Calibration and monitoring for crystal calorimetry

Results of the first performance tests * of the CMS electromagnetic calorimeter

“…An optical monitoring system has been developed consisting of a laser source and an optical fibre distribution system. The system is described in detail elsewhere [10] and a schematic overview is shown in Figure 5. The final system consists of two lasers operating at four different wavelengths (440, 495, 706 and 796 nm) but in these tests only the blue (440 nm) laser was used, whose wavelength is close to the scintillation emission peak of the crystals.…”

“…PN diodes measure the amplitude of the laser pulses as received by groups of 200 crystals, and provide a normalisation of the magnitude of the injected light pulse. The system, including PN diodes and fibres, has been shown to be radiation hard for doses up to those expected for 10 years of high luminosity LHC running [10]. ).…”

Crystals for the HHCAL Detector Concept

“…The physics discovery potential of crystal calorimeter was early demonstrated by the Crystal Ball experiment through its study of radiative transitions and decays of the Charmonium family [2]. With proper calibration and monitoring, crystal calorimeters usually deliver their designed resolution in situ [3].…”

Crystals for the HHCAL detector concept

“…The physics discovery potential of crystal calorimeter was early demonstrated by the Crystal Ball experiment through its study of radiative transitions and decays of the Charmonium family [2]. With proper calibration and monitoring, crystal calorimeters usually deliver their designed resolution in situ [3]. Table I summarizes parameters of past and present crystal electromagnetic calorimeters in high energy physics experiments [1].…”