# Measurement of shower development and its Moli\`ere radius with a four-plane LumiCal test set-up **Authors:** H. Abramowicz, A. Abusleme, K. Afanaciev, Y. Benhammou, L. Bortko, O., Borysov, M. Borysova, I. Bozovic-Jelisavcic, G. Chelkov, W. Daniluk, D., Dannheim, K. Elsener, M. Firlej, E. Firu, T. Fiutowski, V. Ghenescu, M., Gostkin, M. Hempel, H. Henschel, M. Idzik, A. Ignatenko, A. Ishikawa, S., Kananov, O. Karacheban, W. Klempt, S. Kotov, J. Kotula, D. Kozhevnikov, V., Kruchonok, B. Krupa, Sz. Kulis, W. Lange, J. Leonard, T. Lesiak, A. Levy, I., Levy, W. Lohmann, S. Lukic, J. Moron, A. Moszczynski, A.T. Neagu, F.-X., Nuiry, M. Pandurovic, B. Pawlik, T. Preda, O. Rosenblat, A. Sailer, B., Schumm, S. Schuwalow, I. Smiljanic, P. Smolyanskiy, K. Swientek, P. Terlecki,, U.I. Uggerhoj, T.N. Wistisen, T. Wojton, H. Yamamoto, L. Zawiejski, I.S., Zgura, A. Zhemchugov arXiv: 1705.03885 · 2018-03-14 ## TL;DR This study tests a prototype luminometer in a beam environment to analyze electromagnetic shower development and measure the Molière radius, confirming simulation accuracy with experimental data. ## Contribution First measurement of the Molière radius for a LumiCal prototype using a four-plane tungsten-silicon setup at CERN. ## Key findings - Molière radius measured as 24.0 mm with uncertainties. - Excellent agreement between experimental data and Geant4 simulations. - Validated the multi-plane tungsten/silicon operation for future collider detectors. ## Abstract A prototype of a luminometer, designed for a future e+e- collider detector, and consisting at present of a four-plane module, was tested in the CERN PS accelerator T9 beam. The objective of this beam test was to demonstrate a multi-plane tungsten/silicon operation, to study the development of the electromagnetic shower and to compare it with MC simulations. The Moli\`ere radius has been determined to be 24.0 +/- 0.6 (stat.) +/- 1.5 (syst.) mm using a parametrization of the shower shape. Very good agreement was found between data and a detailed Geant4 simulation. --- Source: https://tomesphere.com/paper/1705.03885