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Register a new userRealtime calibration of the A4 electromagnetic lead fluoride calorimeter
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Sufficient energy resolution is the key issue for the calorimetry in particle and nuclear physics. The calorimeter of the A4 parity violation experiment at MAMI is a segmented calorimeter where the energy of an event is determined by summing the signals of neighbouring channels. In this case the precise matching of the individual modules is crucial to obtain a good energy resolution. We have developped a calibration procedure for our total absorbing electromagnetic calorimeter which consists of 1022 lead fluoride (PbF_2) crystals. This procedure reconstructs the the single-module contributions to the events by solving a linear system of equations, involving the inversion of a 1022 x 1022-matrix. The system has shown its functionality at beam energies between 300 and 1500 MeV and represents a new and fast method to keep the calorimeter permanently in a well-calibrated state.
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Lead fluoride ($PbF_{2}$) crystals represent an excellent and relatively innovative choice for high resolution electromagnetic calorimeters with high granularity and fast timing. During the R&D stages of the Crilin calorimeter, three pbfd crystals sized $5times 5 times 40 $ mm$^3$ were irradiated with $^{60}$Co photons up to $sim 4$ Mrad and with 14 MeV neutrons up to a $10^{13}$ n/cm$^2$ total fluence. Their loss in transmittance was evaluated at different steps of the photon and neutron irradiation campaign, and two optical absorption bands associated with the formation of colour centres were observed at $sim 270$ nm and $sim 400$ nm. Natural and thermal annealing in the dark, along with optical bleaching with 400 nm light, were performed on the irradiated specimens resulting in a partial recovery of their original optical characteristics.
We propose to build the Electromagnetic calorimeter for the HADES di-lepton spectrometer. It will enable to measure the data on neutral meson production from nucleus-nucleus collisions, which are essential for interpretation of dilepton data, but are unknown in the energy range of planned experiments (2-10 GeV per nucleon). The calorimeter will improve the electron-hadron separation, and will be used for detection of photons from strange resonances in elementary and HI reactions. Detailed description of the detector layout, the support structure, the electronic readout and its performance studied via Monte Carlo simulations and series of dedicated test experiments is presented. The device will cover the total area of about 8 m^2 at polar angles between 12 and 45 degrees with almost full azimuthal coverage. The photon and electron energy resolution achieved in test experiments amounts to 5-6%/sqrt(E[GeV]) which is sufficient for the eta meson reconstruction with S/B ratio of 0.4% in Ni+Ni collisions at 8 AGeV. A purity of the identified leptons after the hadron rejection, resulting from simulations based on the test measurements, is better than 80% at momenta above 500 MeV/c, where time-of-flight cannot be used.
This paper presents the design, implementation and validation of the software alignment procedure used to perform geometric calibration of the electromagnetic calorimeter with respect to the tracking system of the SND detector which is taking data at the VEPP-2000 e^{+}e^{-}collider (BINP, Novosibirsk). This procedure is based on the mathematical model describing the relative calorimeter position. The parameter values are determined by minimizing a chi^{2} function using the difference between particle directions reconstructed in these two subdetectors for e^{+}e^{-}rightarrow e^{+}e^{-} scattering events. The results of the calibration applied to data and MC simulation fit the model well and give an improvement in particle reconstruction. They are used in data reconstruction and MC simulation.
Shashlyk-type electromagnetic calorimeter (ECal) of the Multi-Purpose Detector at heavy-ion NICA collider is optimized to provide precise spatial and energy measurements for photons and electrons in the energy range from about 40 MeV to 2-3 GeV. To deal with high multiplicity of secondary particles from Au-Au reactions, ECal has a fine segmentation and consists of 38,400 cells (towers). Given the big number of towers and the time constraint, it is not possible to calibrate every ECal tower with beam. In this paper, we describe the strategy of the first-order calibration of ECal with cosmic muons.
In the PHENIX experiment at RHIC, the electro-magnetic calorimeter plays an important role in both the heavy-ion and spin physics programs for which it was designed. In order to measure its performance in the energy range up to 80GeV, a beam test was performed at the CERN-SPS H6 beam line. We describe the beam test and present results on calorimeter performance with pion and electron beams.
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