404 research outputs found
Mass Spectrometric Determination of the Dissociation Energy of Mn2F6
No full textThe gaseous Mn2F6 molecule has been identified for the first time in the vapor produced by MnF3 vaporization and the MnF3(g) dimerization equilibrium studied by the Knudsen cell mass spectrometry technique in the 884–1015 K temperature range. The experimental vapor pressure data were treated by the second- and third-law procedures, and the enthalpy of Mn2F6(g) dissociation has been determined as: equation image. Thermodynamic functions of gaseous MnF3 were calculated from geometrical and vibrational parameters taken from the literature. For gaseous Mn2F6, they were evaluated by comparison with molecular parameters of Co2F6(g). Copyright © 2002 John Wiley & Sons, Ltd
In situ time-resolved X-ray diffraction study of manganese trifluoride thermal decomposition
No full textRadiation damage in the LHCb vertex locator
No full textThe LHCb Vertex Locator (VELO) is a silicon strip detector designed to reconstruct charged particle trajectories and vertices produced at the LHCb interaction region. During the first two years of data collection, the 84 VELO sensors have been exposed to a range of fluences up to a maximum value of approximately 45 × 1012 1 MeV neutron equivalent (1 MeV neq). At the operational sensor temperature of approximately −7 °C, the average rate of sensor current increase is 18 μA per fb−1, in excellent agreement with predictions. The silicon effective bandgap has been determined using current versus temperature scan data after irradiation, with an average value of Eg = 1.16±0.03±0.04 eV obtained. The first observation of n+-on-n sensor type inversion at the LHC has been made, occurring at a fluence of around 15 × 1012 of 1 MeV neq. The only n+-on-p sensors in use at the LHC have also been studied. With an initial fluence of approximately 3 × 1012 1 MeV neq, a decrease in the Effective Depletion Voltage (EDV) of around 25 V is observed. Following this initial decrease, the EDV increases at a comparable rate to the type inverted n+-on-n type sensors, with rates of (1.43±0.16) × 10−12 V/ 1 MeV neq and (1.35±0.25) × 10−12 V/ 1 MeV neq measured for n+-on-p and n+-on-n type sensors, respectively. A reduction in the charge collection efficiency due to an unexpected effect involving the second metal layer readout lines is observed
Контроль дифференциального сопротивления p–n-переходов биполярного транзистора в активном режиме методом импедансной спектроскопии
No full textControlling of parameters of manufactured transistors and interoperational controlling during their production are necessary conditions for production of competitive products of electronic industry. Traditionally for controlling of bipolar transistors the direct current measurements and registration of capacity-voltage characteristics are used. Carrying out measurements on alternating current in a wide interval of frequencies (20 Hz–30 MHz) will allow to obtain additional information on parameters of bipolar transistors. The purpose of the work is to show the possibilities of the method of impedance spectroscopy for controlling of differential resistance of p–n-junctions of the bipolar p–n–p-transistor in active mode.The KT814G p–n–p-transistor manufactured by JSC “INTEGRAL” was studied by the method of impedance spectroscopy. The values of differential electrical resistance and capacitance for base–emitter and base–collector p–n-junctions are defi at direct currents in base from 0.8 to 46 µA.The results of the work can be applied to elaboration of techniques of fi checking of discrete bipolar semiconductor devices.Контроль параметров готовых транзисторов и межоперационный контроль при их изготовлении являются необходимыми условия выпуска конкурентоспособных изделий электронной промышленности. Традиционно для контроля биполярных транзисторов используются измерения на постоянном токе и регистрация вольт-фарадных характеристик. Проведение измерений на переменном токе позволит получить дополнительную информацию о параметрах биполярных транзисторов.Цель работы – показать возможности метода импедансной спектроскопии для контроля дифференциального электрического сопротивления p–n-переходов биполярного p–n–p-транзистора в активном режиме.Методом импедансной спектроскопии исследован p–n–p-транзистор КТ814Г производства ОАО «ИНТЕГРАЛ». На переменном токе в интервале частот 20 Hz–30 MHz определены значения дифференциального электрического сопротивления и емкости p–n-переходов база–эмиттера и база–коллектора при постоянных токах базы от 0,8 до 46 µA.Результаты работы могут быть использованы при отработке методик выходного контроля дискретных биполярных полупроводниковых приборов
Actividades polares de la URSS
