An advanced microstructured semiconductor radiation detector for neutron imaging and oil well logging

Doctor of PhilosophyDepartment of Mechanical and Nuclear EngineeringAmir BahadoriThe work presented in this dissertation will serve as an essential tool for modern nuclear engineers to perform radiation transport with import of complex computer aided design (CAD) models efficiently. Performing radiation transport with complex CAD geometries and obtaining accurate detector response functions has been a major challenge. For micro-structured semiconductor detectors, results obtained from radiation transport alone are not enough to provide a clear picture of expected performance. Hence, the work presented in this dissertation is divided into two major research areas (RAs). RA 1 describes methods for sensor response modelling with hybrid Geant4 geometries consisting of both conventional C++ based models and complex CAD based models in a single simulation. This RA will address the methods developed for radiation transport models and benchmarking experimental detector responses. Additionally, this RA will further discuss how these models were later utilized for finalizing design parameters of a semiconductor radiation detection system (Timepix3 coupled with Dual-Sided Microstructured Semiconductor Neutron Detector). Multiple bugs were identified in Geant4 source code as a result of the work presented in RA 1. RA 2 of this dissertation will provide detailed analysis of the existing boundary conditions of the DS-MSND and MSND detectors. Finite Element Analysis based semiconductor physics modeling was performed to investigate various parameters of the Si-SiO2 interface. The radiation transport models were developed for simulating the Kansas State University Materials Interrogation (KSUMI) test facility that was set up to enable bulk-material irradiation experiments that replicate similar oil-well logging scenarios. These experiments were conducted with an aim to address the problem of replacement of conventional radioisotope sources commonly used in oil-well logging industries. An exploration tool similar to an oil-well logging tool was used to conduct experiments with water and sand as testing materials. The facility includes a 2500-gallon concrete test chamber to be filled with testing material with an aluminum pipe going horizontally through it, permitting placement of a neutron source and radiation sensors. A machine-based 14.1 MeV deuterium-tritium neutron source was used to irradiate the 2500-gallon testing material. Experiments were performed with tap water and sand as bulk testing materials. Irradiation was performed for one hour and results were obtained from a BF3/3He neutron sensor, a BF3 neutron sensor, and two NaI gamma sensors placed at different locations within the exploration tool. Geant4, a Monte-Carlo based toolkit, was deployed on a high-performance computing system to simulate the entire experiment in order to benchmark the experimental responses obtained from the photon and neutron sensors. The facility was modeled in detail with accurate dimensions and material compositions. Materials such as tap water, high-density polyethylene, and aluminum metal were modeled with thermal neutron scattering cross-sections. The reference physics list QGSP_BIC_HP along with G4NDL and S(α,β) cross-sections were found to be appropriate for simulation of neutron interrogation experiments with neutron energies lower than 20 MeV. The experimental results obtained were successful in characterizing the bulk testing materials, and results obtained from Geant4 were found to be in good agreement with the experimental results in most cases. The source code developed for the above method was then utilized to design the physical parameters for an X-DS-MSND system. These detectors have the benefit of doubling neutron detection efficiency as compared to single-sided devices (X-MSND) by staggering 6LiF-filled trenches between the top and bottom surface of a silicon diode. This produces a more complex electric field distribution and depletion characteristics in the diode and creates an indirect path for signal carrier transport between device electrodes. Geant4 was extensively utilized for radiation transport and interaction modeling, and Allpix Squared was used for mobile charge carrier transport and total charge collection. The results of this simulation work provided an estimate of charge cluster shape and intensity for a pixel array configuration corresponding to Timepix3 read-out system. In addition, imaging performance for transmission radiography was demonstrated with a simple two-dimensional shape in a Gaussian beam of thermal neutrons. The simulated neutron detection efficiency was 57.6%. It was discovered that the Allpix Squared is not optimal for simulation of complex boundary conditions and charge carrier transport inside the DS-MSND. To understand the behavior of charge carriers in the presence of a complex electric field and boundary conditions, a simpler non-conformally doped MSND geometry was fabricated and analyzed. This sensor geometry produced a complex electric field distribution and depletion characteristics within the diode. The fixed oxide charge present at the trench walls and its effects on the depletion characteristics and electric field were analyzed. The capacitance-voltage and current-voltage curve characterizations were performed for these prototypes and compared with the COMSOL Multiphysics simulations. An 241Am alpha particle source was further utilized to perform spectral analysis. Geant4 was utilized for radiation transport, interaction modeling, and benchmarking the spectral data. The results of this simulation work provided a reasonable confidence in capability to obtain and benchmark electric fields and spectral data for complex micro-structured semiconductor radiation detectors. Further, COMSOL Multiphysics was used to account for time-dependent charge carrier motion and detector response for these boundary conditions. As a result of work presented in RA 1 and RA 2, important features in the MSND/DS-MSND geometry were discovered that could significantly impact the device's performance. These features were incorporated in the updated Monte-Carlo model of the DS-MSND sensor. Simulated response of the updated DS-MSND sensor as a replacement of BF3/3He was then analyzed for the oil-well logging irradiation environment using Geant4 simulations. The results obtained from these simulations establish DS-MSND as a strong contender for replacing BF3/3He sensors for oil well logging experiments

