Активация фосфоритной муки путем частичного разложения минеральных кислот

The effect of modification of phosphorite powder with low P2O5 content by inorganic acids on extraction of water-soluble and citric-soluble components, as well as on dustiness, has been studied. Formation of new phases on the surface of activated phosphorite powder has been established by X-ray analysis. On the basis of data obtained, the optimal conditions for the phosphorite powder modification have been determined.Изучено влияние модифицирования неорганическими кислотами фосфоритной муки с низким содержанием Р2О5 на извлечение водо- и лимонно-растворимых компонентов и на пылимость. Рентгенофазовым анализом установлено образование новых фаз на поверхности активированной фосфоритной муки. На основании полученных данных выбраны оптимальные условия модифицирования фосфоритной муки

Эффективность комплексных NPK-удобрений, получаемых из конверсионных щелоков производства сульфата калия

Waste-free technology for producing chlorine-free fertilizers (potassium sulphate) and recycling liquid wastes (conversion liquors of potassium sulphate production) for obtaining additional products (various grades of complex fertilizers based on them) allowing to reduce price cost of plant production is vital for agricultural production. The paper dwells on results of studies on production and agrochemical efficiency of complex NPK fertilizer of 16-10-16 grade obtained based on conversion alkaline solution at potassium sulfate and ammophos production. Fertilizer is obtained by method of low-temperature conversion of potassium chloride with ammonium sulfate. It allows to obtain chlorine-free fertilizer (potassium sulfate) and arrange processing of conversion alkaline solution to obtain a wide range of complex fertilizers, including the experimental brand. Agrochemical efficiency of NPK fertilizer (16-10-16 grade) during cultivation of vegetable crops (carrot, cabbage, onion) on sod-podzolic loose soil was determined. It was determined that nitrogen-phosphorus-potassium fertilizer of 16-10-16 brand in equivalent doses with standard solids (urea, ammoniated superphosphate, granulated potassium chloride) during cultivation of vegetable crops provides yield of carrot, cabbage and onion at the level of the standard (standard solids) with no significant changes in product quality, there is only a tendency to increase of sugar and reduction of nitrate content in products. The complex NPK-fertilizer of 16-10-16 brand has been recorded in the “State Register of Plant Protection Products and Fertilizers Allowed on the Territory of the Republic of Belarus” and is allowed to be used at agro-industrial complex and for retail sale.Важное значение для сельскохозяйственного производства имеет использование безотходной технологии получения бесхлорных удобрений (сульфата калия) и утилизация жидких отходов (конверсионных щелоков производства сульфата калия) для получения дополнительной продукции (различных марок комплексных удобрений на их основе), что позволяет снизить себестоимость растениеводческой продукции. В статье приведены результаты исследований по получению и агрохимической эффективности комплексного NPK-удобрения марки 16-10-16, полученного на основе конверсионных щелоков производства сульфата калия и аммофоса. Удобрение получено методом низкотемпературной конверсии хлористого калия сульфатом аммония, что позволяет получить бесхлорное удобрение (сульфат калия) и организовать процесс переработки конверсионных щелоков для получения широкой линейки комплексных удобрений, в том числе и исследуемой марки. Определена агрохимическая эффективность NPK-удобрения (марка 16-10-16) при возделывании овощных культур (моркови, капусты, лука) на дерново-подзолистой рыхлосупесчаной почве. Установлено, что применение азотно-фосфорно-калийного удобрения марки 16-10-16 в эквивалентных дозах со стандартными удобрениями (карбамидом, суперфосфатом аммонизированным, калием хлористым гранулированным) при возделывании овощных культур обеспечивает урожайность моркови, капусты и лука на уровне эталона (стандартные удобрения) без существенных изменений качества продукции, отмечается лишь тенденция увеличения содержания сахаров и снижения содержания нитратов в продукции. Комплексное NPK-удобрение марки 16-10-16 внесено в «Государственный реестр средств защиты растений и удобрений, разрешенных к применению на территории Республики Беларусь» и разрешено для применения в агропромышленном комплексе и для розничной продажи населению

