Determination of Charge State, Energy and Angular Distributions of Tin Ions Emitted From Laser Produced Plasma Based EUV Sources

Journal of Physics: Conference Series 58, 391-394 (2007).

Morris, O., Hayden, P., Dunne, P., O’Reilly, F., O’Sullivan, G., Sokell, E., Antonsen, E. L., Srivastava, S. N., Thompson, K. C., Ruzic, D. N.

We have performed time of flight (TOF) analysis to determine the intensity of ion distribution from tin based plasma for a range of charged tin ions (Sn¹⁺-Sn¹⁰⁺). A Nd:YAG laser operating at 1064 nm with a full width at half maximum pulse duration of 5.2 ns was used to create the plasma under vacuum with a base pressure of 10⁻⁶ Torr. The plasma formation occurred on a custom made optical system, which could be rotated with respect to the detector so TOF analysis could be preformed at various angles of emission, while maintaining a normal angle of incidence for the laser pulse with respect to the target. The detector used was an energy sector analyser (ESA), which is a well-characterised diagnostic capable of measuring ion energy and discriminating by charge state. Analysis was performed on ions of various charge states, with energy/charge state ratios ranging from 3 keV to 50 eV, for angles of emission from the plasma ranging from 90 to 15 degrees.