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

Hydroxyl radical/ozone ratios during ozonation processes. II. The effect of temperature, pH, alkalinity, and DOM properties

The influence of temperature, pH, alkalinity, and type and concentration of the dissolved organic matter (DOM) on the rate of ozone (O-3) decomposition, O-3-exposure, . OH-exposure and the ratio R-ct of the concentrations of . OH and O-3 has been studied. For a standardized single ozone dose of 1 mg/L in all experiments, considerable variations in O-3-exposure and . OH-exposure were found. This has important implications for water treatment plants regarding the efficiency of oxidation and disinfection by O-3. In oligotrophic surface waters and groundwaters, minimal calibration experiments are needed to model and control the ozonation process, whereas in eutrophic surface waters more frequent measurements of O-3 kinetics and R-ct values are required to evaluate seasonal variations

Calibration of full-scale ozonation systems with conservative and reactive tracers

A full-scale ozonation reactor was characterised with respect to the overall oxidation budget by coupling laboratory kinetics with reactor hydraulics. The ozone decomposition kinetics and the ratio of the OK radical to the ozone concentration were determined in laboratory batch experiments. With the computer model AQUASIM these parameters could be coupled with the hydraulics of the ozonation reactor which allowed the prediction of the behaviour of ozone, chlorine, and micropollutants (e.g. atrazine) in the reactor. The comparison of measured and modelled concentration showed an excellent agreement. The present study summarises a general approach of how full scale ozonation reactors can be calibrated to assess disinfection, oxidation and minimise disinfection by-products, such as bromate