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) 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 in bent crystal at FNAL 1991-1995 - focusing of proton beam at IHEP 1993-1996 - extraction of proton beam from Tevatron at FNAL 1997-2004 - multi-turn extraction and collimation of proton beam at IHEP

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

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

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

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

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

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

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

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

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

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

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

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

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

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% Yuri M.Ivanov CC-2005, CERN, March 7-8, 2005

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

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

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

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

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

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

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

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

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

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