Stable transmission of low energy electrons in glass tube with outer surface grounded conductively shielding

• The electron microbeam is useful for modifying certain fragments of biomolecule. It is successful to applythe guiding effect to making the microbeam of positively charged particles by using single glass capillary.However, the mechanism for the electron transport through insulating capillaries is unclear. Meanwhile,previous researches show that there are oscillations of the transmission intensity of electrons with time in theglass capillaries with outer serface having no grounded conductive shielding, So, the application of glasscapillary to making the microbeam of electrons is limited. In this paper, the transmission of 1.5 and 0.9 keV electrons through the glass capillary without/with thegrounded conductive-coated outer surface are investigated, respectively. This study aims to understand themechanism for low energy electron transport in the glass capillaries, and find the conditions for the steadytransport of the electrons. Two-dimensional angular distribution of the transported electrons and its timeevolution are measured. It is found that the intensity of the transported electrons with the incident energythrough the glass capillaries for the glass capillaries without and with the grounded conductive-coated outersurface show the typical geometrical transmission characteristics. The time evolution of the 1.5- keV electrontransport presents an extremely complex variation for the glass capillary without the grounded conductive-coated outer surface. The intensity first falls, then rises and finally oscillates around a certain mean value.Correspondingly, the angular distribution center experiences moving towards positive-negative-settlement. Incomparison, the charge-up process of the 0.9 keV electron transport through the glass capillary with thegrounded conductive-coated outer surface shows a relatively simple behavior. At first, the intensity declines rapidly with time. Then, it slowly rises till a certain value and stays steady subsequently. The angulardistribution of transported electrons follows the intensity distribution in general, but with some delay. It quicklymoves to negative direction then comes back to positive direction. Finally, it regresses extremely slowly andends up around the tilt angle. To better understand the physics behind the observed phenomena, the simulationfor the interaction of the electrons with SiO2 material is performed to obtain the possible deposited chargedistribution by the CASINO code. Based on the analysis of the experimental results and the simulated chargedeposition, the conditions for stabilizing the electron transport through glass capillary arepresented.

Ämnesord

NATURVETENSKAP  -- Fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Materialteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Kemiteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Chemical Engineering (hsv//eng)

NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

Nyckelord

electron guiding

secondary electron

charge deposition

glass capillary

highly-charged ions

guided transmission

dependence

blocking

dynamics

pet

Physics

electron guiding

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