arXiv subjects

K. Voloshin

Publications and source records attributed to K. Voloshin.

8 recordsLinked to original sources

arXiv2008

Long-term operation of a multi-channel cosmic muon system based on scintillation counters with MRS APD light readout

A Cosmic Ray Test Facility (CRTF) is the first large-scale implementation of a scintillation triggering system based on a new scintillation technique known as START. In START, the scintillation light is collected and transported by WLS optical fibers, while light detection is performed by pairs of avalanche photodiodes with the Metal-Resistor-Semiconductor structure operated in the Geiger mode (MRS APD). START delivers 100% efficiency of cosmic muon detection, while its intrinsic noise level is less than 10^{-2} Hz. CRTF, consisting of 160 START channels, has been continuously operated by the ALICE TOF collaboration for more than 25 000 hours, and has demonstrated a high level of stability. Fewer than 10% of MRS APDs had to be replaced during this period.

physics.ins-det↗

arXiv2007

Multiplicity Studies and Effective Energy in ALICE at the LHC

In this work we explore the possibility to perform ``effective energy'' studies in very high energy collisions at the CERN Large Hadron Collider (LHC). In particular, we focus on the possibility to measure in $pp$ collisions the average charged multiplicity as a function of the effective energy with the ALICE experiment, using its capability to measure the energy of the leading baryons with the Zero Degree Calorimeters. Analyses of this kind have been done at lower centre--of--mass energies and have shown that, once the appropriate kinematic variables are chosen, particle production is characterized by universal properties: no matter the nature of the interacting particles, the final states have identical features. Assuming that this universality picture can be extended to {\it ion--ion} collisions, as suggested by recent results from RHIC experiments, a novel approach based on the scaling hypothesis for limiting fragmentation has been used to derive the expected charged event multiplicity in $AA$ interactions at LHC. This leads to scenarios where the multiplicity is significantly lower compared to most of the predictions from the models currently used to describe high energy $AA$ collisions. A mean charged multiplicity of about 1000-2000 per rapidity unit (at $η\sim 0$) is expected for the most central $Pb-Pb$ collisions at $\sqrt{s_{NN}} = 5.5 TeV$.

hep-ph↗

arXiv2006

RPC with low-resistive phosphate glass electrodes as a candidate for the CBM TOF

Usage of electrodes made of glass with low bulk resistivity seems to be a promising way to adapt the Resistive Plate Chambers (RPC) to the high-rate environment of the upcoming CBM experiment. A pilot four-gap RPC sample with electrodes made of phosphate glass, which has bulk resistivity in the order of 10^10 Ohm cm, has been studied with MIP beam for TOF applications. The tests have yielded satisfactory results: the efficiency remains above 95% and the time resolution stays within 120 ps up to the particle rate of 18 kHz/cm2. The increase in rate from 2.25 to 18 kHz/cm2 leads to an increase of estimated "tails" fraction in the time spectrum from 1.5% to 4%.

physics.ins-det↗

arXiv2006

START: low-noise efficient trigger for cosmic muons

Noise characteristics and MIP registration efficiency of the Scintillation Tile with MRS APD Light Readout (START) were measured with cosmic particles. Encouraging results open a broad range of possibilities for using START in large-scale applications, requiring low-noise, efficient and stable trigger for cosmic muons.

physics.ins-det↗

arXiv2006

START as the detector of choice for large-scale muon triggering systems

Further progress in building high-granular large-scale systems based on Scintillation Tiles with MRS APD light readout (START) became possible thanks to the creation of an improved version of MRS APD. The cost of the system may now be significantly reduced by using inexpensive extruded scintillator. More than 160 START samples were assembled based on this design modification and proved to possess 100% MIP detection efficiency and the intrinsic noise rate of less than 0.08 Hz. Long-term stability of START characteristics was confirmed after 3.5 months of operation.

physics.ins-det↗

arXiv2006

Scintillation counter with MRS APD light readout

START, a high-efficiency and low-noise scintillation detector for ionizing particles, was developed for the purpose of creating a high-granular system for triggering cosmic muons. Scintillation light in START is detected by MRS APDs (Avalanche Photo-Diodes with Metal-Resistance-Semiconductor structure), operated in the Geiger mode, which have 1 mm^2 sensitive areas. START is assembled from a 15 x 15 x 1 cm^3 scintillating plastic plate, two MRS APDs and two pieces of wavelength-shifting optical fiber stacked in circular coils inside the plastic. The front-end electronic card is mounted directly on the detector. Tests with START have confirmed its operational consistency, over 99% efficiency of MIP registration and good homogeneity. START demonstrates a low intrinsic noise of about 10^{-2} Hz. If these detectors are to be mass-produced, the cost of a mosaic array of STARTs is estimated at a moderate level of 2-3 kUSD/m^2.

physics.ins-det↗

arXiv2005

100 ps time-of-flight resolution of Dielectric Resistive Plate Chamber

Time of flight of a minimum ionizing particle along a fixed base has been measured with a 100 ps accuracy by means of a Dielectric Resistive Plate Chamber (DRPC) with 4 x 0.3 mm gas gaps. DRPC timing characteristics have been studied with different applied voltages, discriminating thresholds and beam intensities. It may be stated that the time-of-flight resolution of gaseous detectors developed within the ALICE experiment has reached the level of the best known scintillation counters.

physics.ins-det↗

arXiv2004

Dielectric Resistive Plate Chamber as a detector for time-of-flight measurements

Principles of operation, construction and first test results of a Dielectric Resistive Plate Chamber (DRPC) are described. The detector has shown stability of operation in the avalanche mode of gas amplfication within a wide range of applied voltages. Double-gap DRPCs have demonstrated the MIP registration efficiency of 97% and the time resolution of 180-200 ps. No changes in DRPC operation have been observed with test beam intensities up to 10^3 Hz/cm^2.

physics.ins-det↗