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

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

Møllerov polarimetar za elektrone u dvorani A u JLabu

As part of the spin-physics program at Jefferson Laboratory (JLab), a Moller polarimeter was developed to measure the polarization of electron beam of energies 0.8 to 5.0 GeV. A unique signature for Moller scattering is obtained using a series of three quadrupole magnets which provide an angular selection, and a dipole magnet for energy analysis. The design, commissioning and the first results of the polarization measurements of this polarimeter will be presented as well as future plans to use its small scattering angle capabilities to investigate physics in very low Q2 regime.Kao dio programa istraživanja spinske fizike, u Jeffersonovom se laboratoriju sagradio Møllerov polarimetar radi mjerenja polarizacije elektrona energije 0,8 do 5,0 GeV. Jedinstven signal za Møllerovo raspršenje se postiže nizom od tri kvadrupolna magneta koji određuju kut, te dipolnim magnetom za analizu impulsa elektrona. Opis, preuzimanje i prva mjerenja s tim polarimetrom se izlažu, kao i planovi za buduću upotrebu mogućnosti sustava za mjerenja na malim kutovima raspršenja radi istraživanja fizike za vrlo male Q2

СПОСОБ ВЫДЕЛЕНИЯ ЛИЧИНОК Toxocara canis ИЗ ПАРЕНХИМЫ ПЕЧЕНИ И ЛЕГКИХ ПЛОТОЯДНЫХ ЖИВОТНЫХ

The method of allocation of Toxocara canis larvae from parenchyma of liver and lung of carnivorous animals for postmortem diagnostics of toxocarosis is of-fered at a weak infection and in prepatent period. The received culture of larvae of T. canis can be used for studying pathogenesis of the diseases, carrying out genetic researches and receiving proteins with diagnostic and protective properties. The list of the equipment, reactants and solutions for allocation of T. canis larvae is given. The work course which consists of preparation of tests of tissue of a liver and lungs, preparation of artificial gastric juice, digestion of tissues, an assessment of the re-sults, concentration of T. canis larvae is described. For researches take samples of a parenchyma of lungs or a liver weighing 50 g, crush on a meat grinder. Samples digest to the current of 50 min. at a temperature of 41–42 °C. After 10 minute up-holding a deposit merge in Petri's cups and investigate on existence of T. canis lar-vae and their mobility. For concentration of a material a deposit centrifuge during 10 min.Предложен способ выделения личинок Toxocara canis из паренхимы печени и легких плотоядных животных для посмертной диагностики токсокароза при слабой инвазии и в период препатентной стадии. Полученную культуру личинок T. canis можно использовать для изучения патогенеза болезни, проведения генетических исследований и получения белков с диагностическими и протективными свойствами. Дан перечень оборудования, реактивов и растворов для выделения личинок T. canis. Описан ход работы, который состоит из подготовки проб ткани печени и легких, приготовления искусственного желудочного сока, переваривания проб тканей, оценки результатов, концентрации личинок T. canis. Для исследований берут пробы паренхимы легких или печени массой 50 г, измельчают на мясорубке. Пробы переваривают в течение 50 мин при температуре 41-42 оС при постоянном перемешивании. После 10-минутного отстаивания осадок сливают в чашки Петри и исследуют на наличие личинок T. canis и их подвижность. Для концентрации материала осадок центрифугируют 10 мин при 5000 об./мин

ВЛИЯНИЕ ГЕЛЬМИНТОЗОВ НА КАЧЕСТВО МЯСА ОВЕЦ

It is established dictyocaulosis, protostrongylosis, muelleriosis, cystocaulosis, ostertagyosis, trichostrongylosis, nematodirosis, haemonchosis, fasciolosis, cysticercosis and echinococcosis (larva) in sheep in Moscow region. Efficiency of ELISA in diagnostics of helminthosis of sheep has made 75,5–100 %. The most essential deviations in chemical compound of sheep’s meat are marked at pulmonary nematodosis, echinococcosis and fasciolosis.У овец в Московской области установлен диктиокаулез, протостронгилез, мюллериоз, цистокаулез, остертагиоз, трихостронгилез, нематодироз, гемонхоз, фасциолез, цистицеркоз тонкошейный и эхинококкоз. Изучена эффективность метода ИФА в диагностике гельминтозов у овец, которая составила 75,5–100 %. Наиболее существенные отклонения в химическом составе мяса овец отмечены при легочных нематодозах, эхинококкозе и фасциолезе

Møllerov polarimetar za elektrone u dvorani A u JLabu

As part of the spin-physics program at Jefferson Laboratory (JLab), a Moller polarimeter was developed to measure the polarization of electron beam of energies 0.8 to 5.0 GeV. A unique signature for Moller scattering is obtained using a series of three quadrupole magnets which provide an angular selection, and a dipole magnet for energy analysis. The design, commissioning and the first results of the polarization measurements of this polarimeter will be presented as well as future plans to use its small scattering angle capabilities to investigate physics in very low Q2 regime.Kao dio programa istraživanja spinske fizike, u Jeffersonovom se laboratoriju sagradio Møllerov polarimetar radi mjerenja polarizacije elektrona energije 0,8 do 5,0 GeV. Jedinstven signal za Møllerovo raspršenje se postiže nizom od tri kvadrupolna magneta koji određuju kut, te dipolnim magnetom za analizu impulsa elektrona. Opis, preuzimanje i prva mjerenja s tim polarimetrom se izlažu, kao i planovi za buduću upotrebu mogućnosti sustava za mjerenja na malim kutovima raspršenja radi istraživanja fizike za vrlo male Q2