1. TAC SASE FEL Project Dr. Ömer Yavaş * Ankara University * On behalf of TAC SASE FEL Study Group Meeting on the Feasibility of X-Band Linac Based FEL Facility in Turkey January 17, 2013 Institute of Accelerator Technologies Ankara University, Ankara, Turkey

2. 2 Meeting on X-band Linac based FEL facility 17-18 January 2013, Ankara, Turkey Outline  A brief history of the TAC SASE FEL proposal  Main goal of the proposed SASE FEL facility  Modifications on TAC 1 GeV electron linac  Disentanglement of TAC SASE FEL and particle factory proposals  ISAC’s advices for SASE undulator options  SASE FEL optimization studies based on in-vacuum undulators  Some results for X-band linac based SASE FEL  Conclusion

3. 3 Meeting on X-band Linac based FEL facility 17-18 January 2013, Ankara, Turkey A brief history of the TAC SASE FEL proposal The TAC SASE FEL facility was first proposed in 2000 *. It was initially planned that, the electron linac of the e - e + collider may asynchronously be operated to drive the SASE undulators. * Çiftçi, A. K. et al. Linac-ring type Ø factory of basic and applied research, (2000), Turk. J. Phy., 24, 747-758. Electron Source Main Linac Undulator SASE FEL Detector Beam Dump Synchrotron Radiation Synchrotron Radiation Wiggler Linac 1 GeV Positron Main Ring Wiggler Electron Source Energy Booster Electrons

4. Meeting on X-band Linac based FEL facility 17-18 January 2013, Ankara, Turkey 4 Main goal of the proposed SASE FEL facility Main goal of this light source is: to achieve a high power (GWs), ultra bright ( ~ 10 30 photons/s/mm 2 /mrad 2 /0,1%bw), tunable free electron laser (VUV to soft X-rays), aiming to enable femtosecond experiments in Turkey, like: atomic, molecular and cluster physics, plasma and condensed matter physics, chemistry, materials and life sciences etc.

5. Meeting on X-band Linac based FEL facility 17-18 January 2013, Ankara, Turkey 5 Modifications on TAC 1 GeV electron linac Due to considerably high power consumption of the Collider’s 1 GeV electron linac, it was modified 1,2,3 to an Energy Recovery Linac (ERL). 1 Ketenoğlu, B. et al. Plans for SASE FEL facility in frame of the TAC project, (2009), Balkan Physics Letters, 16, 161008. 2 Ketenoğlu, B. et al. Energy recovery linac as an alternative option for TAC and QCD-E projects, (2009), Balkan Physics Letters, 17, 311-314. 3 Ketenoğlu, B. et al. An asynchronously operating ERL-Ring type collider proposal for the TAC particle factory and SASE FEL facility, (2010), Balkan Physics Letters, 18, 142-148.

6. Meeting on X-band Linac based FEL facility 17-18 January 2013, Ankara, Turkey 6 Disentanglement of TAC SASE FEL and particle factory proposals According to the design studies carried out in the past 1, it was shown that the electron beam requirements of SASE operation (i.e. time structure, emittance, beam current, linac power etc.), could not be matched with the Collider’s. 1 Yiğit, Ş. PhD thesis, General design of SASE and oscillator free electron lasers within the scope of TAC project, Graduate School of Natural and Applied Sciences, Ankara University, (2007). 2 First and second reports of ISAC meetings for the TAC project (2009, 2010). Considering International Scientific Advisory Committee’s (ISAC) recommendations 2, particle factory and SASE FEL proposals of TAC were disentangled from each other.

7. Meeting on X-band Linac based FEL facility 17-18 January 2013, Ankara, Turkey 7 ISAC’s advices for SASE undulator options A view of the in-vacuum undulator of ALS, E. O. Lawrence Berkeley National Lab. ISAC advices in-vacuum configurations, due to: In-vacuum feature allows the magnet jaws to be closed to produce a narrower gap around the electron beam, thus increasing the magnetic field felt by the beam. The result is, high-brightness undulator at shorter X-ray wavelengths than possible with conventional undulators with the magnet rows outside the vacuum chamber.

