Recent results of the searches for Supersymmetry in final states with one or two leptons at CMS are presented. Many Supersymmetry scenarios, including the Constrained Minimal Supersymmetric extension of the Standard Model (CMSSM), predict a substantial amount of events containing leptons, while the largest fraction of Standard Model background events -which are QCD interactions -gets strongly reduced by requiring isolated leptons. The analyzed data was taken in 2011 and corresponds to an integrated luminosity of approximately L = 1 fb −1 . The center-of-mass energy of the pp collisions was √ s = 7 TeV.

The optical transparency of perfluorocarbons used as Cherenkov media is of prime importance to many Ring Imaging Cherenkov detectors. We will in this paper show that the main photon absorbers in these fluids are hydrocarbons with double or triple bonds. We will moreover discuss a process which can eliminate these pollutants and restore the intrinsic excellent optical transparency of these fluids in the VUV range.

We report on the development of evaporative fluorocarbon cooling for the semiconductor pixel and micro-strip sensors of inner tracking detector of the ATLAS experiment at the future CERN Large Hadron Collider (LHC). We proceeded with studies using perfluoro-n-propane (3M-"PFG 3 F 8 ), perfluoro-n-butane (3M-"PFG 5040"; C 4 F 10 ), trifluoro-iodo-methane (CF 3 I) and custom C 3 F 8 /C 4 F 10 mixtures. Certain thermo-physical properties had to be verified for these fluids. Sound velocity was calculated for the pure fluids and custom mixtures. A Sonar instrument was developed for the measurement of sound velocity in the above fluids at a variety of temperatures and pressures. Irradiation studies were made on the fluids using neutrons and gamma rays to determine their suitability for use in the high radiation environment at LHC.

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