The Forbush decrease following the large X2 solar flare on mid-February 2011 has been observed by the muon telescopes of the EEE Project, which are located in several Italian sites and at CERN. Data ...from two different telescopes of the EEE network have been analyzed and compared to those measured by neutron monitor stations. The variation of the muon counting rate during the Forbush decrease was also extracted for different intervals of the azimuthal angle of the incoming muons.
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Time correlated events due to cosmic muons from extensive air showers have been detected by means of telescope pairs of the EEE (Extreme Energy Events) Project array. The coincidence rate, properly ...normalized for detector acceptance, efficiency and altitude location, has been extracted as a function of the relative distance between the telescopes. The results have been also compared with additional measurements carried out by small scintillator detectors at various distances.
For ALICE spectator protons and neutrons will be separated from ion beams, using a separator magnet (D1) of the LHC beam optics and respectively detected by a proton and a neutron "Zero-degree ...Calorimeter" (ZDC). An electromagnetic calorimeter is also foreseen for the measurement of the forward photons coming from the decay of /spl pi//sup 0/. The calorimeter performances are discussed.
The Extreme Energy Events Project (EEE Project) is an innovative experiment to study very high energy cosmic rays by means of the detection of the associated air shower muon component. It consists of ...a network of tracking detectors installed inside Italian High Schools. Each tracking detector, called EEE telescope, is composed of three Multigap Resistive Plate Chambers (MRPCs). At present, 43 telescopes are installed and taking data, opening the way for the detection of far away coincidences over a total area of about 3 × 10
5
km
2
. In this paper we present the Monte Carlo simulations that have been performed to predict the expected coincidence rate between distant EEE telescopes.
The proton zero degree calorimeter (ZP) for the ALICE experiment will measure the energy of the spectator protons in heavy ion collisions. The ZP is a spaghetti calorimeter, which collects and ...measures the Cherenkov light produced by the shower particles in silica optical fibres embedded in a brass absorber. The details of its construction will be shown. The calorimeter has been tested at the CERN SPS in July 2004 with pion and electron beams of various momenta ranging from 50 to 200 GeV/c. The linearity of the response of the calorimeter and its energy resolution as a function of the beam energy have been measured. The preliminary results of the test are presented.
Zero degree Cherenkov calorimeters for the ALICE experiment De Falco, A.; Arnaldi, R.; Chiavassa, E. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2008, Letnik:
595, Številka:
1
Journal Article
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The collision centrality in the ALICE experiment will be determined by the Zero Degree Calorimeters (ZDCs) that will measure the spectator nucleons energy in heavy ion collisions. The ZDCs detect the ...Cherenkov light produced by the fast particles in the shower that cross the quartz fibers, acting as the active material embedded in a dense absorber matrix. Test beam results of the calorimeters are presented.
New data on forward neutron emission in fragmentation of 30A-GeV {sup 208}Pb ions on Al, Cu, Sn, and Pb nuclei are presented. The measurements were performed at the CERN SPS in the framework of the ...ALICE-LUMI experiment. The measured cross sections are compared with predictions of the RELDIS model for electromagnetic interactions and with results of the abrasion-ablation model for hadronic interactions. The electromagnetic excitation of a Pb projectile followed by single- and double-neutron emission is found to be the dominant process in full agreement with theoretical estimations. The measured 1nX cross sections are generally well described. The measured 2nX data, which are 4-5 times lower than the 1nX data, are slightly underestimated by theory. Nevertheless, the sum of 1nX and 2nX cross sections is in good agreement with theory. This confirms the predictive power of the RELDIS model, which can be used to calculate the sum of 1nX and 2nX emission rates for the purpose of calibration of luminosity measurements in PbPb collisions at the Large Hadron Collider at CERN.
Performance of a forward neutron calorimeter for the ALICE experiment Arnaldi, R.; Chiavassa, E.; Cicalo, C. ...
1999 IEEE Nuclear Science Symposium. Conference Record. 1999 Nuclear Science Symposium and Medical Imaging Conference (Cat. No.99CH37019),
1999, Letnik:
1
Conference Proceeding
The aim of the ALICE experiment is the study of ultrarelativistic heavy ion collisions in which nuclear matter at high temperatures and energy densities can be produced. The spectator protons and ...neutrons will be separated from the ion beams, using the separator magnet (D1) of the LHC beam optics and respectively detected by a proton (ZP) and a neutron (ZN) "Zero-degree Calorimeter" (ZDC). An electromagnetic calorimeter is also foreseen for the measurement of the forward photons coming from the decay of /spl pi//sup 0/, which is anti-correlated with the impact parameter of the collision. It could be used to make the centrality trigger more selective, and less sensitive to possible effects related to the fragmentation of the nuclei. The detectors will be placed at /spl sim/115 meters away from the beam intersection point. The calorimeters will be placed in a radiation rich environment, of the order of 10/sup 4/ Gy/day at a luminosity of 2/spl times/10/sup 27/ cm/sup -2/s/sup -1/. The high interaction rate, corresponding to /spl sim/8000 minimum bias collisions per second, will require a fast detection method. Moreover, since geometrical constraints will limit the lateral dimensions, the transverse size of the detectable shower should be kept as small as possible. The ZDCs are quartz-fiber calorimeters that exploit the Cherenkov light produced by the shower particles in silica optical fibers. This technique fulfils the above requirements. In addition, quartz-fiber calorimeters are intrinsically insensitive to radioactivation background, which produces particles below the Cherenkov threshold.
The Zero Degree Calorimeters (ZDCs) for the ALICE experiment will measure the energy of the spectator nucleons in heavy ion collisions at the CERN LHC. Since all the spectator nucleons have the same ...energy, the calorimeter response is proportional to their number, providing a direct information on the centrality of the collision. Two identical ZDC systems are located at opposite sides with respect to the interaction point (IP), 116 m away from it. Each ZDC system consists of a neutron (ZN) calorimeter, placed between the two beam pipes, and a proton (ZP) calorimeter, positioned externally to the outgoing beam pipe. The ZDCs are spaghetti calorimeters, which detect the Cherenkov light produced by the shower particles in silica optical fibers embedded in a dense absorber. In summer 2007 the ZN and ZP calorimeters have been assembled on the surface on a movable platform and then installed in the LHC tunnel. The results of the commissioning on the surface, in particular the solutions adopted to control the stability of the PMTs response will be shown: light injection with a laser diode and cosmic rays. The forseen physical calibration in Pb-Pb collisions will be also discussed. Finally the first measurements of the commissioning in the LHC tunnel will be presented.
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