portion between the two ends which may be provided in order to remove particularly fine particles u201c fines u201d from a particle sample being inspected in some instances the volume of fines that are mixed with the larger particles can create a u201c dirt curtain u201d through the image area or otherwise interfere with optimal imaging of the larger particles depending on the type of particles being inspected and the type of analysis being performed the gage of the screened recess may be adjusted or a feeder without a screened recess may be used a gating mechanism may be optionally used in the feeder with or without a screened recess to separate out particles according to size and or to control the rate of migration of the particles through the feeder one example of a gating mechanism shown in fig6 includes a low profile raised portion 61 of tray surface 53 of the feeder raised portion 61 may be a strip of material connected for example by welding to tray surface 53 raised portion 61 is sized so as to extend above the rest of surface 53 enough to divert fine particles toward the edges of tray surface 53 while enabling larger particles to vibrate over raised portion 61 without being significantly diverted by diverting the fines to the edges of the tray surface 53 interference with the imaging of the larger particles is reduced or eliminated the optimal height of raised portion 61 for diverting fine particles will depend on among other factors the size of particles being imaged and the size of fine particles to be diverted for applications in which the fines are an important component.