1. Experiments on strong field QED in crystals (CERN NA63) J.U. Andersen, H. Knudsen, S.P. Møller, A.H. Sørensen, E. Uggerhøj, U.I. Uggerhøj Department of Physics and Astronomy, Aarhus University, Denmark P. Sona Dipartimento di Fisica, Universitá degli Studi di Firenze, Polo Scientifico, Sesto F.no, Italy S. Connell, S. Ballestrero Johannesburg University, Johannesburg, South Africa T. Ketel NIKHEF, Amsterdam, Holland S. Kartal, A. Dizdar Department of Physics, Istanbul University, Turkey A. Mangiarotti Laboratório de Instrumentação e F í sica Experimental de Part í culas, Coimbra, Portugal Status Report

2. Results, Oct. 2007 run 1. Trident production in strong fields 2. Formation length effects

3. Trident production

4. Trident production: Background (no target) in nearly complete agreement with GEANT simulation (= no big surprises) Contributes about 20% Trident (Klein-like) Setup optimized for detection of 1-10 GeV pairs from 200 GeV electrons

5. Non-aligned crystal JETP Lett.88:80-84,2008 Small multi- hit capability Geometric acceptance

6. Spectrometer efficiency

7. Aligned case

8. Single target Shul’ga-Fomin: Reduced multiple scattering – no suppression from LPM effect JETP Lett. 63, 873 (1996) Bethe-Heitler LPM

9. Measurements

10. Results, Oct. 2008 run 1. Restricted energy loss 2. Formation length effects

11. Ogle effect Coherence length: Range for tagged e- beam: gamma: [1  10 3 ;4  10 5 ] Alternative (Akhiezer, Shul’ga): Loss of density effect 1. 2.

12. Sandwich target 10 layers: Ta (10 microns) Air (100 microns) Resonances from formation length

13. Wednesday, 1.10. SPS malfunction in B3 (ground error)  12 hrs. lost, max. energy 180 GeV Ilias Efthymiopoulos, Bruno Chauchaix  back in business (thanks!) 6 days lost, 5 days left

14. Ogle effect – suppression unlikely real, loss of density effect possible

15. Sandwich ’resonances’ (?) ’onset’ for 120 GeV e -

16. Plans for 2009 1 week in June

17. intensity proportional to the logarithm of the thickness intensity linear with thickness 1 week in June

18. Plans for 2009 3 weeks in autumn

19. Spin-flip

20. ’Polarization time’

21. Similar situations ILC / CLIC Bunch-size: 300  0.6  0.006 μm 3, 2·10 10 particles Density: 0.005 Å -3, 0.6 Å -3 (at IP) Si crystal Density: 0.05 Å -3, of Z = 14 Blankenbecler, Drell (PRD 36, 277 (1987), Quantum treatment of beamstrahlung: ”Pulse transforms into a very long narrow ’string’ of N charges.”

22. Spin contr. to beamstrahlung Blankenbecler and Drell, ”Quantum treatment of beamstrahlung”, PRD 36, 277 (1987) Radiation from crystal C ≈ 1/ χ Spin-flip contribution:

23. Blankenbecler and Drell, ”Quantum treatment of beamstrahlung”, PRD 36, 277 (1987) Spin contr. to beamstrahlung

24. Contribution of spin to radiation emission in crystals 2 weeks in autumn Crystals Beamstrahlung Time required for setting up + calibration in autumn: 1 week Total: 1 week in spring, 3 weeks in autumn

25. Strong interest (CTF3, L. Rinolfi) in positron- production studies with aligned crystals – to be used for e.g. CLIC Simulations. NA63 can measure this – addendum in preparation

26. Publications and summary

27. Publications From ’preparatory phase’ of NA63: testrun in 2004 NA63: run in 2007 NA63: 2007, Subm. April ’09 NA63: 2008, Subm. May ’09

28. From the proposal of NA63 Done. Analysis in progr. First observ., systematical 2009 Alternative routes superior 2009