A.Shapovalov (DESY, Zeuthen) (MEPhI, Moscow, Russia) EMSY (Emittance Measurement System) at PITZ – a short introduction – how it works – for what it is needed A.Shapovalov (DESY, Zeuthen) (MEPhI, Moscow, Russia)

Particle acceleration A.Shapovalov 25.04.2017 22:17 Particle acceleration Basic scheme of particle acceleration (3 phases): beam shaping and its injection beam acceleration beam extraction on target Target accelerating chamber Vacuum Source

Particle acceleration A.Shapovalov 25.04.2017 22:17 Particle acceleration The beam source has next basic parameters: average initial energy beam current cross-section size average angular divergence Source 1 ? Source 2

Particle acceleration A.Shapovalov 25.04.2017 22:17 Particle acceleration The beam source has next basic parameters: average initial energy beam current cross-section size average angular divergence Source 1 Source 2

Particle acceleration A.Shapovalov 25.04.2017 22:17 Particle acceleration The beam source has next basic parameters: average initial energy beam current cross-section size average angular divergence Source 1 Source 2

Particle acceleration A.Shapovalov 25.04.2017 22:17 Particle acceleration The beam source has next basic parameters: average initial energy beam current cross-section size average angular divergence Source 1 Source 2

Particle acceleration A.Shapovalov 25.04.2017 22:17 Particle acceleration The beam source has next basic parameters: average initial energy beam current cross-section size average angular divergence Source 1 Source 2

Particle acceleration A.Shapovalov 25.04.2017 22:17 Particle acceleration What are good parameters of a beam? average initial energy -> maximum beam current -> maximum cross-section size -> minimum average angular divergence -> minimum Interacted parameters -> the golden mean Good source

Liouville’s theorem (definitions) A.Shapovalov 25.04.2017 22:17 Liouville’s theorem (definitions) particle has in phase space. all particles are in - 6d phase space volume particles in phase-space density -> phase velocity ->

Liouville’s theorem (definitions) A.Shapovalov 25.04.2017 22:17 Liouville’s theorem (definitions) Liouville equation => The Liouville equation describes the time evolution of phase space distribution -phase-space density -phase velocity The equation is true for projections

Liouville’s theorem (Conclusions) A.Shapovalov 25.04.2017 22:17 Liouville’s theorem (Conclusions) - phase space volume is constant (conservation law) decrease of coordinate dispersion leads to increase of angular dispersion (divergence)

Definition of Emittance A.Shapovalov 25.04.2017 22:17 Definition of Emittance the representation of the phase space => the transverse divergence angles particles in the area The transverse emittance in x-direction: The normalized emittance:

IMPORTANCE of Emittance A.Shapovalov 25.04.2017 22:17 IMPORTANCE of Emittance Emittance is key beam characteristic Quality index of injected beam The smaller is emittance, the greater is quality PITZ: Development of electron sources with minimized transverse emittance XFEL: after gun of at a bunch charge of 1nC must be reached.

Emittance measurement hardware A.Shapovalov 25.04.2017 22:17 Emittance measurement hardware EMSY3 EMSY2 EMSY1 EMSY consists of two orthogonal actuators YAG or OTR screen for measurement of the transverse RMS beam size EMSY has four degrees of freedom: rectilinear vertical and horizontal motion and rotation around both transverse axes

single slit scan technique A.Shapovalov 25.04.2017 22:17 single slit scan technique The Lorentz factors is measured using a dispersive section downstream of EMSY The RMS size is measured directly by observing the beam profile on a screen (OTR or YAG) with scintillating material inserted at the position of the slit mask. CCD camera Scan&Grab is stopped.

single slit scan technique A.Shapovalov 25.04.2017 22:17 single slit scan technique The uncorrelated local divergence is estimated by cutting the electron beam into thin slices and measuring their size on a screen after propagation in a drift space. Normalized RMS emittance 1 2 3 4 5 6 7 8 9 1

single slit scan technique A.Shapovalov 25.04.2017 22:17 single slit scan technique The uncorrelated local divergence is estimated by cutting the electron beam into thin slices and measuring their size on a screen after propagation in a drift space. 1 2 3 4 5 6 7 8 9 2

single slit scan technique A.Shapovalov 25.04.2017 22:17 single slit scan technique The uncorrelated local divergence is estimated by cutting the electron beam into thin slices and measuring their size on a screen after propagation in a drift space. 1 2 3 4 5 6 7 8 9 3

single slit scan technique A.Shapovalov 25.04.2017 22:17 single slit scan technique The uncorrelated local divergence is estimated by cutting the electron beam into thin slices and measuring their size on a screen after propagation in a drift space. 1 2 3 4 5 6 7 8 9 4

single slit scan technique A.Shapovalov 25.04.2017 22:17 single slit scan technique The uncorrelated local divergence is estimated by cutting the electron beam into thin slices and measuring their size on a screen after propagation in a drift space. 1 2 3 4 5 6 7 8 9 5

single slit scan technique A.Shapovalov 25.04.2017 22:17 single slit scan technique The uncorrelated local divergence is estimated by cutting the electron beam into thin slices and measuring their size on a screen after propagation in a drift space. 1 2 3 4 5 6 7 8 9 6

single slit scan technique A.Shapovalov 25.04.2017 22:17 single slit scan technique The uncorrelated local divergence is estimated by cutting the electron beam into thin slices and measuring their size on a screen after propagation in a drift space. 1 2 3 4 5 6 7 8 9 7

single slit scan technique A.Shapovalov 25.04.2017 22:17 single slit scan technique The uncorrelated local divergence is estimated by cutting the electron beam into thin slices and measuring their size on a screen after propagation in a drift space. 6 beamlets 1 2 3 4 5 6 7 8 9 8

single slit scan technique A.Shapovalov 25.04.2017 22:17 single slit scan technique Normalized RMS emittance The uncorrelated divergence is obtained by analyzing the profiles of the beamlets produced from the slits which drift some distance downstream. There the spatial distribution of the beamlets corresponds to the local uncorrelated divergence , which can be derived from the size of the beamlet using (1) The total uncorrelated divergence of the beam is estimated by a weighted average of several measurements of the local divergence taken from different locations across the beam (2) (1) (2)

Emittance measurement wizard 25.04.2017 22:17 A.Shapovalov

Emittance measurement wizard 25.04.2017 22:17 A.Shapovalov

Emittance measurement wizard 25.04.2017 22:17 A.Shapovalov

Video demonstration! 25.04.2017 22:17 A.Shapovalov

THANK YOU FOR YOUR ATTENTION 25.04.2017 22:17 A.Shapovalov