Monochromatic coherent transition and diffraction radiation from a relativistic electron bunch train

Electron beams of most accelerators have a bunched structure and are synchronized with the accelerating RF field. Due to modulation of the electron beam with frequency v[RF] one can expect to observe resonances with frequencies vk= k·v[RF] in radiation spectrum generated via any spontaneous emission mechanism (k is an integer and the resonance order). In this paper we present the results of spectral measurements of coherent transition radiation (CTR) generated by an electron bunch train from the Tomsk microtron with v[RF]=2.63GHz in the spectral frequency range from 8 to 35 GHz. We also measured the spectrum of coherent diffraction radiation and demonstrated that the observed spectra in both cases consist of monochromatic lines. For spectral measurements the Martin-Puplett interferometer with spectral resolution of 800 MHz (FWMH) was employed. Using a waveguide frequency cut-off we were able to exclude several spectral lines to observe higher resonance orders of up to k=7

Health-Saving Competence of Future Primary School Teachers: Indicators of Development

Дослідження виявило зростаючий інтерес науковців до проблеми формування здоров’язбережувальної компетентності майбутніх учителів початкових класів. Ця тенденція зумовлена необхідністю проведення соціального дослідження, щоб модернізувати підготовку майбутніх освітян, удосконалити окремі сфери. Автори досліджень розробили експериментальний тест на формування здоров’язбережувальної компетентності майбутніх учителів початкових класів. Досягнення цієї мети передбачає аналіз стану розвитку проблеми в педагогічній теорії та практиці. Дослідження систематизує життєві навички фізичного, соціального та психічного здоров'я, які сприяють формуванню здоров’язбережувальної компетентності людини. У результаті дослідження була розроблена система діагностики для визначення здоров’язбережувальної компетентності майбутніх учителів початкових класів. Аналіз науково-педагогічних джерел дав змогу виявити такі структурні компоненти підготовки до організації оздоровчої діяльності молодших школярів, як мотиваційні, змістові та технологічні. Мотиваційний компонент оцінювався за критерієм позитивного ставлення до організації здоров’язбережувальної компетентності молодших школярів та формування системи внутрішніх мотивів (інтересів, цінностей, переконань). Знання теоретичного блоку діагностували за допомогою тестів, що включали завдання з виявлення рівня засвоєння інформації про сутність здоров’язбережувальної компетентності дітей. Здатність розробляти власні варіанти педагогічних оздоровчих технологій для збереження здоров’я молодших школярів оцінювали за допомогою творчих завдань.The research revealed an increasing interest of scientists to the problem of formation of health-saving competence of future primary school teachers. This tendency is due to the need for a social inquiry to modernize the training of future educators, to improve the individual areas. The authors of research developed an experimental test of the formation of health-saving competency of future primary school teachers. Achieving this goal involves the analysis of the state of development of a particular problem in pedagogical theory and practice. The study systematizes the physical, social and mental health life skills that contribute to the formation of a person’s health-saving competence. As a result of the study, a diagnostic system was developed to determine the health-saving competency of future primary school teachers. The analysis of scientific and pedagogical sources made it possible to identify such structural components of students’ preparation for the organization of health-saving activities of younger students as motivational, content, and technological ones. The motivational component was assessed according to the criterion of students’ positive attitude towards the organization of health-saving competence of younger students and the formation of a system of internal motives (interests, values, beliefs). Knowledge of the theoretical block was diagnosed with the help of tests that included the task of identifying the level of mastery of information about the essence of health-saving competence of children. The ability to develop their own variants of pedagogical health technologies for preserving younger students was assessed with the help of the creative tasks

Monochromaticity of coherent Smith-Purcell radiation from finite size grating

Investigation of coherent Smith-Purcell Radiation (SPR) spectral characteristics was performed both experimentally and by numerical simulation. The measurement of SPR spectral line shapes of different diffraction orders was carried out at KEK LUCX facility. A pair of room-temperature Schottky barrier diode (SBD) detectors with sensitivity bands of $60-90$~GHz and $320-460$~GHz was used in the measurements. Reasonable agreement of experimental results and simulations performed with CST Studio Suite justifies the use of different narrow-band SBD detectors to investigate different SPR diffraction orders. It was shown that monochromaticity of the SPR spectral lines increases with diffraction order. The comparison of coherent transition radiation and coherent SPR intensities in sub-THz frequency range showed that the brightnesses of both radiation mechanisms were comparable. A fine tuning feasibility of the SPR spectral lines is discussed.Comment: 7 pages, 7 figures, 3 table

SPECIAL FEATURES OF SPECTRAL RADIATION CHARACTERISTICS OF RELATIVISTIC ELECTRONS IN CRYSTALS

The aim is to perform the experimental investigation on the spectral radiation characteristics of the relativistic electrons at axial canalization in the crystals. The experiments were performed on the specialized plants on the electron beam of the synchrotron "Sirius" with electron energy 900 MeV. It has been shown that the radiation at volumetric capture and coherent braking radiation give the basic contribution into the radiation at canalization in the thick crystals. The non-applicability of the dipole approximation in these conditions has been shown firstly. The presence of the radiation plurality in these conditions has been discovered. The distribution of the radiation according to a number of the photons has been obtained firstlyAvailable from VNTIC / VNTIC - Scientific & Technical Information Centre of RussiaSIGLERURussian Federatio

Positron Production in Tungsten Crystals by 1.2-GeV Channeling Electrons

The efficiency of positron production by a 1.2-GeV electron beam incident on a tungsten single crystal oriented in an axially channeling condition has been experimentally studied. Positron yields from a 1.2-mm-thick crystal have been measured to be ∼2.5-3.0 times larger than those from amorphous targets with the same thickness. A simple model simulation of the positron production process shows that coherent bremsstrahlung, as well as channeling radiation, contributes to the enhancement of the positron yields