8. Meeting on X-band Linac based FEL facility 17-18 January 2013, Ankara, Turkey 8 Historical development of in-vacuum undulators * * Tanaka, T. et al. In-vacuum undulators, (2005), in: Proc. of 27th International Free Electron Laser Conference, 370-377. There are pretty much efforts on in-vacuum undulator technologies around the World. Cryogenic permanent magnet in-vacuum undulator of ESRF In-vacuum undulator of SPring-8

9. Meeting on X-band Linac based FEL facility 17-18 January 2013, Ankara, Turkey 9 Proposed 1 GeV electron beam parameters to drive SASE undulators ParameterUnitValue Electron beam energy, E beam GeV1 Bunch charge, QnC1 Normalized emittance, ε N π.mm.mrad2 FWHM bunch length, σ z ps0,5 Peak current, I peak kA2 Beta functions, β x,y m10 Energy spread, ΔE/E-2.10 -4

10. Meeting on X-band Linac based FEL facility 17-18 January 2013, Ankara, Turkey 10 SASE FEL optimization studies based on superconducting in-vacuum undulators Superconducting in-vacuum undulator based optimization * : Choice I: g = 0,8 cm Choice II: g = 1,2 cm * Ketenoğlu, B. et al. Optimization considerations for a SASE free electron laser based on a superconducting undulator, (2012), Optik – International Journal for Light and Electron Optics, 123, 1006-1009. Elleaume, P. et al. Design considerations for a 1 Å SASE undulator, (2000), NIM-A, 455, 503-523. Two choices for the gap, while keeping the same period as: λ u = 1,5 cm

11. Meeting on X-band Linac based FEL facility 17-18 January 2013, Ankara, Turkey 11 Superconducting in-vacuum undulator parameters for Choice I ParameterUnitValue Undulator gap, gcm0,8 Undulator period, λ u cm1,5 Peak magnetic field, B peak T0,787 K parameter-1,1 Number of undulator periods, N u -1580 Undulator length, L u m23,7 ParameterUnitValue Pierce parameter, ρ-6,327.10 -4 1D gain length, L G,1D m1,089 3D gain length, L G,3D m2,659 Saturation length, L sat m21,8 FEL wavelength, λ FEL nm3,15 Saturation power, P sat GW1,265 FEL energy, E FEL keV0,392 Photons per pulse # -1,29.10 13 Energy per pulse # J8,15.10 -4 Peak flux # photons/s1,45.10 25 Peak brilliance # photons/s/mm 2 /mrad 2 /0,1%bw5,82.10 30 L sat [m] vs ∆E [MeV] and I peak [kA] for Choice I

12. Meeting on X-band Linac based FEL facility 17-18 January 2013, Ankara, Turkey 12 Superconducting in-vacuum undulator parameters for Choice II ParameterUnitValue Undulator gap, gcm1,2 Undulator period, λ u cm1,5 Peak magnetic field, B peak T0,344 K parameter-0,482 Number of undulator periods, N u -2598 Undulator length, L u m38,9

13. Meeting on X-band Linac based FEL facility 17-18 January 2013, Ankara, Turkey 13 FEL parameters for Choice II ParameterUnitValue Pierce parameter, ρ-3,847.10 -4 1D gain length, L G,1D m1,79 3D gain length, L G,3D m13,82 Saturation length, L sat m31,9 FEL wavelength, λ FEL nm2,18 Saturation power, P sat GW0,769 FEL energy, E FEL keV0,565 Photons per pulse # -2,37.10 12 Energy per pulse # J2,15.10 -4 Peak flux # photons/s4,29.10 24 Peak brilliance # photons/s/mm 2 /mrad 2 /0,1%bw3,6.10 30 L sat [m] vs ∆E [MeV] and I peak [kA] for Choice II

14. Meeting on X-band Linac based FEL facility 17-18 January 2013, Ankara, Turkey 14 Results of Choice I and II Optimization results based on superconducting in-vacuum undulators, were published in:

15. Meeting on X-band Linac based FEL facility 17-18 January 2013, Ankara, Turkey 15 SASE FEL optimization studies based on hybrid in-vacuum undulators Elleaume, P. et al. Design considerations for a 1 Å SASE undulator, (2000), NIM-A, 455, 503-523. * Ketenoğlu, B. et al. A SASE free electron laser optimization based on new generation in-vacuum undulators, (2012), Optics & Laser Technology, 44, 1083-1088. Hybrid in-vacuum undulator based optimization * : Two choices for the magnetic material, while keeping the same gap and period as: g = 0,5 cm and λ u = 1,5 cm Choice I: hybrid with iron Choice II: hybrid with vanadium permendur

