Electron and ion emission from surfaces bombarded with large molecular ions (10-100 kDa) at keV energies.
- Univ. of Manitoba, Winnipeg (Canada)
Collisions of polyatomic ions with surfaces play an important role in mass spectrometry; they may be involved in ion detection, ion production or ion dissociation. In particular, with the dramatically increased mass range available in mass spectrometry (now several hundred kDa), detection of large (low velocity) molecular ions has become an important problem. The authors have studied secondary ion and electron emission from a variety of surfaces in a tandem time-of-flight mass spectrometer using large molecular ions with energies in the range 1.0 - 30 keV and masses from 276 Da to 113 kDa, produced by matrix-assisted laser desorption. Both ion and electron emission occur for specific energies (velocities) as low as 0.1 eV/Da, well below the predicted threshold for kinetic emission of electrons. Below about 1 eV/Da ion emission is more likely than electron emission. The efficiency of electron or ion production for incident high mass ions at 30 keV is surprisingly high (tens of per cent); presumably the low velocity is compensated by the large number of atoms in the projectile.
- OSTI ID:
- 199870
- Report Number(s):
- CONF-941129-; TRN: 95:005652-0372
- Resource Relation:
- Conference: 13. international conference on the application of accelerators in research and industry, Denton, TX (United States), 7-10 Nov 1994; Other Information: PBD: 1994; Related Information: Is Part Of Thirteenth international conference on the application of accelerators in research and industry; Duggan, J.L.; Morgan, I.L. [eds.]; PB: 201 p.
- Country of Publication:
- United States
- Language:
- English
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