ANN modeling of the bremsstrahlung photon flux in tantalum target

Photoelectron microscopy is as old as electron microscopy itself. Electrons liberated from the object surface by photons are utilized to form an image that is a map of the object's emissivity. This physical property is a function of many parameters, some depending on the physical features of the objects and others on the conditions of the instrument rendering the image.The electron-optical situation is tricky, since the lateral resolution increases with the electric field strength at the object's surface. This, in turn, leads to small distances between the electrodes, restricting the photon flux that should be high for the sake of resolution.The electron-optical development came to fruition in the sixties. Figure 1a shows a typical photoelectron image of a polycrystalline tantalum sample irradiated by the UV light of a high-pressure mercury lamp.

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STUDIES OF PHOTONUCLEAR REACTIONS AND PHOTON ACTIVATION ANALYSIS IN THE GIANT DIPOLE RESONANCE REGION USING MICROTRONS

Communications in Physics ◽

10.15625/0868-3166/14/1/18 ◽

2007 ◽

Vol 14 (1) ◽

pp. 42 ◽

Cited By ~ 3

Author(s):

TRAN DUC THIEP ◽

NGUYEN VAN DO ◽

NGUYEN KHAC THI ◽

TRUONG THI AN ◽

NGUYEN NGOC SON

Keyword(s):

Activation Analysis ◽

Giant Dipole Resonance ◽

Resonance Region ◽

Photon Activation Analysis ◽

Photon Flux ◽

Photon Activation ◽

Applied Physics ◽

Dipole Resonance ◽

Giant Dipole Resonance Region ◽

Fission Neutrons

Mictrorons are accelerators of electrons and are simultaneous sources of bremsstrahlung photon flux and fission neutrons. In 1982, a microtron of seventeen trajectories Microtron MT - 17 was put into operation at the National Institute of Physics of Vietnam. Though very modest, microtons are very useful for developing countries such as Vietnam in both fundamental and applied physics research. During the recent years by using the above mentioned MT - 17 and microtrons from other institutes we have carried out different investigations. In this report we present some results obtained in the studies of photonuclear reactions and photon activation analysis in the giant dipole resonance region.

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Neutron dose evaluation of Elekta Linac at two energies (10 & 18 MV) by MCNP code and comparison with experimental measurements

JOURNAL OF ADVANCES IN PHYSICS ◽

10.24297/jap.v6i1.1820 ◽

2014 ◽

Vol 6 (1) ◽

pp. 1006-1015

Author(s):

Negin Shagholi ◽

Hassan Ali ◽

Mahdi Sadeghi ◽

Arjang Shahvar ◽

Hoda Darestani ◽

...

Keyword(s):

Monte Carlo ◽

Measurement Data ◽

Calculated Data ◽

High Energy ◽

Neutron Dose ◽

Dose Assessment ◽

Photon Flux ◽

Dose Equivalent ◽

Monte Carlo Techniques ◽

Neutron Dose Equivalent

Medical linear accelerators, besides the clinically high energy electron and photon beams, produce other secondary particles such as neutrons which escalate the delivered dose. In this study the neutron dose at 10 and 18MV Elekta linac was obtained by using TLD600 and TLD700 as well as Monte Carlo simulation. For neutron dose assessment in 2020 cm2 field, TLDs were calibrated at first. Gamma calibration was performed with 10 and 18 MV linac and neutron calibration was done with 241Am-Be neutron source. For simulation, MCNPX code was used then calculated neutron dose equivalent was compared with measurement data. Neutron dose equivalent at 18 MV was measured by using TLDs on the phantom surface and depths of 1, 2, 3.3, 4, 5 and 6 cm. Neutron dose at depths of less than 3.3cm was zero and maximized at the depth of 4 cm (44.39 mSvGy-1), whereas calculation resultedÂ in the maximum of 2.32 mSvGy-1 at the same depth. Neutron dose at 10 MV was measured by using TLDs on the phantom surface and depths of 1, 2, 2.5, 3.3, 4 and 5 cm. No photoneutron dose was observed at depths of less than 3.3cm and the maximum was at 4cm equal to 5.44mSvGy-1, however, the calculated data showed the maximum of 0.077mSvGy-1 at the same depth. The comparison between measured photo neutron dose and calculated data along the beam axis in different depths, shows that the measurement data were much more than the calculated data, so it seems that TLD600 and TLD700 pairs are not suitable dosimeters for neutron dosimetry in linac central axis due to high photon flux, whereas MCNPX Monte Carlo techniques still remain a valuable tool for photonuclear dose studies.

