Observation of parametric X-rays produced by 400 GeV/c protons in bent crystals

Spectral maxima of parametric X-ray radiation (PXR) produced by 400 GeV/c protons in bent silicon crystals aligned with the beam have been observed in an experiment at the H8 external beam of the CERN SPS. The total yield of PXR photons was about 10-6 per proton. Agreement between calculations and the experimental data shows that the PXR kinematic theory is valid for bent crystals with sufficiently small curvature as used in the experiment. The intensity of PXR emitted from halo protons in a bent crystal used as a primary collimator in a circular accelerator may be considered as a possible tool to control its crystal structure, which is slowly damaged because of irradiation. The intensity distribution of PXR peaks depends on the crystal thickness intersected by the beam, which changes for different orientations of a crystal collimator. This dependence may be used to control crystal collimator alignment by analyzing PXR spectra produced by halo protons.peer-reviewe

The Investigation of Coupling between Matching Circuit and Input Resonators of Channels in a Microstrip Diplexer

В данной статье приведены результаты исследования коэффициентов связи согласующей цепи с входными резонаторами каналов в микрополосковом диплексере. Каналы диплексера представляют собой двухзвенные фильтры, а согласующая цепь – регулярный нерезонансный отрезок микрополосковой линии, помещенной между входными резонаторами каналов. Общий порт подключен к наружному концу отрезка, а его второй конец разомкнут. Исследования проводили теоретически с помощью компьютерной программы, разработанной на основе математических выражений, полученных применением одномерных моделей и квазистатического приближения. Результаты исследования показывают, что величина связи достаточно велика и использование согласующей цепи в виде нерезонансного отрезка микрополосковой линии позволяет проектировать диплексеры с широкими полосами пропускания каналовThis paper deals with investigation of the coupling coefficients between the matching circuit and the input resonators of channels in a microstrip diplexer. Diplexer channels are two-section filters, and matching circuit is regular non-resonant segment of a microstrip line placed between input resonators of channels. The common port is connected to outer end of the segment and its second end is opened. Research was carried out theoretically using a computer program developed on the basis of mathematical expressions obtained by means of one-dimensional models and quasi-static approximation. The results show that a value of coupling is quite large and the use of the matching circuit in a form of a non-resonant segment of a microstrip line allows to design diplexers with wide fractional bandwidth of the channel