibration of CMS forward calorimeter wedges

We report on the test beam results and calibration methods using high energy electrons, pions and muons with the CMS forward calorimeter (HF). The HF calorimeter covers a large pseudorapidity region (), and is essential for a large number of physics channels with missing transverse energy. It is also expected to play a prominent role in the measurement of forward tagging jets in weak boson fusion channels in Higgs production. The HF calorimeter is based on steel absorber with embedded fused-silica-core optical fibers where Cherenkov radiation forms the basis of signal generation. Thus, the detector is essentially sensitive only to the electromagnetic shower core and is highly non-compensating (e/h≈5). This feature is also manifest in narrow and relatively short showers compared to similar calorimeters based on ionization. The choice of fused-silica optical fibers as active material is dictated by its exceptional radiation hardness. The electromagnetic energy resolution is dominated by photoelectron statistics and can be expressed in the customary form as . The stochastic term a is 198% and the constant term b is 9%. The hadronic energy resolution is largely determined by the fluctuations in the neutral pion production in showers, and when it is expressed as in the electromagnetic case, a = 280% and b = 11%.     

The upgrade of endcap CMS muon system

The configuration and composition of the CMS muon system are presented. The paper is focused on cathode strip chambers (CSC) used as the endcap muon system detectors. The goals and objectives of the endcap muon system upgrade are formulated. The main results of works accomplished for the ME1/1 CSCs upgrade and the new ME4/2 muon station construction during the LHC Long Shutdown-1 (2013–2014) are presented. The improved performances of the endcap muon system are shown using experimental data obtained after the upgrade (Run2 data).     

Muon identification and pion rejection in the 4th concept

We describe a completely new way to reconstruct and identify muons with high efficiency and very high pion rejection in the 4th concept detector. The dual-solenoid magnetic field allows the reconstruction and precision momentum measurement of muons down to a few GeV (just the energy loss in the 10-λ_int calorimeter and the coil) and the dual-readout calorimeter provides a new, unique and powerful separation of muons from pions. We use test beam data for the calorimeter and calculations for the magnetic fields.      

Background neutron in the endcap and barrel regions of resistive plate chamber for compact muon solenoid/large hadron collider using GEANT4

In this study the performance of double gap RPC has been tested by GEANT4 Monte Carlo simulation code. The detector response calculations taken as a function of the neutron energy in the range of 0.01 eV-1 GeV have been simulated through RPC set-up. In order to evaluate the response of detector in the LHC background environment, the neutron spectrum expected in the CMS muon endcap and barrel region were taken into account. A hit rate of about 165.5 Hz cm⁻², 34 Hz cm⁻², 33.6 Hz cm⁻², and 27.0 Hz cm⁻² due to an isotropic neutron source is calculated using GEANT4 standard electromagnetic package for a 20 × 20 cm² RPC in the ME1, ME2, ME3 and ME4, respectively. While for the same neutron source and using GEANT4 package a hit rate of about 0.42 Hz cm⁻², 0.7182 Hz cm⁻² was measured for the MB1 and MB4 stations respectively. Similar characteristics of hit rates have been observed for GEANT4 low electromagnetic package.      

A study of hadronic shower development in the ECAL of the alpha magnetic spectrometer Ⅱ

In this paper, we studied the development of hadronic shower in an electromagnetic calorimeter of Alpha Magnetic Spectrometer Ⅱ. Two parametrized empirical formulae were proposed to describe the hadronic shower shape in calorimeter. Using 100 GeV proton beam incident on the center of the ECAL, detailed plots of lateral and longitudinal hadronic shower behavior were given and we found the formulae can describe the development of the hadronic shower with the test beam data. The possible application of the parametrized formulae including e^±-π^± discrimination and tau jet reconstruction was discussed.