Target dependence of the quadrupole content of the energy distribution of cusp electrons

The cusp electrons for electron capture to the continuum (ECC) of H+ ions impacting on He, Ne and Ar at 30, 50, 70 keV were measured. The double differential cross sections were analysed by Legendre polynomials to obtain the multipole moments of the cusp electron distribution. The results indicated that for k>1, the tendencies of mod B10/B00 mod and mod B20/B00 mod respectively decrease and increase smoothly with decreasing energy of ions H+ as in the results of Knudsen, Andersen and Jensen (1986) and with increasing mass of target as in the results of Yu and Lapicki (1987). However, the cross point of the curves for the tendencies of mod B10/B00 mod and mod B20/B00 mod is at k approximately=1.3, different from k approximately=2 for Knudsen et al. The values of mod B20/B00 mod show a dependence on the target.