Transmission of UV light with high beam quality and pointing stability is desirable for many experiments in atomic, molecular and optical physics. In particular, laser cooling and coherent ...manipulation of trapped ions with transitions in the UV require stable, single-mode light delivery. Transmitting even ~2 mW CW light at 280 nm through silica solid-core fibers has previously been found to cause transmission degradation after just a few hours due to optical damage. We show that photonic crystal fiber of the kagomé type can be used for effectively single-mode transmission with acceptable loss and bending sensitivity. No transmission degradation was observed even after >100 hours of operation with 15 mW CW input power. In addition it is shown that implementation of the fiber in a trapped ion experiment increases the coherence time of the internal state transfer due to an increase in beam pointing stability.
The results of an analysis of data from the SERP-Е-184 experiment devoted to studying mechanisms of the production of charmed particles in proton–nucleus interactions at 70 GeV and their decays are ...presented. The data in question were obtained upon irradiating the SVD-2 active target consisting of carbon, silicon, and lead plates with a beam of 70-GeV protons. A detailed simulation on the basis of the FRITIOF7.02 and GEANT3.21 code packages made it possible to optimize event-selection criteria and to calculate the detection efficiency for Λ
c
+
baryons. After selecting a signal from the threebody decay of a Λ
c
+
baryon, the inclusive cross section for its production at near-threshold energies, its lifetime, and the parameter of the
A
dependence of the cross section were found. The Λ
c
+
-baryon yields are tabulated along with data from other experiments and theoretical predictions.
It is shown that the representation of neutron-irradiation-produced defects in the form of divacancy D clusters with a tetravacancy core adequately describes the observed neutron-irradiation-produced ...effects in float-zone silicon. It is also predicted that the complete-depletion voltage decreases for a dopant concentration exceeding a critical value; this decrease is due to “contraction” of the outer region of the cluster’s space charge. The magnitude of the expected effect is determined by the factor ∼1−(rn/rcl)3−1, where rn and rcl are the radii of the core and cluster, respectively.
The stages of development and the current status of the versatile “Spectrometer with a Vertex Detector” setup designed for physics experiments at the U-70 accelerator of the Institute for High Energy ...Physics (Protvino) is described. The main detectors of the setup are the vertex detector based on silicon microstrip detectors, the wide-aperture magnetic spectrometer based on multiwire proportional chambers, and the lead-glass hodoscope γ detector. In the setup, there is a fast two-level trigger system for selecting required particle interactions. The key characteristics of the setup systems are presented, and the physical results obtained on it are briefly listed.
Sensitivity trimming in testing austenitic welds Ermolov, I. N.; Vopilkin, A. Kh; Grebennikov, V. V. ...
Russian journal of nondestructive testing,
1/2005, Letnik:
41, Številka:
1
Journal Article
Recenzirano
A method for sensitivity trimming during testing of welds by the bottom signal is recommended. A technique for sensitivity correction when changing from the separate to the transceiving operating ...mode is suggested. During the testing of austenitic welds, this technique allows taking into account the ultrasound attenuation in the built-up metal of a joint and checking of the testability with allowance for the weld structure.
Data from the SVD-2 experiment that were obtained at the IHEP accelerator in 70-GeV/c proton-nucleus interactions are analyzed with the aim of searches for an exotic {theta}{sup +} baryon that decays ...through the pK{sup 0}{sub S} channel. The reaction pN {yields} pK{sup 0}{sub S} + X characterized by a bounded multiplicity of charged secondaries is used for this analysis. A resonance of mass M = 1526 {+-} 3(stat.) {+-} 3(syst.) MeV/c{sup 2} and width {gamma} < 24 MeV/c{sup 2} is observed in the invariant-mass spectrum of the pK{sup 0}{sub S} system at a statistical significance of 5.6{sigma}. The mass and the width of this resonance correspond to the recently found positive-strangeness {theta}{sup +} baryon, which was predicted to be an exotic baryon consisting of five quarks (pentaquark), uudds-bar. The total cross section for the production of a {theta}{sup +} baryon in pA interactions is estimated at a value within the range 30-120 {mu}b for x{sub F} {>=} 0. An analysis of the A dependence of the cross section for {theta}{sup +}-baryon production does not reveal a significant deviation from the A dependence for inelastic events ({approx}A{sup 0.7})
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