The ion probe signals from the high temperature superconductor YBa2Cu3O7 (YBCO) have been compared with the signals from a Cu target. The fastest part of the YBCO time-of-flight (TOF) signals in vacuum and at oxygen background pressures up to 0.1 mbar is similar to the same part of the Cu signal. The TOF-signals from YBCO close to normal direction are about a factor of 3 higher than those from Cu. The TOF-signals from YBCO are somewhat narrower than the Cu signals in vacuum as well as at an oxygen pressure up to 0.1 mbar. At higher pressures, there is a distinct peak-splitting of the signals, which is most pronounced for the Cu signals. The total angular distribution of the YBCO plume is significantly narrower in vacuum and at low oxygen pressure than that of the Cu plume. (C) 2002 Elsevier Science B.V. All rights reserved.