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Crystal technology at PNPI

Crystal technology at PNPI. Yuri M.Ivanov Petersburg Nuclear Physics Institute. PNPI involved in channeling studies since 1970s: 1979 - prediction of volume capture effect in bent crystals ( O.I.Sumbaev )

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Crystal technology at PNPI

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  1. Crystal technology at PNPI Yuri M.Ivanov Petersburg Nuclear Physics Institute

  2. PNPI involved in channeling studies since1970s: 1979 - prediction of volume capture effect in bent crystals (O.I.Sumbaev) 1982 - observation of volume capture effect with 1GeV protons at PNPI (V.M.Samsonov, O.I.Sumbaev et al.) 1987 - invention of crystal design to focus charged particle beams(A.I.Smirnov) 1989-1992 - spin precession of particles channeled inbent crystal at FNAL 1991-1995 - focusing of proton beam at IHEP 1993-1996 - extraction of proton beam from Tevatronat FNAL 1997-2004 - multi-turn extraction and collimation of proton beam at IHEP

  3. Processing of the crystals Orienting with X-rays Cutting Grinding and polishing CC-2005, CERN, March 7-8, 2005

  4. Double crystal X-ray spectrometer CC-2005, CERN, March 7-8, 2005

  5. Scheme of rocking curve measurement CC-2005, CERN, March 7-8, 2005

  6. Focusing with bent crystal A.I.Smirnov 1987 Experiment PNPI-IHEP 1991 F2 = 4r2 – R2 F - focal distance R - bending radius of the crystal r - radius of the exit crystal face CC-2005, CERN, March 7-8, 2005

  7. Samples of focusing crystals CC-2005, CERN, March 7-8, 2005

  8. Main results with focusing crystals • Focusing of 1-5 mm parallel beam into 30-50 micron line at distances 1-10 m • Deflection and transformation of divergent beams • New approach to prepare secondary particle beams CC-2005, CERN, March 7-8, 2005

  9. Deflection and transformation of divergent beams Experiment IHEP-PNPI 1995 CC-2005, CERN, March 7-8, 2005

  10. New approach to formation of secondary particle beams with focusing crystals CC-2005, CERN, March 7-8, 2005

  11. Multi-pass extraction of proton beam with short bent crystals IHEP-PNPI 1998 • Short bent crystal - to deflect beam into septum aperture • Magnet system - to extract beam CC-2005, CERN, March 7-8, 2005

  12. Requirements for crystal • Hight of working area ~5 mm • Width of working area ~1 mm • Length along beam 0.5-5 mm • Thickness of broken layer ~0.001 mm • Precision of orientation ~0.3 mrad • Bending angle 1-2 mrad CC-2005, CERN, March 7-8, 2005

  13. O-crystal design Typicaldimensions5 x 5 x 50 mm3 CC-2005, CERN, March 7-8, 2005

  14. Samples of O-crystals prepared in PNPI Slide taken from report to EPAC02 (Paris, France) on Crystal Collimation at RHIC CC-2005, CERN, March 7-8, 2005

  15. Typical interference pattern from a bent face of the O-crystals CC-2005, CERN, March 7-8, 2005

  16. Main results with O-crystals at IHEP • Length along beam 3-5 mm • Extraction efficiency 60-70% • Intensity of extracted beam ~1x1012 • Radiation hardness ~1020 • Still working with efficiency ~ 40% CC-2005, CERN, March 7-8, 2005

  17. New approach – to use Sumbaev (elastic quasimosaic) effect • Studied by Sumbaev in 1957 • Resulted in broadening of gamma-ray diffraction peaks from bent quartz plates • Caused by bending of the reflecting atomic planes (initially flat and normal to large faces of plate) due to crystal anisotropy • Depends on choice of crystallographic plane and orientation angle of plate cutting relative to a normal to the chosen crystallographic plane Figure from article: O.I.Sumbaev, Reflection of gamma-rays from bent quartz plates, 1957 CC-2005, CERN, March 7-8, 2005

  18. Crystal design CC-2005, CERN, March 7-8, 2005

  19. Elastic quasimosaic in dependence on cut angle for Si (111) plane Plate bending radius R = 1 m Dq = 2k9 T , where T – thickness of plate k9 – deformation coefficient CC-2005, CERN, March 7-8, 2005

  20. Cut  = 0 CC-2005, CERN, March 7-8, 2005

  21. Experiment with X-rays Rocking curves for plate with cut angle  = 0 before and after bending. CC-2005, CERN, March 7-8, 2005

  22. Experiment with protons at IHEP CC-2005, CERN, March 7-8, 2005

  23. Some details of experimental setup CC-2005, CERN, March 7-8, 2005

  24. First result CC-2005, CERN, March 7-8, 2005

  25. Quasimosaic crystals prepared for U-70 CC-2005, CERN, March 7-8, 2005

  26. Some preliminaty results with quasimosaic crystals at IHEP • Length along beam 0.3-10 mm • Extraction efficiency 70-80% • Intensity of extracted beam 1-4 x 1012 CC-2005, CERN, March 7-8, 2005

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