Wyniki wyszukiwania - Biblioteka Nauki

1

Numerical simulations of generation of high-energy ion beams driven by a petawatt femtosecond laser

100%

Domański J. , Badziak J. , Jabłoński S.

Nukleonika

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2015

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tom 60

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nr 2

229-232

EN

This contribution presents results of a Particle-in-Cell simulation of ion beam acceleration via the interaction of a petawatt 25 fs laser pulse of high intensity (up to ~1021 W/cm2) with thin hydrocarbon (CH) and erbium hydride (ErH3) targets of equal areal mass density (of 0.6 g/m2). A special attention is paid to the effect that the laser pulse polarization and the material composition of the target have on the maximum ion energies and the number of high energy (>10 MeV) protons. It is shown that both the mean and the maximum ion energies are higher for the linear polarization than for the circular one. A comparison of the maximum proton energies and the total number of protons generated from the CH and ErH3 targets using a linearly polarized beam is presented. For the ErH3 targets the maximum proton energies are higher and they reach 50 MeV for the laser pulse intensity of 1021 W/cm2. The number of protons with energies higher than 10 MeV is an order of magnitude higher for the ErH3 targets than that for the CH targets.

2

Spektrometr mas z pomiarem czasu przelotu jonów w zakładzie fizyki stosowanej UMCS

100%

Giuch K. , Bajuk A. , Michalak L.

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2001

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tom nr 2-3

54-63

PL

Spektrometria mas oparta na pomiarze czasu przelotu jonów (TOF-MS Time Qf Flight Mass Spectrometry) jest obecnie szeroko stosowaną techniką ich rozdzielania. Koncepcja tego typu spektrometru zaproponowana została po raz pierwszy w 1948 roku przez A.E. Camerona. Dopiero wprowadzenie w latach 70-tych i 80-tych ubiegłego stulecia wielu udoskonaleń, zarówno w źródle jonów (zastosowanie nanosekundowych laserów) jak i optyce jonowej (zastosowanie reflektronu), uczyniło je bardzo cenionymi urządzeniami analitycznymi. Główne zalety takich spektrometrów to praktycznie nieograniczony zakres analizowanych mas, stosunkowo prosta konstrukcja oraz możliwość detekcji ciężkich molekuł. Praca przedstawia rozwiązania konstrukcyjne i parametry pomiarowe spektrometru mas z pomiarem czasu przelotu jonów zbudowanego w Zakładzie Fizyki Stosowanej Instytutu Fizyki Uniwersytetu Marii Curie-Sklodowskiej. Spektrometr ten służy do badań zjawisk jonizacyjnych metodą MALDI.

EN

Time of flight mass spectrometry (TOF-MS) is a common technique used to resolve mass difference of ions. The concept of this spectrometer was proposed first time in 1948 by A.E. Cameron. Many improvements in ion source (application of nanosecond lasers) and ions optics (application of the reflectron) at the 70's and 80's made the time of flight mass Spectrometry very useful for analytical applications. The main advantages of such systems are practically unlimited mass range, straightforward construction and possibility of high masses of molecules detection. This work presents construction and measurement parameters of the time of flight mass spectrometer built in the Division of Applied Physics, Institute of Physics, Maria Curie-Sklodowska University. This spectrometer is used for studies of ionization processes by MALDI method.

3

Selected methods of electron-and ion-diagnostics in tokamak scrape-off-layer

75%

Sadowski M. J.

Nukleonika

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2015

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tom 60

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nr 2

199-206

EN

This invited paper considers reasons why exact measurements of fast electron and ion losses in tokamaks, and particularly i n a scrape-off-layer and near a divertor region, are necessary in order to master nuclear fusion energy production. Attention is also paid to direct measurements of escaping fusion products from D-D and D-T reactions, and in particular of fast alphas which might be used for plasma heating. The second part describes the generation of so-called runaway and ripple-born electrons which might induce high energy losses and cause severe damages of internal walls in fusion facilities. Advantages and disadvantages of different diagnostic methods applied for studies of such fast electrons are discussed. Particular attention is paid to development of a direct measuring technique based on the Cherenkov effect which might be induced by fast electrons in appropriate radiators. There are presented various versions of Cherenkov-type probes which have been developed by the NCBJ team and applied in different tokamak experiments. The third part is devoted to direct measurements of fast ions (including those produced by the nuclear fusion reactions) which can escape from a high-temperature plasma region. Investigation of fast fusion-produced protons from tokamak discharges is reported. New ion probes, which were developed by the NCBJ team, are also presented. For the first time there is given a detailed description of an ion pinhole camera, which enables irradiation of several nuclear track detectors during a single tokamak discharge, and a miniature Thomson-type mass-spectrometer, which can be used for ion measurements at plasma borders.

4

Wyznaczanie wartości współczynników dyfuzji efektywnej wybranych jonów w zestalonych strukturach mieszanin odpadów hutniczych i elektrowniach

63%

Wolski P. , Dąbrowska L. , Płoszaj J.

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1998

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tom T. 1, nr 1

57-64

PL

Wyznaczono wartości współczynników dyfuzji efektywnej jonów wapniowych, potasowych, sodowych, glinowych, chlorkowych i chromu (VI), dyfundujących w zestalonych mieszaninach popiołów z dodatkiem hutniczych szlamów poneutralizacyjnych. Obliczone wartości współczynników dyfuzji zmieniały się od 6 × 10(-9) do 3 × 10(-12) m2/s. Najwyższe wartości uzyskano dla jonów sodu i potasu, najniższe dla wapnia. W celu uzyskania pełnego obrazu migracji jonów z podobnych struktur tworzonych na składowiskach stwierdzono konieczność kontynuowania badań w warunkach dynamicznego ługowania.

EN

Effective diffusion coefficients were investigated for ions Ca2+, K+, Na+, Al3+, Cl- and Cr(VI), which were diffusing within the solidified mixtures of ashes, with the addition of neutralization sludges. The values of diffusion coefficients varied from 6 × 10(-9) to 3 × 10(-12) m2/s, the highest being found for K+, Na+ cations, whereas the lowest for Ca2+. To get better insight in ions migration phenomena from similar structures in the dumping sites, it was recommended to carry out leaching experiments under the dynamic conditions.