Crystal Channeling for Large Colliders: Machine and Physics Applications 22 -23 March 2007, CERN Geneva 1 A. Vomiero Characterization of crystals Characterization of crystals for relativistic channeling for relativistic channeling A. Carnera, G. Della Mea, D. De Salvador, R. Milan, A. Sambo, A. Vomiero S. Baricordi, V. Guidi, G. Martinelli, A. Mazzolari, E. Milan
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Characterization of crystals for relativistic channeling
Characterization of crystals for relativistic channeling. A. Carnera, G. Della Mea, D. De Salvador, R. Milan, A. Sambo, A. Vomiero S. Baricordi, V. Guidi, G. Martinelli, A. Mazzolari, E. Milan. Surface defects & noise effects Shape of deflected beam Extraction efficiency Edge effect - PowerPoint PPT Presentation
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Crystal Channeling for Large Colliders: Machine and Physics Applications
22 -23 March 2007, CERN Geneva1A. Vomiero
Characterization of crystalsCharacterization of crystalsfor relativistic channelingfor relativistic channeling
A. Carnera, G. Della Mea, D. De Salvador,
R. Milan, A. Sambo, A. Vomiero
S. Baricordi, V. Guidi, G. Martinelli, A. Mazzolari, E. Milan
Crystal Channeling for Large Colliders: Machine and Physics Applications
Surface preparation & analytical techniquesSurface preparation & analytical techniques Preliminary characterisationsPreliminary characterisations Definition of analytical protocolDefinition of analytical protocol
Silicon crystals devoted to CERN-SPS experiment in H8 Silicon crystals devoted to CERN-SPS experiment in H8 beam line (September 2006)beam line (September 2006)
New materials: Germanium crystalsNew materials: Germanium crystals
ConclusionsConclusions
Crystal Channeling for Large Colliders: Machine and Physics Applications
22 -23 March 2007, CERN Geneva3A. Vomiero
Surface treatment proved useful to improve the Surface treatment proved useful to improve the quality of the extracted beamquality of the extracted beam
Images of the 70 GeV protons deflected through mechanically Images of the 70 GeV protons deflected through mechanically treated and chemically polished crystals (U70 @ IHEP)treated and chemically polished crystals (U70 @ IHEP)
Byriukov et al.
Crystal Channeling for Large Colliders: Machine and Physics Applications
22 -23 March 2007, CERN Geneva4A. Vomiero
What is the best crystal for channeling?What is the best crystal for channeling?
AS-cutAS-cut Chemical etchingChemical etching
Mechanical polishingMechanical polishing
Crystal Channeling for Large Colliders: Machine and Physics Applications
22 -23 March 2007, CERN Geneva5A. Vomiero
Extraction efficiency: theoretical calculations and Extraction efficiency: theoretical calculations and experimental resultsexperimental results
V.M.Biryukov, A.I.Drozhdin, N.V.Mokhov. PAC 1999 Proceedings (New York), pp. 1234-1236. FERMILAB-Conf-99-072 (1999).V.I.Kotov et al. EPAC 2000 Proceedings (Vienna), p.364. CERN-LHC-2000-007-MMS.
Crystal Channeling for Large Colliders: Machine and Physics Applications
22 -23 March 2007, CERN Geneva6A. Vomiero
Surface imperfection & channeling degradationSurface imperfection & channeling degradationRole of the edges (“Septum width effect”)Role of the edges (“Septum width effect”)
Elsener et al.
Crystal Channeling for Large Colliders: Machine and Physics Applications
Rutherford backscattering channeling (c-RBS)Rutherford backscattering channeling (c-RBS) The same effect as high energy channeling Depth profile of lattice perfection
Scanning electron microscopy (SEM)Scanning electron microscopy (SEM) Surface morphology (qualitative)
Atomic force microscopy (AFM)Atomic force microscopy (AFM) Surface morphology Roughness (quantitative)
Refined preparation methodology Refined preparation methodology for experiment at H8 CERN-SPS for experiment at H8 CERN-SPS
(September 2006)(September 2006)
S. Baricordi et al. Appl. Phys. Lett. 87 (2005) 094102.V. Guidi et al. Nucl. Inst. Meth. B 234 (2005) 40.A. Vomiero et al. Nucl. Instr. Meth. B 249 (2006) 903.
CharacterisationCharacterisationofof
Final crystalsFinal crystals
Crystal Channeling for Large Colliders: Machine and Physics Applications
Crystal Channeling for Large Colliders: Machine and Physics Applications
22 -23 March 2007, CERN Geneva25A. Vomiero
AFMAFM
As cut Chemical etching
Crystal Channeling for Large Colliders: Machine and Physics Applications
22 -23 March 2007, CERN Geneva26A. Vomiero
c-RBSc-RBS
Crystal Channeling for Large Colliders: Machine and Physics Applications
22 -23 March 2007, CERN Geneva27A. Vomiero
SummarySummary
Sample AFM c-RBS
Ra (nm) min
As-cut 26±8 0.31
Mechanical polishing / 0.75
Chemical etching 1’ 13±2 0.03
Chemical etching 4’ 11±3 0.03
Crystal Channeling for Large Colliders: Machine and Physics Applications
22 -23 March 2007, CERN Geneva28A. Vomiero
ConclusionsConclusions
Surface analytical techniques successfully applied for the characterisation Surface analytical techniques successfully applied for the characterisation of silicon crystals designed for high-energy-channeling experimentsof silicon crystals designed for high-energy-channeling experiments
Results on morphological & structural investigation can give account for Results on morphological & structural investigation can give account for enhanced channeling efficiencyenhanced channeling efficiency
Application of analytical protocol can be useful benchmark before high-Application of analytical protocol can be useful benchmark before high-energy runsenergy runs
Crystals devoted to CERN-SPS experiment in H8 beam line (September Crystals devoted to CERN-SPS experiment in H8 beam line (September 2006)2006)
New materials: GermaniumNew materials: Germanium
Investigation on crystal edgesInvestigation on crystal edges