LU-10M LINAC synchronization system

The synchronization system is based on STM32F407VG and DP83848. The system generates pulses with a fre-quency of 1 to 600 Hz, a length of up to 2500 ns to synchronize the operation of the klystron modulator, master oscillator, source modulator, control equipment of LINAC. The setting of the delay of the synchronization pulses is adjustable from 0.01 to 20 μs. Synchronization system control is implemented via USB or Ethernet network via TCP/IP protocol. Implemented a set of applications for the organization of system management and monitoring of LINAC, compatible with Windows XP/7/10.Система синхронізації розроблена на основі STM32F407VG та DP83848. Система формує імпульси частотою від 1 до 600 Гц, довжиною до 2500 нс для синхронізації роботи модулятора клістрона, задающого генератора, модулятора джерела, контрольної апаратури ЛПЕ. Установка затримки імпульсів синхронізації регулюється від 0,01 до 20 мкс. Керування системою синхронізації реалізовано за допомогою USB або Ethernet-мережі за протоколом TCP/IP. Реалізований комплекс додатків для організації керування системою та спостереження за роботою ЛПЕ, сумісний з ОС Windows XP/7/10.Система синхронизации разработана на основе STM32F407VG и DP83848. Система формирует импульсы частотой от 1 до 600 Гц, длиной до 2500 нс для синхронизации работы модулятора клистрона, задающего генератора, модулятора источника, контрольной аппаратуры ЛУЭ. Установка задержки импульсов синхронизации регулируется от 0,01 до 20 мкс. Управление системой синхронизации реализовано с помощью USB или Ethernet-сети по протоколу TCP/IP. Реализован комплекс приложений для организации управления системой и наблюдения за работой ЛУЭ, совместимый с ОС Windows XP/7/10

Design and exploitation powerful thyratron swith in modulators accelerators NSC KIPT

Modulators performed according to linear circuit with PFN depletion via pulse transformer are used in NSC KIPT active electron accelerators. Switch and its components determine the reliability of a plant. Hydrogen thyratrons providing the current switching up to 2.3 kA at anode voltage up to 40 kV are used as a switch in modulators of technological accelerators. The results of study of operational reliability of switches in active accelerators are reported in this articleВ действующих в ННЦ ХФТИ ускорителях электронов работают модуляторы, выполненные по линейной схеме с полным разрядом формирующей линии через импульсный трансформатор. Коммутатор и его комплектующие определяют надежность работы установки. В качестве коммутатора в модуляторах технологических ускорителей используются водородные тиратроны, обеспечивающие коммутацию тока до 2,3 кА при анодном напряжении до 40 кВ. Приведены результаты исследования эксплуатационной надежности коммутаторов в режиме действующих ускорителей.У діючих прискорювачах електронів у ННЦ ХФТІ працюють модулятори, що виконані за лінійною схемою з повним розрядом формуючої лінії через імпульсний трансформатор. Комутатор і його комплектуючі визначають надійність роботи установки. Як комутатори у модуляторах технологічних прискорювачів використовуються водневі тиратрони, що забезпечують комутацію струму до 2,3 кА при анодній напрузі до 40 кВ. Приведені результати дослідження експлуатаційної надійності комутаторів у діючих режимах

Research of the state of internal surfaces of a supercritical water loop after a session of irradiation

Made of austenitic steel at the NSC KIPT, the supercritical water convection loop Loop-1a was running for more than 500 hours in the first experimental session (in 2011). The materials tested in the loop were placed into a stream of water (more than 50 g/s) at a temperature of 350…400°C, a pressure of 23… 25 MPa, and were irradiated by an electron beam with an energy of 10 MeV. Sediments that emerged on the inner surface of the loop were examined. The sediment mainly consisted of compounds of calcium and iron mixed with other elements. There is a possibility to increase corrosion induced by radiation due to dislocation damage, hydrogenation of metal and under the impact of active oxygen.Виготовлена з аустенітної стали в ННЦ ХФТІ надкритична водяна конвекційна петля Loop-1a в першому експериментальному сеансі (2011 рік) пропрацювала понад 500 год. Випробовувані у петлі матеріали перебували в потоці води (понад 50 г/с) при температурі 350…400°C, тиску 23…25 МПа і опромінювалися електронним пучком енергією 10 МеВ. Досліджували відкладення на внутрішній поверхні петлі, які складаються в основному із сполук кальцію і заліза з домішкою інших елементів. Можливе посилення корозії під дією випромінювання за рахунок дислокаційних ушкоджень, насичення воднем і активного кисню.Изготовленная из аустенитной стали в ННЦ ХФТИ сверхкритическая водяная конвекционная петля Loop-1a в первом экспериментальном сеансе (2011 год) проработала более 500 ч. Испытываемые в петле материалы находились в потоке воды (более 50 г/с) при температуре 350…400°C, давлении 23… 25 МПа и облучались электронным пучком энергией 10 МэВ. Исследовали отложения на внутренней поверхности петли, которые состоят в основном из соединений кальция и железа с примесью других элементов. Возможно усиление коррозии под действием излучения за счет дислокационных повреждений, наводорoживания и активного кислорода

