A method of investigating a flux of output electrons emanating from a sample in a charged-particle microscope, which flux is produced in response to irradiation of the sample by a beam of input charged particles, the method comprising the following steps: Using a detector to intercept at least a portion of the flux so as to produce a set {Ij} of pixeled images Ij of at least part of the sample, whereby the cardinality of the set {Ij} is M>1. For each pixel p, in each image Ij, determining the accumulated signal strength Sij, thus producing an associated set of signal strengths {Sij}. Using the set {Sij} to calculate the following values: An average signal strength S per pixel position i; A variance σ2S in S per pixel position i. Using these values S and σ2S to at least one map of said part of the sample, selected from the group comprising: A first map, representing variation in energy of detected electrons as a function of position. A second map, representing variation in number of detected electrons as a function of position. The set {Ij} may be produced in different ways, such as: By iteratively repeating a procedure whereby an entire nth image In is captured before proceeding to capture an entire (n+1)th image In+1, or By iteratively repeating a procedure whereby, at an nth pixel position, a plurality M of different detector samples is collected before proceeding to an (n+1)th pixel position.