Experiments on deflection of charged particles using silicon crystals at REFER ring (Hiroshima( University) and Proton Synchrotron (KEK( KEK) S. Sawada KEK High Energy Accelerator Research Organization T. Takahashi, I. Endo, M. Iinuma, H. Sato, S. Strokov, K. Ueda Graduate School of Advanced Sciences of Matter, Hiroshima University H. Kuroiwa, T. Ohnishi Venture Business Laboratory, Hiroshima University V. Biryukov, Yu. Chesnokov Institute for High Energy Physics, Russia
Contents 1. Introduction to the channeling effect 2. Motivation 3. Experiment on electron beam deflection (REFER, Hiroshima University) 4. Experiment on proton beam deflection (Proton Synchrotron, KEK) 5. Conclusion 10 July, 2006 Sergey Strokov/ DESY, Hamburg 2
Introduction (channeling effect) θ angle of incident particle to the crystallographic plane deflection angle proton atoms of bent straight crystal crystal θ < Lindhard angle Æ channeling effect θ > Lindhard angle Æ no channeling effect 10 July, 2006 Sergey Strokov/ DESY, Hamburg 3
Motivation Application to deflection of high energy (50 GeV) and high intensity proton beam at J-PARC (Japan Proton Accelerator Research Complex): beam splitting in a slow-extraction beam, beam collimator, slow beam extraction from the synchrotron in the future. Collimation of the ultra-low emittance beam at ILC (International Linear Collider). Beam extraction from the REFER ring is within the scope. Beam diagnosis by channeling effect (beam divergence and profile). 10 July, 2006 Sergey Strokov/ DESY, Hamburg 4
REFER ring @ Hiroshima University REFER (Relativistic Electron Facility for Education and Research) 150 MeV Electron beam QM3 Beam extraction line beam intensity : 1.0 4 1 10 s 10 July, 2006 Sergey Strokov/ DESY, Hamburg 5
REFER ring @ Hiroshima University 10 July, 2006 Sergey Strokov/ DESY, Hamburg 6
Experimental setup Extraction line thickness of crystal: 16µm QM3 vacuum: 1.0x10-7 torr QM3: for change of beam divergence 10 July, 2006 Sergey Strokov/ DESY, Hamburg 7
Extraction line 10 July, 2006 Sergey Strokov/ DESY, Hamburg 8
Setup MIrror IIT & CCD Goniometer Beam Si crystal Beam 10 July, 2006 Sergey Strokov/ DESY, Hamburg 9
Schematic view of the setup phosphor Beam profile θ direction <100> axis Si crystal thickness of crystal: 16µm electron beam φ direction beam divergence controlled by QM3 10 July, 2006 Sergey Strokov/ DESY, Hamburg 10
Experiment: beam divergence Beam divergence vs. QM3 current ( measured beam profile and optics calculation) divergence beam horizontal vertical Beam divergence [ mr ] Beam divergence [ mr ] QM3 current [A] QM3 current [A] Vertical angle dependence of the profile is the point. Lindhard angle for <100> axis of Si : 0.7 mr Beam divergence > Lindhard angle 10 July, 2006 Sergey Strokov/ DESY, Hamburg 11
Results: Beam Profiles QM3: 2.0A θ = 0, φ = -1.5mr Beam divergence: 3.0 mr QM3: 2.6A θ = 0, φ = -1.5mr Beam divergence: 5.2 mr 10 July, 2006 Sergey Strokov/ DESY, Hamburg 12
Analysis Beam divergence ( vertical ): 3.0 mr QM3: 2.0 A Fitting with double Gaussian projection σ σ vertical position ( mm ) Beam center weighted average in 2σ region 10 July, 2006 Sergey Strokov/ DESY, Hamburg 13
Results (1) Beam divergence ( vertical ) : 3.0 mr θ=0 mr (QM3: 2.0 A) Deflection angle change of beam center + 2.34m φ = -2.5 mr Deflection angle [ mr ] φ = -1.5 mr φ = 0 mr φ [ mr ] (Vertical direction of the crystal) 10 July, 2006 Sergey Strokov/ DESY, Hamburg 14
Results (2) Beam divergence = 3.8 mr θ = 0 mr ( QM3 : 2.2 A ) Deflection angle [mr] φ [ mr ] 10 July, 2006 Sergey Strokov/ DESY, Hamburg 15
