241 research outputs found

    On Sp(2M) Invariant Green Functions

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    Explicit form of two-point and three-point Sp(2M) invariant Green functions is found.Comment: 7 page

    Characterization of lipids A of Ralstonia solanacearum lipopolysaccharides

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    The analysis of fatty acid profiles of lipopolysacharides has shown that R. solanacearum strains tested may be divided into two groups. The first group is represented by R. solanacearum strains (5712, 7945, 7955 and 8110) the lipids A of which contained hydroxylated fatty acids with long chains: 3-hydroxytetradecanoic, 2-hydroxyhexadecanoic and 2-hydroxyoctadecanoic. The second group was represented by R. solanacearum strains the lipids A of which contained hydroxylated fatty acids with short chains: 3-hydroxydecanoic, 2-hydroxydodecanoic and 3-hydroxydodecanoic. 3-hydroxytetradecanoic acid was observed in a small amount. A comparative analysis of the fatty acid composition and biological activity gives a possibility to suppose that 3-hydroxytetradecanoic, 2-hydroxyhexadecanoic and 2-hydroxyoctadecanoic acids may be responsible for the toxicity and pyrogenicity of the lipopolysaccharides tested.Аналіз Тирнокислотних ΠΏΡ€ΠΎΡ„Ρ–Π»Ρ–Π² ліпополісахаридів ΡΠ²Ρ–Π΄Ρ‡ΠΈΡ‚ΡŒ ΠΏΡ€ΠΎ Ρ‚Π΅, Ρ‰ΠΎ дослідТСні ΠΈΡ–Ρ‚Π°ΠΌΠΈ R. solanacearum ΠΌΠΎΠΆΠ½Π° ΠΏΠΎΠ΄Ρ–Π»ΠΈΡ‚ΠΈ Π½Π° Π΄Π²Ρ– Π³Ρ€ΡƒΠΏΠΈ. ΠŸΠ΅Ρ€ΡˆΠ° Π³Ρ€ΡƒΠΏΠ° прСдставлСна ΡˆΡ‚Π°ΠΌΠ°ΠΌΠΈ R. solaΒ­nacearum (5712, 7945, 7955 Ρ– 8110), Π»Ρ–ΠΏΡ–Π΄ΠΈ А яких ΠΌΡ–ΡΡ‚ΡΡ‚ΡŒ оксикислоти Π· Π΄ΠΎΠ²Π³ΠΈΠΌΠΈ Π²ΡƒΠ³Π»Π΅Ρ†Π΅Π²ΠΈΠΌΠΈ Π»Π°Π½Ρ†ΡŽΠ³Π°ΠΌΠΈ: 3-окситСтра-Π΄Π΅ΠΊΠ°Π½ΠΎΠ²Ρƒ, 2-оксигСксадСканову Ρ‚Π° 2-оксиоктадСканову. Π’ Π΄Ρ€ΡƒΠ³Ρƒ Π³Ρ€ΡƒΠΏΡƒ Π²Ρ…ΠΎΠ΄ΡΡ‚ΡŒ ΡˆΡ‚Π°ΠΌΠΈ R. solanacearum, Ρƒ Π»Ρ–ΠΏΡ–Π΄Π°Ρ… А яких присутні оксикислоти Π· ΠΊΠΎΡ€ΠΎΡ‚ΠΊΠΈΠΌΠΈ Π»Π°Π½Ρ†ΡŽΠ³Π°ΠΌΠΈ: 3-оксидСканова, 2-оксидодСканова Ρ‚Π° 3-оксидодСканова. 