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Beam-time, June 2009

Beam-time, June 2009. 8 days of beam time 5 days datataking. 15 days + 3 days ’rescheduled’ PS injection septum replacement. 9 days lost (4 were planned for MD). 4 days used for setting up + calibration 5 days datataking (<half of original aim). Beam-time , Oct . 2009.

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Beam-time, June 2009

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  1. Beam-time, June 2009 • 8 days of beam time • 5 daysdatataking • 15 days + 3 days ’rescheduled’ • PS injection septum replacement. 9 days lost (4 were planned for MD). • 4 days used for setting up + calibration • 5 days datataking (<half of original aim) Beam-time, Oct. 2009

  2. Logarithmic t dependence Transition between Bethe-Heitler and LPM regimes: ’Radiation per interaction as a function of number of scatterings’

  3. ’Spin-flip’ October 2009 run Energies investigated: 10, 20, 50, 100, 120 and 150 GeV with spin Enhancement without spin Preliminary analysis Preliminary analysis

  4. Quantum suppression Previous measurements in tungsten supplemented by values in the ’transition region’ from classical to quantum synchrotron radiation. Spin-flip contribution measured in the same region. Analysis in progress, final results expected summer ‘10

  5. Quantum suppression From: J. Esberg (NA63) – CTF3, GUINEA-PIG implementation

  6. A substantially decreased energy loss for thin targets as the Lorentz factor increases – the ‘Ogle effect’ - is incompatible with our measurements. • A disappearance of the density effect, when becomes longer than the target, is possible.

  7. Proposals 2010-12

  8. Low-Z LPM • Landau-Pomeranchuk-Migdal (LPM) measurements at SLAC (1995) and CERN (2001) indicate that there may be problems with low-Z targets. • We propose to test LPM theory in low-Z targets (10 days requested, 6 days scheduled 2010)

  9. 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...

  10. Magnetic suppression (Same as S on previous slide) • Material immaterial. • Higher fields move effect to higher photon energies. • Magnitude insensitive

  11. Magnetic suppression I. Efthymiopoulos: MBWs available, questions about zone-extension to be clarified Request: 2 weeks in 2011

  12. 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

  13. Theory Now Previous theories BS never becomes the dominating mechanism in energy loss

  14. Planned experiment: 33 TeV Pb82+ → Pb82+ γ = 170 δ - electrons BGO 0.1 – 2 GeV LG 2 – 200 GeV 2 mm Pb Charge +82

  15. Multiple Sampling Ionization Chamber (MUSIC) Charge state identification

  16. Background: δ - electrons These events can be ’flagged’ Pb82+ → γ prop. to Δt thin targets => ’low’ countrate Pb82+ → δelectron→γ prop. to Δt2

  17. Electromagnetic dissociation Target selections in simulations chosen with 2.5% and 5% fragmentation.

  18. 25 Silicon target Fragmentation We propose to measure for targets with Z values of 6, 13, 14, 29, 50, 73 and 82, mounted on a remote-controlled target-wheel. 7 days of running with 33 TeV Pb82+ extracted to the SPS H4 beamline in 2012.

  19. Possibility with silicon Impact parameter dependence (?)

  20. Strong interest (L. Rinolfi, CERN) in positron-production studies with aligned crystals – to be used for e.g. CLIC, LHeC High multiplicity and ’low’ energies (10 MeV e+) NA63 cannot measure this with the present setup and manpower Applications for funding in preparation (deadline nov. ’10)

  21. Summary • Done in 2009: • Logarithmic thickness dependence BH -> LPM (published) • ‘Ogle effect’ – changing dE/dx in thin targets (published) • ‘Spin-flip’ in radiation emission (analysis in progr.) • Quantum synchrotron radiation emission (analysis in progr.) • Proposed: • Low-Z LPM (2010, 6 days) • Magnetic suppression (2011, 2 weeks) • Heavy ion bremsstrahlung (2012, 7 days) • Positron production in crystals – possibilities under study

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