Crystal technology at pnpi
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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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Crystal technology at pnpi

Crystal technology at PNPI

Yuri M.Ivanov

Petersburg Nuclear Physics Institute


Crystal technology at pnpi

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


Processing of the crystals

Processing of the crystals

Orienting with X-rays

Cutting

Grinding and polishing

CC-2005, CERN, March 7-8, 2005


Double crystal x ray spectrometer

Double crystal X-ray spectrometer

CC-2005, CERN, March 7-8, 2005


Scheme of rocking curve measurement

Scheme of rocking curve measurement

CC-2005, CERN, March 7-8, 2005


Focusing with bent crystal

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


Samples of focusing crystals

Samples of focusing crystals

CC-2005, CERN, March 7-8, 2005


Main results with focusing crystals

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


Deflection and transformation of divergent beams

Deflection and transformation of divergent beams

Experiment IHEP-PNPI 1995

CC-2005, CERN, March 7-8, 2005


New approach to formation of secondary particle beams with focusing crystals

New approach to formation of secondary particle beams with focusing crystals

CC-2005, CERN, March 7-8, 2005


Multi pass extraction of proton beam with short bent crystals

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


Requirements for crystal

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


O crystal design

O-crystal design

Typicaldimensions5 x 5 x 50 mm3

CC-2005, CERN, March 7-8, 2005


Samples of o crystals prepared in pnpi

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


Typical interference pattern from a bent face of the o crystals

Typical interference pattern from a bent face of the O-crystals

CC-2005, CERN, March 7-8, 2005


Main results with o crystals at ihep

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


New approach to use sumbaev elastic quasimosaic effect

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


Crystal design

Crystal design

CC-2005, CERN, March 7-8, 2005


Elastic quasimosaic in d ependence on cut angle for si 111 plan e

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


Cut 0

Cut  = 0

CC-2005, CERN, March 7-8, 2005


E xperiment with x rays

Experiment with X-rays

Rocking curves for plate with cut angle  = 0 before and after bending.

CC-2005, CERN, March 7-8, 2005


Experiment with protons at ihep

Experiment with protons at IHEP

CC-2005, CERN, March 7-8, 2005


Some details of experimental setup

Some details of experimental setup

CC-2005, CERN, March 7-8, 2005


First r esult

First result

CC-2005, CERN, March 7-8, 2005


Quasimosaic crystals prepared for u 70

Quasimosaic crystals prepared for U-70

CC-2005, CERN, March 7-8, 2005


Some preliminaty results with quasimosaic crystals at ihep

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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