In this article, we present estimates of diurnal and semidiurnal harmonics of variations in integrated water vapor content (IWV) according to data from 16 GPS stations in the Volga–Ural region of ...Russia during 2013–2015. Amplitudes of diurnal harmonics are maximal in summer and reach values from 0.37 to 1.01 mm. Time at the maximum of diurnal harmonic is typically in the period from 14:00 to 17:00. Semidiurnal harmonics have the largest amplitudes in spring and autumn, but they do not exceed 0.19 mm. A comparison of the diurnal cycle from GPS data and ERA-Interim reanalysis has revealed significant differences in the phase. It is established that, as a result of evaporation from the underlying surface and convective lifting of moist air, the summer diurnal variations in IWV and surface density of water vapor are in antiphase. The diurnal cycle of IWV is determined by surface air temperature to be 88 % in summer and less than at 35 % in other seasons. It is noted that maximal amplitudes of diurnal harmonic of IWV are observed at stations located on the windward side of mountains.
COMET Phase-I technical design report Abramishvili, R; Adamov, G; Allin, A ...
Progress of theoretical and experimental physics,
03/2020, Letnik:
2020, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Abstract
The Technical Design for the COMET Phase-I experiment is presented in this paper. COMET is an experiment at J-PARC, Japan, which will search for neutrinoless conversion of muons into ...electrons in the field of an aluminum nucleus ($\mu$–$e$ conversion, $\mu^{-}N \rightarrow e^{-}N$); a lepton flavor-violating process. The experimental sensitivity goal for this process in the Phase-I experiment is $3.1\times10^{-15}$, or 90% upper limit of a branching ratio of $7\times 10^{-15}$, which is a factor of 100 improvement over the existing limit. The expected number of background events is 0.032. To achieve the target sensitivity and background level, the 3.2 kW 8 GeV proton beam from J-PARC will be used. Two types of detectors, CyDet and StrECAL, will be used for detecting the $\mu$–$e$ conversion events, and for measuring the beam-related background events in view of the Phase-II experiment, respectively. Results from simulation on signal and background estimations are also described.
In the COMET experiment, the electromagnetic calorimeter will be assembled on long LYSO:Ce crystals. The distribution of the light yield in such crystals is not uniform along the length and volume. ...This will lead to the non-uniformity of the calorimeter detector response and to a deterioration in the energy resolution. Therefore, to obtain a high energy resolution of the electromagnetic calorimeter, it is necessary to take into account the light yield non-uniformity of the scintillators. In this work, for the calorimeter prototype of the COMET experiment, the non-uniformity of the detector response along the crystal length and at the incidence angles of cosmic muons relative to the scintillators end surfaces of 9° and 19° was measured. An estimate of the energy resolution of the calorimeter of the COMET experiment was obtained, which is 4% for straight tracks and 6% for tracks at an angle of 19°.
Scintillation properties of LYSO:Ce and LYSO:Ce,Сa crystals, such as energy resolution, response time, and distribution of light yield along the crystal length, have been studied for the ...electromagnetic calorimeter of the COMET experiment searching for the process of neutrinoless muon-electron conversion in the aluminum nuclei. The non-uniformity of the responses along the scintillator length are calculated and comparison with the scintillation properties of LYSO:Ce and LYSO:Ce,Ca crystals from Saint-Gobain (France) is performed. The obtained mean of the non-uniformity of the scintillator response is ~4.6 and ~ 1.1%, variation of the values of energy resolution at the middle of the length are ±0.21 and ±0.19% for LYSO:Ce and LYSO:Ce,Сa crystals, respectively.
The article compares the coordinates of the satellite monitoring stations of the Zagorsk PSPP-2 obtained by the double differences method and the PPP method when processing the same measurements with ...a duration of at least 5 h. It has been established that the discrepancies in the coordinates in the northern and eastern directions are characterized by an RMS of 2 mm, and in the vertical direction—by an RMS of 7 mm. Proposals for the development of a new standard that allows using the PPP method in monitoring networks for hydraulic structures have been made.
The cross-comparison of different techniques for atmospheric integrated water vapour (IWV) measurements is the essential part of their quality assessment protocol. We inter-compare the synchronised ...data sets of IWV values measured by the Bruker 125 HR Fourier-transform infrared spectrometer (FTIR), RPG-HATPRO microwave radiometer (MW), and Novatel ProPak-V3 global navigation satellite system receiver (GPS) at the St. Petersburg site between August 2014 and October 2016. As the result of accurate spatial and temporal matching of different IWV measurements, all three techniques agree well with each other except for small IWV values. We show that GPS and MW data quality depends on the atmospheric conditions; in dry atmosphere (IWV smaller than 6 mm), these techniques are less reliable at the St. Petersburg site than the FTIR method. We evaluate the upper bound of statistical measurement errors for clear-sky conditions as 0.29 ± 0.02 mm (1.6 ± 0.3 %), 0.55 ± 0.02 mm (4.7 ± 0.4 %), and 0.76 ± 0.04 mm (6.3 ± 0.8 %) for FTIR, GPS, and MW methods, respectively. We propose the use of FTIR as a reference method under clear-sky conditions since it is reliable on all scales of IWV variability.
Cerium-doped lutetium yttrium oxyorthosilicate (LYSO:Ce) crystals are known to have considerable variation in scintillation light yield. Thus, the use of long LYSO:Ce crystals in energy measurements ...requires improved uniformity to realize high resolution. As it is known that differences in crystal characteristics can originate from differences in manufacturing techniques using the Czochralski method, it is useful to measure and compare the non-uniformity of LYSO:Ce crystals from different manufacturers. Comprehensive comparison of such crystals can be achieved using two methods, namely, gamma spectroscopy and optical spectroscopy. In this study, we examined two long crystals obtained from Saint-Gobain (France) and JT Technology Co. Ltd. (China). The Saint-Gobain crystal was found to have a more uniform distribution of scintillation properties and to contain fewer optical traps and crystal structure defects.
Time series of integrated water-vapor (IWV) content for 2015–2017 at eight paired GNSS stations and solar photometry data from the AERONET network in Europe have been compared. The distance between ...station pairs was no more than 20 km. The average and standard deviations of discrepancies have been shown to vary seasonally. The GNSS–photometer bias in winter was from –0.61 to 0.34 mm. The IWV content in summer is overestimated by the GNSS relative to photometers by 0.52 to 2.26 mm. The standard deviation is from 1.31 to 1.64 mm with a maximum in summer and decreases to 0.49–0.86 mm in winter, which is 5–6% of IWV.
New high precision measurements of the Collins and Sivers asymmetries of charged hadrons produced in deep-inelastic scattering of muons on a transversely polarised
6LiD target are presented. The data ...were taken in 2003 and 2004 with the COMPASS spectrometer using the muon beam of the CERN SPS at 160
GeV
/
c
. Both the Collins and Sivers asymmetries turn out to be compatible with zero, within the present statistical errors, which are more than a factor of 2 smaller than those of the published COMPASS results from the 2002 data. The final results from the 2002, 2003 and 2004 runs are compared with naive expectations and with existing model calculations.
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