3-окситСтрадСканову кислоту Π·Π½Π°ΠΉΠ΄Π΅Π½ΠΎ Π² Π½Π΅Π·Π½Π°Ρ‡Π½Ρ–ΠΉ ΠΊΡ–Π»ΡŒΠΊΠΎΡΡ‚Ρ–. ΠŸΠΎΡ€Ρ–Π²Π½ΡΠ»ΡŒΠ½ΠΈΠΉ Π°Π½Π°Π»Ρ–Π· Тирнокислотного складу Ρ‚Π° Π±Ρ–ΠΎΠ»ΠΎΠ³Ρ–Ρ‡Π½ΠΎΡ— активності Π΄Π°Ρ” підставу припустити, Ρ‰ΠΎ 3-окситСтрадСканова, 2-оксигСкса-Π΄Π΅ΠΊΠ°Π½ΠΎΠ²Π° Ρ‚Π° 2-оксиоктадСканова кислоти ΠΌΠΎΠΆΡƒΡ‚ΡŒ Π²Ρ–Π΄ΠΏΠΎΠ²Ρ–Π΄Π°Ρ‚ΠΈ Π·Π° Ρ‚ΠΎΠΊΡΠΈΡ‡Π½Ρ–ΡΡ‚ΡŒ Ρ‚Π° ΠΏΡ–Ρ€ΠΎΠ³Π΅Π½Π½Ρ–ΡΡ‚ΡŒ дослідТуваних ліпополіса­харидів.Анализ Тирнокислотных ΠΏΡ€ΠΎΡ„ΠΈΠ»Π΅ΠΉ липополисахаридов выявил, Ρ‡Ρ‚ΠΎ исслСдованныС ΡˆΡ‚Π°ΠΌΠΌΡ‹ R. solanacearum ΠΌΠΎΠ³ΡƒΡ‚ Π±Ρ‹Ρ‚ΡŒ Ρ€Π°Π·Π΄Π΅Π»Π΅Π½Ρ‹ Π½Π° Π΄Π²Π΅ Π³Ρ€ΡƒΠΏΠΏΡ‹. ΠŸΠ΅Ρ€Π²Π°Ρ Π³Ρ€ΡƒΠΏΠΏΠ° прСдставлСна ΡˆΡ‚Π°ΠΌΒ­ΠΌΠ°ΠΌΠΈ R. solanacearum (5712, 7945, 7955 ΠΈ 8110), Π»ΠΈΠΏΠΈΠ΄Ρ‹ А ΠΊΠΎΡ‚ΠΎΡ€Ρ‹Ρ… содСрТат оксикислоты с Π΄Π»ΠΈΠ½Π½Ρ‹ΠΌΠΈ цСпями: 3-окси-Ρ‚Π΅Ρ‚Ρ€Π°Π΄Π΅ΠΊΠ°Π½ΠΎΠ²ΡƒΡŽ, 2-ΠΎΠΊΡΠΈΠ³Π΅ΠΊΡΠ°Π΄Π΅ΠΊΠ°Π½ΠΎΠ²ΡƒΡŽ ΠΈ 2-ΠΎΠΊΡΠΈΠΎΠΊΡ‚Π°Π΄Π΅ΠΊΠ°Π½ΠΎΠ²ΡƒΡŽ. Π’ΠΎ Π²Ρ‚ΠΎΡ€ΡƒΡŽ Π³Ρ€ΡƒΠΏΠΏΡƒ входят ΡˆΡ‚Π°ΠΌΠΌΡ‹ R. solanacearum, Π² Π»ΠΈΠΏΠΈΠ΄Π°Ρ… А ΠΊΠΎΡ‚ΠΎΡ€Ρ‹Ρ… ΠΏΡ€ΠΈΡΡƒΡ‚ΡΡ‚Π²ΡƒΡŽΡ‚ оксикислоты с ΠΊΠΎΡ€ΠΎΡ‚ΠΊΠΈΠΌΠΈ цСпями: 3-оксидСкановая, 2-оксидодСкановая ΠΈ 3-оксидодСкановая. 3-окситСтрадСкановая кислота ΠΎΠ±Π½Π°Ρ€ΡƒΠΆΠ΅Π½Π° Π² Π½Π΅Π·Π½Π°Ρ‡ΠΈΡ‚Π΅Π»ΡŒΠ½ΠΎΠΌ количСствС. Π‘Ρ€Π°Π²Π½ΠΈΡ‚Π΅Π»ΡŒΠ½Ρ‹ΠΉ Π°Π½Π°Π»ΠΈΠ· Тирнокислотного состава ΠΈ биологичСской активности Π΄Π°Π΅Ρ‚ основаниС ΠΏΡ€Π΅Π΄ΠΏΠΎΒ­Π»ΠΎΠΆΠΈΡ‚ΡŒ, Ρ‡Ρ‚ΠΎ 3-окситСтрадСкановая, 2-оксигСксадСкановая ΠΈ 2-оксиоктадСкановая кислоты ΠΌΠΎΠ³ΡƒΡ‚ ΠΎΡ‚Π²Π΅Ρ‡Π°Ρ‚ΡŒ Π·Π° Ρ‚ΠΎΠΊΡΠΈΡ‡Β­Π½ΠΎΡΡ‚ΡŒ ΠΈ ΠΏΠΈΡ€ΠΎΠ³Π΅Π½Π½ΠΎΡΡ‚ΡŒ исслСдованных липополисахаридов

