Measuring Detector Gains with Electronic Recoils and a Doke Plot

Searches for dark matter in dual-phase time-projection chambers distinguish electronic recoils (ER) from nuclear recoils (NR) by comparing the strengths of prompt scintillation (S1) to delayed electroluminescence (S2). Utilizing both internal and external ER calibration sources, the LUX-ZEPLIN (LZ) experiment measures the S1 and S2 response to recoil events. Position dependent gain factors, g1 and g2, are defined that convert the S1 and S2 signals to the average number of photons and average number of electrons, respectively. The gain factor values may be measured in data using the Doke plot technique, in which the mean light yield is plotted against the mean charge yield. In this talk, I will present the status of this work and the values of g1 and g2 - critical indicators of an instrument's overall performance, thus determined.