arXiv subjects

A. Zaitsev

Publications and source records attributed to A. Zaitsev.

6 recordsLinked to original sources

arXiv2020

The Cesium Source Calibration and Monitoring System of the ATLAS Tile Calorimeter: Design, Construction and Results

This article describes the design, construction and use of a calibration and monitoring system, based on movable 137Cs gamma-ray sources, for the ATLAS Tile Calorimeter (TileCal). The sources, propelled by a water-based liquid through tubes that traverse all the calorimeter's cells, produce signals that precisely characterise the response of each tile, thereby providing very granular and accurate data on the response of TileCal to particles. The system has been used to guide and control the quality of the optical instrumentation of all TileCal modules, to set and equalise the dynamic range of the response to physics data, and to set the energy scale of the readout system. In the ATLAS cavern, periodic measurements of the whole detector's response to 137Cs sources allow monitoring the uniformity and stability of all the calorimeter's cells as well as maintaining precise knowledge of its energy calibration. The design of the source hydraulic drive system's hardware and software, the data acquisition system and the data processing algorithms are described. Finally, the results of this two-decade program are shown.

physics.ins-det↗

arXiv2019

High temperature annealing enhanced diamond 13C hyperpolarization at room temperature

Methods of optical dynamic nuclear polarization (DNP) open the door to the replenishable hyperpolarization of nuclear spins, boosting their NMR/MRI signature by orders of magnitude. Nanodiamond powder rich in negatively charged Nitrogen Vacancy (NV) defect centers has recently emerged as one such promising platform, wherein 13C nuclei can be hyperpolarized through the optically pumped defects completely at room temperature and at low magnetic fields. Given the compelling possibility of relaying this 13C polarization to nuclei in external liquids, there is an urgent need for the engineered production of highly "hyperpolarizable" diamond particles. In this paper, we report on a systematic study of various material dimensions affecting optical 13C hyperpolarization in diamond particles -- especially electron irradiation and annealing conditions that drive NV center formation. We discover surprisingly that diamond annealing at elevated temperatures close to 1720C have remarkable effects on the hyperpolarization levels, enhancing them by upto 36-fold over materials annealed through conventional means. We unravel the intriguing material origins of these gains, and demonstrate they arise from a simultaneous improvement in NV electron relaxation time and coherence time, as well as the reduction of paramagnetic content, and an increase in 13C relaxation lifetimes. Overall this points to significant recovery of the diamond lattice from radiation damage as a result of the high-temperature annealing. Our work suggests methods for the guided materials production of fluorescent, 13C hyperpolarized, nanodiamonds and pathways for their use as multi-modal (optical and MRI) imaging and hyperpolarization agents.

physics.app-ph↗

arXiv2007

Search for $f_1(1285) \to π^+π^-π^0$ decay with VES detector

The isospin violating decay $f_1(1285)\toπ^+π^-π^0$ has been studied at VES facility. This study is based at the statistics acquired in $π^- Be$ interactions at 27, 36.6 and 41 GeV/c in diffractive reaction $π^- N \to (f_1 π^-) N$. The $f_1(1285) \to π^+π^-π^0$ decay is observed. The ratio of decay probabilities $BR(f_1(1285) \to π^+π^-π^0)$ to $BR(f_1(1285) \to ηπ^+π^-) \cdot BR(η\to γγ)$ is $\sim\:1.4%$.

hep-ex↗

arXiv2006

Study of $η'\toηπ^+π^-$ Dalitz plot

Dalitz plot of the $η' \to ηπ^+π^-$ decay is studied using the data collected with the VES spectrometer in two different exclusive reactions. The coefficients for the matrix element squared decomposition are measured on the largest statistics of $η'$ decays reported so far.

hep-ph↗

arXiv2005

Influence of Coriolis force on propagation and reflection of long waves

Influence of Coriolis force on propagation and reflection of the stimulated long waves generated pulsing and harmonic concentrated sources is studied. Geostrophic stream are found, is received asymptotics for transition mode. It is established that in case of presence of rectilinear boundary as a result of reflection Kelvin wave propagating along a boundary is formed.

physics.ao-ph↗

arXiv2002

Prospects to measure neutrino oscillation pattern with very large area underground detector at very long baselines

The concept of a very long baseline neutrino experiment with quasi monochromatic neutrino beam and very large area underground detector is discussed. The detector could be placed in the existing 20 km tunnel at IHEP, Protvino. The High Intensity Proton Accelerators (HIPA) which are planned to be built in Japan (JAERI-KEK, baseline of 7000 km) and Germany (GSI, baseline of 2000 km) as well as the Main Injector at Fermilab (7600 km) are considered as possible sources of neutrino beams. The oscillations are analysed in the three-neutrino scheme taking into account terrestrial matter effects. In the proposed experiment it is feasible to observe the oscillation pattern as an unique proof of the existence of neutrino oscillations. Precise measurements of disappearance oscillation parameters of the muon neutrinos and antineutrinos can be done within a reasonable time.

hep-ph↗