    Desenvolvimento de sistema de poupança de energia baseado em bomba de calor

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    This article describes the structure and the operation of energy-saving systems based on a heat pump with the use of renewable energy sources. Using the method of an experiment three-factor active planning, the response surfaces and their two-dimensional cross sections were constructed in the isolines of the transition process duration and the amount of the energy carrier heat from the the electric heater power. The developed energy-saving systems support the temperature regime of an agricultural object by using solar energy, low-potential and artificial energy sources throughout the year. The developed system (option one), installed in hard-to-reach places at agricultural facilities, is designed to generate thermal energy, electricity, and provides significant energy savings during energy supply. Due to the speed of the electric regulator with solid filler and electric heater, the efficiency of the heat pump is increased, which maintains the microclimate parameters of the agricultural object.Este artΓ­culo describe la estructura y el funcionamiento de los sistemas de ahorro de energΓ­a basados en una bomba de calor con el uso de fuentes de energΓ­a renovables. Utilizando el mΓ©todo de un experimento de planificaciΓ³n activa de tres factores, las superficies de respuesta y sus secciones transversales bidimensionales se construyeron en las isolinas de la duraciΓ³n del proceso de transiciΓ³n y la cantidad de calor del portador de energΓ­a de la potencia del calentador elΓ©ctrico. Los sistemas de ahorro de energΓ­a desarrollados apoyan el rΓ©gimen de temperatura de un objeto agrΓ­cola mediante el uso de energΓ­a solar, potencial bajo y fuentes de energΓ­a artificial durante todo el aΓ±o. El sistema desarrollado (opciΓ³n uno), instalado en lugares de difΓ­cil acceso en las instalaciones agrΓ­colas, estΓ‘ diseΓ±ado para generar energΓ­a tΓ©rmica, electricidad y proporciona ahorros de energΓ­a significativos durante el suministro de energΓ­a. Debido a la velocidad del regulador elΓ©ctrico con relleno sΓ³lido y calentador elΓ©ctrico, se incrementa la eficiencia de la bomba de calor, lo que mantiene los parΓ‘metros de microclima del objeto agrΓ­cola.Este artigo descreve a estrutura e a operação de sistemas de economia de energia baseados em uma bomba de calor com o uso de fontes de energia renovΓ‘veis. Utilizando o mΓ©todo de um planejamento ativo de trΓͺs fatores experimentais, as superfΓ­cies de resposta e suas seçáes transversais bidimensionais foram construΓ­das nas isolinhas da duração do processo de transição e na quantidade de calor do portador de energia a partir da potΓͺncia do aquecedor elΓ©trico. Os sistemas de economia de energia desenvolvidos suportam o regime de temperatura de um objeto agrΓ­cola usando energia solar, fontes de energia artificiais e com baixo potencial ao longo do ano. O sistema desenvolvido (opção 1), instalado em locais de difΓ­cil acesso em instalaçáes agrΓ­colas, Γ© projetado para gerar energia tΓ©rmica, eletricidade e proporcionar economias de energia significativas durante o fornecimento de energia. Devido Γ  velocidade do regulador elΓ©trico com enchimento sΓ³lido e aquecedor elΓ©trico, a eficiΓͺncia da bomba de calor Γ© aumentada, o que mantΓ©m os parΓ’metros microclima do objeto agrΓ­cola

