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Status: Structured target resonance Magnetic suppression

Status: Structured target resonance Magnetic suppression Low-Z LPM, Undulator-rad ., Quantum suppression Plans: Heavy ion bremsstrahlung Positron production. STATUS. Structured target resonance. 2x20 micron Au/Ta foils separated by 0 – 5000 microns (tolerance about 2 microns ).

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Status: Structured target resonance Magnetic suppression

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  1. Status: Structured target resonance Magnetic suppression Low-Z LPM, Undulator-rad., Quantum suppression Plans: Heavy ion bremsstrahlung Positron production

  2. STATUS

  3. Structured target resonance • 2x20 micron Au/Ta foils separated by 0 – 5000 microns (tolerance about 2 microns) Signal ‘on top of’ about 2.0 (in these units) for separations in microns 120 20 40 100

  4. Structured target resonance Measuring the formation length with a micrometer screw.... Preliminary SPS H4 exp., Sept. 2011

  5. Magnetic suppression If the deflection angle over half a formation length exceeds the ‘emission angle’ which happens for photons: Suppression (crude model): More elaborate theory needed...

  6. Magnetic suppression • Material immaterial. • Higher fields move effect to higher photon energies. • Magnitude insensitive • BUT: The effect will not be visible due to LPM suppression! 10% effect...

  7. Magnetic suppression NB! • Material immaterial. • Higher fields move effect to higher photon energies. • Magnitude insensitive 300% effect!

  8. Magnetic suppression MCS Field The effect will not be visible due to LPM suppression!

  9. Low-Z LPM • SLAC (1995) and CERN (2001) indicate problems withlow-Ztargets. • Test LPM theory in low-Ztargets • Analysis in progress (deconvolution of synchr. rad. poses problems)

  10. Undulator radiation fromElectron/Positron Channeling in a Single Crystal A. Solov’yov, A. Korol, W. Greiner et al. Initially tested (unsuccesfully) by NA63

  11. Undulator radiation H. Backe, W. Lauth, A. Solov’yov, W. Greiner, U. Uggerhøj, J. Esberg, J.L. Hansen MAinzMIcrotron (MAMI) Il NuovoCimento C, 34, 157-165, 2011 Il NuovoCimento C, 34, 175-180, 2011

  12. Quantum Suppression

  13. Quantum Suppression Classical: -> 0 => Cb -> infty

  14. Quantum Suppression ‘Fudge-factor’ normalization MonteCarlo • Analysis in progress • Factor 2 problem withnormalization…

  15. PLANS

  16. Heavy ion bremsstrahlung 33 TeV Pb82+ → Pb82+ γ = 170 Intact projectile Weizsäcker-Williams type calculation Scattering on a single rigid object of charge Ze and mass M Approx. binding energy per nucleon Coherent scattering on Z quasi-free protons each of mass Mp Wavelength corresp. to nuclear size Incoherent scattering on individual quasi-free protons

  17. Heavy ion bremsstrahlung Previous theories Now BS never becomes the dominating mechanism in energy loss

  18. Heavy ion bremsstrahlung Delta-electrons Finite nuclear size

  19. Positron production …studies withalignedcrystals – to beused for e.g. CLIC, LHeCprevious studies with tungsten Highmultiplicity and ’low’ energies (10 MeV e+)

  20. Positron production • MIMOSA detectors (M. Winter, Strasbourg) • Vertex detectors for CLIC (?)

  21. Positron production Applications for funding – 100 kCHF – submitted Funding expected by December 2011 11 MIMOSAs + DAQ delivered February 2012

  22. Status: Structured target resonance Magnetic suppression Low-Z LPM, Undulator-rad., Quantum suppression Plans: Heavy ion bremsstrahlung Positron production

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