The Competition Of Scattering And Guiding Force To Intermediate Velocity Ions In Insulating Capillaries

This thesis includes two main parts:the test of a2D-MCP detector and the measurement by using this detector. First, we build up a2D-PSMCP detector. In detail, we design the holder, set the electronic chain and control the electronic noises. Via the test of the detector, it is found that the angular resolution is about0.02degree, which is much less than the tilt angle (1-2degree) of the PC membrane in the measurement. The output noise from142A is better than10mV, and it is much lower than the signal amplitude of the ion hitting on MCP surface. The resolution is good and the noise is low enough for the measurement in this work.By using this detector, we measured the time evolution of the charge state and angular distribution of the ions and atoms transmitted form200nm diameter and30μm length PC nanocapillaries. The dependences of these characters on incident angle and beam intensity are obtained. The main conclusions are:the outgoing particles all move to the direction parallel to the incident beam, and the FWHM of angular distribution is2～3times larger than the geometry angle of the capillary hole. When the incident beam intensity is sufficient high, most of the outgoing particles hold their initial charge state.These indicate that, the transmission of several tens keV ions in capillary is quite different from that of keV energy ions. For keV energy ions, the deposited charges not only inhibit the charge exchange but also significantly decrease the perpendicular momentum of the incident ion. Then, the ion will be pushed to the direction along the capillary hole by the charges near the entrance. For low to intermediate velocity ions, the charge exchange can be inhibited by the deposited charges, but the large perpendicular momentum of the incident ion cannot be decreased. So, ions contain their initial charge will be scattered to the opposite side near the exit, then another strong charge patch will be formed.In summary, large perpendicular momentum of the incident ion leads to the appearance of two strong charge patches after equilibrium. One is near the entrance and another is at the exit. These two charge parches make the direction of the outgoing particle parallel to the direction of incident beam and most of them have their initial charge state.