High performance stability of the ATLAS Tile Calorimeter is achieved with a procedure including a multi-step calibration. One step of the calibration is based on measurements of the response ...stability to laser excitation of the PMTs that are used to read out the calorimeter cells. A facility to study the performance of the PMT stability response has been operating in the PISA-INFN laboratories since 2015. Goals of the tests are to study the time evolution of the PMT response in order to reproduce and understand the origin of the response drifts observed with the Tile Calorimeter PMTs during LHC Run I and Run II. A new statistical approach was used to measure the drift of the absolute PMT gain. A new procedure which combines studies of the time evolution of the global PMT responses and of the individual PMT gains was adopted to derive the evolution of the cathode quantum efficiency. The experimental setup of the Pisa facility and the first results obtained by testing about 30 PMTs are presented.
Abstract
The article discusses monitoring water bodies pH level automated system implementation using an unmanned aerial vehicle (UAV). Floating structure prototype for supporting UAV on water ...surface is described, taking into account creating a rotor thrust theory. Water hydrogen ions monitoring activity concept using a UAV is presented. Testing results water monitoring system in Lake Boyarskoye (Tomsk, Russia) are presented.
The scintillation crystal bismuth germanate (BGO) is widely used in many applications. The unique technique developed in the Nikolaev Institute of Inorganic Chemistry, Novosibirsk, Russia, allows ...routine production of top quality large-sized BGO crystals. One of the important properties of a scintillation crystal is its radiation hardness. The intensive study of the radiation hardness of BGO crystals has been carried out by the collaboration of the Institutes of Siberian Branch of the Russian Academy of Science, Novosibirsk. The influence of the raw material purity and growth procedure on radiation hardness has been studied. The final tests of the crystal radiation hardness were performed by irradiating it with gamma rays from the radioactive source. The degradation of a light output of the best crystals is less than 10% after irradiation with doses of 10-100 krad expected in astrophysics experiments at a satellite. Based on the results of this study, the radiation hard BGO crystals for the "INTEGRAL" and "ASTRO-H" satellite missions have been made. A selfrecovery of the crystal light output is clearly seen. The time scale of the self recovery strongly depends on a dose of irradiation. It is days for 1 krad irradiation, weeks - for a 10 krad dose and a much longer period is required for 100 krad irradiation. All the crystals irradiated with a dose of 100 krad completely recover after annealing. The study reveals that there will be no essential degradation if this dose will be integrated over years of operation.
Since 2010 the electromagnetic endcap calorimeter based on BGO crystals is used in experiments as one of the systems of the CMD-3 detector. The spacial resolution is one of crucial parameters of the ...calorimeter. Inaccurate knowledge of the real calorimeter position can limit the resolution. In this work the alignment of the center of the calorimeter with respect to the tracking system of the CMD-3 detector has been performed using events of two-quantum annihilation. The alignment technique that has been used to determine the position of the calorimeter is described. Finally, the improvement in spacial resolution of the calorimeter after applying the correction for the real calorimeter position is shown.
The paper describes an experimental study of the influence of multiple cyclic pressure loading on the service life and sorption performance of a composite sorbent whose granules consist of ...selectively permeable (to helium) microspheres as a filler and pseudoboehmite as a porous binder. A test bench is specially designed and fabricated for the study, which makes it possible to model various operation regimes of gas-separation plants in the pressure range up to 10 MPa. Cyclic tests of pressure loading of the granulated composite sorbent are performed, and the sorption capacity of the sorbent with respect to helium is measured. It is found that the composite sorbent retains its integrity and sorption performance under cyclic loading of 1000 cycles and more at pressures up to 10 MPa.
In this article the prototype of the L-1 trigger electronics for the electromagnetic calorimeter of COMET experiment is described. A signal processing algorithm for on-line determination of the ...energy deposited by incident particles has been developed and optimized on the basis of the results of simulation.
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A method is presented for measuring the energy density of X-ray pulses with a duration of approximately 200 ns from a source with an energy of 2–3 J in its discharge circuit. A bismuth germanate ...(BGO) scintillator crystal is used for measurements. The absolute calibration of the energy scale has been carried out by measuring the amplitude spectrum of cosmic muons. The energy flux of an X-ray pulse, measured at a distance of 1 m from the anode of the source, is 20 GeV/cm
2
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Calorimetry of the CMD-3 detector Akhmetshin, R R; Anisenkov, A V; Aulchenko, V M ...
Journal of physics. Conference series,
11/2017, Letnik:
928, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The CMD-3 detector has been collecting data since 2010 at the e+e− collider VEPP-2000 in the Budker Institute of Nuclear Physics. VEPP-2000 uses the novel round beam technique and provides high ...luminosity in a wide c.m.energy range from 0.32 to 2 GeV. The physics goal of the CMD-3 experiment is a study of the e+e− annihilation into hadrons. CMD-3 is a general-purpose detector, which provides high efficiency for both charged and neutral particles. The electromagnetic calorimeter consists of the barrel calorimeter based on liquid xenon and CsI crystals, and the endcap calorimeter based on BGO crystals. The main parameters of the calorimeters are presented.
A hyperbolic character of the convective part of the flow of an air–helium mixture through a granulated sorbent layer with allowance for the Forchheimer filtration is demonstrated. A numerical model ...of a one-dimensional flow of the air–helium mixture through an adsorber filled by a granulated sorbent with due allowance for air and helium diffusion inward cylindrical granules and helium confinement in microspheres is developed. Within the framework of this model, verification of a numerical algorithm in problems of gas filtration through a porous medium and propagation of a pressure wave formed by the incident shock wave over a gas medium is performed. Experimental and numerical data are obtained and are found to be in good agreement. The enrichment phase is modeled by the method of pressure swing adsorption with the use of a bifunctional sorbent based on microspheres. It is demonstrated that the mass fraction of helium in the air–helium mixture can be almost doubled (from 0.7 to 1.3%) with the helium extraction degree of 90.4%.
The BGO endcap calorimeter was successfully operated in the CMD-2 detector at the VEPP-2M collider. It consists of 680 BGO crystals, each with a size of 25x25x150 mm super(3), arranged in two ...identical endcaps, with a total crystal weight of 450 kg. The light readout used vacuum phototriodes. The endcap calorimeter has been upgraded to operate in the CMD-3 detector at the new collider VEPP-2000. The major part of the endcap calorimeter, the BGO crystals, remains the same. The main upgrade is the use of silicon PIN photodiodes and new electronics. The main reason to change a photosensitive device is the strong non-uniform magnetic field in the endcap calorimeter volume and reduced available space. The Hamamatsu PIN photodiode S3590-08 was chosen as an optimal solution, as it is insensitive to magnetic fields and is both compact and stable. An order of magnitude larger capacitance of silicon photodiodes requires design and produce new custom electronics. The upgrade is expected to bring an overall improvement of parameters. The endcap calorimeter has been installed in the detector and participates in data taking which started in 2010. The preliminary energy resolution is measured in the energy range 160-1000 MeV. It is better to compare to the CMD-2 detector.
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