 Already, annular or quadrant solid-state detectors have been employed for this purpose but their geometry is not easily adaptable to the requirements of ESEM for optimum operation.As a result, no much use has been reported of these detectors on genuine ESEM instruments at high pressure.The "Robinson" BSE detector is tuned for operation up to around 100 Pa at the usual working distance of conventional SEM for the suppression of specimen charging, whilst electron collection at the short working distance and high pressure conditions make it inadequate for the ESEM.