1. NTA-HCCC Stato aggiornato della sperimentazione Vincenzo Guidi Sezioni di FE, LNL, MIB (Como e TS) Partecipazione esperimento UA9– CERN Coordinato da W. Scandale 2 5 3 1 4 6

2. Outlook Sample preparation Runs with negative charges (H4) Runs with positive charges (H8) Connection with UA9 experiment Activity under way in 2009

3. Demand for lower roughness An application of crystals would be the collimation of beam halo in next generation of hadron machines (e.g. the LHC) Particles in the halo drift outwards at the rate of ~2 nm per turn. Since the tune is not integer, the particles will hit the crystal every ~10-20 turns and thereby the first impact parameter of the particles onto the crystal will be in the range of ~100 nm (curtesy of V. Previtali and R. Assmann) It demands a crystal with a roughness lower than 100 nm on the lateral faces of the crystal

4. Anisotropic etching I Anistropic etching is a feasible way to realize sub-surface damage free crystals entirely by wet chemical methods (100)(110)(111) 7.1  m/h10.7  m/h Negligeable Etch rate on different silicon planes for KOH 20% at 40 °C

5. Photolythography a) Starting material: (110) silicon wafer b) LPCVD deposition of silicon nitride thin layer c) Silicon nitride patterning d) Etching of Si in KOH solution, silicon nitride acts as masking layer e) Silicon strips release f) Removal of silicon nitride

6. Fabrication of multistrips Fabrication of either a multistrip or a batch of strips is possible through wet chemical methods

7. Structural characterization Lateral surface (AFM) Sub-nm roughness was achieved Entry surface (HRTEM) High-quality surfaces achieved via ACE Sub-nm roughness was achieved

8. Previous runs August and September data acquisition setup for 400 GeV/c protons and 150 GeV/c µ -, π -, K -  1.92x1.92 cm 2 telescopes with reading steps 50 µm  Spatial resolution:5 µm  DAQ rate = 2.1 kHz

9. Goniometer Perpendicular planes orientation (to looking for axial channeling) Stage rotativo “culla” goniometer crystal Vertical direction Bended planes orientations (to looking for planar channeling)

10. Axial channeling First observation of axial channeling with high efficiency. Capability to divert 90% of beam particles towards an ordered direction

11. Negative particles I First observation of: planar channeling volume reflection with negative particles

12. Negative particles II First observation of axial channeling with negative particles in a single strip P(θ x >0)=90.6%

13. MST14 Multistrips I 12 crystals aligned in ~400µm ~40µm volume reflection region with: -no channeling -109µrad deflection angle New crystal holder conception

14. MST14 Multistrips II 12 crystals aligned in ~100µm ~160µm volume reflection region with: -no channeling -109µrad deflection angle Different mass charge distribution over strips

15. MST14 Multistrips III Volume Reflection Deflection angle: 109 µrad Efficiency: 94% Surprisingly high level

16. MVR 2007 vs 2008 20072008

17. MVR 2007 vs 2008 Deflection angle: 40.5  rad Efficiency: 93% Deflection angle: 109  rad Efficiency: 94%

18. MST curvature dependence Volume Reflection: Deflection Angle VS Radius Channeling: Efficiency VS Radius

19. MST15 Multistrips I Low efficiency channeling peak ~400 µm volume-50µrad deflection angle Changed bending angle

20. MST15 Multistrips II No channeling peak ~750 µm volume-25µrad deflection angle Changed bending angle

21. Multiple volume reflection in a single crystal Volume reflection from different planes Clear observation of multiple volume reflection in single strip crystal (V. Tikhomirov, PLB 655, 5-6, 2007)

22. Schemes for beam collimation Planar channeling ( ST9 for UA9) Volume reflection ( MST14 for UA9) Axial channeling Multiple volume reflection in a single crystal The steering committee of the UA9 selected two crystals fabricated by INFN

23. Scientific production NIM B 249 (2006) 302 PRL 97 (2006) 144801 NIM B 252 (2006) 11 APL 90 (2007) 114107 APL 91 (2007) 061908 PRL 98 (2007) 154801 PLB 658 (2008) 109 RSI 79 (2008) 023303 PR ST 11 (2008) 063501 JPD 41 (2008) 245501 PRL 101 (2008) 164801 PRL 101 (2008) 234801 PRL 102 (2009) to appear PRA 79 (2009) to appear PRL 102 (2009) to appear

24. 2009 Activity I External line H4 10 days  Negative particles (µ - and π - ) beam 150 GeV/c  Electron beam 150 GeV/c External line H8 38 days  Proton beam 400 GeV/c

25. 2009 Activity II Planned experimental activity on H8 1.Investigation on multiple volume reflection 2.Observation of multichanneling (with piezo-systems) 3.New material (Tungsten) 4.New concept: silicon lens for channeling experiment 5.Observation of PXR with 400 GeV protons

26. 2009 Activity III Planned experimental activity on H4 1.Precise measurements of dechanneling length 2.Study of multiple volume reflection with negative charges.

27. Super-acceptance channeling I With a silicon lens it is possibile to reduce the number of dechanneled particles by focusing the proton beam onto the center of the potential well, with a precise cut in the crystal

28. Super-acceptance channeling II Simulation of particle trajectories Silicon crystalSilicon Lens

29. Super-acceptance channeling III Channeling with focusing results in 99% efficiency!

30. Super-acceptance channeling IV Implementation of the method of the cut through a buried SIMOX layer

31. Richiesta di integrazione MEInv FE4.516 LNL2 MIB4.5