Gamma Photon Exposure Buildup Factors for Some Spin Ice Compounds Using G-P Fitting Method

Exposure buildup factors(EBF) for some spin ice compounds such as Dysprosium Titanate (Dy2Ti2O7), Dysprosium Stannate (Dy2Sn2O7), holmium Titanate (Ho2Ti2O7) and holmium Stannate (Ho2Ti2O7) useful in nuclear engineering have been computed for photon energy range 0.015 to 15 MeV upto penetration depth of 40 mean free path. The eBF for these compounds were found to be the largest at photon energy 15 MeV excepts in low energy. The eBF for the compounds containing tin were found to be the largest as well as shown a peak at 30 keV photon energy

Determination of the Thermal Neutron Flux by Measuring Gamma Radiations with High and Low Resolution Detectors

Thermal neutron flux (Фth) of Americium-Beryllium (Am-Be) neutron source has been measured by adopting the foil activation method. The neutrons emitted from Am-Be source are used to activate the indium-115 (115In) foil. The gamma radiations emitted from the activated isomer 116m1In are measured with NaI(Tl) and HPGe detectors. The thermal neutron flux is measured by adopting the cadmium (Cd) foil difference technique in which the Cd foil placed in front of the source to prevent the thermal neutrons from entering into the indium foil. The neutron flux is determined by measuring the gamma radiation emitted from indium foil using a low and high energy resolution NaI(Tl) and HPGe detectors respectively. The measured thermal neutron flux obtained from both detectors has been compared and found that the Фth does not depend on the resolution and type of the detectors used in the present investigations

The Top 100 questions for the sustainable intensification of agriculture in India’s rainfed drylands

India has the largest area of rainfed dryland agriculture globally, with a variety of distinct types of farming systems producing most of its coarse cereals, food legumes, minor millets, and large amounts of livestock. All these are vital for national and regional food and nutritional security. Yet, the rainfed drylands have been relatively neglected in mainstream agricultural and rural development policy. As a result, significant social-ecological challenges overlap in these landscapes: endemic poverty, malnutrition and land degradation. Sustainable intensification of dryland agriculture is essential for helping to address these challenges, particularly in the context of accelerating climate change. In this paper, we present 100 questions that point to the most important knowledge gaps and research priorities. If addressed, these would facilitate and inform sustainable intensification in Indian rainfed drylands, leading to improved agricultural production and enhanced ecosystem services. The horizon scanning method used to produce these questions brought together experts and practitioners involved in a broad range of disciplines and sectors. This exercise resulted in a consolidated set of questions covering the agricultural drylands, organized into 13 themes. Together, these represent a collective programme for new cross- and multi-disciplinary research on sustainable intensification in the Indian rainfed drylands

Effective atomic numbers of dosimetric interest organic compounds

Effective atomic numbers of some dosimetric interest organic compounds, like glucose, ethanol, acetic acid, trichloroethylene, chloroform, benzene, acetone, phenol, chlorobenzene, naphthalene, adenine, alanine, anthracene, carbon tetrachloride, diethyl either and sucrose are calculated using Auto-Zeff, direct, logarithmic interpolation, ratio, power law and single-value XmuDat methods. The calculated effective atomic numbers are compared with experiment data wherever possible and results show a good agreement. The Auto-Zeff, direct, logarithmic interpolation and ratio methods are the most suitable for intermediate photon energy (50 keV < E < 20 MeV), where Compton scattering dominates. Mixture law is applicable in intermediate energy region for computation of theoretical effective atomic numbers. Kerma relative to air of the selected organic compounds are also calculated for photon energy 1 keV - 20 MeV. The kerma reaches unity beyond 200 keV and up to 10 MeV

Measurement of Energy Loss Straggling of Relativistic Electrons in Thin Aluminum Foils

The mean energy loss straggling per unit path length of relativistic electrons in aluminum has been determined by recording electrons with a Si(Li) detector coupled to 8K multi channel analyzer. The energy loss straggling is determined by measuring the full width at half maximum of the spectrum of the incident and transmitted internal conversion electrons of energies 942 keV and 1016 keV from Bi 207 source. Measured values have been compared with theoretical values indicating that the present method can be used for measuring mean energy loss straggling

An investigation on gamma and neutron shielding efficiency of lead-free compounds and alloys

