APPLICATION OF HIGH-RESOLUTION, HIGH-SENSITIVITY SPECTROMETRY IN THE EXTREME-ULTRAVIOLET WAVELENGTH RANGE FOR DIAGNOSTICS OF SINGLE AND DOUBLE-ELECTRON CAPTURE PROCESSES IN HE2++HE AND AR8++HE COLLISIONS

We have applied a new, more efficient diagnostic technique for studies of extreme ultraviolet (EUV) radiation from multicharged ions interac ting with He gas. Following single and double electron capture and one electron capture plus target-ion excitation in He2++He and Ar8++He co llisions, the subsequent emitted EUV photons are analyzed with a high- resolution 2.2 m grazing incidence monochromator in conjunction with a new type of glass capillary converter (GCC) specifically designed for the EUV wavelength region. This new optical device images a horizonta l cylindrical ion beam segment onto the vertical entrance slit of the monochromator. With this new imaging technique a spectral intensity en hancement of about 10 has been achieved over a distance of about 60 cm . By further optimizing this method an enhancement of the flux density of EUV radiation of about 20-30 is expected. As prototype examples, n ew advanced EUV spectra arising from He2++He and Ar8++He collisions ar e presented and discussed. (C) 1997 American Institute of Physics.