Results (3) Beam divergence : 5.2 mr θ = 0 mr ( QM3 : 2.6 A ) Deflection angle [mr] φ [ mr ] 10 July, 2006 Sergey Strokov/ DESY, Hamburg 16
Results: deflection vs. beam divergence Deflection vs. beam divergence ( normalized at 3 mr ) 1.2 1 0.8 0.6 0.4 0.2 0 2.5 3 3.5 4 4.5 5 5.5 Beam divergence [mr] The magnitude of the deflection,, was determined by fitting the plot with 1 st derivative of Gaussian function 0.3 0.2 0.1 0-0.1-0.2-0.3-10 -5 0 5 10 φ [ mr ] Larger beam divergence Smaller deflection 10 July, 2006 Sergey Strokov/ DESY, Hamburg 17
Simulation Lindhard string continuous potential 2 2Ze U = ln 1+ d Conditions for simulation 3R 2 ρ 4 th order of Runge-Kutta method 2 R : ρ : d : Z : Thomas-Fermi radius Distance from <100> axis lattice constant in <100> axis ( 5.43A for Si) Atomic number ( 14 for Si ) Without consideration of multiple scattering and channeling radiation Energy of electrons : 150 MeV Thickness of the crystal : 16 µm 10 July, 2006 Sergey Strokov/ DESY, Hamburg 18
Simulation: trajectory Trajectory of an electron Y [A ] Initial position : X=0A,Y=0.3A 0.3 0.2 0.1 0.0-0.1-0.2-0.3-0.2 0.0 0.2 X [A ] Y [A ] Initial position: X=0A,Y=0.5A 10 5 0 <100> 軸 -5-5 0 5 10 X [A ] 10 July, 2006 Sergey Strokov/ DESY, Hamburg 19
Simulation (1) Preliminary results Beam divergence : 3.0 mr Beam divergence : 5.2 mr Deflection angle [mr] φ [ mr ] φ [ mr ] Larger beam divergence Smaller deflection 10 July, 2006 Sergey Strokov/ DESY, Hamburg 20
Simulation (2) Comparison with experimental data Beam divergence : 3.0 mr ( QM3 : 2.0 A ) Deflection angle [mr] φ [ mr ] φ [ mr ] The tendency of the deflection as a function of the vertical direction of the crystal (φ) is same. But, in quantitative comparison, the peak-to-peak difference of the deflection angle of the measurement is about 0.4 mr, while it s around 0.04 mr for the simulation. 10 July, 2006 Sergey Strokov/ DESY, Hamburg 21
Simulation (3) Comparison with experimental data Beam divergence : 5.2 mr ( QM3 : 2.6 A ) Deflection angle [mr] φ [ mr ] φ [ mr ] Experimental data agree with simulation qualitatively. Study with more realistic beam profiles etc. is underway. 10 July, 2006 Sergey Strokov/ DESY, Hamburg 22
Summary Performed experiment on beam deflection at REFER with the150-mev electron beam. Systematic investigation of the beam deflection as a function of the beam divergence. Preliminary comparison with simulation: Qualitative agreements Quantitative comparison being studied 10 July, 2006 Sergey Strokov/ DESY, Hamburg 23
Prospect Experiment at KEK-ATF (Accelerator Test Facility) E = 1.28 GeV Normalized emittace: ε x = 3.4 x10-6 m, ε y = 4.5x10-8 m Just a similar experiment at ATF as the REFER experiment See channeling effects with the super-low emittance beam. 10 July, 2006 Sergey Strokov/ DESY, Hamburg 24
Experiment at KEK-PS North counter hall Experiment was done in EP2 line EP2 line 12 GeV Proton Synchrotron East counter hall 10 July, 2006 Sergey Strokov/ DESY, Hamburg 25
Experimental setup Fluorescence plate p Crystal Al plate CsI plate Fluorescence plates Goniometer ±θ o Distance 145cm ±20 cm 10 July, 2006 Sergey Strokov/ DESY, Hamburg 26
Crystal, proton beam Parameters of crystal Material: Silicon Size: 3 x 0.3 x 10 mm Bending angle: ~ 32.6 mrad Plane: (111) Lindhard angle: 0.066 mrad Parameters of the proton beam 15mm bending angle, 32.6 mrad Energy: 12 GeV Intensity: 10 12 protons/spill Size: 15 x 12 mm Divergence: < 5 mrad 12mm 10 July, 2006 Sergey Strokov/ DESY, Hamburg 27