    Application of the INR proton LINAC for development of methods of radiotherapy and nuclear medicine

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    The review of the results of researches in the field of proton therapy and contact radiotherapy (high-dose-rate brachytherapy) is presented. Medical beam formation elements for a wide range of proton energies were calculated, elaborated and tested with proton beams. These therapeutic beams cover most sizes and localizations of tumors. Researches of a new source for high-dose-rate brachytherapy with Yb-169 were carried out. This source has several important advantages compared to conventional sources. Experiments of activation of the new source at the INR Neutron complex were performed and therapeutic properties of the new source were confirmed. We also present in this paper the current status of the new target assembly for producing of some PET isotopes with 20 MeV protons.ΠŸΡ€ΠΎΠ²Π΅Π΄Π΅Π½ΠΎ огляд Ρ€Π΅Π·ΡƒΠ»ΡŒΡ‚Π°Ρ‚Ρ–Π² Π΄ΠΎΡΠ»Ρ–Π΄ΠΆΠ΅Π½ΡŒ Π² області ΠΏΡ€ΠΎΡ‚ΠΎΠ½Π½ΠΎΡ— Ρ‚Π΅Ρ€Π°ΠΏΡ–Ρ— Ρ‚Π° ΠΊΠΎΠ½Ρ‚Π°ΠΊΡ‚Π½ΠΎΡ— Ρ€Π°Π΄Ρ–ΠΎΡ‚Π΅Ρ€Π°ΠΏΡ–Ρ— (високо-Π΄ΠΎΠ·ΠΎΠ²ΠΎΡ— Π±Ρ€Π°Ρ…Ρ–Ρ‚Π΅Ρ€Π°ΠΏΡ–Ρ—). На