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

2. PNPI involved in channeling studies since 1970s:
prediction of volume capture effect in bent crystals (O.I.Sumbaev)
observation of volume capture effect with 1GeV protons at PNPI (V.M.Samsonov, O.I.Sumbaev et al.)
invention of crystal design to focus charged particle beams (A.I.Smirnov)
spin precession of particles channeled in bent crystal at FNAL
focusing of proton beam at IHEP
extraction of proton beam from Tevatron at FNAL
multi-turn extraction and collimation of proton beam at IHEP

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

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

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

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

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

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

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

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

11. Multi-pass extraction of proton beam with short bent crystals
IHEP-PNPI
Short bent crystal - to deflect beam into septum aperture
Magnet system - to extract beam
Yuri M.Ivanov
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 mm
Thickness of broken layer ~0.001 mm
Precision of orientation ~0.3 mrad
Bending angle mrad
Yuri M.Ivanov
CC-2005, CERN, March 7-8, 2005

13. O-crystal design Typical dimensions 5 x 5 x 50 mm3 Yuri M.Ivanov
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
Yuri M.Ivanov
CC-2005, CERN, March 7-8, 2005

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

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

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

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

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

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

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

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

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

26. Some preliminaty results with quasimosaic crystals at IHEP
Length along beam mm
Extraction efficiency %
Intensity of extracted beam x 1012
Yuri M.Ivanov
CC-2005, CERN, March 7-8, 2005