Schematic drawing of the experiment view from above crystal deflection angle CsI plate (5x2.5cm) deflected beam fluorescence plate (10x10cm) bent crystal goniometer main beam 12 GeV protons 10 July, 2006 Sergey Strokov/ DESY, Hamburg 28
Typical pictures image after background subtraction raw image CsI plate fluorescence plate Deflected beam Primary beam intensity of deflected beam bending angle crystal efficiency 10 July, 2006 Sergey Strokov/ DESY, Hamburg 29
Results (1) 1.2 position of deflected beam on CsI plate, (mm) 1.0 0.8 0.6 0.4 1450 mm 0.2 0.0-0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 angle between crystal and beam axis, (mrad) Such dependence agrees with estimations 10 July, 2006 Sergey Strokov/ DESY, Hamburg 30
Results (2) N deflected ~10 7 N deflected, (protons) 9x10 7 8x10 7 7x10 7 6x10 7 5x10 7 4x10 7 3x10 7 2x10 7 1x10 7 0-0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 angle between crystal and beam axis, (mrad) N beam 10 12 10 12 protons ~ 10 7 deflected protons 10 July, 2006 Sergey Strokov/ DESY, Hamburg 31
Crystal efficiency N deflected = Crystal Efficiency x Angle Efficiency x N incident upon the crystal. Incident particles within critical (Lindhard) angle to the crystallographic plane. At the beam divergence <5 mrad and Lindhard angle 0.066 mrad, angle efficiency is > 1% Crystal Efficiency could be: 100% at 5 mrad ~ 26% at 1 mrad ~ 13% at 0.5 mrad only small part of all protons hits crystal, that is 0.3% N incident upon the crystal = 3x10 9 N deflected = 4x10 7 protons 10 July, 2006 Sergey Strokov/ DESY, Hamburg 32
Simulation picture at the distance 145 cm from the crystal Catch code Initial parameters Beam Energy: 12 GeV Size: 15 x 12 mm Divergence: 0.3, 0.5, 1, 5 mrad Crystal Size: ~103 deflected 108 initial 3 x 0.3 x 10 mm Bending angle: ~ 32.6 mrad Plane: (111) 108 protons Æ ~ 103 deflected protons 10 July, 2006 Sergey Strokov/ DESY, Hamburg 33
Simulation N deflected = Crystal Efficiency x Angle Efficiency x N incident upon the crystal. Crystal Efficiency is 15% 10 July, 2006 Sergey Strokov/ DESY, Hamburg 34
Simulation vs. Experimental data (1) Position of the deflected beam at the distance 145 cm from the crystal, (mm) experimental data simulation 1.5 1.2 0.9 0.6 0.3 0.0-0.3 0.0 0.2 0.4 0.6 0.8 mrad 10 July, 2006 Sergey Strokov/ DESY, Hamburg 35
Simulation vs. Experimental data (2) 8.0x10 7 5 mrad 8.0x10 7 0.5 mrad 6.0x10 7 6.0x10 7 4.0x10 7 4.0x10 7 2.0x10 7 2.0x10 7 0.0-0.8-0.4 0.0 0.4 0.8 0.0-0.8-0.4 0.0 0.4 0.8 8.0x10 7 1 mrad 8.0x10 7 0.3 mrad 6.0x10 7 6.0x10 7 4.0x10 7 4.0x10 7 2.0x10 7 2.0x10 7 0.0-0.8-0.4 0.0 0.4 0.8 0.0-0.8-0.4 0.0 0.4 0.8 10 July, 2006 Sergey Strokov/ DESY, Hamburg 36
Crystal efficiency At the beam divergence 0.3-0.5 mrad crystal efficiency in experiment was 8-13% From the simulation it is 15% 10 July, 2006 Sergey Strokov/ DESY, Hamburg 37
Summary Experiment on the deflection of proton beam by the bent crystal was successfully done. The crystal shows good deflection efficiency which is 8-13%. Performed Monte-Carlo simulation proves the experimental data 10 July, 2006 Sergey Strokov/ DESY, Hamburg 38
Future projects Next experiment on the channeling of ultra-low emittance electron beam will be performed at KEK-ATF (Autumn, 2006). Participation at the experiment on proton collimation at the Fermilab. Experiment at the REFER ring, Hiroshima University with the 150 MeV electron beam (channeling radiation) Application for the J-PARC 10 July, 2006 Sergey Strokov/ DESY, Hamburg 39