arXiv subjects

T. K. Nayak

Publications and source records attributed to T. K. Nayak.

11 recordsLinked to original sources

arXiv2018

Time resolution and characteristic study of MWPC detectors with different Argon based gas

A prototype of Multi-Wire Proportional Chambers (MWPC) has been fabricated for the study of its various characteristics. The detector contains gold-coated tungsten wires (20 $μm$ diameter) on the anode frame, with a pitch of 2.8 mm. The gap between the anode and the cathode is 3 mm and the gap between anode and read-out is also 3 mm. Detailed study of MWPC in terms of gain, energy and timing resolution and efficiency measurements have been performed. The detector has been operated using Ar/CO$_{2}$ gas mixtures with 70:30 and 90:10 ratio. Energy spectrum of $^{55}$Fe X-ray source is obtained for the detector. The gain and energy resolution of the detector were calculated using X-ray spectrum. Time resolution is obtained $\sim$10 ns.

physics.ins-det↗

arXiv2016

Long-term stability test of a triple GEM detector

The main aim of the study is to perform the long-term stability test of gain of the single mask triple GEM detector. A simple method is used for this long- term stability test using a radioactive X-ray source with high activity. The test is continued till accumulation of charge per unit area > 12.0 mC/mm2. The details of the chamber fabrication, the test set-up, the method of measurement and the test results are presented in this paper.

physics.ins-det↗

arXiv2015

Characterizations of GEM detector prototype

At NISER-IoP detector laboratory an initiative is taken to build and test Gas Electron Multiplier (GEM) detectors for ALICE experiment. The optimisation of the gas flow rate and the long-term stability test of the GEM detector are performed. The method and test results are presented.

physics.ins-det↗

arXiv2013

Method for the Analysis of Forward-Backward Multiplicity Correlations in Heavy-Ion Collisions

In heavy-ion ({\it A-A}) collisions, the correlations among the particles produced across wide range in rapidity, probe the early stages of the reaction. The analyses of forward-backward multiplicity correlations in these collisions are complicated by several effects, which are absent or minimized in hadron-hadron collisions. This includes effects, such as the centrality selection in the {\it A-A} collisions, which interfere with the measurement of the dynamical correlations. A method, which takes into account the fluctuations in centrality selection, has been utilized to determine the forward-backward correlation strength {$b_{\rm corr}$} in {\itA-A} collisions. This method has been validated by using the HIJING event generator in case of Au-Au collisions at $\sqrt{s_{NN}}$= 200 GeV and Pb-Pb collisions at $\sqrt{s_{NN}}$= 2.76 TeV. It is shown that the effect of impact parameter fluctuations is to be considered properly in order to obtain meaningful results.

nucl-ex↗

arXiv2003

Search for DCC in relativistic heavy-ion collisions : Possibilities and Limitations

The experimental observation of disoriented chiral condensate is affected due to various physical and detector related effects. We study and quantify the strength of the experimental signal, ``neutral pion fraction'' within the framework of a simple DCC model, using the analysis methods based on the multi-resolution discrete wavelet technique and by evaluating the signal to background ratio. The scope and limitations of DCC search in heavy-ion collision experiments using various combination of detector systems are investigated.

nucl-ex↗

arXiv2002

The STAR Photon Multiplicity Detector

Details concerning the design, fabrication and performance of STAR Photon Multiplicity Detector (PMD) are presented. The PMD will cover the forward region, within the pseudorapidity range 2.3--3.5, behind the forward time projection chamber. It will measure the spatial distribution of photons in order to study collective flow, fluctuation and chiral symmetry restoration.

nucl-ex↗

arXiv2002

A Fluctuation Probe of Disoriented Chiral Condensates

We show that an event-by-event fluctuation of the ratio of neutral pions or resulting photons to charged pions can be used as an effective probe for the formation of disoriented chiral condensates. The fact that the neutral pion fraction produced in case of disoriented chiral condensate formation has a characteristic extended non gaussian shape, is shown to be the key factor which forms the basis of the present analysis.

nucl-ex↗

arXiv2001

A Honeycomb Proportional Counter for Photon Multiplicity Measurement in the ALICE Experiment

A honeycomb detector consisting of a matrix of 96 closely packed hexagonal cells, each working as a proportional counter with a wire readout, was fabricated and tested at the CERN PS. The cell depth and the radial dimensions of the cell were small, in the range of 5-10 mm. The appropriate cell design was arrived at using GARFIELD simulations. Two geometries are described illustrating the effect of field shaping. The charged particle detection efficiency and the preshower characteristics have been studied using pion and electron beams. Average charged particle detection efficiency was found to be 98%, which is almost uniform within the cell volume and also within the array. The preshower data show that the transverse size of the shower is in close agreement with the results of simulations for a range of energies and converter thicknesses.

nucl-ex↗

arXiv1999

Localized Domains of Disoriented Chiral Condensates

A new method to search for localized domains of disoriented chiral condensates (DCC) has been proposed by utilising the (eta-phi) phase space distributions of charged particles and photons. Using the discrete wavelet transformation (DWT) analysis technique, it has been found that the presence of DCC domains broadens the distribution of wavelet coefficients in comparison to that of normal events. Strength contours have been derived from the differences in rms deviations of these distributions by taking into account the size of DCC domains and the probability of DCC production in ultra-relativistic heavy ion collisions. This technique can be suitably adopted to experiments measuring multiplicities of charged particles and photons.

nucl-ex↗

arXiv1998

Search for DCC in Relativistic Heavy-Ion Collision Through Event Shape Analysis

Event shape analysis has been used to look for DCC signals in simulated ultra-relativistic heavy-ion collision data at SPS energy. A simple redistribution of particles, with two detectors to detect charged particles and photons, is seen to result in the same flow direction with the flow angle difference peaking at zero. However, events where the neutral pion fraction has been modified according to the DCC probability distribution, show the flow angles in two detectors to be almost $90^o$ apart. The results presented here show that the technique is complementary to the one based on the discrete wavelet transformation. Together the techniques are seen to provide a very powerful tool for DCC search in ultra relativistic heavy ion collision.

nucl-ex↗

arXiv1998

A Preshower Photon Multiplicity Detector for the WA98 Experiment

A high granularity preshower detector has been fabricated and installed in the WA98 Experiment at the CERN SPS for measuring the spatial distribution of photons produced in the forward region in lead ion induced interactions. Photons are counted by detecting the preshower signal in plastic scintillator pads placed behind a 3 radiation length thick lead converter and applying a threshold on the scintillator signal to reject the minimum ionizing particles. Techniques to improve the imaging of the fibre and performance of the detector in the high multiplicity environment of lead-lead collisions are described. Using Monte-Carlo simulation methods and test beam data of pi- and e- at various energies the photon counting efficiency is estimated to be 68% for central and 73% for peripheral Pb+Pb collisions.

hep-ex↗