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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Sensitivity in MALDI MS with small spot sizes

Yamchuk, Andriy 15 January 2014 (has links)
In MALDI, for laser fluences below the saturation point the ion yield per shot follows a cubic dependence on the irradiated area, leading to a conclusion that smaller spots produce overall less ions and therefore are less viable. However, Qiao et al. showed that by decreasing the laser spot size it is possible to raise the saturation point, and thus increase the ion yield per unit area, also known as sensitivity. Here we explore laser spots below 10 micrometer diameter to determine whether they offer any practical advantage. We show that sensitivity is greater for a flat-top 3-4 micrometer spot than for a 10 micrometer spot. The sensitivity is greater for a Gaussian-like 3-5 micrometer spot than for flat-top 5-25 micrometer spots. We also report for the first time sensitivity versus theoretical fluence profile for a Gaussian-like beam focused to a spot of 3-5 micrometer.

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