Tevatron Crystal Collimation Dean Still 10-24-2005

1. Tevatron Crystal CollimationDean Still 10-24-2005 • History and motivation for using a bent crystal collimation system in the Tevatron. • Explanation of a bent Crystal Collimator. • Results of Crystal Collimator Studies. • Concluding statements.

2. Motivation for Crystal Collimation Implemented double scrape Looked to see if Crystal Collimator Could help reduce Proton Halo Losses Over 2004 shutdown improved Tevatron Vacuum and alignment. Also installed Crystal collimator. Proton Halo Loss Limit

3. Crystal Channeling If particles entering a crystal are properly aligned to the crystal planes, they will follow the planes, even if the crystal is bent. (Courtesy R. Fliller- Halo 03 Conference)

4. Volume Capture Particles that enter the crystal, not aligned to the planes, can scatter so that they have the correct angle to the planes, then channel the remaining distance in the crystal. (Courtesy R. Fliller- Halo 03 Conference)

5. Collimator Scattered trajectories Target @ ~5s Collimator @~6s Where to Install Crystal Collimator System Install Crystal Collimator at E0 to replace a Tungsten Target and utilize the rest of the collimator 2 stage System. Proton Set 1 D49 Tar, E03 & F172 2nd Proton Set 2 D171Tar, D173 & A0 Pbar Set 1 F49 Tar, F48 & D172 Pbar Set 2 F173 Tar, F171 & E02

6. Crystal Collimator System Laser – angular measurement PIN Diode BLM E0 Scintillater Paddles BLM 31.542 m 14 mm crystal channeled beam Pin Diode E03H 2nd Collimator E03 Secondary Collimator E0 Crystal Collimator Assembly

7. Bent Crystal: 980GeV Channeling (Analysis by V. Shiltsev)

8. Collimating the Channeled Beam Circulating Beam Bent Crystal Channeled beam Collimator

9. Channeled Beam is Aperture Limited Displaced beam bychannel Should follow this line. Data implies there is an aperture limit between crystal and collimator. Therefore, hard to conclude about effects on halo reduction

10. Hopeful Future Result Shoulder of channeled beam Intercepted by collimator. CDF halo is reduced Collimator moving into the beam

11. Future Plans • Finish data collection and analysis using current BNL crystal with purpose of answering “Does CC reduce CDF and D0 proton halo losses?” • Next long shutdown - install custom crystal from Protvino and gather data, analyze and prepare conclusion. Custom 1 Tev crystal Bend = .15mrad Length = 3 mm

12. Concluding Statements • Demonstrated channeling in a bent crystal with good efficiencies. • Unable to make a conclusion about reduction of halo effect due to limited aperture effects of current crystal • Hopeful with new crystal that we can come to a conclusion about amount of halo reduction that can be seen.

13. Acknowledgements • Nikolai Mokhov • Sasha Drozhdin • Ray Fliller • Dick Carrigan • Todd Johnson • Vladimir Shiltsev • Jerry Annala • Rob Reilly • Derek Plant

14. Extra Slides

15. Checking Angle of Channel particles. This does not match the ~440 urad determined by the volume capture Area.

16. The Channeled beam Data for inserting E03H secondary Collimator with the no channeling. Crystal is pulled out. Data for inserting E03H Secondary Until it reaches the core beam with Beam channeled ~ volume capture area.

17. Beam Direction 5mm Crystal Courtesy of IHEP, Protvino Crystal

18. Simulation of Data from RHIC 2001 Run Machine optics has a great effect on channeling efficiency! (Courtesy R. FLiller. Halo 03 Conference)

19. Results of a 3urad scan from a 36x36 end of store study 9-30-2005