Wave Function Based Characteristics of Hybrid Mesons

We propose some extensions of the quark potential model to hybrids, fit them to the lattice data and use them for the purpose of calculating the masses, root mean square radii and wave functions at the origin of the conventional and hybrid charmonium mesons. We treat the ground and excited gluonic field between a quark and an antiquark as in the Born-Oppenheimer expansion, and use the shooting method to numerically solve the required Schr$\ddot{\textrm{o}}$dinger equation for the radial wave functions; from these wave functions we calculate the mesonic properties. For masses we also check through a Crank Nichelson discretization. For hybrid charmonium mesons, we consider the exotic quantum number states with $J^{PC} = 0^{+ -}, 1^{- +}$ and $2^{+ -}$. We also compare our results with the experimentally observed masses and theoretically predicted results of the other models. Our results have implications for scalar form factors, energy shifts, magnetic polarizabilities, decay constants, decay widths and differential cross sections of conventional and hybrid mesons.Comment: 13 pages, 6 figures, Erratum is submitted to EPJ

Search for composite and exotic fermions at LEP 2

A search for unstable heavy fermions with the DELPHI detector at LEP is reported. Sequential and non-canonical leptons, as well as excited leptons and quarks, are considered. The data analysed correspond to an integrated luminosity of about 48 pb^{-1} at an e^+e^- centre-of-mass energy of 183 GeV and about 20 pb^{-1} equally shared between the centre-of-mass energies of 172 GeV and 161 GeV. The search for pair-produced new leptons establishes 95% confidence level mass limits in the region between 70 GeV/c^2 and 90 GeV/c^2, depending on the channel. The search for singly produced excited leptons and quarks establishes upper limits on the ratio of the coupling of the excited fermio

Search for lightest neutralino and stau pair production in light gravitino scenarios with stau NLSP

Promptly decaying lightest neutralinos and long-lived staus are searched for in the context of light gravitino scenarios. It is assumed that the stau is the next to lightest supersymmetric particle (NLSP) and that the lightest neutralino is the next to NLSP (NNLSP). Data collected with the Delphi detector at centre-of-mass energies from 161 to 183 \GeV are analysed. No evidence of the production of these particles is found. Hence, lower mass limits for both kinds of particles are set at 95% C.L.. The mass of gaugino-like neutralinos is found to be greater than 71.5 GeV/c^2. In the search for long-lived stau, masses less than 70.0 to 77.5 \GeVcc are excluded for gravitino masses from 10 to 150 \eVcc . Combining this search with the searches for stable heavy leptons and Minimal Supersymmetric Standard Model staus a lower limit of 68.5 \GeVcc may be set for the stau mas

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table, corrected author list, matches final version in Physical Review Letter

Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS

We present the results of a search for new, heavy particles that decay at a significant distance from their production point into a final state containing charged hadrons in association with a high-momentum muon. The search is conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV and an integrated luminosity of 33 pb^-1 collected in 2010 by the ATLAS detector operating at the Large Hadron Collider. Production of such particles is expected in various scenarios of physics beyond the standard model. We observe no signal and place limits on the production cross-section of supersymmetric particles in an R-parity-violating scenario as a function of the neutralino lifetime. Limits are presented for different squark and neutralino masses, enabling extension of the limits to a variety of other models.Comment: 8 pages plus author list (20 pages total), 8 figures, 1 table, final version to appear in Physics Letters

Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02