Atomic electron motion for Møller polarimetry in a double-arm mode

We analyse an effect of electron Fermi motion at atomic shells on the accuracy of electron beam polarization measurements with a M\"oller polarimeter operating in a double--arm mode. It is demonstrated that the effect can result in either {\it increase} or {\it decrease} of the measured polarization depending on the detector positions. The effect is simulated for the M\"oller polarimeter to be installed at CEBAF Hall A

Energy Calibration of the JLab Bremsstrahlung Tagging System

In this report, we present the energy calibration of the Hall B bremsstrahlung tagging system at the Thomas Jefferson National Accelerator Facility. The calibration was performed using a magnetic pair spectrometer. The tagged photon energy spectrum was measured in coincidence with $e^+e^-$ pairs as a function of the pair spectrometer magnetic field. Taking advantage of the internal linearity of the pair spectrometer, the energy of the tagging system was calibrated at the level of $\pm 0.1$. The absolute energy scale was determined using the $e^+e^-$ rate measurements close to the end-point of the photon spectrum. The energy variations across the full tagging range were found to be $<3$ MeV.Comment: 15 pages, 12 figure

Millimeter-wave study of London penetration depth temperature dependence in Ba(Fe0.926Co0.074)2As2 single crystal

In-plane surface Ka-band microwave impedance of optimally doped single crystals of the Fe-based superconductor Ba(Fe0.926Co0.074)2As2 (Tc= 22.8K) was measured. Sensitive sapphire disk quasi-optical resonator with high-Tc cuprate conducting endplates was developed specially for Fe-pnictide superconductors. It allowed finding temperature variation of London penetration depth in a form of power law, namely \Delta \lambda (T)~ Tn with n = 2.8 from low temperatures up to at least 0.6Tc consisted with radio-frequency measurements. This exponent points towards nodeless state with pairbreaking scattering, which can support one of the extended s-pairing symmetries. The dependence \lambda(T) at low temperatures is well described by one superconducting small-gap (\Delta \cong 0.75 in kTc units, where k is Boltzman coefficient) exponential dependence.Comment: 6 pages, 2 figures, to be published in Low Temperature Physics,vol.37, August 201

Visual Inspection of Chimney Pipes Using Quadro-Copters

Секция II : Строительные конструкции зданий и сооружений, современные методы расчета и проектированияТрадиционно визуальное обследование дымовых труб производится альпинистами, специализирующимися на обследованиях и мелких ремонтах промышленных объектов. Однако эта практика имеет ряд недостатков, таких как высокая стоимость работ, большая длительность процесса, недостаточная конкретизация координат местонахождения повреждений и недостаточная точность определения геометрических характеристик повреждений. Пред-ложен метод визуального обследования дымовых труб при помощи квадрокоптеров, позволяющий удешевить и ускорить процесс, а также впервые предложено применить разработанный метод «determination of color density» для обработки результатов фотосьемки поверхности стены трубы, производимой с помощью квадрокоптера.=Traditionally, visual inspection of chimneys is carried out by alpinists who specialize in surveys and minor repairs of industrial facilities. However, this practice has a number of disadvantages, such as the high cost of work, the long duration of the process, insufficient specification of the coordinates of the location of damage, and insufficient accuracy in determining the geometric characteristics of damage. A method of visual inspection of chimneys using quadrocopters is proposed, which makes it possible to reduce the cost and speed up the process, and for the first time it is proposed to apply the “graiscaile color model” method for processing the results of photographing the surface of the chimney wall pro-duced by a quadrocopter

Using Heat Batteries for Electrical Systems Heat Supplies

Секция V : Энергоресурсосберегающие и природоохранные инновационные решения в инженерных системах зданий и сооруженийВ статье рассмотрена проблема выравнивания ночного провала в использовании электроэнергии при помощи теплоаккумуляционных систем теплоснабжения, использующих электроэнергию в качестве источника теплоты. Предложены решения с использованием тепловых аккумуляторов с теплоаккумулирующим материалом в виде высокотемпературных органических теплоносителей (ВОТ) в комбинации с другими источниками теплоты для покрытия пиковых нагрузок.=The article considers the problem of leveling the night gap in the use of electricity using heat storage heat supply systems that use electricity as a source of heat. Solutions using heat accumulators with heat-accumulating material in the form of high-temperature organic heat transfer fluids (BOT) in combination with other heat sources to cover peak loads are proposed

Using Heat Batteries for Electrical Systems Heat Supplies

Секция V : Энергоресурсосберегающие и природоохранные инновационные решения в инженерных системах зданий и сооруженийВ статье рассмотрена проблема выравнивания ночного провала в использовании электроэнергии при помощи теплоаккумуляционных систем теплоснабжения, использующих электроэнергию в качестве источника теплоты. Предложены решения с использованием тепловых аккумуляторов с теплоаккумулирующим материалом в виде высокотемпературных органических теплоносителей (ВОТ) в комбинации с другими источниками теплоты для покрытия пиковых нагрузок.=The article considers the problem of leveling the night gap in the use of electricity using heat storage heat supply systems that use electricity as a source of heat. Solutions using heat accumulators with heat-accumulating material in the form of high-temperature organic heat transfer fluids (BOT) in combination with other heat sources to cover peak loads are proposed

Preliminary Results from Integrating Compton Photon Polarimetry in Hall A of Jefferson Lab

A wide range of nucleon and nuclear structure experiments in Jefferson Lab's Hall A require precise, continuous measurements of the polarization of the electron beam. In our Compton polarimeter, electrons are scattered off photons in a Fabry-Perot cavity; by measuring an asymmetry in the integrated signal of the scattered photons detected in a GSO crystal, we can make non-invasive, continuous measurements of the beam polarization. Our goal is to achieve 1% statistical error within two hours of running. We discuss the design and commissioning of an upgrade to this apparatus, and report preliminary results for experiments conducted at beam energies from 3.5 to 5.9 GeV and photon rates from 5 to 100 kHz.Comment: 6 pages, 7 figures. To appear in the Proceedings of the International Nuclear Physics Conference (INPC 2010), July 4-9 2010, Vancouver, Canada (Journal of Physics: Conference Series