arXiv subjects

D. Kozhevnikov

Publications and source records attributed to D. Kozhevnikov.

5 recordsLinked to original sources

arXiv2018

Measurement of shower development and its Molière radius with a four-plane LumiCal test set-up

A prototype of a luminometer, designed for a future e+e- collider detector, and consisting at present of a four-plane module, was tested in the CERN PS accelerator T9 beam. The objective of this beam test was to demonstrate a multi-plane tungsten/silicon operation, to study the development of the electromagnetic shower and to compare it with MC simulations. The Molière radius has been determined to be 24.0 +/- 0.6 (stat.) +/- 1.5 (syst.) mm using a parametrization of the shower shape. Very good agreement was found between data and a detailed Geant4 simulation.

physics.ins-det↗

arXiv2017

Properties of GaAs:Cr-based Timepix detectors

It is the hybrid pixel detector technology which brought to the X-ray imaging a low noise level at a high spatial resolution, thanks to the single photon counting. However, silicon as the most widespread detector material is marginally sensitive to photons with energy more than 30 keV. That's why the high-Z alternatives to silicon such as gallium arsenide and cadmium telluride are increasingly attracting attention of the community for the development of X-ray imaging systems in recent years. We present in this work the results of our investigations of the Timepix detectors bump-bonded with sensors made of gallium arsenide compensated by chromium (GaAs:Cr). The properties which are mostly important from the practical point of view: IV characteristics, charge transport characteristics, operational stability, homogeneity, temperature dependence as well as energy and spatial resolution are considered. Applicability of these detectors for spectroscopic X-ray imaging is discussed.

physics.ins-det↗

arXiv2017

Response of Timepix detector with GaAs:Cr and Si sensor to heavy ions

The response of the Timepix detector to neon ions with kinetic energy 77 and 158.4 MeV has been studied at the cyclotron U-400M of the JINR Flerov Laboratory of Nuclear Reaction. Sensors produced from gallium arsenide compensated by chromium and from silicon are used for these measurements. While in Timepix detector with Si sensor the well-known so-called "volcano effect" observed, in Timepix detector with GaAs:Cr sensor such effect was completely absent. In the work the behavior of the Timepix detector with GaAs:Cr sensor under irradiation with heavy ions is described in comparison with the detector based on Si sensor. Also the possible reason for absence of "volcano" effect in GaAs:Cr detector is proposed.

physics.ins-det↗

arXiv2015

Performance of fully instrumented detector planes of the forward calorimeter of a Linear Collider detector

Detector-plane prototypes of the very forward calorimetry of a future detector at an e+e- collider have been built and their performance was measured in an electron beam. The detector plane comprises silicon or GaAs pad sensors, dedicated front-end and ADC ASICs, and an FPGA for data concentration. Measurements of the signal-to-noise ratio and the response as a function of the position of the sensor are presented. A deconvolution method is successfully applied, and a comparison of the measured shower shape as a function of the absorber depth with a Monte-Carlo simulation is given.

physics.ins-det↗

arXiv2015

Alignment and resolution studies of a MARS scanner

The MARS scanner is designed for the x-ray spectroscopic study of samples with the aid of computer tomography methods. Computer tomography allows the reconstruction of slices of an investigated sample using a set of shadow projections obtained for different angles. Projections in the MARS scanner are produced using a cone x-ray beam geometry. Correct reconstruction in this scheme requires precise knowledge of several geometrical parameters of a tomograph, such as displacement of a rotation axis, x-ray source position with respect to a camera, and camera inclinations. Use of inaccurate parameters leads to a poor sample reconstruction. Non-ideal positioning of camera, x-ray source and cylindrical rotating frame (gantry) itself on which these parts are located, leads to the need for tomograph alignment. In this note we describe the alignment procedure that was used to get different geometrical corrections for the reconstruction. Also, several different estimations of the final spatial resolution for reconstructed images are presented.

physics.ins-det↗