16. Meeting on X-band Linac based FEL facility 17-18 January 2013, Ankara, Turkey 16 ParameterUnitValue Undulator gap, gcm0,5 Undulator period, λ u cm1,5 Peak magnetic field, B peak T0,798 K parameter-1,118 Number of undulator periods, N u -1065 Undulator length, L u m16 In-vacuum undulator parameters of Choice I ParameterUnitValue Pierce parameter, ρ-9,364.10 -4 1D gain length, L G,1D m0,735 3D gain length, L G,3D m0,886 Saturation length, L sat m15,501 FEL wavelength, λ FEL nm3,182 Saturation power, P sat GW1,653 FEL energy, E FEL keV0,388 Photons per pulse # -1,325.10 13 Energy per pulse # J8,272.10 -4 Peak flux # photons/s1,472.10 25 Peak brilliance # photons/s/mm 2 /mrad 2 /0,1%bw5,812.10 30 L sat [m] vs ∆E [MeV] and I peak [kA] for Choice I

17. Meeting on X-band Linac based FEL facility 17-18 January 2013, Ankara, Turkey 17 In-vacuum undulator parameters of Choice II ParameterUnitValue Undulator gap, gcm0,5 Undulator period, λ u cm1,5 Peak magnetic field, B peak T0,807 K parameter-1,131 Number of undulator periods, N u -1065 Undulator length, L u m16 ParameterUnitValue Pierce parameter, ρ-9,425.10 -4 1D gain length, L G,1D m0,731 3D gain length, L G,3D m0,878 Saturation length, L sat m15,405 FEL wavelength, λ FEL nm3,211 Saturation power, P sat GW1,676 FEL energy, E FEL keV0,384 Photons per pulse # -1,356.10 13 Energy per pulse # J8,386.10 -4 Peak flux # photons/s1,496.10 25 Peak brilliance # photons/s/mm 2 /mrad 2 /0,1%bw5,802.10 30 L sat [m] vs ∆E [MeV] and I peak [kA] for Choice II

18. Meeting on X-band Linac based FEL facility 17-18 January 2013, Ankara, Turkey 18 Results of hybrid in-vacuum undulator based optimization Optimization results based on hybrid in-vacuum undulators, were published in:

19. Some results for X-band linac based SASE FEL 19 Meeting on X-band Linac based FEL facility 17-18 January 2013, Ankara, Turkey

20. Tentative Electron Round-Beam Parameters ParameterUnitValue Electron beam energyGeV6 Bunch chargepC250 Normalized emittancesπ.mm.mrad1 Bunch lengthµm20 Energy spread-2x10 -4 Beam peak currentkA3.75 Transverse bunch sizesµm29.2 Beam peak powerTW22.5 Beta functionsm10 20 Meeting on X-band Linac based FEL facility 17-18 January 2013, Ankara, Turkey

21. Undulator option: In-Vacuum, Hybrid with Iron, Planar ParameterUnitValue Undulator gapcm0.4 Undulator periodcm1.3 Peak magnetic fieldT0.88 K parameter-1.07 Undulator lengthm40 Number of undulator periods-3076 Hybrid technology consisting of permanent magnets and poles made of Iron *. * P. Elleaume et al., NIM-A, 455, 2000, 503-523. 21

22. ρ x 10 -4 g (cm) λ u (cm) 1.8 1.7 1.6 1.5 1.4 1.3 1.2 1.1 ~ 1.8 x 10 -4 Pierce (Rho) parameter vs undulator period & gap 22 Meeting on X-band Linac based FEL facility 17-18 January 2013, Ankara, Turkey I peak (kA) ΔE (MeV) L sat (m) ~ 40.1 m 41 40. 5 40 39. 5 39 38. 5 38 Saturation length vs energy spread & peak current

23. Expected SASE FEL Parameters ParameterUnitValue Pierce (Rho) parameter-1.81x10 -4 1D gain lengthm3.76 Saturation lengthm40.1 FEL wavelengthÅ0.74 Saturation powerGW0.4 Rayleigh lengthm144 FEL energykeV2.03 Peak fluxphotons/s1.53x10 23 23 Meeting on X-band Linac based FEL facility 17-18 January 2013, Ankara, Turkey

24. 24 Conclusion  It is shown that, soft X-rays (i.e. few nanometers) can be achieved via diverse in-vacuum configurations, driven by a 1 GeV electron linac.  Decision on deticated TAC-SASE FEL proposal give oppurtunity to consider few GeV electron beam energies (up to 5-6 GeV) to achieve shorter wavelengths.  An X-band 5-6 GeV linac based SASE FEL facility may be considered in this frame.  A Conceptual and technical design reports can be prepared by TAC-CLIC collaboration in next 3-4 years depending on the support of government.

25. Meeting on X-band Linac based FEL facility 17-18 January 2013, Ankara, Turkey 25 Thank you for your attention…