Schematic top view of the DPP source. Two rotating disk electrodes are covered with a layer of liquid Sn. A laser pulse is used to evaporate the liquid Sn in between the electrodes, initiating the discharge.
Schematic of the electrostatic spectrometer based on the design of Hughes and Rojansky (Ref. 13). Two cylindrical surfaces having radii of curvature and are maintained on potentials and . The angle between the entrance slit and the exit slit equals to 127.3°. The particles that exit the spectrometer are detected using a MCP detector, read out by an oscilloscope.
A typical oscilloscope image of the measurement with the spectrometer. Trace represents the laser pulse igniting the discharge, trace shows the time derivative of the discharge current, and trace gives the signal of the ion spectrometer for an value of 3.7 keV. The charges of the Sn ions of up to are visible. At the start of the signal some noise can be seen.
The intensity of the Sn ion peaks from the spectrometer selection for different values are shown as a function of the charge number . The weighted average charge number for low values equals and for high equals .
Schematic of the dedicated FC detector configuration. The cup has a length of 60 mm and a diameter of 18 mm. In order to repel external secondary electrons it is biased with a voltage of −1.4 V. A magnetic field, with a field strength of at the center of the cup, is used to prevent internal secondary electrons from exiting the cup. The current through the load resistor is a measure of the captured ions.
The averaged FC signal measured as a function of time for , , and . The negative signal right in the beginning is because of collected electrons at the time of the pinch, and is taken as zero on the time scale.
The IED calculated from the FC signal using Eq. (7) shown as a function of . For the calculation it is assumed that all detected particles are Sn ions and kinetic energies are not shown.
The measured IED for is shown together with the calculated from Eq. (8) as a function of . As input parameters , , and .
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