Enhanced X-ray yields from insulating samples

• Published in: Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms Beam interactions with materials and atoms, 1998-03, Vol.136, p.837-840
• Main Authors: Jesus, A.P., Reis, M.A., Alves, L.C.
• Format: Article
• Language: English
• ISSN: 0168-583X; 1872-9584
• DOI: 10.1016/S0168-583X(97)00670-8

Some insulating samples under proton bombardment produce a very large bremsstrahlung background and enhanced X-ray lines. X-ray energy spectra of several insulating samples (fluorides of metals with valence 4, 3, 2 and 1, a fluoride glass and three fluoride free samples) are presented for proton energies from 0.175 to 2.00 MeV. Also, multiscaling spectra have been collected in order to relate the X-ray yield enhancement with the sample charging up process. It may be concluded that the enhancement effect is obtained during the charged state of the samples and not during the discharge and that structural properties of the samples rather than their insulating properties play an important role in producing and keeping that charged state. Considerations of ionization cross section values suggest high energy electrons as the main ionizing agent. It is also shown that some samples can hold the charged state, with corresponding high X-ray yields, for long periods, suggesting their use as X-ray sources.