2. Beam-time, June 2009 Beam-time, Oct. 2009 8 days of beam time
5 days datataking
Beam-time, Oct. 2009
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)

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

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

7. 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

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

9. 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.

10. Proposals

11. 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)

12. 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...

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

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

15. 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

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

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

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

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

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

21. Silicon target 25 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.

22. Possibility with silicon
Impact parameter dependence (?)

23. 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)

24. Summary Done in 2009: Proposed:
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