W.S. Graves ASAC Review Sept 18-19, 2003 R&D at Bates William S. Graves MIT-Bates Laboratory Presentation to MIT X-ray laser Accelerator Science Advisory Committee September 18-19, 2003

W.S. Graves ASAC Review Sept 18-19, Achieve ~10 fs timing synchronization between FEL output, seed lasers, and pump-probe lasers. 2.Necessary RF phase and amplitude stability for timing above. 3.Stability in energy per pulse, timing, and pointing appropriate for a user facility. 4.Reduced power consumption for CW operation. 5.Reliable laser seed generation including tunability and stability. 6.Development of fast RF or ferrite switches necessary to deliver beam to multiple undulators. 7.Development of a high repetition rate, high brightness photoinjector. 8.Development of tunable undulators. Matching of undulator resonance. Orbit correction over tuning range. 9.Electron beam diagnostics. 10.Coherent photon beam diagnostics at short wavelength. Technical Challenges

W.S. Graves ASAC Review Sept 18-19, 2003 Bates accelerator layout 500 MeV per pass 1 kHz rep rate 2856 MHz Energy compressor chicane R56 = mm 200 m DC photoinjector GaAs cathode 360 kV thermionic source

W.S. Graves ASAC Review Sept 18-19, 2003 R&D program at Bates Demonstrate some of the key technologies at lower energy including 1.Development of stable HHG seed source. 2.Seeding FEL with ultrashort HHG pulses. 3.Development of tunable seed laser 4.Cascaded HGHG FEL output 5.Cascaded HGHG at BNL 6.Timing synchronization of FEL, seed, and pump lasers below 100 fs 7.Timing synchronization of laser and RF and e-beam. 8.Support for LUX injector development. An FEL using an upgraded Bates linac could drive a 10 nm FEL enabling prototype user experiments and development of coherent optical beam handling methods.

W.S. Graves ASAC Review Sept 18-19, 2003 Hardware for R&D program Equipment to be added includes 1.S-band photoinjector 2.Chicane bunch compressor? 3.Multiple undulators 4.Ti:Sapp and equipment for HHG seed generation 5.Diagnostics 6.RF upgrade or cryomodules? 7.Photon beamlines

W.S. Graves ASAC Review Sept 18-19, 2003 Switch-Tube Specifications Maximum Operating Hold-Off Voltage175kV Maximum Peak Pulse Current 50 Amps per output (100A total) Minimum voltage across the modulator 18kV Output Pulse Duration0-55  s Maximum Duty factor4% (limited by Switch Tube Cooling) Maximum Pulse Repetition 5kHz Short Term Stability  0.02% Current to 80A (fixed beam switch tube collector voltage) Rise: 0.6  s Fall: 0.2  s Solid-State Switch Specifications High voltage Input1-17.5kV DC (positive polarity) Maximum Pulse Current75 A 1  sec Peak Current100 A Intrapulse Voltage 100 A Pulse Width1 to 50  sec Maximum Repetition Rate5 kHz Rise Time~ 1  sec Fall Timeload dependent CoolingPassive Oil Cooling Maximum Power Dissipation3,000 W New Solid State Modulator deck with Switch Tubes Bates Modulators A. Zolfaghari, W. North

W.S. Graves ASAC Review Sept 18-19, 2003 Schedule Laser/RF timing synchronization currently under development (Kaertner group). NSF and DOE expected to solicit accelerator R&D proposals for FY05. Submit proposal by 1/04

W.S. Graves ASAC Review Sept 18-19, 2003 Budget Laser timing measurements ~$20k + postdoc HGHG cascade at BNL ~$100k? S-band injector at Bates ~$1M Undulator at Bates ~$1-2M RF upgrade at Bates ~$4M for 1 GeV single pass Test RF recycler at BESSY ~$20k Modulator for LUX ~$300k Fast e-beam switch ~$100k HHG seed generation $1M