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N. Marimuthu

Publications and source records attributed to N. Marimuthu.

8 recordsLinked to original sources

Current problems of studying relativistic dissociation of light nuclei in nuclear emulsion

The progress of the study of unstable states in relativistic dissociation events of light nuclei in nuclear emulsion is presented. Identification of these states is possible by means of the invariant mass determined from the most accurate and complete measurements of relativistic fragment emission angles in the approximation of conservation of momentum per nucleon of the parent nucleus. It is established that excitations $^{12}\mathrm{C}(0^{+}_{2})$ and $^{12}\mathrm{C}(3^{-})$ lead in the dissociation $^{12}\mathrm{C} \rightarrow 3\alpha$ and $^{16}\mathrm{O} \rightarrow 4\alpha$. The contribution of $^{9}\mathrm{B}$ and $^{12}\mathrm{C}(0^{+}_{2})$ decays to the leading channel of $^{3}\mathrm{HeH}$ dissociation of the $^{14}\mathrm{N}$ nucleus is estimated. The motivation and the beginning of the analysis of the relativistic dissociation $^{16}\mathrm{O}$$\rightarrow$$^{12}\mathrm{C}\alpha$ are presented. The presented relativistic dissociation events at the $^{7}\mathrm{Be}$$\rightarrow$$^{6}\mathrm{Li}p$ and $^{11}\mathrm{C}$$\rightarrow$$ ^{7}\mathrm{Be}\alpha$ coupling threshold point to the prospect of moving beyond $\alpha$-particle clustering.

nucl-ex

Cosmophysical aspects of relativistic nuclear fragmentation

The status of the study of multiple fragmentation of 950 MeV per nucleon Kr nuclei in a nuclear track emulsion aimed at determining the contributions of 2$α$ decays of $^{8}$Be, the Hoyle 3$α$ state, and the search for a 4$α$ particle condensate state, is presented. In events with the production of few relativistic fragments of He and H, the possibility of estimating the multiplicity of neutrons in the fragmentation cone of a projectile nucleus is studied. For the planar component of neutron transverse momenta estimated from the angles of observed secondary stars, the Rayleigh distribution parameter was 35 $\pm$ 7 MeV/$c$. The importance of such events for the interpretation of cosmophysical observations is noted.

nucl-ex

Study of relativistic charged particles production in ^{84}Kr$_{36}+Em interaction at around 1 A GeV with wounded nucleon model

This article is focused on the multiplicity and probability distribution of the emitted charged pions for interaction of ^{84}Kr_{36} projectile with nuclear emulsion targets at kinetic energy 1 GeV per nucleon. In the wounded nucleon model frame work, we have calculated the total number of wounded nucleons (W) and total number of interactions (ν). The obtained results revealed that the average multiplicity of the charged pions is dependent on the projectile and target mass. The calculated values of the wounded nucleons (W) and total number of interactions (ν) shows strong dependence on the mass of the colliding nuclei. The emission rate of mean multiplicity of the and increases with increasing the total number of wounded nucleons (W) and total number of interactions (ν). The mean multiplicity value of and linearly increases with increasing the projectile mass number (A_{P}) and independent of the incident energy.

nucl-ex

Characteristic Study and Development of Surface Resistivity Measuring Device for Resistive Plate Chamber Detector

The India-based Neutrino Observatory (INO) is an approved multi-institutional experiment of India. It will use maximum 30,000 Resistive Plate Chamber (RPC) of size 2x2m as an active detector in which each will be sandwiched between two iron plates. Each RPC detectors will be made up of 3mm thick glass (or Bakelite) plates whose one surface will be coated with graphite paint to work as electrode. To achieve effective and uniform electric field, the coated graphite paint must have uniform distribution over the glass surface. Uniformity can be demonstrated by measuring the surface resistance of the coated graphite paint. However, manual measurement of 60,000 electrodes with the help of multimeter and the jig demands huge amount of person-hour with compromised accuracy, and therefore that requires the need and importance of the automatic scanning system. An advanced automatic scanning system (ASS) has been designed & developed to fulfill the required needs and overcome the shortcomings of the initially developed system. Measurement are sensitive to the contact pressure between the jig and RPC electrode's surface. In this paper, various parameters of the ASS have been precisely fixed. Obtained results are compared with the standard one and found satisfactory within error. It has been observed that for obtaining the correct and safe value of surface resistance, applied pressure value in terms of force should be in the range of 9-11 Newton.

