Apparatus for detecting thermal radiation emanating from two different intracranial depths in a patient includes a transducer having a surface for placement against the patient’s cranium. To this end, a magnetic flux pattern is rectified outside any one N-pole of forward and aft end poles of a field magnet. The interface file system also looks for changes made to the contents of files already stored in the work file system and creates an update file in a mirror file system if a change to the contents of a file stored in the work file system is observed by the interface file system.