5/3/2023 0 Comments Deflector meaningSome examples conjunctions are: and, but, or, nor, although, yet, so, either, and also. It tells what kind, how many, or which one.Ĭonjunction - A conjunction is a word that joins words or word groups together. It may stand for a person, place, thing, or idea.Īdjective - An adjective is a word that describes a noun or pronoun. Proper Noun - The pronoun is a word used in place of one or more nouns. Nouns are the subject of a sentence.Ĭommon Noun - A noun that does not name a specific person, place or thing. Noun - A noun is a person, place, thing, or idea. They tell how much, how often, when and where something is done. The term \(\overline = r\).Verb - A verb is a word that expresses an action or a state of being.Īdverb - An adverb describes how the action is performed. Finally, in “ Discussion”, the promising advantages of the non-conventional layout are discussed. In section “ Experimental verification”, a preliminary experimental validation on CLEAR at CERN is reported. In section “ Validation using tracking simulations”, the mathematical derivation is numerically validated through a reference simulation tool, the ELEGANT code 33. In particular, in section “ Methods”, the general theory is derived analytically. Furthermore, the metrological performance of the method with the focusing element is analyzed. ![]() It will be proven that the focusing element does not introduce additional effects that can invalidate the measurement. In this paper, a theoretical derivation of the bunch length measurement, when focusing elements are present between the RFD and the screen, is presented. However, the impact on the RFD measurement quality of the position of the focusing element was not investigated until now. Furthermore, quadrupoles could be used to focus the beam on the screen. In other cases, dimensional problems arise in the physical installation as a whole, e.g. to reduce the space between the klystron and the deflecting cavity, by consequently shortening the necessary waveguides. Usually, the space between the RFD and the screen is just needed to deflect enough the bunch (Fig. CLEAR 11, ATF 31, and DESY 32) for various reasons. In various accelerators, focusing elements are installed between the RFD and the screen (e.g. an Optical Transition Radiation screen) which produces a light pulse of the same length as the electron bunch 20 (ii) Electro-Optical Sampling (EOS), which uses an external laser that passes through a non linear crystal parallel to the beam, to measure the polarization modulation on the laser pulse due to the electric field associated with the bunch 21, 22 (iii) spectral analysis of the bunch frequency content the bunch length is assessed by analyzing the frequency spectrum of coherent emission from the bunch 23, 24, 25, 26, 27, and (iv) the measurement of the beam energy spread when using an accelerating cavity not on the RF crest 28, 29, 30. ![]() Other well-known techniques to perform bunch length measurements are: (i) the streak camera: a high time resolution camera (based on the use of a photo-multiplier and a rapidly changing electric field) collects the light from a specific screen (e.g. For example, RFDs are used at CERN Linear Electron Accelerator for Research (CLEAR) 11, Stanford Linear Accelerator Center (SLAC) 12, 13, Deutsches Elektronen–Synchrotron (DESY) 14, Massachusetts Institute of Technology (MIT) Plasma Science and Fusion Center (PSFC) 15, Sources for Plasma Accelerators and Radiation Compton with Lasers And Beams (SPARC LAB) 16, 17, the ultraviolet and soft X-ray FEL facility Free-electron LASer in Hamburg (FLASH) 18, the Accelerator Test Facility (ATF) in Brookhaven National Lab (BNL) 19, and so on. RFDs are widely used in LINACs around the world, owing to their very high resolutions. a dipole) can be exploited to measure the longitudinal phase space distribution of the beam 7, 10. The combination of an RFD and a dispersive element (i.e. The method allows to measure ultra-short electron beam bunches down to few fs 1, 3, 8, 9. The bunch length can then be obtained from the measurement of the spot size in the direction of the deflection, after a suitable calibration of the displacement dependence on the deflecting voltage RF phase 7. In this way, the longitudinal and transverse bunch dimensions of the beam on the screen are correlated.
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