Optimization of the Liquid Scintillator Composition

Nowadays, many particle detectors use liquid scintillator (LS) as a detection medium. In particular, Water-based Liquid Scintillator (WbLS) that is a new material currently under development. It is based on the idea of dissolving the organic scintillator in water using special surfactants. This material strives to achieve the novel detection techniques by combining the Cherenkov and scintillation light, as well as the total cost reduction compared to pure liquid scintillator. An important part of either the pure LS or WbLS production is to choose the right fluor and shifter and their concentrations. The choice affects the spectral distribution of the light output and the detection efficiency as each photodetector has its own spectral sensitivity region. This work presents the results of the study on the pseudocumen (PC) based LS with the PPO and POPOP/MSB as a fluor and shifters of choice. Both the total light yield and the spectral differences in the outputs with different amounts of components are shown. This study can be applied to plastic scintillators as well. 38t

Optimization of the Liquid Scintillator Composition

Nowadays, many particle detectors use liquid scintillator (LS) as a detection medium. In particular, Water-based Liquid Scintillator (WbLS) that is a new material currently under development. It is based on the idea of dissolving the organic scintillator in water using special surfactants. This material strives to achieve the novel detection techniques by combining the Cherenkov and scintillation light, as well as the total cost reduction compared to pure liquid scintillator. An important part of either the pure LS or WbLS production is to choose the right fluor and shifter and their concentrations. The choice affects the spectral distribution of the light output and the detection efficiency as each photodetector has its own spectral sensitivity region. This work presents the results of the study on the pseudocumen (PC) based LS with the PPO and POPOP/MSB as a fluor and shifters of choice. Both the total light yield and the spectral differences in the outputs with different amounts of components are shown. This study can be applied to plastic scintillators as well. 38t

Improved technique of a complex analysis of crack resistance of WWER-1000 nuclear reactor cold leg nozzle under termal shock. Report 1. Thermo-hydraulic and transient thermal calculations

