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Experimental Studies on the Self-Shielding Effect in Fissile Fuel Breeding Measurement in Thorium Oxide Pellets Irradiated with 14 MeV Neutrons

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Plasma Science and Technology 2013年第2期15卷 166-170页

作者： Mitul ABHANGI Nupur JAIN rajnikant makwana Sudhirsinh VALA Shrichand JAKHAR T. K. BASU C. V. S. RAO Fusion Neutronics Laboratory Institute for Plasma ResearchBhat Gandhinagar-382428Gujarat India School of Nuclear Energy Pandit Deendayal Petroleum UniversityGandhinagarGujarat 382007 India

The 14 MeV neutrons produced in the D-T fusion reactions have the potential of breeding Uranium-233 fissile fuel from fertile material Thorium-232. In order to estimate the amount of U-233 produced, experiments are carried out by irradiating thorium dioxide pellets with neutrons produced from a 14 MeV neutron generator. The objective of the present work is to measure the reaction rates of 232Th ＋ in --＊ 233Th --＊ 2a^Pa --＊ 2a3U in different pellet thicknesses to study the self-shielding effects and adopt a procedure for correction. An appropriate assembly consisting of high-density polyethylene is designed and fabricated to slow down the high-energy neutrons, in which Thorium pellets are irradiated. The amount of fissile fuel （~3~U） produced is estimated by measuring the 312 keV gammas emitted by Protactinium-233 （half-life of 27 days）. A calibrated High Purity Germanium （HPGe） detector is used to measure the gamma ray spectrum. The amount of 233U produced by Th232 （n, ~） is calculated using MCNP code. The self-shielding effect is evaluated by calculating the reaction rates for different foil thickness. MCNP calculation results are compared with the experimental values and appropriate correction factors are estimated for self-shielding of neutrons and absorption of gamma rays.

关键词： 233U breeding fissile fuel MCNP 14 MeV neutron source

Systematic study of the(n,2n)reaction cross section for^(121)Sb and^(123)Sb isotopes

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Chinese Physics C 2022年第5期46卷 77-94页

作者： R.K.Singh N.L.Singh R.D.Chauhan Mayur Mehta S.V.Suryanarayana rajnikant makwana B.K.Nayak H.Naik Tarak Nath Nag K.Katovsky Department of Physics Faculty of Sciencethe M.S.University of BarodaVadodara-390002INDIA Department of Physics Netaji Subhas University of TechnologyDwarkaNew Delhi-110078INDIA Institute for Plasma Research Gandhinagar-382428INDIA Nuclear Physics Division Bhabha Atomic Research CentreMumbaiINDIA Radiochemistry Division Bhabha Atomic Research CentreMumbaiINDIA Department of Electrical Power Engineering Brno University of TechnologyBrno-61600Czech Republic

The cross sections of the^(121)Sb(n,2n)^(120)Sb^(m) and ^(123)Sb(n,2n)^(122)Sb reactions were measured at 12.50,15.79 and 18.87 MeV neutron energies relative to the standard ^(27)Al(n,α)^(24)Na monitor reaction using neutron activation and offline γ-ray *** of the samples was performed at the BARC-TIFR Pelletron Linac Facility,Mumbai,*** quasi-monoenergetic neutrons were generated via the ^(7)Li(p,n)*** model calculations were performed by nuclear reaction codes TALYS(ver.1.9)and EMPIRE(ver.3.2.2)using various input parameters and nuclear level density *** cross sections of the ground and the isomeric state as well as the isomeric cross section ratio were studied theoretically from reaction threshold to 26 MeV *** effect of pre-equilibrium emission is also discussed in detail using different theoretical *** present measured cross sections were discussed and compared with the reported experimental data and evaluation data of the JEFF-3.3,ENDF/B-VIII.0,JENDL/AD-2017 and TENDL-2019 libraries.A detailed analysis of the uncertainties in the measured cross section data was performed using the covariance analysis ***,a systematic study of the(n,2n)reaction cross section for^(121)Sb and^(123)Sb isotopes was also performed within 14-15 MeV neutron energies using various systematic *** work helps to overcome discrepancies in Sb data and illustrate a better understanding of pre-equilibrium emission in the(n,2n)reaction channel.