підставі Ρ€ΠΎΠ·Ρ€Π°Ρ…ΡƒΠ½ΠΊΡ–Π² Π±ΡƒΠ»ΠΈ Π²ΠΈΠ³ΠΎΡ‚ΠΎΠ²Π»Π΅Π½Ρ– Ρ– Π²ΠΈΠΏΡ€ΠΎΠ±ΡƒΠ²Π°Π½Ρ– Π½Π° ΠΏΡ€ΠΎΡ‚ΠΎΠ½Π½ΠΎΠΌΡƒ ΠΏΡƒΡ‡ΠΊΡƒ Π΅Π»Π΅ΠΌΠ΅Π½-Ρ‚ΠΈ систСми формування Π±Π°Π·ΠΎΠ²ΠΈΡ… Ρ‚Π΅Ρ€Π°ΠΏΠ΅Π²Ρ‚ΠΈΡ‡Π½ΠΈΡ… ΠΏΡƒΡ‡ΠΊΡ–Π² КПВ Π†Π―Π” РАН Π² ΡˆΠΈΡ€ΠΎΠΊΠΎΠΌΡƒ Π΄Ρ–Π°ΠΏΠ°Π·ΠΎΠ½Ρ– Π΅Π½Π΅Ρ€Π³Ρ–ΠΉ ΠΏΡ€ΠΎΡ‚ΠΎΠ½Ρ–Π². Π¦Ρ– ΠΏΡƒΡ‡ΠΊΠΈ Π΄ΠΎΠ·Π²ΠΎΠ»ΡΡŽΡ‚ΡŒ ΠΏΡ€ΠΎΠ²ΠΎΠ΄ΠΈΡ‚ΠΈ ΠΏΡ€ΠΎΡ‚ΠΎΠ½Π½Ρƒ Ρ‚Π΅Ρ€Π°ΠΏΡ–ΡŽ для Π½ΠΎΠ²ΠΎΡƒΡ‚Π²ΠΎΡ€Π΅Π½ΡŒ ΠΏΡ€Π°ΠΊΡ‚ΠΈΡ‡Π½ΠΎ Π±ΡƒΠ΄ΡŒ-якої Π»ΠΎΠΊΠ°Π»Ρ–Π·Π°Ρ†Ρ–Ρ—. Π‘ΡƒΠ»ΠΈ ΠΏΡ€ΠΎΠ²Π΅Π΄Π΅Π½Ρ– дослідТСння Π½ΠΎΠ²ΠΎΠ³ΠΎ Π΄ΠΆΠ΅Ρ€Π΅Π»Π° для високодозової Π±Ρ€Π°Ρ…Ρ–Ρ‚Π΅Ρ€Π°ΠΏΡ–Ρ— Π½Π° основі Ρ–Π·ΠΎΡ‚ΠΎΠΏΡƒ Yb-169, Ρ‰ΠΎ ΠΌΠ°Ρ” ряд ΠΏΡ€ΠΈΠ½Ρ†ΠΈΠΏΠΎΠ²ΠΈΡ… ΠΏΠ΅Ρ€Π΅Π²Π°Π³ порівняно Π· Ρ–Π½ΡˆΠΈΠΌΠΈ Π΄ΠΆΠ΅Ρ€Π΅Π»Π°ΠΌΠΈ. ΠŸΡ€ΠΎΠ²ΠΎΠ΄ΠΈΠ»ΠΈΡΡ СкспСримСнти Π· Π°ΠΊΡ‚ΠΈΠ²Π°Ρ†Ρ–Ρ— Π½ΠΎΠ²ΠΎΠ³ΠΎ Π΄ΠΆΠ΅Ρ€Π΅Π»Π° Π½Π° Π½Π΅ΠΉΡ‚Ρ€ΠΎΠ½Π½ΠΎΠΌΡƒ комплСксі Π†Π―Π” РАН, які ΠΏΡ–Π΄Ρ‚Π²Π΅Ρ€Π΄ΠΈΠ»ΠΈ ΠΉΠΎΠ³ΠΎ Ρ‚Π΅Ρ€Π°ΠΏΠ΅Π²Ρ‚ΠΈΡ‡Π½Ρ– властивості. Показано стан справ Π·Ρ– збирання ΠΌΡ–ΡˆΠ΅Π½Ρ– для Π½Π°ΠΏΡ€Π°Ρ†ΡŽΠ²Π°Π½Π½Ρ ΠŸΠ•Π’ Ρ–Π·ΠΎΡ‚ΠΎΠΏΡ–Π² Π½Π° ΠΏΡƒΡ‡ΠΊΡƒ ΠΏΡ€ΠΎΡ‚ΠΎΠ½Ρ–Π² Π· Π΅Π½Π΅Ρ€Π³Ρ–Ρ”ΡŽ 20 ΠœΠ΅Π’.