1. Beam Monitoring from Beam Strahlung work by summer students  Gunnar Klämke (U Jena, 01)  Marko Ternick (TU Cottbus, 02)  Magdalena Luz (HU Berlin, 03)  Regina Kwee (HU Berlin, 03)  New student, summer 04 Achim Stahl DESY Zeuthen 16.Apr.2004

2. Beam Strahlung GeV/mm 2 Diagnostics of bunches at IP 3 potential sources of information energy-distribution of pairs number-distribution of pairs distribution of photons Over-simplified detector simulation detectors subdivided into cells sum energy impact on cells main source of uncertainty  stat. fluctuations of beam-str. Linear approximation

3. Redesign for larger L*

4. Observables  total energy  first radial moment  first moment in 1/r  thrust value  angular spread  E(ring ≥ 4) / E tot  (A + D) – (B + C)  (A + B) – (C + D)  E / N A BC D forward / backward calorimeter

5. Current Analysis Concept Beam Parameters determine collision creation of beamstr. creation of e + e - pairs guinea-pig Observables characterize energy distributions in detectors analysis program 1 st order Taylor-Exp. Observables Δ BeamPar Taylor Matrix nom = + * Solve by matrix inversion (Moore-Penrose Inverse)

6. Slopes beam parameter i observable j 1 point = 1 bunch crossing by guinea-pig parametrization (polynomial) slope at nom. value  taylor coefficient i,j

7. Example: Slopes

8. ((A+C) – (B+D)) / total energy Analysis Problem bunch rotation in mrad total energy slope = 0 at nom. Parameter linear approximation fails true for all observables  analysis fails

9. 1 st Results: Single Parameter Analysis 1 st Results: Single Parameter Analysis nominal our precisionBeam Diag. Bunch width x Ave. Diff. 553 nm 1.2 nm 2.8 nm ~ 10 % Bunch width y Ave. Diff. 5.0 nm 0.1 nm Shintake Monitor Bunch length z Ave. Diff. 300 μm 4.3 μm 2.6 μm ~ 10 % Emittance in x Ave. Diff. 10.0 mm mrad 1.0 mm mrad 0.4 mm mrad ? Emittance in y Ave. Diff. 0.03 mm mrad0.001 mm mrad ? Beam offset in x Beam offset in y 0 7 nm 0.2 nm 5 nm 0.1 nm Horizontal waist shift Vertical waist shift 0 μm 360 μm 80 μm 20 μm None

10. What’s new:  consolidation of code  new observable: E(ring ≥ 4) / Etot  normalization of observables O/σ  use of external measurments  first look at real bunch trains

11. Single Parameter Analysis nominaloldnewnorm.Beam Diag. Bunch width x Ave. Diff. 553 nm 1.2 2.8 2.0 3.6 1.5 2.1 ~ 10 % Bunch width y Ave. Diff. 5.0 nm 0.1 0.2 0.5 0.2 0.5 Shintake Monitor Bunch length z Ave. Diff. 300 μm 4.3 2.6 7.5 3.5 4.3 2.7 ~ 10 % Emittance in x Ave. Diff. 10.0 mm mrad 1.0 0.4 --- 0.7 --- 0.7 ? Emittance in y Ave. Diff. 0.03 mm mrad0.001 0.004 0.001 0.002 ? Beam offset in x Beam offset in y 0 7 0.2 30 0.6 6 0.4 5 nm 0.1 nm Horizontal waist shift Vertical waist shift 0 μm 360 μm 80 20 --- 23 --- 24 None

12. Single Parameter Analysis Test of Linearity Range

13. Single Parameter Analysis weight of individual observables

14. Two Parameter Analysis Example: horizontal beam size Sngl Param Reso: 1.5 nm

15. Multi Parameter Analysis σxσx σyσy σzσz Δσ x Δσ y Δσ z 0.3 %0.4 %3.4 %9.5 %1.4 %0.8 % 0.3 % 0.4 %3.5 % 11 % 1.5 % 0.9 % 0.9 % 1.0 % 11 % 24 % 5.7 % 24 % 1.6 % 1.9 % 1.8 % 1.1 % 16 % 27 % 3.2 % 2.1 %

