L x-ray production in ionization of 60Nd by 100-250Â keV protons

L x rays of Nd have been measured for the bombardment of protons with the energies of 100-250 keV. It is found that Lγ2 (abbreviation of Lγ2,3,4,4′) x-ray emission is largely enhanced by proton impact, compared to the case of photon radiation. It is proposed that is caused by the multiple-ionization of outer-shell electrons. To verify this explanation, the enhancement for relative intensity ratio of Lι and Lβ2 to Lα x ray and the energy shift of various L-subshell x rays are discussed. In addition, the production cross sections of Lι, Lα, Lβ and Lγ x ray are obtained and compared with theoretical calculations of PWBA, ECPSSR and ECUSAR, along with various atomic parameter databases.