ΠŸΡ€ΠΎΠ²Π΅Π΄Π΅Π½ ΠΎΠ±Π·ΠΎΡ€ Ρ€Π΅Π·ΡƒΠ»ΡŒΡ‚Π°Ρ‚ΠΎΠ² исслСдований Π² области ΠΏΡ€ΠΎΡ‚ΠΎΠ½Π½ΠΎΠΉ Ρ‚Π΅Ρ€Π°ΠΏΠΈΠΈ ΠΈ ΠΊΠΎΠ½Ρ‚Π°ΠΊΡ‚Π½ΠΎΠΉ Ρ€Π°Π΄ΠΈΠΎΡ‚Π΅Ρ€Π°ΠΏΠΈΠΈ (высокодозовой Π±Ρ€Π°Ρ…ΠΈΡ‚Π΅Ρ€Π°ΠΏΠΈΠΈ). На основании расчСтов Π±Ρ‹Π»ΠΈ ΠΈΠ·Π³ΠΎΡ‚ΠΎΠ²Π»Π΅Π½Ρ‹ ΠΈ испытаны Π½Π° ΠΏΡ€ΠΎΡ‚ΠΎΠ½Π½ΠΎΠΌ ΠΏΡƒΡ‡ΠΊΠ΅ элСмСнты систСмы формирования Π±Π°Π·ΠΎΠ²Ρ‹Ρ… тСрапСвтичСских ΠΏΡƒΡ‡ΠΊΠΎΠ² КПВ ИЯИ РАН Π² ΡˆΠΈΡ€ΠΎΠΊΠΎΠΌ Π΄ΠΈΠ°ΠΏΠ°Π·ΠΎΠ½Π΅ энСргий ΠΏΡ€ΠΎΡ‚ΠΎΠ½ΠΎΠ². Π­Ρ‚ΠΈ ΠΏΡƒΡ‡ΠΊΠΈ ΠΏΠΎΠ·Π²ΠΎΠ»ΡΡŽΡ‚ ΠΏΡ€ΠΎΠ²ΠΎΠ΄ΠΈΡ‚ΡŒ ΠΏΡ€ΠΎΡ‚ΠΎΠ½Π½ΡƒΡŽ Ρ‚Π΅Ρ€Π°ΠΏΠΈΡŽ для Π½ΠΎΠ²ΠΎΠΎΠ±Ρ€Π°Π·ΠΎΠ²Π°Π½ΠΈΠΉ практичСски любой Π»ΠΎΠΊΠ°Π»ΠΈΠ·Π°Ρ†ΠΈΠΈ. Π‘Ρ‹Π»ΠΈ ΠΏΡ€ΠΎΠ²Π΅Π΄Π΅Π½Ρ‹ исслСдования Π½ΠΎΠ²ΠΎΠ³ΠΎ источника для высокодозовой Π±Ρ€Π°Ρ…ΠΈΡ‚Π΅Ρ€Π°ΠΏΠΈΠΈ Π½Π° основС ΠΈΠ·ΠΎΡ‚ΠΎΠΏΠ° Yb-169, ΠΈΠΌΠ΅ΡŽΡ‰Π΅Π³ΠΎ ряд ΠΏΡ€ΠΈΠ½Ρ†ΠΈΠΏΠΈΠ°Π»ΡŒΠ½Ρ‹Ρ… прСимущСств ΠΏΠΎ ΡΡ€Π°Π²Π½Π΅Π½ΠΈΡŽ с Π΄Ρ€ΡƒΠ³ΠΈΠΌΠΈ источниками. ΠŸΡ€ΠΎΠ²ΠΎΠ΄ΠΈΠ»ΠΈΡΡŒ экспСримСнты ΠΏΠΎ Π°ΠΊΡ‚ΠΈΠ²Π°Ρ†ΠΈΠΈ Π½ΠΎΠ²ΠΎΠ³ΠΎ источника Π½Π° Π½Π΅ΠΉΡ‚Ρ€ΠΎΠ½Π½ΠΎΠΌ комплСксС ИЯИ РАН, ΠΏΠΎΠ΄Ρ‚Π²Π΅Ρ€Π΄ΠΈΠ²ΡˆΠΈΠ΅ Π΅Π³ΠΎ тСрапСвтичСскиС свойства. Показано состояниС Π΄Π΅Π» ΠΏΠΎ сборкС мишСни для Π½Π°Ρ€Π°Π±ΠΎΡ‚ΠΊΠΈ ПЭВ ΠΈΠ·ΠΎΡ‚ΠΎΠΏΠΎΠ² Π½Π° ΠΏΡƒΡ‡ΠΊΠ΅ ΠΏΡ€ΠΎΡ‚ΠΎΠ½ΠΎΠ² с энСргиСй 20 ΠœΡΠ’

