The extremely harsh conditions, in which the detectors will have to operate during the High Luminosity phase of the Large Hadron Collider at CERN, set stringent requirements on the properties of the ...scintillators which can be used. Among different scintillating materials under study, inorganic crystals such as LuAG:Ce and YAG:Ce represent good candidates for such application. A detailed investigation of the radiation hardness of LuAG:Ce and YAG:Ce crystal samples (1 ×1 ×1 cm 3 cubes) produced by Crytur is presented in this study. Given their potential in many calorimeter designs, YAG:Ce samples with high aspect ratio ( 1 ×1 ×14 cm 3 ) have also been tested. Optical and scintillating properties of the samples were studied before and after irradiation with different sources and at different intensities. Irradiation with gamma-rays to the doses of 1 and 100 kGy and with 24 GeV protons up to an integrated fluence of 10 14 cm -2 were performed at CERN. The scintillating properties of the crystals, as emission and excitation spectra and light yield remained unchanged after irradiation and only small levels of induced absorption were observed. The results obtained in this test confirm the potential of LuAG:Ce and YAG:Ce crystals as good candidates for calorimetry applications in future high energy physics experiments.
Lead Tungstate (PbWO 4 , PWO) has become presently the most commonly used scintillator material for electromagnetic calorimetry in medium and high-energy physics. There exists substantial demand for ...future calorimeters such as the completion of the PANDA electromagnetic compatibility (EMC) as well as various detector projects under discussion at Jefferson Lab or Brookhaven National Laboratory in the United States. Nearly, 6700 crystals are missing for the barrel section of the PANDA-EMC since the successful mass production of PWO using the Czochralski method was stopped after bankruptcy of the Bogoroditsk Technical Chemical Plant (BTCP) in Russia. Intermediate research and development efforts with the Shanghai Institute of Ceramics, Chinese Academy of Science, Shanghai, China, as an existing producer exploiting the modified Bridgman method could not reach the required quality in a consistent manner. End of 2014, the CRYTUR (Turnov, Czech Republic) has restarted the development of lead tungstate based again on the Czochralski method with impressive progress. The modified and optimized technology has already produced full size samples of PWO-II quality. This paper will present a detailed status report on a first preproduction run of 89 crystals focusing on the achieved optical performance, light yield, kinetics, and temperature dependence and radiation hardness.
We present performance studies of a full-length prototype for the CASTOR quartz-tungsten sampling calorimeter, installed in the very forward region of the CMS experiment at the LHC. The response ...linearity and energy resolution, the uniformity, as well as the showers’ spatial properties in the prototype have been studied with electrons, pions and muons of various energies. A special study was also carried out for testing the light-output with a 90-degree cut of the quartz plates of the calorimeter. The data were taken during the CASTOR test beam at CERN/SPS in 2007.
This report presents results on the optical transmission damage of undoped and Ce doped Y3Al5O12 scintillation crystals under high fluence of 24GeV protons. We observed that, similarly to other ...middle heavy scintillators, it possesses the unique radiation hardness at fluence values as high as 5×1014p/cm2 and it is thus promising for the application in the detectors at High Luminosity LHC. The crystalline structure of the garnet scintillator allows to control and further optimize its scintillation parameters, such as scintillation decay time and emission wavelength, and shows a limited set of the radioisotopes after the irradiation with protons.
A measurement is presented of differential cross sections for Higgs boson (H) production in pp collisions at Formula omitted Formula omitted. The analysis exploits the Formula omitted decay in data ...corresponding to an integrated luminosity of 19.7 Formula omitted collected by the CMS experiment at the LHC. The cross section is measured as a function of the kinematic properties of the diphoton system and of the associated jets. Results corrected for detector effects are compared with predictions at next-to-leading order and next-to-next-to-leading order in perturbative quantum chromodynamics, as well as with predictions beyond the standard model. For isolated photons with pseudorapidities Formula omitted, and with the photon of largest and next-to-largest transverse momentum ( Formula omitted) divided by the diphoton mass Formula omitted satisfying the respective conditions of Formula omitted and Formula omitted, the total fiducial cross section is Formula omitted Formula omitted.
Pre-Production of PWO-II Crystals for the PANDA-EMC Novotny, R. W.; Brinkmann, K.-T.; Dormenev, V. ...
2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC),
2017-Oct.
Conference Proceeding
Lead Tungstate (PbWO 4 , PWO) has become presently the most commonly used scintillator material for electromagnetic (EM) calorimetry in medium and high-energy physics. There exists substantial demand ...for future calorimeters such as the completion of the PANDA EMC 2 as well as various detector projects under discussion at Jefferson Lab or BNL in the United States. Nearly 6,700 crystals are missing for the barrel section of the PANDA-EMC since the successful mass production of PWO using the Czochralski method was stopped after bankruptcy of the Bogoroditsk Technical Chemical Plant (BTCP) in Russia. Intermediate R&D efforts with the Shanghai Institute of Ceramics, Chinese Academy of Science (China) as an existing producer exploiting the modified Bridgman method could not reach the required quality in a consistent manner. End of 2014 the company CRYTUR (Turnov, Czech Republic) has re-started the development of lead tungstate based again on the Czochralski method with impressive progress. The modified and optimized technology has already produced full size samples of PWO-II quality. This paper will present a detailed status report on a first pre-production run of 89 crystals focusing on the achieved optical performance, light yield, kinetics, temperature dependence and radiation hardness.
Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, ...including the transverse momenta ( ) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta ( ), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb super(-1). The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the distributions of the leading jets at high values, the distributions of the at high- and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.
A peaking structure in the J/ psi phi J/ psi phi mass spectrum near threshold is observed in B super( plus or minus ) arrow right J/ psi phi K super( plus or minus )B plus or minus arrow right J/ psi ...phi K plus or minus decays, produced in pp collisions at s=7 TeV collected with the CMS detector at the LHC. The data sample, selected on the basis of the dimuon decay mode of the J/ psi J/ psi , corresponds to an integrated luminosity of 5.2 fb super(-1). Fitting the structure to an S -wave relativistic Breit-Wigner lineshape above a three-body phase-space nonresonant component gives a signal statistical significance exceeding five standard deviations. The fitted mass and width values are m=4148.0 plus or minus 2.4(stat.) plus or minus 6.3(syst.)MeV and Gamma =28-11+15(stat.) plus or minus 19(syst.)MeV, respectively. Evidence for an additional peaking structure at higher J/ psi phi J/ psi phi mass is also reported.
PDF
