SLAC has long encouraged and supported Research and Development in High Energy Physics

1. SLAC has long encouraged and supported Research and Development in High Energy Physics through an active program of providing beams for the purpose of testing detector prototypes or for use in small experiments. Use of SLAC’s test beams is open to all in the scientific community and proposals for their use are actively invited. Through the clever use of parasitic beams, many such tests or small experiments have been successfully carried out during periods when the linac is dedicated to providing beam for others. These parasitic beams of electrons are available in the Final Focus Test Beam tunnel and in End Station A. SLAC provides beam time, mechanical support, technical support, computer and network Access.

2. LCLS ESA FFTB Pulsed Magnets SABER BSY Linac T. Fieguth

3. How a Parasitic Beam is produced T. Fieguth

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8. Tagged Photons T. Fieguth

9. Test Beams in ESA T. Fieguth

10. Test Beams in ESA T. Fieguth

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13. Test Beams in FFTB T. Fieguth

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15. Parasite beam from LCLS? Location of Hadron Target and Pulse Magnets Linac LCLS Halo Collimators Linac Movable Collimators L. Keller, using EGS, has estimated a yield of 8 electrons per pC-pulse At 2.25 GeV into A-line acceptance from the halo of 13 GeV LCLS beam Hitting a 9mm Tungsten Target Can we obtain a pC of halo hits from Dark Current and Gas Scattering? T. Fieguth

16. Structure dark current Contribution of structure dark current: • X-band gives the largest contribution, however, deflected • Structures withE~24 MV/m will give additional particle loss Green: difference Black: total Red: Gun DC only T. Fieguth

17. Tracking and Collimation, by Juhao Wu, LCLS new energy collimators new b collimators BC1 coll. BC2 coll. ‘under ground’ existing collimators (4 x and 4 y) ‘L0-b’ start undulator T. Fieguth

18. 2-Phase, 2-Plane Und. Collimation, 1½ Times p/2 ~p/2 70s (2.5 mm) By Juhao Wu, LCLS 40s (2.2 mm) 40s (2.2 mm) 45s halo e- beam edge scattering undulator beam pipe x1 x2 x3 phase-1 again phase-2 phase-1 (also collimation in y and energy – see next slides) T. Fieguth

19. Collimation in Linac-To-Undulator (LTU) By Juhao Wu, LCLS y1 y2 y3 E1 E2 x1 x2 x3 muon shielding undulator m-spoiler T. Fieguth

20. Particle losses up to, and through BC1 By Juhao Wu, LCLS 1-inch ID 7-mm ID L0-b DL1 L1 BC1 X-band 300 pC lost per pulse = 9 W @ 120 Hz, 250 MeV  = 30 120 pC lost per pulse = 1.9 W @ 120 Hz, 135 MeV T. Fieguth

21. Particle losses through undulator and dump By Juhao Wu, LCLS 1 newBC2E-coll. 36-mm (d = 10%) 2 newE-coll. 2.5 mm (d = 2%) under ground BC1 BC2 undulator 4 existingx-coll.’s 4 existingy-coll.’s 1.6 & 1.8 mm 3 newx-coll.’s 3 newy-coll.’s 2.2 mm… 1 newBC1E-coll. 45-mm (d = 20%) 2.6 pC/pulse 3.5 W (120 Hz, 11.3 GeV) 0.7 pC/pulse 1.1 W (120 Hz, 13.6 GeV) 0.1 pC/pulse 0.2 W (120 Hz, 13.6 GeV) DE/E of 1 dropped klystron = -1.7% T. Fieguth

22. Options for test beam with LCLS • Independent intermittent operation • Advantage--High energy high current beam from present CID guns • Up to ~45 GeV, 6x1011 e-/pulse 120Hz, • Damping Rings optional • Not LCLS Compatible, switchover not fast • Secondary beams (hadron) could also be available, but inefficient use of machine • LCLS promised 75% of operating time, problematic future for this option T. Fieguth

23. Options for test beam with LCLS Share LCLS beam using pulse magnets • At beginning LCLS will operate at 5 GeV. The existing pulse magnets can handle 10 GeV. • Beam Limited to LCLS parameters, ~5GeV < 109 electrons/pulse, ~10Hz • Two more Pulse Magnets exist but must be refurbished and two Power Supplies provided, ~$200k Allow operation at LCLS design energy of ~14 GeV • Could also switch beam to SABER but low current not too useful. Plasma Acceleration needs high charge, short pulse. SPPS type use may be possible. (?) T. Fieguth

24. Options for test beam with LCLS Bypass Lines around LCLS • A feasiblity study SABER in BTR is ongoing. A bypass line has been shown to be optically possible. Transactions PAC05, P. Emma, et. al. “Proposal for a Multi-Use Test Beam in the SLAC B-line • Would provide beam suitable for Plasma Acceleration, SPPS type fast Xrays, Final Focus studies (A. Seryi) • Expensive • The present design for a bypass to BTR is assymetric. It is not known if it would accommodate beam to ESA. Perhaps a wholly different beam line design is necessary. • Problematic T. Fieguth

25. Options for test beam with LCLS Beams Parasitic to LCLS • Would be available on call. • Suitable for some detector tests but not for ILC instrumentation. • Not a proven concept, needs much more work. • Problematic T. Fieguth

26. Options for test beam with LCLS • Independent intermittent operation • All these options are being looked at • Assistance or other Suggestions welcomed • Input concerning the usefulness of each is helpful Share LCLS beam using pulse magnets Bypass Lines around LCLS Beams Parasitic to LCLS T. Fieguth