Dr. Yashodhara I
@msrit.edu
Assistant Professor, Department of Physics
M S Ramaiah Institute of Technology (MSRIT)
EDUCATION
M.Sc., Ph.D.
RESEARCH, TEACHING, or OTHER INTERESTS
Nuclear and High Energy Physics, Radiation, Materials Science, Environmental Science
Scopus Publications
Scopus Publications
Jayadev Pattar, S. Sarvesh Chandra, R. Sreekanth, M. Srinivas, K. Mahendra, Nagaraja Madihally, I. Yashodhara, and K. Sudeep Kumara
Elsevier BV
C. Aparna, M. G. Mahesha, N. Karunakara, I. Yashodhara, and Pramoda Kumara Shetty
Springer Science and Business Media LLC
Abstract This study focuses on investigating the radiation tolerance and dosimetric potential of tungsten-doped indium oxide (W:In₂O₃) thin films under high-dose gamma irradiation. The novelty of this work lies in the first systematic evaluation of gamma irradiation effects on the structural, optical and electrical properties of W:In₂O₃ thin films prepared by spray pyrolysis, which has not been previously explored. Nanostructured 2 at.% W-doped indium oxide thin film deposited using spray pyrolysis technique was irradiated with different gamma doses from 1 to 10 kGy. Structural analysis through XRD and Raman confirmed the stability of the crystalline phase even at higher doses, while subtle modifications indicated the presence of irradiation-induced point defects. The presence of oxygen vacancies was confirmed using structural, optical and electrical characterization, further supported by PL and XPS analysis. According to the XPS study, high doses of gamma radiation broke bonds rather than altering the oxidation states of the component elements. The materials’ applicability for dosimetric purposes is validated by the thermoluminescence it displayed after being exposed to radiation. Electrical characterization corroborated defect-assisted conduction, establishing strong correlation between structural disorder and transport behavior under irradiation. The study demonstrated that W-doped In₂O₃ thin films exhibit strong resistance to high doses of gamma radiation. The importance of this work lies in establishing W-doped In₂O₃ thin films as promising candidates for radiation-hardened electronics and reliable gamma dosimetry, crucial for applications in nuclear, aerospace, and medical environments.
C. Aparna, M.G. Mahesha, N. Karunakara, I. Yashodhara, and Pramoda Kumara Shetty
Elsevier BV
A. Amudha, K. Mahendra, I. Yashodhara, Jayadev Pattar, H.N. Anil Rao, H.D. Shashikala, and S. Nagaraja Hosakoppa
Elsevier BV
C. Aparna, M.G. Mahesha, N. Karunakara, I. Yashodhara, and Pramoda Kumara Shetty
Elsevier BV
Mahesha Hegde, Rajashree Panda, Mitrabhanu Behera, I. Yashodhara, N. Karunakara, and R. Arun Kumar
Springer Science and Business Media LLC
U. J. Ramesh Babu, K. Mahendra, I. Yashodhara, and Jayadev Pattar
Springer Science and Business Media LLC
Sidharth S Menon, S. Arshia, Amarnath Pasupathi, Arun Prasath Ramaswamy, Karunakara Naregundi, Yashodhara Indaje, Arvind Kumar Yogi, and Yugeswaran Subramaniam
Elsevier BV
I. Yashodhara, K. Sudeep Kumara, and N. Karunakara
Springer Science and Business Media LLC
C. Aparna, Pramoda Kumara Shetty, M. G. Mahesha, I. Yashodhara, and N. Karunakara
Springer Science and Business Media LLC
AbstractThis article aims to study the modification in the structural, optical and electrical properties of indium oxide thin film after gamma irradiation and estimation of sensitivity for gamma sensing applications. The thin film of indium oxide was deposited on a 450 °C preheated glass substrate using the spray pyrolysis technique. The deposited thin film of molar concentration 0.15 M and thickness of around 600 nm was irradiated with different gamma doses (100 Gy, 200 Gy, 300 Gy and 400 Gy). The optical properties of the irradiated film are studied using UV–Visible spectroscopy. Transmittance increased after irradiation up to 200 Gy and beyond that, it decreased. Indium oxide is an n-type semiconductor which exhibits both direct and indirect transitions. Both direct and indirect bandgap energy are calculated using Tauc’s plot. Extinction coefficient and refractive index variation with irradiation were also estimated. Photoluminescence study confirmed the gamma-induced defect formation and annihilation for an irradiation dose of 400 Gy and 200 Gy, respectively. Resistivity also decreased up to 200 Gy and beyond that, it increased. The sensitivity of the deposited film was estimated from the electrical measurements, and it lies between 10.7 and 53.4 mA/cm2/Gy. Graphical abstract
P. Ujwal, I. Yashodhara, K. Sudeep Kumara, P. M. Ravi, and N. Karunakara
Springer Science and Business Media LLC
AbstractThe radionuclide transfer between compartments is commonly described by transfer parameters representing the ratio of concentrations of an element in two compartments for equilibrium conditions. This is a comprehensive study on the soil-to-grass transfer factor (Fv) and grass-to-cow milk transfer coefficient (Fm) for stable strontium (Sr) for soil-grass (pasture)-cow (Bos taurus) milk environmental pathway under field conditions for a high rainfall tropical monsoonal climatic region of the Indian subcontinent. The study was conducted in the vicinity of the Kaiga nuclear power plant (NPP), situated ~ 58 km inland of the West Coast of the Indian subcontinent. A grass field was developed exclusively for this study, and two cows of the native breed were raised to graze on it. The soil, grass, and milk were analyzed to evaluate the Fv and the Fm values for the stable Sr. For comparison, several pasture lands and the cows raised by the villagers and a dairy farm were also studied. The Fv values were in the range 0.18—8.6, the geometric mean (GM) being 1.8. The correlations of Fv values with a range of physicochemical parameters are presented. The GM values for Fm were 2.2 × 10–3 d L-1 and 7.2 × 10–3 d L-1 for the two cows raised for this study, 2.6 × 10–3 d L-1 for those raised by the villagers, and 4.2 × 10–3 d L-1 for the dairy farm. The site-specific Fm value for the region was determined as 3.2 × 10–3 d L-1. The concentration ratio (CR), defined as the ratio of Sr concentration in milk to that in feed under equilibrium conditions, exhibited less variability (1.8 × 10–2—5.4 × 10–2) among the three categories of cows.
