NLCTA Facility Capabilities E. R. Colby 5/18/09

NLCTA Overview RF PhotoInjector Ti:Sapphire Laser System Next Linear Collider Test Accelerator Cl. 10,000 Clean Room Counting Room (b. 225) E163 Optical Microbuncher Gun Spectrometer ESBESB Next Linear Collider Test Accelerator E-163 NLCTA capabilities: * S-band Injector producing high-brightness 60 MeV beams (to ~100 pC); ultrashort, ultracold * (4) x-band rf stations and >300 MeV of installed structures * (2) L-band rf stations * Skilled operations group with significant in-house controls capability SX-0X-1X-2 X-3 (2-pack) L-1 (SNS) Space available for experiments 20 feet 30 feet

Capabilities Electron Beam (from injector) –60 MeV, 5 pC,  p/p≤10 -4,  ~1.5x1.5 mm-mrad  t  psec –Beamline & laser pulse optimized for very low energy spread, short pulse operation Laser Beams –10 GW-class Ti:Sapphire system (800nm, 2 mJ) KDP/BBO Tripler for photocathode(266nm, 0.16 mJ) –Active and passive stabilization techniques –5 GW-class Ti:Sapphire system (800nm, 1 mJ) 100 MW-class OPA ( nm,  J) 5 MW-class DFG-OPA( ,000 nm, 1-3  J) Precision Diagnostics –Picosecond-class direct timing diagnostics Micron-resolution beam diagnostics –Femtosecond-class indirect timing diagnostics –Picocoulomb-class beam diagnostics BPMS, Profile screens, Cerenkov Radiator, Spectrometer –A range of laser diagnostics, including autocorrelators, crosscorrelators, profilometers, etc.

NLCTA Laser & LSS Modest changes required to support EEHG Experiment: Install evacuated transport line (vacuum components in-hand; pumping is in place) Install second laser safety shutter (no new logic; add second driver + shutter) Seek LSC approval for 1-3 micron operation in NLCTA vault and modify SOP

EEHG Experiment and Diagnostics are similar to the E-163 Attosecond Bunching Experiment Experimental Parameters: Electron beam γ = 127 Q ~ 5-10 pC Δγ/  = 0.05% Energy Collimated ε N = 1.5 mm-mrad IFEL: ¼ +3+ ¼ period 0.3 mJ/pulse laser 100 micron focus Z 0 = 10 cm (after center of und.) 2 ps FWHM Gap 8mm Chicane 20 cm after undulator Pellicle (Al on mylar) COTR foil

Attosecond Bunch Train Generation First- and Second-Harmonic COTR Output as a function of Energy Modulation Depth (“bunching voltage”) Left: First- and Second-Harmonic COTR output as a function of temporal dispersion (R 56 ) Inferred Electron Pulse Train Structure Bunching parameters: b 1 =0.52, b 2 =0.39 C. M. Sears, et al, “Production and Characterization of Attosecond Electron Bunch Trains“, Phys. Rev. ST-AB, 11, , (2008). 800 nm400 nm 800 nm =800 nm

Inferred Electron Beam Satellite Pulse EE 400 nm 800 nm Q(t) I(t) Electron Beam Satellite! Machine stability supports sub-picosecond class e/  experiments e.g. This cross-correlation measurement of the electron bunch profile took 5 minutes. Much of the visible spread is due to COTR intensity jitter (~Q 2 ) rather than timing jitter

Preliminary Beam Quality Measurement at EEHG Experiment Location 20 pC, 60 MeV, Measured 4/13/09 Dispersion measurement was not yet working in downstream linac!  Horizontal emittance had significant residual dispersion contribution Beam at 60 MeV (drifting through all linac x-band structures) EEHG Location Measurement Locations

Summary Existing NLCTA laser systems meet EEHG experimental requirements –Modest extension of the LSS functionality required (shutter+driver) –Laser transport installation required (components in-hand) Existing NLCTA electron beam quality meets EEHG experimental requirements at 120 MeV, likely also at 60 MeV, with further machine studies. –Some additional beam diagnostics ahead of the EEHG experiment would speed commissioning Sub-picosecond-class timing stability has been demonstrated E-163 experience with near-IR e/  experiments is directly relevant and provides significant leverage –Experience designing experiments and hardware in this low-charge sub- psec regime –Wealth of advanced automated measurement software in LabVIEW and Matlab