Overview of XFELO parameters

Transcription

1 Overview of XFELO parameters Ryan R. Lindberg Advanced Photon Source, Argonne NaBonal Laboratory Joint ERL- FEL Session ICFA Workshop of Future Light Sources Thomas Jefferson NaBonal Accelerator Facility

2 Canonical Parameters and performance Δ P (MW) spectrum R total T P(ω) t (ps) E - E H (mev) 2

3 Canonical Parameters and performance Δ Compress the beam further to increase current and FEL gain P (MW) t (ps) spectrum R total T P(ω) E - E H (mev) 3

4 Higher current for more gain E beam Δ 100 A Δ 0.02% 20 m G 1.64 R tot 0.5 P (MW) P(t) I(t) output P(t) ebeam I(t) t (fs) MW mev 170 fs R, I, P(ω) R total tot T thin P(ω) output P(ω) ΔE (mev) 4

5 Higher current for more gain E beam E beam 100 A 100 A 0.4 mm-mrad Δ Δ Δ 20 m 40 m G 1.64 R tot 0.5 G 1.23 R tot MW 1.1 MW mev 15 mev 170 fs 165 fs 5

6 Canonical Parameters and performance Δ Beam brightness is far from opbmal for our parameters P (MW) t (ps) spectrum If emi_ance, energy spread (and/or temporal durabon) decreased one can consider many other possibilibes R total T P(ω) E - E H (mev) 6

7 Canonical Parameters and performance Negligible emi_ance: γ λ 4π 0.01 mm mrad G 1.3 Δ 7

8 Canonical Parameters and performance Δ Negligible emi_ance: 0.01 mm mrad Negligible energy spread: γ λ 4π 100 kev γ γ 1 2N u G 1.3 G 2.3 8

9 Canonical Parameters and performance Δ Negligible emi_ance: γ λ 4π 0.01 mm mrad Negligible energy spread: 100 kev γ γ 1 2N u G 1.3 G 2.3 Both G 11 9

10 Canonical Parameters and performance Δ Negligible emi_ance: 0.01 mm mrad Negligible energy spread: γ λ 4π 100 kev γ γ 1 2N u G 1.3 G 2.3 Both G 11 Halving emi_ance and energy spread: =0.1 mm mrad, =0.7 MeV G

11 Canonical Parameters and performance Δ Negligible emi_ance: 10 2 mm mrad Negligible energy spread: γ λ 4π 100 kev γ γ 1 2N u G 1.3 G 2.3 Both G 11 Halving emi_ance and energy spread: =0.1 mm mrad, =0.7 MeV G 1.8 One way to decrease emi_ance is to decrease charge 11

12 Smaller emittance beams for XFELO Decrease in emi_ance ~50%, energy spread by factor of 6, and width by 2 permits proposed XFELO in JAERI- KEK ERL design to operate 5 GeV and lower peak current* Decrease in emi_ance by ~2.5, energy spread by factor of 14, and width by 4 permits lasing at the 3 rd harmonic at 3.5 GeV As an extreme example of the possible uses of low charge, we have adapted the 1pC, ultra- short beams first proposed for high- gain FELs in the single spike regime = 1 pc, σ e = 250 fs è I = 1.6 A ε xn = mm mrad ΔE = 250 kev * R. Hajima and N. Nishimori, Proc. of 2009 FEL Conf Dai, H. Deng, and Z. Dai, Phys. Rev. Le_. 108, (2012). J.B. Rosenzweig, et al.,, Nucl. Instrum. Methods A. 593, 39 (2008). 12

13 XFELO using ultra-small emittance 1pC E beam 1 pc 1.6 A mm-mrad Δ Δ 250 kev G 0.74 R tot kw mev 0.42 ps 13

14 XFELO using ultra-small emittance 1pC E beam 1 pc 1.6 A mm-mrad Δ Δ 250 kev G kw mev 0.42 ps 14

15 XFELO using ultra-small emittance 1pC E beam E beam 1 pc 1 pc 1.6 A 1.6 A mm-mrad mm-mrad Δ Δ 250 kev Δ 250 kev 35 m G 0.74 G kw 650 MW mev 5.6 mev 0.42 ps 0.4 fs 15

16 Tevatron-size Ultimate storage ring Michael Borland invesbgated the possibility of a Tevatron- sized ulbmate storage, and found the se_led on the following 2 damping undulators 11 GeV beam energy with 2 damping undulators Geometric emi_ance = 1.1 pm Energy spread = 15.4 MeV Bunch length ~8 100 pc (I ~ 5 A) Energy spread dominated, with single pass gain ~1% Naïve scaling to è Energy spread = 6.3 MeV and negligible emi_ance N u = 500 è G = 6% N u = 1000 è G = 9% Caveats: beam damping Bme probably quite long, how will other parameters change? Storage ring- based XFELO not impossible, but the large natural energy spread makes this very challenging is there an opportunity here? M. Borland, A Tevatron- sized UlBmate Storage Ring Light Source Based on the PEP- X Lauce, AOP- TN (2011) 16