1. 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)

2. Particle acceleration
A.Shapovalov
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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

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

4. Particle acceleration
A.Shapovalov
: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

5. Particle acceleration
A.Shapovalov
: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

6. Particle acceleration
A.Shapovalov
: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

7. Particle acceleration
A.Shapovalov
: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

8. Particle acceleration
A.Shapovalov
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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

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

10. Liouville’s theorem (definitions)
A.Shapovalov
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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

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

12. Definition of Emittance
A.Shapovalov
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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:

13. IMPORTANCE of Emittance
A.Shapovalov
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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.

14. Emittance measurement hardware
A.Shapovalov
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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

15. single slit scan technique
A.Shapovalov
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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.

16. single slit scan technique
A.Shapovalov
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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

17. single slit scan technique
A.Shapovalov
: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

18. single slit scan technique
A.Shapovalov
: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

19. single slit scan technique
A.Shapovalov
: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

20. single slit scan technique
A.Shapovalov
: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

21. single slit scan technique
A.Shapovalov
: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

22. single slit scan technique
A.Shapovalov
: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

23. single slit scan technique
A.Shapovalov
: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

24. single slit scan technique
A.Shapovalov
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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)

25. Emittance measurement wizard
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A.Shapovalov

26. Emittance measurement wizard
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A.Shapovalov

27. Emittance measurement wizard
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A.Shapovalov

28. Video demonstration!
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A.Shapovalov

29. THANK YOU FOR YOUR ATTENTION
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A.Shapovalov