The effective atomic numbers, ZPleff and half value layer, HVL for lead-free shielding materials, tungsten compounds and alloys for gamma ray over an energy range from 1 keV to 100 GeV have been calculated in the present work. As well as the macroscopic effective removal cross-sections (ΣR) for fast neutron (2-12 MeV) had been calculated. From results, it has been concluded that HVL and ΣR values of the tungsten alloys are half of the lead shielding material. The values of ZPleff have been compared with possible experimental results, and good agreement has been observed. We found that the theoretical values of ZPleff of the tungsten alloys agree with experiment where the ratio of atomic number of the elements is near to unity and shows weak energy dependence for ratio away from unity. The tungsten alloys show better the degree of protection against gamma ray and neutron as compared to the lead, resulting in an overall reduction in thickness and volume of the shielding material. The tungsten alloys containing gold, silver, platinum, copper, nickel and iron were found superior lead-free radiation shielding materials. This study is expected to be useful for design and application of lead-free radiation shielding for nuclear engineering, radiation application to control lead hazard

A Comprehensive Study on Gamma-Ray Exposure Build-Up Factors and Fast Neutron Removal Cross Sections of Fly-Ash Bricks

Geometric progression (GP) method was utilized to investigate gamma-ray exposure build-up factors of fly-ash bricks for energies from 0.015 to 15 MeV up to 40 mfp penetration depth. The EBFs of the fly-ash bricks are dependent upon the photon energy, penetration depths, and the chemical compositions of the elements. Appreciable variations in exposure build-up factor (EBF) are noted for the fly-ash bricks. The EBFs were found to be small in low and high photon energy regions whereas very large in medium energy region. EBF of the bricks is inversely proportional to equivalent atomic number below 10 mfp for entire energy region of interest 0.015 to 15 MeV. The EBFs of fly-ash, brick of mud, and common brick were similar at 1.5 MeV photon energy. The EBF of the fly-ash bricks was found to be higher than that of the brick of mud, and common brick. The fast neutron removal cross sections of the fly-ash bricks, brick of mud, and common bricks were also calculated which were found to be in the same order. It is expected that this study should be very directly useful for shielding effectiveness of fly-ash brick materials and dose estimation

An investigation on gamma and neutron shielding efficiency of lead-free compounds and alloys

443-448The effective atomic numbers, ZPleff and half value layer, HVL for lead-free shielding materials, tungsten compounds and alloys for gamma ray over an energy range from 1 keV to 100 GeV have been calculated in the present work. As well as the macroscopic effective removal cross-sections (ΣR) for fast neutron (2-12 MeV) had been calculated. From results, it has been concluded that HVL and ΣR values of the tungsten alloys are half of the lead shielding material. The values of ZPleff have been compared with possible experimental results, and good agreement has been observed. We found that the theoretical values of ZPleff of the tungsten alloys agree with experiment where the ratio of atomic number of the elements is near to unity and shows weak energy dependence for ratio away from unity. The tungsten alloys show better the degree of protection against gamma ray and neutron as compared to the lead, resulting in an overall reduction in thickness and volume of the shielding material. The tungsten alloys containing gold, silver, platinum, copper, nickel and iron were found superior lead-free radiation shielding materials. This study is expected to be useful for design and application of lead-free radiation shielding for nuclear engineering, radiation application to control lead hazard

Effective atomic numbers of dosimetric interest organic compounds

333-338<span style="font-size:11.0pt;mso-bidi-font-size: 10.0pt;font-family:" times="" new="" roman";mso-fareast-font-family:"arial="" unicode="" ms";="" mso-bidi-font-family:"times="" roman";background:white;mso-ansi-language:en-us;="" mso-fareast-language:en-us;mso-bidi-language:ar-sa"="" lang="EN-US">Effective atomic numbers of some dosimetric interest organic compounds, like glucose, ethanol, acetic acid, trichloroethylene, chloroform, benzene, acetone, phenol, chlorobenzene, naphthalene, adenine, alanine, anthracene, carbon tetrachloride, diethyl either and sucrose are calculated using Auto-Zeff, direct, logarithmic interpolation, ratio, power law and single-value XmuDat methods. <span style="font-size:11.0pt;mso-bidi-font-size: 10.0pt;font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" mso-bidi-font-family:"times="" roman";mso-ansi-language:en-us;mso-fareast-language:="" en-us;mso-bidi-language:ar-sa"="" lang="EN-US">The calculated effective atomic numbers are <span style="font-size: 11.0pt;mso-bidi-font-size:10.0pt;font-family:" times="" new="" roman";mso-fareast-font-family:="" "times="" roman";mso-bidi-font-family:"times="" roman";mso-ansi-language:="" en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="" lang="EN-US">compared with experiment data wherever possible and results show a good agreement. The Auto-Zeff, direct, logarithmic interpolation and ratio methods are the most suitable for intermediate photon energy (50 keV E is applicable in intermediate energy region for computation of theoretical effective atomic numbers. Kerma relative to air of the selected organic compounds are also calculated for photon energy 1 keV - 20 MeV. The kerma reaches unity beyond 200 keV and up to 10 MeV.</span