Jefferson Lab Infrastructure and Technology

1. Jefferson Lab Infrastructure and Technology Stephen Benson and Pavel Evtushenko Jefferson Lab The Big picture Possible Jefferson Lab developmental light sources Engineering advances required for next generation light sources. Physics advances required for next generation light sources. Summary of potential Jefferson Lab contributions

2. Long-term Landscape : 21st Century Light Source • Key technologies for 21st Century Light Source • SRF (CW operation) • Recirculation • Seeded FEL amplifiers • fs pulse generation • ERL oscillators

3. Accelerator-based light source challenges Linacs are expensive! • Linacs presently achieve < 12 MV/m real estate gradient CW • 10 GeV means > 800m of linear accelerator, >$500M for the linac! Undulators are also expensive • > 0.4M/m x 100m = $40M per undulator x 10? = $ 400M Add in cost of cryogenic facility, conventional facilities, etc. and the total is well above $1B.

4. Engineering Challenges (SRF) • Optimize Cost/MeV for cryomodule (potentially several $100M savings) • Good real estate gradient to minimize conventional facilities (several $10Ms possible) • Low loss (high Q0) cavities reduce He refrigeration capital and operating costs (>$10M potential capital savings and several $M/year in operating costs) • LHe plant design and process cycle optimization to minimize capital and operating cost (Ganni cycle by JLab introduced to BNL saves > $100k of electric operating costs/week)

5. Engineering Challenges (acc. systems) • Multiple cavity drive from single RF source (RF systems cost > $1M/srf module and have only weak power dependence) • Multipass BPMs for control in recirculation and energy recovery • Synchronization of beams and external lasers to ~10 fsec. • Beam stabilization to get energy, pointing, and position stability comparable to storage rings. • RF separation to provide simultaneous beams to multiple wigglers. • Diagnostics for ultra-bright beams (measure geometric emittance of 0.01 nm-rad)

6. Required Physics Advances • Injectors: ultimate brightness at low and high charge • Approaches: DC gun, copper RF gun, SCRF gun, ... • Blow-out mode or beer can? • How much can we compress bunches? • Brightness preservation: • Solutions/control for CSR, LSC, pulse compression, wakes, etc. • Is recirculation feasible while retaining brightness? • Cut linac cost by 2-3X! • Use recirculator compactions for intermediate compressions • Halo control • HOM & BBU control in cavities • Wakefield and propagating mode damping

7. Jefferson Lab Infrastructure • FEL shielded vault with PSS. • 5(10) kW of 2 K helium refrigeration. • RF power to drive all cavities to max gradient. • 1.1 (2.2) GeV of SRF acceleration in CEBAF • 0.12 GeV of SRF acceleration in FEL • Cryomodule test and production facility (undergoing massive upgrade) • RF and diagnostic groups

8. Site Plan Legend New Buildings New Roads, Parking & Sidewalks New Security Fencing Test Lab Rehab Existing Site Plan

9. TED Bldg – Rendering Technology and Engineering Development (TED) Building

10. Test Lab Addition - Rendering Test Lab Addition

11. Project Funding

12. Approach A: The Jefferson Lab FEL (Upgrade)2 = Superflash *Quantities are rms **to keep average current reasonable

13. Physics and Technologies Potentially Addressed by SuperFlash • High gradient cryomodules • RF separation of high brightness beams. • Production of high brightness, moderate average current electron beams. • Preservation of high brightness, moderate average current beams through multiple passes. • Bunch compression in a machine with recirculation • CSR, LSC, wakes, in high brightness beams. • Multipass BPMs. • RF drive of multiple cavities. • Halo control

14. Approach B: CEBAFX • 12 GeV Upgrade offers new capabilities and higher brightness along with possibility of short pulse length (also works at 5 GeV) • Open questions: Arc 9, BSY, Hall A? • Beam characteristics: < 30 fs • Might be able to get high brightness pC bunches. AIP Conf. Proc. 705, 29 (2004)  

15. Physics and Technology Potentially Addressed by CEBAFX • Preservation of ultra-high-brightness beam in a big machine. • Diagnostics with ultra-high-brightness beams. • RF separation of ultra-high-brightness beams. • Timing and stabilization issues with large machines. • FEL tests with kV photons. • SR tests with ultra-low-emittance beams.

16. High Brightness at Low Charge Spot sizes and transverse emittances Energy, energy spread, bunch length, and long. Emitt.

17. Conclusions • Jefferson Lab is uniquely well-suited to development projects on the next generation light sources. • On the scale of the next generation light source these projects are pretty inexpensive (<30M$). • Can be up and running relatively quickly(few years). • We look forward to working with partners to develop these technologies.

18. Flux Brightness CEBAF as a sub-picosecond X-ray Source Calculations assume 100 mA at 3 GeV CEBAF undulator 70 x 28mm periods 10mm gap

19. Flux Brightness CEBAF as a sub-picosecond X-ray Source Calculations assume 100 mA at 3 GeV CEBAF undulator 70 x 28mm periods 10mm gap