ELIXIR ACTION OF AYURVEDA IN KHALITYA

Hair plays an important role in making body externally beautiful. Healthy and good looking long hair makes a person mentally enthusiastic and healthy. But in modern era due to extremely busy schedule, pollution and unhealthy diet, hair fall i.e. “Khalitya” is increasing day by day, and the main victims who are facing this problem are youngsters. Susceptibility of hair fall is more in males than in females. In Ayurvedic approach, falling of hair is coined out as in term of ‘Khalitya’. The medical term of baldness is alopecia; any type of hair loss is called alopecia. The aim of this article is to elaborate & explore the aetiology, patho-physiology & overall Ayurvedic treatment of Khalitya i.e., Nasya, Virechana, Leech therapy, Rasayana, Abhyang, different type of Lepa & Yoga. For Khalitya, Nasya is one of the best choices of management for its prime role in maintaining hair growth & preventing Khalitya. As per Ayurveda, ‘Khalitya’ (hairs fall) is a sign of ageing process and Rasayana therapy is paramount for ageing disorder. Massage (Abhyang) greatly improves the blood circulation, thus increasing the health of the hair & also scalp. Yoga like Sarvangasan increase blood flow toward brain. So we hope to get excellent result of Ayurveda in Khalitya

Quantum scattering cross sections of O(3P^3P) + N2_2 collisions for planetary aeronomy

"Hot atoms", which are atoms in their excited states, transfer their energy to the surrounding atmosphere through collisions. This process of energy transfer is known as thermalization, and it plays a crucial role in various astrophysical and atmospheric processes. Thermalization of hot atoms is mainly governed by the amount of species present in the surrounding atmosphere and the collision cross-section between the hot atoms and surrounding species. In this work, we investigated the elastic and inelastic collisions between hot oxygen atoms and neutral N$_2$ molecules, relevant to oxygen gas escape from the martian atmosphere and for characterizing the chemical reactions in hypersonic flows. We conducted a series of quantum scattering calculations between various isotopes of O($^3P$) atoms and N$_2$ molecules across a range of collision energies (0.3 to 4 eV), and computed both their differential and collision cross-sections using quantum time$-$independent coupled-channel approach. Our differential cross-section results indicate a strong preference for forward scattering over sideways or backward scattering, and this anisotropy in scattering is further pronounced at higher collision energies. By comparing the cross-sections of three oxygen isotopes, we find that the heavier isotopes consistently have larger collision cross-sections than the lighter isotopes over the entire collision energy range examined. However, for all the isotopes, the variation of collision cross-section with respect to collision energy is the same. As a whole, the present study contributes to a better understanding of the energy distribution and thermalization processes of hot atoms within atmospheric environments. Specifically, the cross$-$sectional data presented in this work is directly useful in improving the accuracy of energy relaxation modeling of O and N$_2$ collisions over Mars and Venus atmospheres.Comment: 7 pages, 5 figures, 4 tables, submitted to MNRA

Funding Opportunities of Extramural Grants for Oral Health Researchers in India - A Prospective Approach

Dental research funding is increasing all throughout the globe, yet India has a very small presence at this conference. These organizations fund studies and organize research programs to further dentistry and medical study in India. Writing a grant application for research in the field of oral health is a challenging task for modern dental health professionals. The administrative load at dentistry schools is only one example of the many obstacles to research in the Indian context. In the Indian context, the significance of oral health and associated research is low. Oral health research funding agency, and other related terms were used in a search of Google Scholar, Scopus, and PubMed Medline. This analysis aims to educate Indian oral health professionals about the availability of financial support from a variety of sources

Baveno-VII criteria to predict decompensation and initiate non-selective beta-blocker in compensated advanced chronic liver disease patients

