1. Experimental Setup of the H8-RD22 Experiment Massimiliano Fiorini (on behalf of the H8-RD22 Collaboration) University of Ferrara – INFN Ferrara CARE HHH 2007 Workshop Crystal Channeling for Large Colliders: Machine and Physics Applications CERN – 22 March 2007

2. Outlook Experiment in the H8 beam line of the SPS north area  Silicon crystals  Experimental layout  High precision goniometric system  Proton Beam  Tracking detectors AMS microstrips detectors AGILE microstrips detectors Parallel plate chamber  Scintillators and trigger system  Crystal alignment and angular scans Concluding remarks

3. Crystals sizes: 0.9 × 70 × 3 mm 3 and 0.5 × 70 × 3 mm 3 beam Main bending Anticlastic bending Strip silicon crystals Strip Crystals have been fabricated in the Sensors and Semiconductor Laboratory (U. of Ferrara) Mechanical bending exploits anticlastic forces

4. Crystal plate sizes: ~ 1 × 30 × 55 mm 3 critical angle for 400 GeV/c protons: θ c ≈ 10 μrad O.I.Sumbaev (1957) Quasi-mosaic bending Anticlastic bending Main bending R Quasy-mosaic silicon crystals Quasi-Mosaic Crystals fabricated in PNPI (Gatchina, Russia) mechanical bending of the crystal induces bending of the atomic planes (initially flat and normal to large faces of plate) due to anisotropy  depends on the choice of crystallographic plane and on the angle of n 111 respect to the crystal face

5. H8-RD22 apparatus S1 Si microstrips (AGILE) S3 GC S5 vacuum Si microstrips (AMS) p S2 70 m H S4 S6 B5 B6 Goniometer with crystal holders Scintillators (S1-S6) Scintillating Hodoscope (H) Bending Magnets (B5-B6) Gas Chamber (GC)

6. Proton beam CERN SPS H8 beamline Primary 400 GeV/c proton beam Typical beam intensity at T4 target: ~20 × 10 11 ppp The experiment required reduced rates ~5 × 10 4 ppp Measurement results ~8 μrad divergence ~2 mm beam spot size at crystal location μrad

7. Silicon detector Goniometer Granite Block Crystals Scintillator High precision goniometer

8. Goniometer (1) two translational stages  2 μm bidirectional repeatability  full range of 102 mm (upper stage) and 52 mm (lower stage) one rotational stage  360° rotation  1.5 μrad accuracy  1 μrad repeatability

9. Rotation axis of the goniometer Crystal holder Goniometer for planar channeling Rotation axis of the goniometer Linear stage to put the crystal holder on rotational axis of the goniometer Linear stage to put the goniometer on the beam Rotation axis of the goniometer Proton beam Rotation axis of the goniometer Rotational stage for the alignement of the crystal with the beam (planar channeling) Proton beam Rotation axis of the goniometer Rotational stage also allows the change of the crystal with the rotation of 180° Proton beam Goniometer (2)

10. Goniometer (3) Interferometric measurements capability to return to the defined position within 1.5 μrad ± 1 μrad angular steps

11. Silicon thickness: 300 μm 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 × 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 × 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 × 7 cm 2

12. 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 AGILE silicon detector 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

13. Gas chamber and scintillators Gas Chamber  Parallel plate chamber  0.6  12.8 mm 2 active area  filled with Ar 70% + CO2 30%  64 strips (pitch equal to 200 μm)  mounted on X-Y table  able to withstand rates up to 10 8 ppp Scintillating detectors  Finger scintillators: 0.1  1  10 mm 3  Scintillating hodoscope: 16 strips with 2  4  30 mm 3 read-out by MAPMT (fast beam monitoring)  Scintillator plates 100  100  4 mm 3 used for triggering silicon detectors

14. Laser pre-alignment laser beam, parallel to proton beamline measurement of laser beam deflection (1 mm precision) considering prism-crystal distance (~1 m) and prism- laser distance (~ 4 m), accuracy of crystal pre- alignment was about 0.1 mrad crystal screen LASER pentaprism

15. Angular scan: example Fast identification of channeling position with parallel plate chamber Fine step angular scan Detailed angular measurement with silicon detectors All data are stored to disk for offline analysis

16. Conclusive remarks SPS H8 beamline excellent facility for crystal channeling and volume reflection studies (very low beam divergence ~8 μrad) Goniometric system with ~1 μrad precision and the possibility to host two crystals Set-up of tracking system with excellent spatial resolution and minimal material budget 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)

17. SPARES

18. Double reflection on Quasi-Mosaic crystal Experimental setup: exploited rotational stage for off-axis alignment of the first crystal (preliminary scan) used upper linear stage for alignment of second crystal many steps for finding perfect alignment conditions