الفهرس | Only 14 pages are availabe for public view |
Abstract An electron - atom crossed beam apparatus was built, tomeasure the optical excitation function and the polarisation of the Callᶋ - 3933 % ( 42P3/2-> 42 S1/2 ) line following simultaneous ionisation and excitation from calcium ground state atoms by electron impact. The measurements were carried out in the energy range from 10 eV to 200 eV. The measured data for the excitation function of the Call ᶋ= 3933 A (4 2P3/2 -> 4 2S1/2 ) line showed a steep rise from threshold to a maximum at ≈ 18 eV, then it decreased rather quickly with increasing the electron energy. The polarisation measurements of the Call ᶋ = 3933 % ( 42P3/2-► 42’S1/2 ) line gave a peak value of 19 % near threshold and converged to zero at high electron energies. To check our polarisation measurements, we measured the excitation functions and the polarisation of the Cal ᶋ= 4227 % ( 41P1 41S0) Hel ᶋ= 4713Å (43 S--> 23 P ) lines and compared with early workers. The agreement between the present data and the previous published work is very good. |