Brauch, A. Arnold, M. Dutine, M. Enders, J. Grewe, R. Jürgensen, L.E. Pietralla, N. Schließmann, F. Schneider, D. JACoW Publishing Geneva, Switzerland 2673-5350 978-3-95450-236-3 10.18429/JACoW-IBIC2023-TUP009 English 200-203 operation linac optics electron radiation Contribution to a conference proceedings 2023 2023-12 https://doi.org/10.18429/JACoW-IBIC2023-TUP009 https://jacow.org/ibic2023/papers/tup009.pdf The S-DALINAC is a thrice recirculating electron accelerator for high resolution electron scattering experiments with a continuous-wave beam at a frequency of 2.9972(1) GHz. Short bunches are crucial to enable tuning of the machine for operation as an energy-recovery linear accelerator* **. Currently, measurements of this beam parameter are accomplished by using the radio-frequency zero-crossing method: here, a momentum spread chirp is induced and the transverse beam profile in a downstream located dispersive section is measured with a scintillating screen providing an upper limit of the bunch length. Since this method is time consuming, a new setup for these measurements using a streak camera is developed. Optical transition radiation from an aluminum-coated Kapton target is used to map the bunch length information to a light pulse which enables an accurate measurement compared to a scintillating screen. The light pulse can then be evaluated with the streak camera by projecting its length onto the transverse dimension on a phosphor screen. This contribution will present the current status of the measurement setup as well as its design and properties.