physics.ins-det

Analysis of various projectile interactions with Nuclear Emulsion Detector nuclei at ~ 1 GeV per nucleon using Coulomb modified Glauber model

The total nuclear reaction cross-section is calculated considering with and without medium effect by employing Coulomb Modified Glauber Model (CMGM) for interactions of projectiles 56^Fe_26, 84^Kr_36, 132^Xe_54, 197^Au_79 and 238^U_92 with nuclear emulsion detector (NED) nuclei at around 1 GeV per nucleon incident kinetic energy. These calculated reaction cross-sections are correlated with the different target groups of the NED nuclei. The average value of various parameters are also calculated and compared with the corresponding experimental results. The number of shower particles emitted in an interaction is also calculated and showed good agreement with the experimental result. We observed that the total reaction cross-section increases with increasing the target mass number in case of all the considered projectiles. In addition, it shows that the average value of reaction cross-section with nuclear medium effect is in good agreement with the experimental results for projectiles 56^Fe, 84^Kr, 132^Xe, although results of projectiles 197^Au and 238^U are not in agreement with the experimental observations. This study sheds some light on the energy dependence of the nuclear reaction cross-section.

nucl-ex

Measurement of Characteristic Impedance of Silicon Fiber Sheet based readout strips panel for RPC detector in INO

The India based Neutrino Observatory (INO) is a mega science project of India, which is going to use near about 30, 000 Resistive Plate Chambers (RPC) as active detector elements for the study of atmospheric neutrino oscillations. Each RPC detector will consist of two orthogonally placed readout strips panel for picking the signals generated in the gas chamber. The area of RPC detector in INO-ICAL (Iron Calorimeter) experiment will be 2m x 2m, therefore the dimension of readout strips panel will also be of 2m x 2m. To get undistorted signals pass through the readout strips panel to frontend electronics, their Characteristic Impedance should be matched with each other. For the matching of Characteristic Impedance we have used the principle of termination. In the present paper we will describe the need and search of new dielectric material for the fabrication of flame resistant, waterproof and flexible readout pickup strips panel. We will also describe the measurement of Characteristic Impedance of plastic honeycomb based readout strips panel and Silicon Fiber sheet based readout strips panel in a comparative way, and its variation under loading and with time.

physics.ins-det

Characteristics study of projectiles lightest fragment for 84Kr36 - emulsion interaction at around 1 A GeV

The present article significantly investigated projectiles lightest fragments (proton) multiplicity distribution and probability distribution with 84Kr36 emulsion collision at around 1 A GeV. The multiplicity and normalized multiplicity of projectiles lightest fragments (proton) is correlated with the compound particles, shower particles, black particles, grey particles, helium fragments particles and heavily ionizing charged particles. It is found that projectiles lightest fragments (proton) are strongly correlated with compound particles and shower particles rather than other particles and the average multiplicity of projectiles lightest fragments (proton) increases with increasing compound, shower and heavy ionizing particles. Normalized projectiles lightest fragments (proton) are strongly correlated with compound particles, shower particles and heavy ionizing charge particles. The multiplicity distribution of the projectiles lightest fragments (proton) emitted in the 84Kr36 + emulsion interaction at around 1 A GeV with different target has well explained by KNO scaling. The mean multiplicity of projectiles lightest fragments (proton) depends on the mass number of the projectile and does not significantly dependent of the projectile energy. The mean multiplicity projectiles lightest fragment (proton) increases with increasing the target mass number.

nucl-ex