Centroid depth determinations by angle-resolved self-ratio x-ray fluorescence spectrometry on ion-implanted depth profiles have been carried out at a synchrotron radiation source using "white" radiation. For ion implants of phosphorus in silicon wafers at the 10(16) CM-2 level, the results are very satisfactory. The wafer temperature can be kept to a tolerable level if the low-energy component is preabsorbed in a suitable filter (foil) and if additionally the specimen is placed in an environment of helium at atmospheric pressure. The helium atmosphere is indispensable also for avoidance of the deposition of adventitious carbon on the specimen surface. Extrapolating from the results obtained so far, one can conclude that (with the specimen properly mounted in a helium atmosphere) centroid depth measurements should be possible also at a few times 10(14) CM-2 dose density level.