Background/Aims The utility of Baveno-VII criteria of clinically significant portal hypertension (CSPH) to predict decompensation in compensated advanced chronic liver disease (cACLD) patient needs validation. We aim to validate the performance of CSPH criteria to predict the risk of decompensation in an international real-world cohort of cACLD patients. Methods cACLD patients were stratified into three categories (CSPH excluded, grey zone, and CSPH). The risks of decompensation across different CSPH categories were estimated using competing risk regression for clustered data, with death and hepatocellular carcinoma as competing events. The performance of “treating definite CSPH” strategy to prevent decompensation using non-selective beta-blocker (NSBB) was compared against other strategies in decision curve analysis. Results One thousand one hundred fifty-nine cACLD patients (36.8% had CSPH) were included; 7.2% experienced decompensation over a median follow-up of 40 months. Non-invasive assessment of CSPH predicts a 5-fold higher risk of liver decompensation in cACLD patients (subdistribution hazard ratio, 5.5; 95% confidence interval, 4.0–7.4). “Probable CSPH” is suboptimal to predict decompensation risk in cACLD patients. CSPH exclusion criteria reliably exclude cACLD patients at risk of decompensation, regardless of etiology. Among the grey zone, the decompensation risk was negligible among viral-related cACLD, but was substantially higher among the non-viral cACLD group. Decision curve analysis showed that “treating definite CSPH” strategy is superior to “treating all varices” or “treating probable CSPH” strategy to prevent decompensation using NSBB. Conclusions Non-invasive assessment of CSPH may stratify decompensation risk and the need for NSBB in cACLD patients

Chronic pain evaluation in breast cancer patients using the Self-Report Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS): a single center cross-sectional retrospective study

Background: Breast cancer is the most common cancer in India, and the number of survivors has increased over the last few years. Pain is one of the most common symptoms during cancer treatment due to either the disease itself or adverse effects of treatment. The available data suggests that breast cancer patients have a high prevalence of neuropathic pain. Patients and methods: A cross sectional observational study was done at the Department of Radiation Oncology, between November 2021 to June 2022. The patients were admitted and screened for participation, non-metastatic post operative breast cancer on regular follow up for 2 years after their last chemotherapy or radiotherapy and not having any chronic neuropathy disease and the Self-Report Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS) pain scale was used to assess the neuropathy pain status of patients. Patients’ demographics, clinical characteristics, and treatment of surgery, radiation therapy, and chemotherapy were collected and the comparison of the pain score between the patients was analysed. Results: Total of 149 patients were included in the study. S-LANSS score was calculated in the study population and more than 61% of participants reported a score equal or greater than 12, suggesting a predominant neuropathic pain component. Autonomic dysfunction, thermal pain, and allodynia were more prevalent in patients who underwent mastectomies compared to breast-conserving surgery. Whereas the dysesthesia and autonomic dysfunction score was higher in only the anthracycline group. Conclusions: The most important index for quality of life in cancer patients is the presence of persistent chronic pain and it is important to classify it accordingly in order to provide the best management. Using the S-LANSS score, the pattern of neuropathic pain can be determined early which leads to early intervention

Chronic pain evaluation in breast cancer patients using the Self-Report Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS): a single center cross-sectional retrospective study

© 2024 The Authors. Published by VM Media Group. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.5603/PMPI.a2023.0027Background: Breast cancer is the most common cancer in India, and the number of survivors has increased over the last few years. Pain is one of the most common symptoms during cancer treatment due to either the disease itself or the adverse effects of treatment. The available data suggests that breast cancer patients have a high prevalence of neuropathic pain. Patients and methods: A cross-sectional observational study was done at the Department of Radiation Oncology, between November 2021 to June 2022. The patients were admitted and screened for participation, non-metastatic post-operative breast cancer on regular follow-up for 2 years after their last chemotherapy or radiotherapy and not having any chronic neuropathy disease and the Self-Report Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS) pain scale was used to assess the neuropathy pain status of patients. Patients’ demographics, clinical characteristics, and treatment of surgery, radiation therapy, and chemotherapy were collected and the comparison of the pain scores between the patients was analysed. Results: A total of 149 patients were included in the study. S-LANSS score was calculated in the study population and more than 61% of participants reported a score equal to or greater than 12, suggesting a predominant neuropathic pain component. Autonomic dysfunction, thermal pain, and allodynia were more prevalent in patients who underwent mastectomies compared to breast-conserving surgery. Whereas the dysesthesia and autonomic dysfunction score was higher in only the anthracycline group. Conclusions: The most important index for quality of life in cancer patients is the presence of persistent chronic pain and it is important to classify it accordingly in order to provide the best management. Using the S-LANSS score, the pattern of neuropathic pain can be determined early which leads to early intervention.This study did not receive any financial support/funding.Published onlin

BLOOM: A 176B-Parameter Open-Access Multilingual Language Model

Large language models (LLMs) have been shown to be able to perform new tasks based on a few demonstrations or natural language instructions. While these capabilities have led to widespread adoption, most LLMs are developed by resource-rich organizations and are frequently kept from the public. As a step towards democratizing this powerful technology, we present BLOOM, a 176B-parameter open-access language model designed and built thanks to a collaboration of hundreds of researchers. BLOOM is a decoder-only Transformer language model that was trained on the ROOTS corpus, a dataset comprising hundreds of sources in 46 natural and 13 programming languages (59 in total). We find that BLOOM achieves competitive performance on a wide variety of benchmarks, with stronger results after undergoing multitask prompted finetuning. To facilitate future research and applications using LLMs, we publicly release our models and code under the Responsible AI License