It is impossible to monitor the position of the detector relative to the specimens or vice versa, inside the SEM when it is in operation, something that is vital not only to achieve the best possible results, but also to prevent damage to expensive equipment. Surveillance equipment is therefore essential in the form of 'in-chamber' cameras. K.E. Developments has a range of 'chamberscope' cameras for use with most makes of SEM, which use low levels of infra red illumination not normally detected by the SEM detector, thereby allowing simultaneous operation.