关键词： antimony (n,2n)reaction cross section 7Li(p,n)reaction neutron source neutron activation and offlineγ-ray spectrometry systematic formulae covariance analysis TALYS(ver.1.9)and EMPIRE(ver.3.2.2)codes

Partial genomic organization of ribosomal protein S7 gene from malaria vector Anopheles stephensi

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Insect Science 2007年第2期14卷 101-106页

作者： rajnikant DIXIT SARITA DIXIT UPAL ROY YOGESH S.SHOUCHE SURENDRA GAKHAR Department of Biosciences Maharshi Dayanand University RohtakPune University Campus Pune India National Centre for Cell Science Pune University Campus Pune India

In this study, we describe the partial genomic organization of ribosomal protein S7 gene isolated from the mosquito Anopheles stephensi. Initially a 558 bp partial cDNA sequence was amplified as precursor mRNA sequence containing 223 bp long intron. 5＇ and 3＇ end sequences were recovered using end specific rapid amplification of cDNA ends （RACE） polymerase chain reaction. The full-length cDNA sequence was 914 nucleotide long with an open reading frame capable of encoding 192 amino acid long protein with calculated molecular mass of 22174 Da and a pI point of 9.94. Protein homology search revealed 〉75% identity to other insect＇s S7 ribosomal proteins. Analysis of sequence alignment revealed several highly conserved domains, one of which is related to nuclear localization signal （NLS） region of human rpS7. Interestingly, intron nucleotide sequence comparison with A. gambiae showed a lesser degree of conservation as compared to coding and untranslated regions. Like this, early studies on the genomic organization and cDNA/ Expressed sequence tag analysis （EST） could help in genome annotation ofA. stephensi, and would be likely to be sequenced in the future.

关键词： Anopheles malaria mosquito ribosomal protein vector

Investigation on the key aspects of l-arginine para nitrobenzoate monohydrate single crystal:A non-linear optical material

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Chinese Journal of Chemical Engineering 2019年第3期27卷 701-708页

作者： Sonia N.Vijayan Mahak Vij Kanika Thukral Naghma Khan D.Haranath rajnikant M.S.Jayalakshmy Academy of Scientific and Innovative Research CSIR-National Physical Laboratory CSIR-National Physical Laboratory Department of Physics University of Jammu International and Inter University Centre for Nanoscience and Nanotechnology Mahatma Gandhi University

In the contemporary days, non-linear optical materials(NLO) are getting higher attention as per the increasing demand in optical communication and data storage technology. Consequently, they explore various physical properties of the NLO material for their industrial applications. In current report, l-arginine p-nitrobenzoate monohydrate(LANB) single crystals were obtained by adopting slow cooling technique. The structural confirmation of grown single crystal was carried out using single crystal X-Ray diffractometer. Presence of strain within single crystal was deduced using Hall–Williamson relation. Various defects associated within single crystal were assessed using high resolution XRD. Additionally, its crystalline quality was again confirmed by time resolved photoluminescence spectroscopy(TRPL). Using transmission spectra, the cut off wavelength and band gap of the host material was determined to be nearly 420 nm and 2.9 e V respectively. The dielectric property has been recorded by varying the frequency ranging from 50 Hz to 100 k Hz. The curve suggests that dielectric loss value is less at high frequency ensures the suitability of crystal in photonics and NLO based *** laser damage threshold values were also measured for single and multiple shots. Thermal parameters of the titled compound were calculated using PPE. In photoconductivity measurement, negative photoconductivity has been observed in titled compound. Microhardness studies were also performed on single crystal to explore its mechanical properties.

关键词： Photoluminescence Thermal conductivity Specific heat Thermal effusivity Damage threshold

Growth,structural,optical,thermal and dielectric properties of a novel semi-organic nonlinear optical crystal:Dichloro-diglycine zinc Ⅱ

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Progress in Natural Science:Materials International 2014年第4期24卷 378-387页

作者： B.Uma rajnikant K.Sakthi Murugesan S.Krishnan B.Milton Boaz Department of Physics R.M.K.Engineering College X-ray Crystallography Laboratory Post-Graduate Department of Physics & ElectronicsUniversity of Jammu PG and Research Department of Physics Presidency College Department of Physics B.S.Abdur Rehman University

Dichloro-diglycine zinc II(DCDGZ II),a semi-organic nonlinear optical material has been synthesized and single crystals were grown from the aqueous solution up to dimensions 20×10×3 *** title compound,DCDGZ II(C4H10Cl2N2O4Zn H2O) crystallizes into monoclinic structure with the space group of C2/*** unit-cell parameters were found to be a=14.4191(7),b=6.9180(2),c=12.9452(6) and Z=*** the crystal structure,DCDGZ II layer is building up alternatingly with layers of water in which the zinc ions lie on a twofold *** calculations for polarizability,which are useful for device fabrication were made using Clausius–Mosotti equation and Penn analysis and the results were *** transform infrared(FTIR) spectroscopic studies were performed for the identification of the different functional groups presented in the *** UV–vis–NIR absorption spectrum reveals that the lower UV cut-off wavelength is 240 *** optical band gap of the crystal was estimated as 2.2 *** surface morphology,thermal behaviour,dielectric properties have been studied using SEM,TG/DTA and LCR HITESTER *** nonlinear optical property of the crystal was also confirmed using Kurtz powder technique.

关键词： Crystal structure Growth from solutions Characterization Non-linear optic materials