Quasimosaic crystals

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Quasimosaic crystals. Yu.M.Ivanov. Elastic quasimosaic (Sumbaev) effect. Studied by Sumbaev in 1957 Resulted in broadening of gamma-ray diffraction peaks from bent quartz plates - PowerPoint PPT Presentation

Text of Quasimosaic crystals

  • Quasimosaic crystalsYu.M.Ivanov

  • Elastic quasimosaic (Sumbaev) effectStudied 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 planeFigure from article: O.I.Sumbaev, Reflection of gamma-rays from bent quartz plates, Sov. JETP 32(1957)1276

  • Quasimosaic effect in siliconCalculations of deformed crystal plate done by V.M.Samsonov (Preprint No. 278, LIYaF AN SSSR, 1976).Resulted in predictions of elastic quasimosaic effect for some other quartz and silicon plate orientationsLarge elastic quasimosaicity for (011) plane of silicon predicted Zero result in the first experiments in 1999New calculations using Samsonov approach and new measurements: - (111) plane, not (011) - published in JETP Letters 81, 99, 2005

    Figure from article: V.M.Samsonov and E.G.Lapin, On some possibilities and pequliarities of a curved crystal use in crystal diffraction instruments, Preprint No. 587, LIYaF AN SSSR, 1980

  • Elastic quasimosaic in dependence on cut angle for Si (111) planeT thickness of platek9 deformation coefficientDq = 2k9 T , where Plate bending radius R = 1 m ( formula taken from V.M.Samsonov, E.G.Lapin, Preprint No. 587, LIYaF AN SSSR, 1980 )

  • Silicon cutsCut without quasimosaicCut with quasimosaicOriented ingot

  • Quasimosaic effect in Si with X-raysRocking curves for Si plate with quasimosaic before and after bending.Rocking curves for Si plate without quasimosaic before and after bending.

  • Shape of bent Si plate with elastic quasimosaic

  • Bending device

  • First quasimosaic silicon crystal prepared in 2002 for channeling experiment with 70 GeV protons

  • Layout of experiment at IHEP in April, 2002

  • Profile of 70 GeV proton beam passed through the crystal measured with emulsion: superposition of channeling and volume reflection effects

  • Explanation of the observed picture on emulsionsProton trajectories crossing the crystal and emulsions in horizontal plane (top view)

  • Samples 0.3 mm and 2.7 mm with ~0.4 mrad bending angle

  • Sample 10 mm with ~100 rad bending angle

  • Crystals for experiment on extraction of high entensive proton beam at IHEPPlane (111)Length along beam 2.65 mmBending angle 400 rad

  • Crystal station at IHEP ring

  • Crystal mounted on station

  • ResultBeam in the U-70 ring 5.51012 p

    Intensity of extracted beam 4.01012 p

    Efficiency 70%

  • Experiment on observation of volume reflection effect with 1 GeV protons at PNPI, Gatchina Beam divergence ~ 160 radBeam size ~ 0.8 mmCritical angle for channeling ~ 170 radCrystal length along beam ~ 30 mBend angle of (111) planes ~ 380 rad

  • One of unsuccessful attempts to bend a 30 m crystal on 20 mm radius

  • Bent crystals in bending devices

  • Check of crystal shape with laser~1m

  • Measurement of bending angle with X-rays

  • Collimator Crystal mounted on goniometer

  • Horizontal profiles of the p-beam vs. crystal angle measured with PPCp-beamreflectionchannelingp-beamCrystal angle, step 62.5 radChannel number, step 200mm

  • Channeling experiment with 400 GeV protonsH8 beam lineFAR_DETECTOR areaCRYSTAL area

  • QM2

  • QM2

  • QM2Channeling angle (68.2 0.4) rad

    Volume reflection deflection (12.7 0.6) rad

    Volume capture (1.8 0.7) %

  • QM1

  • QM1

  • QM1Channeling angle (77.0 0.4) rad

    Volume reflection deflection (11.6 0.8) rad

    Volume capture (2.6 0.8) %

  • QM2+QM1

  • QM2+QM1

  • QM2+QM1Channeling angle

    Volume reflection deflection (23.4 0.7) rad

    Volume capture (5 1) %

  • QM3

  • QM3

  • QM3

    Channeling angle (72.7 0.8) rad

    Volume reflection deflection (11.9 0.7) rad

    Volume capture (5 1) %

  • QM4

  • QM4

  • QM4Channeling angle (120.0 0.4) rad

    Volume reflection deflection (12.7 0.5) rad

    Volume capture (4.4 0.7) %

  • Design: sequence of quasimosaic crystals cut from a single initial plate p1 Si plate 0.3 x 30 x 60 mm312 Si plates 0.3 x 8 x 14 mm3

  • Check of plate wedging with optical goniometer

  • Prototype assembly from 5 plates

  • Check with narrow X-ray beamN0.017x N rad < 40 radX, mmN, countsXN1N2N=N2-N1X

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    3/17/07

    . 1

    XY

    15.7045000Func.1sqrtFit123Func.2sqrtFit

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    15.751618015.745532000.000000011729.3833011524511205.246125320-2680-2680525083.33724.626340491511205.24612Chi^2 = 9842.11852

    15.761310015.755308000.000000007554.9774770205280386.468963080-2240440306000.00553.1726674376280386.46896P1166174.7014233896.60314

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    :

    ,

    1- (Func.1) 3- (Func.2)

    2.Chi^2 = 9654.57314

    1- .P1166174.7014233587.71282

    , - .P2659495.435293847.42758

    P315.72950.00568

    P40.0320.00364

    . 2

    Xy

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    0.0000.3950.4340.4740.5130.5520.5920.6310.6710.7100.7500.7890.8290.8680.9080.947

    .mkradq15.2115.1115.1015.0915.0815.0715.0615.0515.0415.0315.0215.0115.0014.9914.9814.97

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    231.651123.50343061041515513208124941335515500176641995820595196901819918120194042120