A Simple Model to Describe Smoke Ring Shaped Beam Profile Measurements With Scintillating Screens at the European XFEL
| Autor: | Kube, Gero, Liu, Shan, Novokshonov, Artem, Scholz, Matthias |
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| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: | |
| Zdroj: | JACoW 5 pp. (2018). doi:10.3204/PUBDB-2018-03837 7th International Beam Instrumentation Conference, IBIC2018, Shanghai, China, 2018-09-09-2018-09-13 |
| DOI: | 10.18429/jacow-ibic2018-weoc03 |
| Popis: | 7th International Beam Instrumentation Conference, IBIC2018, Shanghai, China, 9 Sep 2018 - 13 Sep 2018; JACoW 5 pp. (2018). Standard beam profile measurements of high-brightness electron beams based on optical transition radiation (OTR) may be hampered by coherence effects induced by the micro–bunching instability which render a direct beam imaging impossible. For the European XFEL it was therefore decided to measure transverse beam profiles based on scintillating screen monitors using LYSO:Ce as scintillator material.While it is possible to resolve beam sizes down to a few micrometers with this kind of scintillator, the experience during the commissioning of the XFEL showed that the measured emittance values were significantly larger than the expected ones. In addition, beam profiles measured at bunchc harges of a few hundreds of pico-Coulomb show a ‘smokering’ shaped structure. While coherent OTR emission and beam dynamical influence can be excluded to explain this observation, it is assumed that the beam profile distortions are caused by effects from the scintillator material. A simplemodel is presented which takes into account quenching effects of excitonic carriers inside a scintillator in a heuristic way. Based on this model, the observed beam profiles can be understood qualitatively. Together with the model description, first comparisons with experimental results are presented. Published by JACoW |
| Databáze: | OpenAIRE |
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