arXiv subjects

Alexander Nozik

Publications and source records attributed to Alexander Nozik.

6 recordsLinked to original sources

arXiv2020

Electron evaporation from magnetic trap in Troitsk nu-mass experiment

This paper is dedicated to the simulation of the so-called trapping-effect observed in the Troitsk nu-mass experiment. The effect is caused by the magnetic trapping of decay electrons in the windowless gaseous tritium source and the gradual evaporation of those electrons. As a result, alongside regular tritium beta-spectrum electrons, we see additional electrons that are initially trapped in the source and escape it with changed energy. The spectrum of evaporated electrons is quite peculiar (almost flat for monochromatic initial electrons) and could not be directly measured in the experiment. So one has to rely on simulations. Also, it is possible that the same effect could be observed in other cases of magnetic traps.

physics.ins-det↗

arXiv2020

Simulation of VHF signal generated by RREA

Relativistic runaway electron avalanches (RREAs) developing in electrified clouds produce gamma radiation which could be observed both on the ground surface and on near-Earth orbit. Radio emission of RREAs is a much less studied manifestation of the avalanche process. Meanwhile, VHF-radiation can be used as an additional source of information on conditions of the RREA development. We present the method of calculating the VHF signal produced by RREAs using Monte-Carlo simulation with GEANT4. We show that VHF radiation produced by runaway electrons has a maximum at frequency range 0.1--1 MHz, the amplitude is below the background noise.

physics.ao-ph↗

arXiv2020

Prototype of a segmented scintillator detector for particle flux measurements on spacecraft

In this paper, we introduce a laboratory prototype of a solar energetic particle (SEP) detector which will operate along with other space-based instruments to give us more insight into the SEP physics. The instrument is designed to detect protons and electrons with kinetic energies from 10 to 100 MeV and from 1 to 10 MeV respectively. The detector is based on a scintillation cylinder divided into separated disks to get more information about detected particles. Scintillation light from isolated segments is collected by optical fibers and registered with silicon photo-multipliers (SiPM). The work contains the result of laboratory testing of the detector prototype. The detector channels were calibrated, energy resolution for every channel was obtained. Moreover, we present an advanced integral data acquisition and analysis technique based on Bayesian statistics, which will allow operation even during SEP events with very large fluxes. The work is motivated by the need for better measurement tools to study acceleration and transport of SEP in the heliosphere as well as by the need for the monitoring tool to mitigate radiation hazard for equipment and people in space.

physics.ins-det↗

arXiv2019

Cosmic-ray muon flux at Canfranc Underground Laboratory

Residual flux and angular distribution of high-energy cosmic muons have been measured in two underground locations at the Canfranc Underground Laboratory (LSC) using a dedicated Muon Monitor. The instrument consists of three layers of fast scintillation detector modules operating as 352 independent pixels. The monitor has flux-defining area of 1 m${}^{2}$, covers all azimuth angles, and zenith angles up to $80^\circ$. The measured integrated muon flux is $(5.26 \pm 0.21) \times 10^{-3}$ m${}^{-2}$s${}^{-1}$ in the Hall A of the LAB2400 and $(4.29 \pm 0.17) \times 10^{-3}$ m${}^{-2}$s${}^{-1}$ in LAB2500. The angular dependence is consistent with the known profile and rock density of the surrounding mountains. In particular, there is a clear maximum in the flux coming from the direction of the Rioseta valley.

physics.ins-det↗

arXiv2018

Shape-based event pileup separation in Troitsk nu-mass experiment

Nowadays continuous signal digitization becomes a standard procedure in experimental physics. Though, signal pileup separation at high count rate remains a problem. The article presents algorithms for detecting and extracting events based on shape of a single pulse. An example of applied use of the described algorithms is also given on the example of the Troitsk nu-mass experiment.

physics.ins-det↗

arXiv2018

Statistical time analysis for regular events with high count rate

In physics, it is frequently needed to precisely measure the count rate of some process. Quite often one needs to account for electronics dead time, pile-up and other features of data acquisition system to avoid systematic shifts of the count rate. In this article, we present a statistical mechanism to diminish or completely eliminate systematic errors arising from the correlation between the events. Also, we present examples of application of this method to the analysis of "Troitsk nu-mass" and "Tristan in Troitsk" experiments.

physics.ins-det↗