1. IRIDE: The Photon Machine
Luca Serafini, Fabio Villa INFN/Milano, INFN/LNF
WG2 Conveners
High Power High Quality Optical Photon Beams as Converters of Electron Beams Brightness into High Brilliance (X/) Photon Beams via high efficiency Compton/Thomson back-scattering of new generation (photons/electron >>1)
Two main cathegories of Optical Photon Beams: Amplified Pulsed Lasers (J-class, 100 Hz) Enhanced CW Lasers in Fabry-Perot Cav. (mJ-class, 100 MHz)
Luminosity Issues for Nuclear Photonics, -g Colliders and e- Colliders
IRIDE Study Day - LNF - March 14th 2013

2. Some Basics of Inverse Compton Scattering in the Thomson LimitlL
energy = Ee= g me q lX
Normal Compton Scattering the photon has higher energy than the electron
The inverse process has the Thomson cross-section when
The scattered photon satisfies the undulator equation with period lL/2 for head-on collisions
lX = lL
(1+a02/2+gq)
4g2
Therefore, the x-ray energy decreases substantially at an angle 1/g
IRIDE Study Day - LNF - March 14th 2013

3. Relative deviation of Compton vs. Thomson frequency/wavelength
IRIDE
Sapphire
ELI-NP x1=0.02
Thomson (elastic)
negligible recoil
Classical Synchrotron
radiation in e.m. undulator
Intermediate zone
Quantum Effects Dominant
e- (1 GeV); l0=1µm lT=6 x10-8µm, ET=20 MeV
e- (200 MeV); l0=1µm lT=1.56 x10-6µm, ET=800 KeV
e- (29 MeV); l0=0.8µm lT=0.5 x10-4µm, ET=20 KeV
IRIDE Study Day - LNF - March 14th 2013

4. SAPPHiRE: a Small gg Higgs Factory (courtesy Frank Zimmerman)
scale ~ European XFEL,
about 10-20k Higgs per year
SAPPHiRE: Small Accel. for Photon-Photon Higgs prod. using Recirculating Electrons

5. EuroGammas Proposal for ELI-NP-GBS
IRIDE Study Day - LNF - March 14th 2013

6. EuroGammas Proposal for ELI-NP-GBS
IRIDE Study Day - LNF - March 14th 2013

7. IRIDE Study Day - LNF - March 14th 2013

8. Quantum shift DE in quasi-Thomson limit
CAIN
Comp_Cross
TSST
A part from the quantum shift, the spectra are very similar
IRIDE Study Day - LNF - March 14th 2013

9. Angular and Frequency Spectrum (560 MeV electrons)
IRIDE Study Day - LNF - March 14th 2013

10. Efficiency of Compton Conversion
What happens to electron beam after scattering
Polarization of g-ray beam
Emittance of g-ray beam
IRIDE Study Day - LNF - March 14th 2013

11. Scattered photons in collision
electrons
laser
Thomson cross-section
Scattered flux
Luminosity as in HEP collisions
Many photons, electrons
Focus tightly z s b
s’=s/b x x’
seq
s’high
s’low
IRIDE Study Day - LNF - March 14th 2013

12. IRIDE Study Day - LNF - March 14th 2013

14. Classical Syncr. Radiation from undulators
IRIDE Study Day - LNF - March 14th 2013

15. Angular and spectral distribution of the TS radiation in the case of 3 ps laser pulse (12.5 µm beam waist) Linear Thomson Scattering
IRIDE Study Day - LNF - March 14th 2013

16. ELI
IRIDE Study Day - LNF - March 14th 2013

17. Efficiency of Compton Conversion
What happens to electron beam after scattering
Polarization of g-ray beam
Emittance of g-ray beam
IRIDE Study Day - LNF - March 14th 2013

18. IRIDE Study Day - LNF - March 14th 2013

19. Efficiency of Compton Conversion
What happens to electron beam after scattering
Polarization of g-ray beam (99% in quasi-Thomson Limit)
no need of polarized electron beam!
Emittance of g-ray beam (Sqrt[2]*electron beam emittance)
in Thomson Limit: g-ray beam focusability as for e- beam
IRIDE Study Day - LNF - March 14th 2013