C. Aparna, Pramoda Kumara Shetty, M.G. Mahesha, N. Karunakara, and I. Yashodhara
Elsevier BV
S. Sowmya, P.D. Rekha, I. Yashodhara, N. Karunakara, and A.B. Arun
Elsevier BV
Miroslaw Janik, Shinji Tokonami, Kazuki Iwaoka, Naregundi Karunakara, Shetty Trilochana, Mandya Purushotham Mohan, Sudeep Kumara, Indaje Yashodhara, Weihai Zhuo, Chao Zhao,et al.
MDPI AG
Comparison is an important role in the quality control and quality assurance for any measuring system. Due to the future legal regulations regarding radon levels in the air, maintaining the system quality and harmonization of results as well as validation of radon and thoron measuring systems is important. The aim of this work is to validate the degrees of equivalence and measurement precisions of the existing five radon and four thoron measuring systems located in four Asian countries (China, India, Japan and Thailand) through comparison experiment. In this project, comparison experiment was performed in order to derive the ratio between assigned value obtained from one transfer measurement device for radon and one transfer measurement device for thoron belongs to National Institutes for Quantum and Radiological Science and Technology and participants’ value from their measuring instrument. As a result, the ratio value associated with measurement uncertainty was derived for each activity concentration. Finally, measurement bias and degrees of equivalence between the assigned values and values of measurement quantity from participants’ measuring instruments were statistically analysed and presented.
M.P. Mohan, Renita Shiny D'Souza, S. Rashmi Nayak, Srinivas S. Kamath, Trilochana Shetty, K. Sudeep Kumara, I. Yashodhara, Y.S. Mayya, and N. Karunakara
Elsevier BV
N. Karunakara, P. Ujwal, I. Yashodhara, K. Sudeep Kumara, M.P. Mohan, K. Bhaskar Shenoy, P.V. Geetha, B.N. Dileep, Joshi P. James, and P.M. Ravi
Elsevier BV
N. Karunakara, K. Sudeep Kumara, I. Yashodhara, B.K. Sahoo, J.J. Gaware, B.K. Sapra, and Y.S. Mayya
Elsevier BV
A. Jayasheelan, S. Manjunatha, I. Yashodhara, and N. Karunakara
Oxford University Press (OUP)
The activity concentration of (226)Ra, (232)Th and (40)K was measured for soil samples collected from 34 locations of Tumkur District, Karnataka, India, using HPGe detector. The activity concentration of (226)Ra, (232)Th and (40)K varied from 9.6 to 71.6, 12.3 to 333.3 and 194.3 to 1527.7 Bq kg(-1) with an average value of 33.15, 123.01 and 877.76 Bq kg(-1), respectively. The absorbed and annual effective outdoor doses were found to be highest at Ponnasamudra with 258.98 nGy h(-1) and 317.62 μSv and lowest at Sira with 36.42 nGy h(-1) and 44.67 μSv, respectively. The external hazard index ranged from 0.21 to 1.58 with an average of 0.75. It was significant in 11 locations as it exceeded unity.
N. Karunakara, I. Yashodhara, K. Sudeep Kumara, R.M. Tripathi, S.N. Menon, S. Kadam, and M.P. Chougaonkar
Elsevier BV
N. Karunakara, P. Ujwal, I. Yashodhara, Chetan Rao, K. Sudeep Kumara, B.N. Dileep, and P.M. Ravi
Elsevier BV
N. Karunakara, Chetan Rao, P. Ujwal, I. Yashodhara, Sudeep Kumara, and P.M. Ravi
Elsevier BV