В Україні для тепло-гідравлічних розрахунків різних сценаріїв, можливих на реакторних установках АЕС,використається розрахунковий комплекс RELAP5. Проблема полягає в тім, що розрахунки в RELAP5 звичайно проводять у районі патрубка корпуса реактора на грубій одновимірній сітці (2-3 елемента), що не дозволяє надалі одержувати достатню точність при аналізі крихкої міцності корпуса реактора з гіпотетичною тріщиною. Запропоновано зазначений розрахунок (глобальну модель) доповнювати уточненим тепло-гідравлічним розрахунком в околиці гіпотетичної тріщини (локальна модель).Локальне моделювання проводили із застосуванням коду FLUENT з ANSYS, що сертифікований для застосування в атомній енергетиці України, причому граничними умовами служили результати моделювання в RELAP5. Відпрацьовування методики проведене на прикладі реактора В-320 реакторної установки типу ВВЕР-1000 першого енергоблоку Запорізької АЕС для режиму аварійного охолодження, що приводить до так називаного термошоку. У Повідомленні 1 наведені результати тільки тепло-гідравлічного й теплового розрахунків, проведених в FLUENT на звичайної персональної ЕОМ. Для тепло-гідравлічного розрахунку застосували двопараметричну RANS-модель "в’язких вихрів" у варіанті k – ε моделі Realizable. Ця модель турбулентної течії в’язкої рідини дає більше реалістичні результати, чим інші двопараметричні моделі, реалізовані в FLUENT. Для наступного розрахунку теплового поля корпуса реактора в зоні патрубка із тріщиною застосували код ANSYS. Отримані результати мають достатню для інженерного застосування точність. Повідомлення 2 буде присвячено аналізу крихкої міцності корпуса реактора, проведеного із застосуванням ANSYS.It is commonly known that fast cooling of the nuclear reactor parts can provoke a state of thermal shock with considerable rate of thermal stress as a result. In this case, a profound investigation of the thermo-hydraulic mechanism as well as evaluation of thermal stress is strongly required. The main mechanism of the reactor shell possible fracture is cracking due to steel embrittlement during decades of intensified radiation. After considering all this issues, the cold leg nozzle part of the WWER-1000 nuclear reactor has been chosen as the most vulnerable area. Computational fluid dynamic (CFD) code provided by ANSYS FLUENT has been used in this research in order to assess the thermo-hydraulic mechanism of the cold leg nozzle intensified cooling. The cooling process has been considered to correspond to an approved scenario developed in Ltd “ENERGORISK”. The, boundary conditions have been derived by approximating the preliminary calculations made by Ltd “ENERGORISK” on RELAP5 hydraulic code. The reason of using CFD code instead of RELAP5 is that it permits to obtain much more accurate solution in a small area of interest, whileRELAP5 analyses the first circuit as a whole without taking into account some relatively small areas. The hydraulic calculation have been performed using the 2-d order turbulence models k – ε and k – ε Realizable provided by FLUENT on a PC with moderate calculation capacity. The process has been considered transient. Period of interest is 100s. The total time of calculation is approximately 40 hours. The results have shown the good correlation between 2-d order turbulence models, however, k – ε Realizable model has shown a better behavior in the near-wall zones that is expected. The accuracy of the results is satisfactory for engineering purposes. The transient problem of thermal conductivity has been also modelled using ANSYS thermal transient code that operates a uniform thermal equation. This equation contains convection, diffusion and heat transfer parts. The results of these calculations contain thermal fields in near-crack zone. These thermal fields have shown to be much more accurate than those derived from RELAP5 and, as a result, they can be used in a more precise procedure of strength calculation with initiated cracks.В Украине для тепло-гидравлических расчетов различных сценариев, возможных на реакторных установках АЭС, используется расчетный комплекс RELAP5. Проблема заключается в том, что расчеты в RELAP5 обычно проводят в районе патрубка корпуса реактора на грубой одномерной сетке (2-3 элемента), что не позволяет в дальнейшем получать достаточную точность при анализе хрупкой прочности корпуса реактора с гипотетической трещиной. Предложено указанный расчет (глобальная модель) дополнять уточненным тепло-гидравлическим расчетом в окрестности гипотетической трещины (локальная модель). Локальное моделирование проводили с применением кода FLUENT из ANSYS, сертифицированного для применения в атомной энергетике Украины, причем граничными условиями служили результаты моделирования в RELAP5. Отработка методики проведена на примере реактора В-320 реакторной установки типа ВВЭР-1000 первого энергоблока Запорожской АЭС для режима аварийного охлаждения, приводящего к так называемому термошоку. В Сообщении 1 приведены результаты только тепло-гидравлического и теплового расчетов, проведенных в FLUENT на обычной персональной ЭВМ. Для тепло-гидравлического расчета применили двухпараметрическую RANS-модель "вязких вихрей" в варианте k – ε модели Realizable. Эта модель турбулентного течения вязкой жидкости дает более реалистические результаты, чем другие двухпараметрические модели, реализованные в FLUENT. Для последующего расчета теплового поля корпуса реактора в зоне патрубка с трещиной применили код ANSYS. Полученные результаты имеют достаточную для инженерного применения точность. Сообщение 2 будет посвящено анализу хрупкой прочности корпуса реактора, проведенного с применением ANSYS

Horizon - T Experiment Calibrations - Cables

An innovative detector system called Horizon-T is constructed to study Extensive Air Showers (EAS) in the energy range above 1016 eV coming from a wide range of zenith angles (0o - 85o). The system is located at Tien Shan high-altitude Science Station of Lebedev Physical Institute of the Russian Academy of Sciences at approximately 3340 meters above the sea level. The detector consists of eight charged particle detection points separated by the distance up to one kilometer as well as optical detector to view the Vavilov-Cherenkov light from the EAS. Each detector connects to the Data Acquisition system via cables. The calibration of the time delay for each cable and the signal attenuation is provided in this article

Simulation and design of the HT-KZ Ultra-high energy cosmic rays detector system for cosmic rays with energies above 1017 eV

In the field of High Energy Physics today there are several open topics left. The Higgs boson has been recently discovered, neutrino oscillations are being studied, and some hints of the dark matter have been detected as well. Another remaining mystery is the origin and the nature of the Ultra-High Energy Cosmic Rays. There is an active project at Nazarbayev University to construct the HorizonT-Kazakhstan detector system in collaboration with the Tien Shan high-altitude Science Station (TSHSS), a part of Lebedev Physical Institute of the Russian Academy of Sciences. The full R&D is underway. A significant part of this process is the simulation, testing and construction of individual particle detectors due to the requirements of robustness and high linear range of such detectors combined with low cost and long-term operations with minimal maintenance. In this paper, the latest results of the simulation activities and experiment testing of different detection components as applicable to the HorizonT-Kazakhstan requirements are presented

Simulation and design of the HT-KZ Ultra-high energy cosmic rays detector system for cosmic rays with energies above 1017 eV

