Shishlo, A.P. Aleksandrov, A.V. JACoW Geneva, Switzerland 978-3-95450-177-9 10.18429/JACoW-IBIC2016-WEAL01 English 564-568 WEAL01 linac cavity diagnostics space-charge simulation Contribution to a conference proceedings 2017 2017-02 http://dx.doi.org/10.18429/JACoW-IBIC2016-WEAL01 http://jacow.org/ibic2016/papers/weal01.pdf A summary of the longitudinal diagnostics for linacs is presented based on the Spallation Neutron Source (SNS) linac example. It includes acceptance phase scans, Bunch Shape Monitors (BSM), and a method based on the analysis of the stripline Beam Position Monitors (BPM) signals. The last method can deliver the longitudinal Twiss parameters of the beam. The accuracy, applicability, and limitations of this method are presented and discussed.