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Quantitative Ratiometric pH Imaging Using a 1,2-Dioxetane Chemiluminescence Resonance Energy Transfer Sensor

10.26434/chemrxiv.12235361 ◽

2020 ◽

Author(s):

Lucas S. Ryan ◽

Jeni Gerberich ◽

Uroob Haris ◽

ralph mason ◽

Alexander Lippert

Keyword(s):

Energy Transfer ◽

Resonance Energy Transfer ◽

Resonance Energy ◽

Whole Body ◽

Photon Flux ◽

Ph Homeostasis ◽

Ph Imaging ◽

Confounding Variables ◽

Significant Difference

Regulation of physiological pH is integral for proper whole-body and cellular function, and disruptions in pH homeostasis can be both a cause and effect of disease. In light of this, many methods have been developed to monitor pH in cells and animals. In this study, we report a chemiluminescence resonance energy transfer (CRET) probe Ratio-pHCL-1, comprised of an acrylamide 1,2-dioxetane chemiluminescent scaffold with an appended pH-sensitive carbofluorescein fluorophore. The probe provides an accurate measurement of pH between 6.8-8.4, making it viable tool for measuring pH in biological systems. Further, its ratiometric output is independent of confounding variables. Quantification of pH can be accomplished both using common fluorimetry and advanced optical imaging methods. Using an IVIS Spectrum, pH can be quantified through tissue with Ratio-pHCL-1, which has been shown in vitro and precisely calibrated in sacrificed mouse models. Initial studies showed that intraperitoneal injections of Ratio-pHCL-1 into sacrificed mice produce a photon flux of more than 10^10 photons per second, and showed a significant difference in ratio of emission intensities between pH 6.0, 7.0, and 8.0.

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Machinability Studies and ANN Modeling Of Turning Al-SiC(10p) Metal Matrix Composites

i-manager’s Journal on Future Engineering and Technology ◽

10.26634/jfet.5.1.1021 ◽

2009 ◽

Vol 5 (1) ◽

pp. 67-72 ◽

Cited By ~ 1

Author(s):

N. Muthukrishnan ◽

Keyword(s):

Metal Matrix Composites ◽

Metal Matrix ◽

Matrix Composites ◽

Ann Modeling

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The Role of La2O3 in Enhancement the Radiation Shielding Efficiency of the Tellurite Glasses: Monte-Carlo Simulation and Theoretical Study

Materials ◽

10.3390/ma14143913 ◽

2021 ◽

Vol 14 (14) ◽

pp. 3913

Author(s):

Aljawhara H. Almuqrin ◽

Mohamed Hanfi ◽

K. G. Mahmoud ◽

M. I. Sayyed ◽

Hanan Al-Ghamdi ◽

...

Keyword(s):

Monte Carlo Simulation ◽

Theoretical Study ◽

Radiation Shielding ◽

Photon Flux ◽

Transmission Factor ◽

Tellurite Glasses ◽

Attenuation Coefficients ◽

Binary Glass ◽

Buildup Factors

The radiation shielding competence was examined for a binary glass system xLa2O3 + (1 − x) TeO2 where x = 5, 7, 10, 15, and 20 mol% using MCNP-5 code. The linear attenuation coefficients (LACs) of the glasses were evaluated, and it was found that LT20 glass has the greatest LAC, while LT5 had the least LAC. The transmission factor (TF) of the glasses was evaluated against thicknesses at various selected energies and was observed to greatly decrease with increasing thickness; for example, at 1.332 MeV, the TF of the LT5 glass decreased from 0.76 to 0.25 as the thickness increased from 1 to 5 cm. The equivalent atomic number (Zeq) of the glasses gradually increased with increasing photon energy above 0.1 MeV, with the maximum values observed at around 1 MeV. The buildup factors were determined to evaluate the accumulation of photon flux, and it was found that the maximum values for both can be seen at around 0.8 MeV. This research concluded that LT20 has the greatest potential in radiation shielding applications out of the investigated glasses due to the glass having the most desirable parameters.

