Abstract: A location detection system for detecting a location of a wafer within a transfer robot vacuum chamber (TRVC), the detection system may include (i) an illumination unit that is configured to direct a transmitted radiation pattern through a transparent window of the TRVC and towards one or more TRVS reflecting elements located below an upper side of a wafer holding element of the transfer robot; wherein the illumination unit is located outside the TRVC; (ii) a sensing unit that is configured to generate one or more detection signals indicative of a received radiation pattern that is reflected from the one or more TRVS reflecting elements; and (iii) a location processing circuit that is configured to detect a location of the wafer based on the one or more detection signals.