1. H8-RD22 Experiment to test Crystal Collimation for the LHC Organized by: Walter Scandale Conducted at CERN Geneva, 27 September 2006 Participants included: Italian group: Russian group: 1 American:

2. 980-GEV BEAM CHANNELING Independent simulations by V. Biryukov and Y. Ivanov show channeling efficiencies of 90% to 95% possible. Particles are channeled Lattice of crystal. Volume Capture: Volume reflections from atomic planes

3. 3/19 September 2006Walter Scandale  A bent crystal should efficiently deflect halo particles away from the beam core toward a downstream massive absorber selective and coherent scattering random scattering  The selective and coherent scattering on atomic planes of an aligned Si- crystal replaces the random scattering process on single atoms of an amorphous target Crystal channeling: a smart approach for primary collimation Amorphous scatterer

4. 4/19 September 2006Walter Scandale Silicon crystals Strip Crystals have been fabricated in the Sensors and Semiconductor Laboratory (Ferrara, Italy) Crystal sizes: ~ 0.9 x 70 x 3 mm 3 Quasi-Mosaic Crystals have been fabricated in PNPI (Gatchina, Russia) Crystal plate sizes: ~ 1 x 30 x 55 mm 3 critical angle for 400 GeV/c protons ≈ 10 μrad

5. 5/19 September 2006Walter Scandale Layout scheme (not to scale) Scintillators (S1-S6) Scintillating Hodoscope (H) vacuum Goniometer with crystal holders Si microstrips (AMS) p S1 S2 70 m Si microstrips (AGILE) S3 GC H S4 S5 S6 BM Gas Chamber (GC) Bending Magnet (BM)

6. 6/19 September 2006Walter Scandale Volume reflection (110) Si crystal – simulation results H8 microbeam – 400 GeV protons, divergence – 3 μrad Angular distribution Crystal bending angle α=100 μrad, length S=1 mm Volume reflection angle θ VR = 14.3 μrad, σ=5.1 μrad Volume reflected fraction with θ<0, VR – 96% Volume captured fraction at the exit from the crystal, VC – about 1.5% VR VC

7. 7/19 September 2006Walter Scandale Channeling (110) Si crystal – simulation results H8 microbeam – 400 GeV protons, divergence – 3 μrad Crystal bending angle α=100 μrad, length S=1 mm Deflection efficiency of channeled fraction – 80% Full width of deflected fraction – 20 μrad Reduction of channeled fraction due to multiple scattering – about 6% Angular distribution 0 Ch

8. 8/19 September 2006Walter Scandale Scan of Strip Crystal (1) Orientation (111) Bending angle: ~ 200 microrad Crystal sizes: 0.5 × 70 × 1.85 mm 3 (mm)

9. 9/19 September 2006Walter Scandale Scan of Strip Crystal (1) measured volume reflection angle: ~ 10 μrad

10. 10/19 September 2006Walter Scandale Scan of Strip Crystal (2) Orientation (110) Crystal sizes: 0.9 × 70 × 3 mm 3

11. 11/19 September 2006Walter Scandale Scan of Quasi-Mosaic Crystal (1) Orientation (111) Bending angle: ~ 80 microrad Crystal sizes: 30 × 58 × 0.84 mm 3 measured volume reflection angle: ~ 10 μrad

12. 12/19 September 2006Walter Scandale Double Reflection on Quasi-Mosaic Crystals (1) double reflection angle: ~ 20 μrad

13. 13/19 September 2006Walter Scandale Double Reflection on Quasi-Mosaic Crystals (2) Two crystals displaced by 1 mm: not perfect alignment

14. 14/19 September 2006Walter Scandale Conclusive remarks  First observation of Volume Reflection Effect in bent silicon crystals with 400 GeV/c protons with efficiency close to unity  Measurement of volume reflection angle: ~ 10 μrad  First observation of Double Reflection using two crystals in series: combined reflection angle is ~ 20 μrad and efficiency close to 1  Channeling and Volume Reflection phenomena studied with Strip and Quasi-Mosaic Silicon Crystals (different fabrication techniques)  Measurement of crystals with different crystalline planes orientations: (111) and (110)

15. Future Plans There was talk of a crystal workshop in a couple of months to propose experiments in the Tevatron and/or SPS to collimate channeled and volume reflected beams to be conducted spring 2007. We are proceeding with installing the crystal FNAL has but have many problems with inchworm drive.

16. Extra Slides

17. 17/19 September 2006Walter Scandale The beam Beam parameters Beam parameters Primary 400 GeV/c proton beam Typical beam intensity at T4 target: ~ 20  10 11 ppp The experiment requires reduced rates < 10 4-5 ppp (for silicon detectors DAQ) Beam measurements Beam measurements ~ 10 μrad divergence ~ 1 mm (r.m.s.) beam dimension at 65 m with not aligned crystal Crystal not aligned 1 ch = 0.110 mm

18. 18/19 September 2006Walter Scandale High precision goniometric system Silicon detector Goniometer Granite Block Crystals Scintillator

19. 19/19 September 2006Walter Scandale AMS Silicon Detectors Detector upstream of the crystal (on the granite block): 1 double-sided silicon microstrip detector: - Resolution ~ 10 μm in bending direction (X coordinate) - Resolution ~ 30 μm in non-bending direction (Y coordinate) - Active area ~ 7.0 x 2.8 cm 2 Detector downstream of the crystal (on the granite block) : 1 BABY double-sided microstrip detectors (IRST): –Resolution better than 10 μm in bending direction –Resolution better than 20 μm in non-bending direction –Active area ~ 1.9 x 1.9 cm 2 DOWNSTREAM TELESCOPE (at 65 m from crystal location): 4 AMS LADDERS: –Resolution ~ 10 μm in bending direction –Resolution ~ 30 μm in non-bending direction –Active area ~ 4 x 7 cm 2 Silicon thickness: 300 μm

20. 20/19 September 2006Walter Scandale AGILE Silicon Detectors Single-sided silicon strip detectors Built by Agile (INFN/TC-01/006) active area 9.5×9.5 cm 2 Spatial resolution: ~ 40  m at normal incidence (~ 30  m for tracks at 11°) Silicon thickness: 410 μm Upstream detector (before goniometer): -2 silicon detectors at 90° (corresponds to 1 X-Y plane) Downstream detector 1 (at 65 m from crystal location): - 4 X-Y silicon planes Downstream detector 2 (at 65 m from crystal location): - 6 X-Y silicon planes interleaved with 300  m tungsten planes

21. 21/19 September 2006Walter Scandale Scintillators and trigger system SCINTILLATING DETECTORS: –finger scintillators (S1,S5): 0.1 × 1 × 10 mm 3 (S1,S5): and 0.05 × 1 × 10 mm 3 (S2) to choose a narrow beam fraction –1 finger scintillator (S6): 2 × 1 × 10 mm 3 –scintillating Hodoscope (H): 16 strips with 3.2 × 3.0 cm 2 sensitive area (each strip is 2 × 4 × 40 mm 3 ) read-out by 16 ch. MAPMT (fast beam monitoring) –2 scintillator plates (S3,S4): 100 × 100 × 4 mm 3 used for triggering the silicon detectors SCINTILLATORS ELECTRONICS and TRIGGER: –programmable Trigger Logic Unit (high flexibility: many trigger conditions possible)