Smaluk, V.V. JACoW Geneva, Switzerland 978-3-95450-187-8 10.18429/JACoW-eeFACT2016-TUT3AH3 English 112-119 TUT3AH3 ion impedance vacuum simulation damping Contribution to a conference proceedings 2017 2017-07 https://doi.org/10.18429/JACoW-eeFACT2016-TUT3AH3 http://jacow.org/eefact2016/papers/tut3ah3.pdf Characterization of a vacuum chamber impedance is necessary to estimate stability conditions of a particle beam motion, to find a limit of the beam intensity and characteristic times of single-bunch and multi-bunch instabilities. For new accelerator projects, minimization of the vacuum chamber impedance is now the mandatory requirement. For an accelerator in operation, the impedance can be measured experimentally using various beam-based techniques. The beam-impedance interaction manifests itself in measurable beam parameters, such as betatron tunes, closed orbit, growth rates of instabilities, bunch length and synchronous phase. The beam-based techniques developed for measurement of the longitudinal and transverse impedance are discussed, including theoretical basics and experimental results.