    Subcarrier Wave Quantum Key Distribution in Telecommunication Network with Bitrate 800 kbit/s

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    In the course of work on creating the first quantum communication network in Russia we demonstrated quantum key distribution in metropolitan optical network infrastructure. A single-pass subcarrier wave quantum cryptography scheme was used in the experiments. BB84 protocol with strong reference was chosen for performing key distribution. The registered sifted key rate in an optical cable with 1.5 dB loss was 800 Kbit/s. Signal visibility exceeded 98%, and quantum bit error rate value was 1%. The achieved result is a record for this type of systems

    Development of a Momentum Determined Electron Beam in the 1 -45 GeV Range

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    A beam line for electrons with energies in the range of 1 to 45 GeV, low contamination of hadrons and muons and high intensity up to 10^6 per accelerator spill at 27 GeV was setup at U70 accelerator in Protvino, Russia. A beam tagging system based on drift chambers with 160 micron resolution was able to measure relative electron beam momentum precisely. The resolution sigma_p p was 0.13% at 45 GeV where multiple scattering is negligible. This test beam setup provided the possibility to study properties of lead tungstate crystals (PbWO_4) for the BTeV experiment at Fermilab.Comment: 12 pages, 8 figures; work done by the BTeV Electromagnetic Calorimeter grou

    Comparison of Radiation Damage in Lead Tungstate Crystals under Pion and Gamma Irradiation

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    Studies of the radiation hardness of lead tungstate crystals produced by the Bogoroditsk Techno-Chemical Plant in Russia and the Shanghai Institute of Ceramics in China have been carried out at IHEP, Protvino. The crystals were irradiated by a 40-GeV pion beam. After full recovery, the same crystals were irradiated using a 137Cs^{137}Cs Ξ³\gamma-ray source. The dose rate profiles along the crystal length were observed to be quite similar. We compare the effects of the two types of radiation on the crystals light output.Comment: 10 pages, 8 figures, Latex 2e, 28.04.04 - minor grammatical change

    Correlation of Beam Electron and LED Signal Losses under Irradiation and Long-term Recovery of Lead Tungstate Crystals

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    Radiation damage in lead tungstate crystals reduces their transparency. The calibration that relates the amount of light detected in such crystals to incident energy of photons or electrons is of paramount importance to maintaining the energy resolution the detection system. We report on tests of lead tungstate crystals, read out by photomultiplier tubes, exposed to irradiation by monoenergetic electron or pion beams. The beam electrons themselves were used to measure the scintillation light output, and a blue light emitting diode (LED) was used to track variations of crystals transparency. We report on the correlation of the LED measurement with radiation damage by the beams and also show that it can accurately monitor the crystals recovery from such damage.Comment: 9 pages, 6 figures, LaTeX2

    LED Monitoring System for the BTeV Lead Tungstate Crystal Calorimeter Prototype

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    We report on the performance of a monitoring system for a prototype calorimeter for the BTeV experiment that uses Lead Tungstate crystals coupled with photomultiplier tubes. The tests were carried out at the 70 GeV accelerator complex at Protvino, Russia.Comment: 12 pages, 8 figures, LaTeX2e, revised versio

    Design and performance of LED calibration system prototype for the lead tungstate crystal calorimeter

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    A highly stable monitoring system based on blue and red light emitting diodes coupled to a distribution network comprised of optical fibers has been developed for an electromagnetic calorimeter that uses lead tungstate crystals readout with photomultiplier tubes. We report of the system prototype design and on the results of laboratory tests. Stability better than 0.1% (r.m.s.) has been achieved during one week of prototype operation.Comment: 10 pages, 6 figures, LaTeX2
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