Patent ID: 7317515
Filing Date: 2008-01-08
Classification: G01N,H01J

Abstract:
1. A method of determining the location of markers that are excitable by radiation in a sample to be investigated, comprising: providing a sample having markers; irradiating the sample with a first radiation beam, as a result of which an excitation region is formed in the sample, in which excitation region markers are excited; detecting fluorescence radiation emanating from markers in response to the excitation, and; reducing, with the aid of a second radiation beam, the detectable fluorescence radiation in a portion of the excitation region, characterized in that: the second radiation beam is a focused particle beam that is scanned across a portion of the sample, the portion including at least a portion of the excitation region; the focus of the particle beam has a cross section smaller than the cross section of the excitation region; the energy of the particles in the particle beam is sufficient to lower the flux of fluorescence radiation emanating from markers impacted by the particles; and the position of the focused particle beam with respect to the sample at the time that the flux decreases by at least a previously determined threshold value is registered.