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.
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.
A
bstract
The cross section of the process
e
+
e
−
→ ηπ
+
π
−
is measured using the data collected with the CMD-3 detector at the VEPP-2000 collider in the center-of-mass energy range from 1
.
1 to 2
....
0 GeV. The decay mode
η → γγ
is used for
η
meson reconstruction in the data sample corresponding to an integrated luminosity of 78
.
3 pb
−
1
. The energy dependence of the
e
+
e
−
→ ηπ
+
π
−
cross section is fitted within the framework of vector meson dominance in order to extract the Γ(
ρ
(1450)
→ e
+
e
−
)
B
(
ρ
(1450)
→ ηπ
+
π
−
) and the Γ(
ρ
(1700)
→ e
+
e
−
)
B
(
ρ
(1700)
→ ηπ
+
π
−
) products. Based on conservation of vector current, the analyzed data are used to test the relationship between the
e
+
e
−
→ ηπ
+
π
−
cross section and the spectral function in
τ
−
→ ηπ
−
π
0
ντ
decay. The
e
+
e
−
→ ηπ
+
π
−
cross section obtained with the CMD-3 detector is in good agreement with the previous measurements.
The cross section of the process e + e − → π + π − has been measured in the center of mass energy range from 0.32 to 1.2 GeV with the CMD-3 detector at the electron-positron collider VEPP-2000. The ...measurement is based on a full dataset collected below 1 GeV during three data taking seasons, corresponding to an integrated luminosity of about 62 pb − 1 . In the dominant ρ -resonance region, a systematic uncertainty of 0.7% has been reached. At energies around ϕ -resonance the π + π − production cross section was measured for the first time with high beam energy resolution. The forward-backward charge asymmetry in the π + π − production has also been measured. It shows a strong deviation from the theoretical prediction based on the conventional scalar quantum electrodynamics framework, and it is in good agreement with the generalized vector-meson-dominance and dispersive-based predictions. The impact of the presented results on the evaluation of the hadronic contribution to the anomalous magnetic moment of muon is discussed. Published by the American Physical Society 2024
Full text
Available for:
CMK, CTK, FMFMET, IJS, NUK, PNG, UM
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.
Calorimetry of the CMD-3 detector Shebalin, V.E.; Akhmetshin, R.R.; Anisenkov, A.V. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
07/2016, Volume:
824
Journal Article
Peer reviewed
CMD-3 is a general purpose detector designed to study e+e− annihilation into hadrons. It is mounted at VEPP-2000 collider which operates in the wide energy range, Ec.m.s=0.32−2GeV. The calorimetry at ...the detector is based on three subsystems: closest to the beam pipe barrel Liquid Xenon calorimeter, outer barrel calorimeter based on CsI scintillation crystals and the endcap calorimeter made of BGO scintillation crystals. We describe the structure of the calorimeters, their electronics and the energy calibration procedures.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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.
COMET Phase-I technical design report Abramishvili, R; Adamov, G; Allin, A ...
Progress of theoretical and experimental physics,
03/2020, Volume:
2020, Issue:
3
Journal Article
Peer reviewed
Open access
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.
The process e+e−→ϕ→K+K− has been studied with the CMD-2 detector using about 542 000 events detected in the center-of-mass energy range from 1.01 to 1.034 GeV. The systematic error of the cross ...section is estimated to be 2.2%. The ϕ(1020) meson parameters in the ϕ→K+K− decay channel have been measured: σ0(ϕ→K+K−)=2016±8±44 nb, mϕ=1019.441±0.008±0.080 MeV/c2, Γϕ=4.24±0.02±0.03 MeV, Be+e−BK+K−=(14.27±0.05±0.31)×10−5.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Calorimetry of the CMD-3 detector Akhmetshin, R R; Anisenkov, A V; Aulchenko, V M ...
Journal of physics. Conference series,
11/2017, Volume:
928, Issue:
1
Journal Article
Peer reviewed
Open access
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.
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