In the field of High Energy Physics today there are several open topics left. The Higgs boson has been recently discovered, neutrino oscillations are being studied, and some hints of the dark matter have been detected as well. Another remaining mystery is the origin and the nature of the Ultra-High Energy Cosmic Rays. There is an active project at Nazarbayev University to construct the HorizonT-Kazakhstan detector system in collaboration with the Tien Shan high-altitude Science Station (TSHSS), a part of Lebedev Physical Institute of the Russian Academy of Sciences. The full R&D is underway. A significant part of this process is the simulation, testing and construction of individual particle detectors due to the requirements of robustness and high linear range of such detectors combined with low cost and long-term operations with minimal maintenance. In this paper, the latest results of the simulation activities and experiment testing of different detection components as applicable to the HorizonT-Kazakhstan requirements are presented

Horizon-T Experiment Calibrations – MIP Signal from Scintillator and Glass Detectors

Horizon-T, a modern Extensive Air Showers (EAS) detector system, is constructed at Tien Shan high-altitude Science Station of Lebedev Physical Institute of the Russian Academy of Sciences at approximately 3340 meters above the sea level in order to study in the energy range above 1016 eV coming from a wide range of zenith angles (0o - 85o). The detector includes eight charged particle detection points and a Vavilov-Cherenkov radiation detector. Each charged particle detector response is calibrated using single MIP (minimally ionizing particle) signal. The details of this calibration are provided in this article. This note is valid for data before March 2017 and will not be updated following any detector calibration and configuration changes as a large upgrade has been implemente

Horizon-T extensive air showers detector system operations and performance

“Horizon-T” is an innovative detector system located at Tien Shan high-altitude Science Station (TSHASS) at approximately 3340 meters above the sea level. It consists of eight detection points separated by the distance up to one kilometer that can measure time characteristics of the Extensive Air Showers (EAS) and record signal shapes with time resolution of ~10 ns. It was constructed to register EAS in the energy range above 1016 eV coming from a wide range of zenith angles (0o - 85o). The system includes both the plastic scintillator particle detectors as well as the Vavilov - Cerenkov radiation detectors subsystem to observe the Cerenkov light from the EAS in the atmosphere directly. The time resolution and signal shape analysis capabilities of the detection points are used to study EAS development in the atmosphere. The development of the EAS is a process that can be studied both spatially and temporally. For the spatial part, a distributed network of detection points is required. For the time part, a signal shape must be recorded and analysed at each point with time resolution on the order of ~10 ns. In this paper, the current system description and performance level are described. Additionally, the latest data examples showing the unusual EAS examples above 1017 eV are included

Horizon-T extensive air showers detector system operations and performance

“Horizon-T” is an innovative detector system located at Tien Shan high-altitude Science Station (TSHASS) at approximately 3340 meters above the sea level. It consists of eight detection points separated by the distance up to one kilometer that can measure time characteristics of the Extensive Air Showers (EAS) and record signal shapes with time resolution of ~10 ns. It was constructed to register EAS in the energy range above 1016 eV coming from a wide range of zenith angles (0o - 85o). The system includes both the plastic scintillator particle detectors as well as the Vavilov - Cerenkov radiation detectors subsystem to observe the Cerenkov light from the EAS in the atmosphere directly. The time resolution and signal shape analysis capabilities of the detection points are used to study EAS development in the atmosphere. The development of the EAS is a process that can be studied both spatially and temporally. For the spatial part, a distributed network of detection points is required. For the time part, a signal shape must be recorded and analysed at each point with time resolution on the order of ~10 ns. In this paper, the current system description and performance level are described. Additionally, the latest data examples showing the unusual EAS examples above 1017 eV are included

Artificial coherent states of light by multi-photon interference in a single-photon stream

Coherent optical states consist of a quantum superposition of different photon number (Fock) states, but because they do not form an orthogonal basis, no photon number states can be obtained from it by linear optics. Here we demonstrate the reverse, by manipulating a random continuous single-photon stream using quantum interference in an optical Sagnac loop, we create engineered quantum states of light with tunable photon statistics, including approximate weak coherent states. We demonstrate this experimentally using a true single-photon stream produced by a semiconductor quantum dot in an optical microcavity, and show that we can obtain light with $g^{(2)}(0)\rightarrow1$ in agreement with our theory, which can only be explained by quantum interference of at least 3 photons. The produced artificial light states are, however, much more complex than coherent states, containing quantum entanglement of photons, making them a resource for multi-photon entanglement.Comment: 6 pages + supplemental materia