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In search of the spectral composition of an effective light trap for the mushroom pest Lycoriella ingenua (Diptera: Sciaridae)

Scientific Reports ◽

10.1038/s41598-021-92230-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Sándor Kecskeméti ◽

András Geösel ◽

József Fail ◽

Ádám Egri

Keyword(s):

Light Intensity ◽

Spectral Sensitivity ◽

Fungal Pathogens ◽

Light Trap ◽

Spectral Composition ◽

Wavelength Dependence ◽

Crop Damage ◽

Photon Flux ◽

Compound Eyes ◽

Behavioural Experiments

AbstractCertain fungus gnats, like Lycoriella ingenua are notorious pests in agriculture, especially in mushroom production. While larvae cause mainly direct crop damage, adults are vectors of several dangerous fungal pathogens. To promote the development of pesticide-free management methods, such as light trapping, we measured the spectral sensitivity of L. ingenua compound eyes with electroretinography and performed two different behavioural experiments to reveal the wavelength dependence of phototaxis in this species. The spectral sensitivity of the compound eyes is bimodal with peaks at 370 nm (UV) and 526 nm (green). Behavioural experiments showed that attraction to light as a function of wavelength depends on light intensity. In our first experiment, where the minimal photon flux (105–109 photons/cm2/s) needed for eliciting a phototactic response was determined wavelength by wavelength, phototaxis was strongest in the green spectral range (~526 nm). In the other behavioural experiment, where wavelength preference was tested under a higher but constant light intensity (~1013 photons/cm2/s), the highest attraction was elicited by UV wavelengths (398 nm). Our results suggest that both UV and green are important spectral regions for L. ingenua thus we recommend to use both UV (~370-398 nm) and green (~526 nm) for trapping these insects.

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Light Emitting Diodes (LEDs) as Agricultural Lighting: Impact and Its Potential on Improving Physiology, Flowering, and Secondary Metabolites of Crops

Sustainability ◽

10.3390/su13041985 ◽

2021 ◽

Vol 13 (4) ◽

pp. 1985

Author(s):

Musa Al Murad ◽

Kaukab Razi ◽

Byoung Ryong Jeong ◽

Prakash Muthu Arjuna Samy ◽

Sowbiya Muneer

Keyword(s):

Crop Production ◽

Morphological Changes ◽

Light Emitting Diode ◽

Crop Productivity ◽

Photon Flux ◽

Flower Initiation ◽

Nutrient Metabolism ◽

Light Emitting ◽

Cultivation Systems ◽

Lighting Systems

A reduction in crop productivity in cultivable land and challenging environmental factors have directed advancement in indoor cultivation systems, such that the yield parameters are higher in outdoor cultivation systems. In wake of this situation, light emitting diode (LED) lighting has proved to be promising in the field of agricultural lighting. Properties such as energy efficiency, long lifetime, photon flux efficacy and flexibility in application make LEDs better suited for future agricultural lighting systems over traditional lighting systems. Different LED spectrums have varied effects on the morphogenesis and photosynthetic responses in plants. LEDs have a profound effect on plant growth and development and also control key physiological processes such as phototropism, the immigration of chloroplasts, day/night period control and the opening/closing of stomata. Moreover, the synthesis of bioactive compounds and antioxidants on exposure to LED spectrum also provides information on the possible regulation of antioxidative defense genes to protect the cells from oxidative damage. Similarly, LEDs are also seen to escalate the nutrient metabolism in plants and flower initiation, thus improving the quality of the crops as well. However, the complete management of the irradiance and wavelength is the key to maximize the economic efficacy of crop production, quality, and the nutrition potential of plants grown in controlled environments. This review aims to summarize the various advancements made in the area of LED technology in agriculture, focusing on key processes such as morphological changes, photosynthetic activity, nutrient metabolism, antioxidant capacity and flowering in plants. Emphasis is also made on the variation in activities of different LED spectra between different plant species. In addition, research gaps and future perspectives are also discussed of this emerging multidisciplinary field of research and its development.

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