No full textCon motivo de su visita a la URSS para entrevistar al académico Marchuk, el Dr. Taba tuvo la oportunidad de hablar con el Dr. Krutskikh, director del Instituto de Investigación del Ártico y el Antártico de Leningrado, en donde se organiza el trabajo científico de la Unión Soviética en las regiones polares. También tuvo ocasión de escuchar de primera mano el relato de dos graves incidentes ocurridos en la Antártida: del Dr. A.N. Chilingarov, Presidente Adjunto del Comité Estatal de la URSS para la Hidrometeorología y la vigilancia del medio ambiente natural, sobre el rescate del buque de investigación Mikhail Somov; y el del Dr. P.G. Astakhov sobre un incendio ocurrido en la base terrestre remota de Vostok
Testing of bulk radiation damage of n-in-p silicon sensors for very high radiation environments
No full textWe are developing n+-in-p, p-bulk and n-readout, microstrip sensors, fabricated by Hamamatsu Photonics, as a non-inverting radiation hard silicon detector for the ATLAS tracker upgrade at the super-LHC (sLHC) proposed facility. The bulk radiation damage after neutron and proton irradiations is characterized with the leakage current, charge collection and full depletion voltage. The detectors should provide acceptable signal, signal-to-noise ratio exceeding 15, after the integrated luminosity of 6000 fb−1, which is twice the sLHC integrated luminosity goal
Development of n-on-p silicon sensors for very high radiation environments
No full textWe have developed a novel and highly radiation-tolerant n-in-p silicon microstrip sensor for very high
radiation environments such as in the Super Large Hadron Collider. The sensors are designed for a
fluence of 1x10
15
neq/cm2
and are fabricated from p-type, FZ, 6 in. (150 mm) wafers onto which we
lay out a single 9.75 cmx9.75 cm large-area sensor and several 1 cm x 1 cm miniature sensors with
various n-strip isolation structures. By evaluating the sensors both pre- and post-irradiation by protons
and neutrons, we find that the full depletion voltage evolves to approximately 800 V and that the
n-strip isolation depends on the p
+
concentration. In addition, we characterize the interstrip resistance,
interstrip capacitance and the punch-through-protection (PTP) voltage. The first fabrication batch
allowed us to identify the weak spots in the PTP and the stereo strip layouts. By understanding the
source of the weakness, the mask was modified accordingly. After modification, the follow-up
fabrication batches and the latest fabrication of about 30 main sensors and associated miniature sensors
have shown good performance, with no sign of microdischarge up to 1000 V
Measurement of flow harmonics with multi-particle cumulants in Pb plus Pb collisions at root(NN)-N-S=2.76 TeV with the ATLAS detector
No full textATLAS measurements of the azimuthal anisotropy in lead-lead collisions at root(NN)-N-S = 2.76 TeV are shown using a dataset of approximately 7 mu b(-1) collected at the LHC in 2010. The measurements are performed for charged particles with transverse momenta 0.5 < p(T) < 20 GeV and in the pseudorapidity range vertical bar eta vertical bar < 2.5. The anisotropy is characterized by the Fourier coefficients, vn, of the charged-particle azimuthal angle distribution for n = 2-4. The Fourier coefficients are evaluated using multi-particle cumulants calculated with the generating function method. Results on the transverse momentum, pseudorapidity and centrality dependence of the v(n) coefficients are presented. The elliptic flow, v(2), is obtained from the two-, four-, six-and eight-particle cumulants while higher-order coefficients, v(3) and v(4), are determined with two-and four-particle cumulants. Flow harmonics v(n) measured with four-particle cumulants are significantly reduced compared to the measurement involving two-particle cumulants. A comparison to v(n) measurements obtained using different analysis methods and previously reported by the LHC experiments is also shown. Results of measurements of flow fluctuations evaluated with multiparticle cumulants are shown as a function of transverse momentum and the collision centrality. Models of the initial spatial geometry and its fluctuations fail to describe the flow fluctuations measurements
Testing of surface properties pre-rad and post-rad of n-in-p silicon sensors for very high radiation environment
No full textWe are developing n+-in-p, p-bulk and n-readout, microstrip sensors as a non-inverting radiation hard silicon detector for the ATLAS Tracker Upgrade at the super LHC experiment. The surface radiation damages of the sensors fabricated by Hamamatsu Photonics are characterized on the interstrip capacitance, interstrip resistance and punch-through protection evolution. The detector should provide acceptable strip isolation, exceeding the input impedance of the signal readout chip ∼1 kΩ, after the integrated luminosity of 6 ab−1, which is twice the luminosity goal
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