Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8041285 | Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms | 2014 | 6 Pages |
Abstract
Time of flight spectra are currently acquired with a single-hit time-to-digital converter. Pulsed ion beam produces a shower of secondary ions that are ejected from positively biased target and accelerated towards MCP. We start our time measurement simultaneously with the start of the beam pulse. Signal of the first ion hitting MCP is used to stop the time measurement. Standard pulses proportional to the time of flight are produced with time to analog converter (TAC) and fed into analog-to-digital converter to obtain a time histogram. To enable efficient detection of desorbed fragments with higher molecular masses, which are of particular interest, we recently implemented a state-of art Field Programmable Gate Array (FPGA)-based multi-hit TOF acquisition. To test the system we used focused 8Â MeV 35Cl7+ ion beam with pulse length of 180Â ns. Mass resolution of measured SIMS spectra, dominantly determined by the duration of the beam pulse, is in good agreement with resolution estimated from pulse length. With improved high-voltage switching ability that will enable beam pulses with duration of 50Â ns, a mass resolution of better than 500 is anticipated.
Related Topics
Physical Sciences and Engineering
Materials Science
Surfaces, Coatings and Films
Authors
Luka Jeromel, Zdravko SiketiÄ, Nina Ogrinc PotoÄnik, Primož VavpetiÄ, Zdravko Rupnik, Klemen BuÄar, Primož Pelicon,