20. Amplified Pulsed Lasers (J-class, 100 Hz)
IRIDE Study Day - LNF - March 14th 2013

21. Laser Recirculator
ELI-NP-GS Workshop, Milano, May 14th 2012

22. IRIDE Study Day - LNF - March 14th 2013

23. LAL MightyLaser experiment at KEK-ATF
Enhanced CW Lasers in Fabry-Perot Cav. (mJ-class, 100 MHz)
LAL MightyLaser experiment at KEK-ATF
non-planar high finesse four mirror Fabry-Perot cavity;
first Compton collisions observed in October 2010
I. Chaikovska, N. Delerue, A. Variola, F. Zomer et al
Vacuum vessel for Fabry-Perot cavity installed at ATF
Optical system used for laser power amplification and to inject laser into FPC
Plan:
improve laser
and FPC mirrors
& gain several
orders
Comparison of measured and simulated gamma-ray energy spectra from Compton scattering
Gamma ray spectrum for different FPC stored laser power
I. Chaikovska, PhD thesis to be published

24. passive optical cavity → relaxed laser parameters
K. Moenig et al, DESY Zeuthen

25. Mighty Laser 100 kW 100 MHz (1 mJ)
Mighty Laser ultimate 1 MW 100 MHz (10 mJ)
HHG-Japan 1 kW 10 MHz (0.1 mJ)
IRIDE Study Day - LNF - March 14th 2013

26. Nuclear Photonics
IRIDE Study Day - LNF - March 14th 2013

27. Colliders
ELI-NP like
IRIDE Study Day - LNF - March 14th 2013

28. The Institute for Solid State Physics, The University of Tokyo, Japan
VUV frequency comb generation based on Yb-doped fiber lasers and its application for comb spectroscopy Akira Ozawa and Yohei Kobayashi
The Institute for Solid State Physics, The University of Tokyo, Japan
and
Core Research for Evolutional Science and Technology (CREST), JST, Japan

29. Laser system for high harmonic generation at 10MHz
CPA system with Yb fiber laser
Cavity enhanced HHG can be driven at 10 MHz repetition rate

30. Laser system for high harmonic generation at 10MHz Amplifier (20W)
10MHz Yb fiber oscillator
FROG trace
Achieved: 20W, 200fs, 10MHz
2uJ
stretcher
preamplifiers
power amplifier
compressor
oscillator

31. Large-scale external cavity for intracavity HHG
~15ｍ

32. Vibration and sound isolation for external cavity
~17 m
~4.5m
4-mirrors bow-tie cavity
(30m cavity length)
~15 m
~15m

33. HHG with 30m enhancement cavity (1kW, 200fs, 10 MHz)
MgO Outcoupling plate
Gas-nozzle for HHG

34. CONCLUSION: there is certainly a further chance for optimization with Quasi-CW Beams, running at a few MHz, matched to a 10 MHz FP Cavity in asymmetric mode Working Group, tomorrow…. i) interaction regions for e-g, -g ii) injector portfolio iii) parallel implementation of FP cavities and amplified recirculated lasers iv) comparison with self-excited (FELs?) opt. cavities
IRIDE Study Day - LNF - March 14th 2013

35. Envelopes of the laser beam (dotted line), first electron beam (for Compton back-scattering, dashed) deflected after collision with laser to clear the second electron beam (solid line).
laser envelope
envelope of first
electron beam deflected
x [mm]
Laser intensity distribution
and first electron bunch at
Compton back-scattering
Collision point
collision
point
second electron beam
envelope to collision
incoming gamma
photon beam envelope
z [mm]

36. Enlarged view (zoomed out over 1 cm in z and microns in x) to show laser envelope clearance and deflecting dipole poles (0.3 T B field applied).
laser envelope
x [mm]
envelope of first
electron beam deflected
collision
point
second electron beam
envelope to collision
incoming gamma
photon beam envelope
z [mm]