Study the effects of a Robinson wiggler at SOLEIL towards brightness increase

1. Study the effects of a Robinson wiggler at SOLEIL towards brightness increase H. Abualrob, P. Brunelle, M. Labat, L. Cassinari, M.A. Tordeux, L. Nadolski, R. Nagaoka, A. Nadji, M.E. Couprie, O. Marcouillé

2. Outline • Synchrotron radiation & its properties • Robinson wiggler & emittance reduction • Experimental observation of Robinson effect @ SOLEIL • Predicted influence of a Robinson wiggler on the spectral performances • Preliminary magnetic design of Robinson wiggler H. Abualrob Journées Accélérateur, Roscoff, october 2013

3. Light source A bright photon beam is: Intense Emitted from a small size and low divergence source Monochromatic H. Abualrob Journées Accélérateur, Roscoff, october 2013

4. Synchrotron SOLEIL H. Abualrob Journées Accélérateur, Roscoff, october 2013

5. Beam Brightness and emittance Effective emittance is the beam size times the angular divergence e- Effective photon beam emittance Effective electron beam emittance Beam size Beam divergence high brightnesslow emittance  H. Abualrob Journées Accélérateur, Roscoff, october 2013

6. Momentum compaction factor Energyspread & bunchlength Number of electrons Energy spread Energy of electrons L+ΔL L Bunchlength in seconds Synchrotron frequency Energy spread H. Abualrob Journées Accélérateur, Roscoff, october 2013

7. Emittancereduction: motivation Spectroscopy • high spectral resolution • high flux throughnarrowslit Crystallography • high angularresolution • wavelengthmatching to crystal dimensions High flux withinsmallbeam size and divergence High brightness lowemittance (H & V) H. Abualrob Journées Accélérateur, Roscoff, october 2013

8. Emittance reductionmethods • Increasing the number of dipoles: MAX IV S. Leemans, Phys. Rev. Spec. Topics AB 12, 120701, 2009. • Introducing a transverse gradient in the dipoles: ALBA D. Einfeld, Status of ALBA project, IPAC10, Japan. • Installing tens of meters of damping wigglers: PETRA III M. Tischer, Damping wigglers for PETRA III light source, proceeding PAC05, Knox ville, Tennessee. • Installing a Robinson wiggler H. Abualrob Journées Accélérateur, Roscoff, october 2013

9. Robinson wiggler Robinson wiggler: magnetic system of alternated field gradient superimposed to the main field, to be installed in a non-zero dispersion straight section (1) Compact, less expensive, can be adopted by compact & large machines x B dB/dx<0 B dB/dx<0 B dB/dx<0 B dB/dx<0 s (1) K. W. Robinson, Radiation effects in circularelectronaccelerators, physical review, vol. 111, number 2, 1958. H. Abualrob Journées Accélérateur, Roscoff, october 2013

10. Previousprojects • First observation @ Cambridge Electron Accelerator (CEA) A. Hofmann, Design and performance of the damping system for beam storage in the CEA, ICHEA, Cambridge, 1967. • Installtion in the PS @ CERN showing 50% horizontal emittancereduction Y. Baconnier et al, Emittance control of the PS e+/e beams using a Robinson wiggler, Nucl. Instr. and Meth. in PhysicsResearchA234 (1985) 224-252. H. Abualrob Journées Accélérateur, Roscoff, october 2013

11. Experimentalstudyof Robinson effects on:-The horizontal emittance-The energyspread@ SOLEIL H. Abualrob Journées Accélérateur, Roscoff, october 2010

12. Robinson effect @ SOLEIL • Presently, thereis no Robinson wiggler @ SOLEIL ! IDEA… • Use the 4 undulators U20 to obtain a strongperiodicmagneticfield • Simultaneous off-axis propagation in the 4 undulators to create a periodicfield gradient • Measure the transverse beam size using a pinhole camera • Measure the bunchlengthusing a streak camera e- H. Abualrob Journées Accélérateur, Roscoff, october 2013

13. The in vacuum undulator U20 H. Abualrob Journées Accélérateur, Roscoff, october 2013

14. Beam size measurementto deducethe emittance variation Beam size measurementusing a pinhole camera H. Abualrob Journées Accélérateur, Roscoff, october 2013

15. Bunchlengthmeasurement to deduce the energyspread variation Bunchlengthmeasurementusing a streak camera H. Abualrob Journées Accélérateur, Roscoff, october 2013

16. Emittancereduction, energy spread increase& spectral performances with a Robinson wiggler • Assumingthat a Robinson wigglerisinstalled @ SOLEIL • Assuming horizontal emittancereduction by a factor of 2 (from 3.9 nm rad to 1.95 nm rad) • Assumingenergyspreadincrease by (from 1.01 10-3 to 1.428 10-3) H. Abualrob Journées Accélérateur, Roscoff, october 2013

17. Photon flux calculation/lowenergy range Flux calculationwith SRW (1)through an aperture of 0.1 * 0.1 mm2located @ 10 m from the source (1) O. Chubar, Accurate and efficient computation of synchrotron radiation in the near field region, EPAC 98, Stockholm. H. Abualrob Journées Accélérateur, Roscoff, october 2013

18. Photon flux calculation/high energy range Flux calculationwith SRW through an aperture of 0.1 * 0.1 mm2located @ 10 m from the source H. Abualrob Journées Accélérateur, Roscoff, october 2013

19. Brightnesscalculation Brightnessdecrease for lowenergy range (HU640) Rememberthat 90% Brightnessincreasefor high energy range (U20) H. Abualrob Journées Accélérateur, Roscoff, october 2013

20. Robinson wiggler...preliminarymagnetic design e- Design performedusing RADIA code. O. Chubar, Computing 3D magnetic fields from insertion devices, PAC 1997, Vancouver, Canada. H. Abualrob Journées Accélérateur, Roscoff, october 2013

21. Conclusion • Robinson effects on reducing the emittance and increasing the energy spread were observed and validated experimentally, for the first time, in a synchrotron light source at SOLEIL. • Considering a Robinson wiggler at SOLEIL reduces the emittance, leading to brightness increase “in the high energy range”. However, Robinson wiggler increases the energy spread leading to flux reduction. H. Abualrob Journées Accélérateur, Roscoff, october 2013

22. Thankyou for your attention H. Abualrob Journées Accélérateur, Roscoff, october 2013