Mechanical Configuration v 1 0 The mechanical design

Mechanical Configuration v 1. 0 The mechanical design will allow for following data-taking configurations: 1) R will translate to 3 positions in Y, be fixed in X, rotate around the X-axis by 0, 4, 8, 20 degrees, and be fixed around the Y-axis at 0 degrees. 2) Phi will translate to 3 positions in Y, be fixed in X, and be fixed around both the X-axis and Y-axis at 0 degrees. (The coordinate system is given in slide 2. The X and Y positions are given by the center of the three pixel aperture boxes in slide 3 and detailed in the table on slide 4. ) Data can be taken independently for R and Phi. They will be separated by ~5 cm. R and Phi will be centered between the two pixel stations (upstream+downstream), in the case of a short or a long lever arm. The beam may be moved around in the pixel aperture by translating the entire box (pixel+velo) remotely, to select the region of highest statistics. (See photo in slide 5. )

R 2 yy b a x z z Phi 2 yy b a x z z c x c

(0, 11 cm) (4. 5, 11 cm) Position 1 Position 2 Position 3 A C B (1. 0, 7. 5 cm) (0, 0) 3

Beam Pixel Acceptance (mm) Position X 1 X 2 Y 1 Y 2 A 0 35 -45 -10 B 0 35 10 45 C 0 35 -17. 5 y R 2 B Beam f~30 mm (defocused) Pixel coverage ~35 35 mm 2 C f ~10 mm (focused) x A d z Reference position: center of pixel and VELO planes are aligned to the center of beam, and perpendicular to the beam. d ~ 100 mm For each configuration we will move the whole box with respect to the beam to get maximum event rates on interesting areas.

Old Photo of Box (as it was used by another group) BEAM BOX PORT XY STAGE