Search for Neutrinoless Double-Beta Decay in 136^{136}Xe with EXO-200

We report on a search for neutrinoless double-beta decay of $^{136}$Xe with EXO-200. No signal is observed for an exposure of 32.5 kg-yr, with a background of ~1.5 x 10^{-3} /(kg yr keV) in the $\pm 1\sigma$ region of interest. This sets a lower limit on the half-life of the neutrinoless double-beta decay $T_{1/2}^{0\nu\beta\beta}$($^{136}$Xe) > 1.6 x 10$^{25}$ yr (90% CL), corresponding to effective Majorana masses of less than 140-380 meV, depending on the matrix element calculation

Deep Neural Networks for Energy and Position Reconstruction in EXO-200

We apply deep neural networks (DNN) to data from the EXO-200 experiment. In the studied cases, the DNN is able to reconstruct the relevant parameters - total energy and position - directly from raw digitized waveforms, with minimal exceptions. For the first time, the developed algorithms are evaluated on real detector calibration data. The accuracy of reconstruction either reaches or exceeds what was achieved by the conventional approaches developed by EXO-200 over the course of the experiment. Most existing DNN approaches to event reconstruction and classification in particle physics are trained on Monte Carlo simulated events. Such algorithms are inherently limited by the accuracy of the simulation. We describe a unique approach that, in an experiment such as EXO-200, allows to successfully perform certain reconstruction and analysis tasks by training the network on waveforms from experimental data, either reducing or eliminating the reliance on the Monte Carlo.Comment: Accepted version. 33 pages, 28 figure

Search for nucleon decays with EXO-200

A search for instability of nucleons bound in $^{136}$Xe nuclei is reported with 223 kg$\cdot$yr exposure of $^{136}$Xe in the EXO-200 experiment. Lifetime limits of 3.3$\times 10^{23}$ and 1.9$\times 10^{23}$ yrs are established for nucleon decay to $^{133}$Sb and $^{133}$Te, respectively. These are the most stringent to date, exceeding the prior decay limits by a factor of 9 and 7, respectively

Measurement of the Spectral Shape of the beta-decay of 137Xe to the Ground State of 137Cs in EXO-200 and Comparison with Theory

We report on a comparison between the theoretically predicted and experimentally measured spectra of the first-forbidden non-unique $\beta$-decay transition ^{137}\textrm{Xe}(7/2^-)\to\,^{137}\textrm{Cs}(7/2^+). The experimental data were acquired by the EXO-200 experiment during a deployment of an AmBe neutron source. The ultra-low background environment of EXO-200, together with dedicated source deployment and analysis procedures, allowed for collection of a pure sample of the decays, with an estimated signal-to-background ratio of more than 99-to-1 in the energy range from 1075 to 4175 keV. In addition to providing a rare and accurate measurement of the first-forbidden non-unique $\beta$-decay shape, this work constitutes a novel test of the calculated electron spectral shapes in the context of the reactor antineutrino anomaly and spectral bump.Comment: Version as accepted by PR

Investigation of radioactivity-induced backgrounds in EXO-200

The search for neutrinoless double-beta decay (0{\nu}{\beta}{\beta}) requires extremely low background and a good understanding of their sources and their influence on the rate in the region of parameter space relevant to the 0{\nu}{\beta}{\beta} signal. We report on studies of various {\beta}- and {\gamma}-backgrounds in the liquid- xenon-based EXO-200 0{\nu}{\beta}{\beta} experiment. With this work we try to better understand the location and strength of specific background sources and compare the conclusions to radioassay results taken before and during detector construction. Finally, we discuss the implications of these studies for EXO-200 as well as for the next-generation, tonne-scale nEXO detector.Comment: 9 pages, 7 figures, 3 table