Beam tests of the trigger and digital processing electronics for the electromagnetic calorimeter of the CMS experiment

A prototype of the trigger and digital processing electronics for the electromagnetic calorimeter of the CMS experiment, coupled to a prototype of the PbWO4 crystal calorimeter, was tested during summer 96 in the H4 beamline at the CERN SPS. A very successful operation was achieved for this system, which runs in synchronous and pipelined mode at the LHC clock frequency, and performs the basic trigger and data acquisition functions needed in the CMS electromagnetic calorimeter. The performance of the trigger front-end electronics is well within the established requirements: a highly efficient bunch crossing identification ( > 99.9%), a good trigger energy resolution ( s/E ~9%/sq( E)+2%) and a highly efficient electron cluster shape identification ( ~99%) have been achieved. The FERMI digitizing system based on a dynamic analog compressor and a sampling ADC showed a very good perform ance, in particular the energy resolution for 150 GeV electrons was 0.54%, equal to the resolution obtained with a conventional charge integration ADC system

The CMS Electromagnetic Calorimeter Data Acquisition System at the 2006 Test Beam

The Electromagnetic Calorimeter of the CMS experiment at the CERN LHC is an homogeneous calorimeter made of about 80000 Lead Tungstate crystals. From June to November 2006, eleven barrel Supermodules (1700 crystals each) were exposed to beam at CERN SPS, both in stand-alone and in association with portions of the Hadron Calorimeter. We present the description of the system used to configure and readout the calorimeter during this period. The full set of final readout electronics boards was employed, together with the pre-series version of the data acquisition software. During this testbeam, the hardware and software concepts for the final system were validated and the successfull operation of all the ten supermodules was ensured

Radiation hardness qualification of PbWO4 scintillation crystals for the CMS Electromagnetic Calorimeter

This is the Pre-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2010 IOPEnsuring the radiation hardness of PbWO4 crystals was one of the main priorities during the construction of the electromagnetic calorimeter of the CMS experiment at CERN. The production on an industrial scale of radiation hard crystals and their certification over a period of several years represented a difficult challenge both for CMS and for the crystal suppliers. The present article reviews the related scientific and technological problems encountered

Intercalibration of the barrel electromagnetic calorimeter of the CMS experiment at start-up

Calibration of the relative response of the individual channels of the barrel electromagnetic calorimeter of the CMS detector was accomplished, before installation, with cosmic ray muons and test beams. One fourth of the calorimeter was exposed to a beam of high energy electrons and the relative calibration of the channels, the intercalibration, was found to be reproducible to a precision of about 0.3%. Additionally, data were collected with cosmic rays for the entire ECAL barrel during the commissioning phase. By comparing the intercalibration constants obtained with the electron beam data with those from the cosmic ray data, it is demonstrated that the latter provide an intercalibration precision of 1.5% over most of the barrel ECAL. The best intercalibration precision is expected to come from the analysis of events collected in situ during the LHC operation. Using data collected with both electrons and pion beams, several aspects of the intercalibration procedures based on electrons or neutral pions were investigated

CMS physics technical design report : Addendum on high density QCD with heavy ions

Peer reviewe

Polycyclic Aromatic Hydrocarbons in Air

Policiklički aromatski ugljikovodici (PAU) spojevi su koji se sastoje od dva ili više kondenziranih aromatskih prstenova. Nastaju prilikom nepotpunog izgaranja ili pirolize organskih tvari. Dokazano je da neki PAU imaju kancerogena, a neki mutagena svojstva, pa je stoga potrebno kontinuirano pratiti koncentracije PAU u zraku, vodi i tlu, te pokušati sanirati izvore PAU. PAU s dva ili tri aromatska prstena postojani su u plinovitoj fazi, dok se PAU s više aromatskih prstenova nalaze u zraku uglavnom vezani na čestice. Visoke koncentracije PAU prisutne su u atmosferi urbanih područja, a najviše su zimi kada su pojačane emisije iz kućnih ložišta. U ljetno doba koncentracije su niže jer je većina policikličkih aromatskih ugljikovodika nestabilna na visokim temperaturama, a osim toga dolazi do njihove oksidacije i fotooksidacije. Metode mjerenja PAU u zraku uključuju uzorkovanje prosisavanjem na filterski papir ili kruti adsorbens, ekstrakciju i kromatografsku analizu. U ovom radu prikazani su rezultati mjerenja benzo[a]pirena (BaP) kao glavnog predstavnika PAU na nekim lokacijama u svijetu. Razine BaP u svijetu uspoređene su s rezultatima mjerenja provedenim do sada u Hrvatskoj.Polycyclic aromatic hydrocarbons (PAHs) are a large group of organic compounds consisting of two or more condense aromatic rings. They are products of incomplete combustion or pyrolysis of organic matter. Because some PAHs such as Benzo[a]pyrene (BaP) are proven carcinogens and mutagens, it is necessary to continuously monitor their concentrations in the air, water, and soil. PAHs with two or three aromatic rings are stable in the gas phase, while most PAHs with five or more aromatic rings bond to particles. Higher concentrations of PAHs are present in the atmosphere of urban areas, mostly in the winter, due to heating. In the summer, these concentrations drop because most PAHs are unstable at high temperatures and break down by oxidation and photooxidation. Measurements of PAHs in the air include sampling on the filter paper or solid adsorbent, extraction, and chromatographic analysis. This review presents the measurements of BaP in some locations in the world and compares them with the findings in Croatia