16. Multi Parameter Analysis Test with non-nominal bunches: e - e + nom. bunch size x: 575nm 575nm 553nm bunch size y: 5nm 7nm 5nm bunch size z: 290μm 320μm 300μm

17. Full Analysis nominal1-Par.constraintResultBeam Diag. Bunch width x Ave. Diff. 553 nm1.5 2.1 --- 25 12 ~ 10 % Bunch width y Ave. Diff. 5.0 nm0.2 0.5 --- 1.3 2.2 Shintake Monitor Bunch length z Ave. Diff. 300 μm4.3 2.7 --- 20 24 ~ 10 % Beam offset in x Beam offset in y 0 6 0.4 5 0.5 6.4 0.8 5 nm 0.1 nm Vertical waist shift360 μm24---300None Bunch charge Ave. Diff. 2 10 10 0.002 0.007 0.1 0.08 0.07 None

18. Real Beams: first look Example of 2 observables:

19. Real Beams: first look Single Parameter Analysis: σ x

20. 3 Sources of Information energy-distribution of pairs number-distribution of pairs distribution of photons up to now: only energy distribution of pairs used test: number-distribution of pairs new observable  N pairs / E tot 1 st layer: measures N all layers: measure E LumiCal

21. Number Distribution weight of new variable

22. Number Distribution nominal1-Par.6-Par. without N 6.-Par with N Bunch width x Ave. Diff. 553 nm1.5 2.1 9.9 6.2 8.3 6.0 Bunch width y Ave. Diff. 5.0 nm0.2 0.5 0.8 1.3 0.6 0.9 Bunch length z Ave. Diff. 300 μm4.3 2.7 9.5 6.2 9.4 6.1 Example: 6-Par. Analysis  roughly 10% improvement

23. First Look at Photons

24. nominal setting (550 nm x 5 nm) σ x = 650 nmσ y = 3 nm

25. Next Steps:  Include non-linear terms  understand realistic beam simulation  include photons ? impact on calorimeter design ? Conclusions:  Interesting resolutions achieved from single bunches  Multi-parameter analysis possible  Electron – Positron bunch can be separated  Not all parameters measurable

26. 1st Fit with non-linear Terms nominaloldnorm.fitBeam Diag. Bunch width x Ave. Diff. 553 nm 1.2 2.8 1.5 2.1 1.5 2.2 ~ 10 % Bunch width y Ave. Diff. 5.0 nm 0.1 0.2 0.5 0.2 0.3 Shintake Monitor Bunch length z Ave. Diff. 300 μm 4.3 2.6 4.3 2.7 4.6 2.7 ~ 10 % Emittance in x Ave. Diff. 10.0 mm mrad 1.0 0.4 --- 0.7 --- 1.0 ? Emittance in y Ave. Diff. 0.03 mm mrad0.001 0.002 0.001 0.003 ? Beam offset in x Beam offset in y 0 7 0.2 6 0.4 7 0.03 5 nm 0.1 nm Horizontal waist shift Vertical waist shift 0 μm 360 μm 80 20 --- 24 --- 73 None bunch rot. horizontal0 mrad --- 49 0.06 ???? bunch rot. vertical0 mrad --- 0.9 0.07 ????

27. 1st Fit with non-linear Terms

28. The Mask LumiCal shields detector against  back scattered beam strahlung  synchrotron radiation of final focus QUADs  neutrons from the dump

29. The Mask LumiCal shields detector against  back scattered beam strahlung  synchrotron radiation of final focus QUADs  neutrons from the dump 10 cm graphits 5 cm graphits

30. VTX-Detector: Simulations by Karsten Büsser, Hamburg

31. TPC: Simulations by Karsten Büsser TDR new: 0 crossing new: 20 mrad crossing slight increase in background ? optimization possible ?  more in Paris