Dynamic switching of a detector switch matrix

A non-transitory computer-readable medium that stores a set of instructions that is executable by at least one processor of an apparatus to cause the apparatus to perform a method of reducing noise of an electron detector of a multi-beam SEM, the method comprising:

• receiving, by sensing elements of an electron detector, electrons from multiple secondary electron beams emitted by a sample in response to a plurality of primary beams of the multi-beam SEM interacting with the sample, each of the secondary beams being associated with a different one of the plurality of primary beams;
• based on the received electrons, coupling a first grouping of the sensing elements of the electron detector corresponding to a first beam spot of one of the secondary electron beams;
• and
• coupling a first sensing element to the first grouping in response to a first detected charge at the first sensing element exceeding a first threshold, wherein coupling the first sensing element to the first grouping enables charge to be passed from the first sensing element to a signal readout path of the first grouping;
• or
• decoupling a second sensing element from the first grouping in response to a second detected charge at the second sensing element falling below a second threshold, wherein decoupling the second sensing element from the first grouping prevents charge from being passed from the second sensing element to the signal readout path of the first grouping.

A detector comprising:

• a substrate;
• a plurality of switching elements formed on the substrate and configured to form a switching matrix, the switching matrix having a plurality of inputs, each of the inputs being configured to connect to a different one of a plurality of sensing elements, each of the sensing elements being configured to generate a signal in response to an arrival of energy at the sensing element, the switching matrix being configured to combine a grouping of signals generated from a grouping of sensing elements, the grouping of sensing elements being associated with a beam spot formed on the detector;
• and
• a plurality of transistors forming a plurality of threshold circuits, each of the threshold circuits being coupled to a different one of the plurality of sensing elements,
• wherein a first threshold circuit of the plurality of threshold circuits is coupled to a first sensing element of the plurality of sensing elements and is configured to actuate a first switching element of the switch matrix based on a comparison of a signal level of the first sensing element to a threshold.