APEX expriment s knob M. Bai, Y. Hao, G. Robert-Demolaize, S. - PowerPoint PPT Presentation

APEX expriment s ∗ knob M. Bai, Y. Hao, G. Robert-Demolaize, S. White, X. Shen, Z. Duan April 25, 2014

Motivation Luminosity reduction due to hourglass effect and s ∗ σ z = k z β ∗ , s ∗ 1 = k 1 β ∗ , s ∗ 2 = k 2 β ∗ , � ∞ exp( − t 2 ) dt 2 L = L 0 2 + ( k z t − k 1 ) 2 + ( k z t − k 2 ) 2 , √ π −∞

Theory Matching using quad knobs in insertion region Figure 1 : One half of insertion region (IR).

Theory Required v.s. matched s ∗ (Courtesy M. Bai). 50 s * 40 y y=x 30 y [cm] 20 10 Matched s * 0 -10 -20 -30 -40 -50 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 Required s * y [cm] 50 s * 40 x y=x 30 x [cm] 20 10 Matched s * 0 -10 -20 -30 -40 -50 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 Required s * x [cm]

Theory Required v.s. matched s ∗ (Courtesy M. Bai). 0.006 s * y 0.004 y [cm] 0.002 Matched s * 0 -0.002 -0.004 -0.006 -1 -0.5 0 0.5 1 Required s * y [cm] 50 s * 40 x y=x 30 x [cm] 20 10 Matched s * 0 -10 -20 -30 -40 -50 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 Required s * x [cm]

Theory Required v.s. matched s ∗ (Courtesy M. Bai). 50 s * 40 y y=x 30 y [cm] 20 10 Matched s * 0 -10 -20 -30 -40 -50 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 Required s * y [cm] 0.006 s * x 0.004 x [cm] 0.002 Matched s * 0 -0.002 -0.004 -0.006 -1 -0.5 0 0.5 1 Required s * x [cm]

Theory Beta-beat after mathcing (Courtesy M. Bai). 0.4 Horizontal 0.35 Vertical 0.3 0.25 0.2 ∆β / β 0.15 0.1 0.05 0 -0.05 -0.1 -0.15 550 600 650 700 750 Longitudinal distance [m] 0.4 Horizontal 0.35 Vertical 0.3 0.25 0.2 ∆β / β 0.15 0.1 0.05 0 -0.05 -0.1 -0.15 0 500 1000 1500 2000 2500 3000 3500 4000 Longitudinal distance [m]

Experimental results Predicted s ∗ shift v.s. measured s ∗ shift. Error bars reflect standard deviation. 10 Horizontal Vertical 0 -10 Measured s * shift [cm] -20 -30 -40 -50 -60 V -20cm H/V -10cm Baseline H +20cm Predicted s * shift [cm]

Experimental results Predicted s ∗ shift v.s. measured β ∗ . Error bars reflect stan- dard deviation. 80 Horizontal Vertical 75 Measured β * [cm] 70 65 60 55 V -20cm H/V -10cm Baseline H +20cm Predicted s * shift [cm]

Experimental results s ∗ and β ∗ . Error bars reflect standard deviation. 120 Horizontal β * Vertical β * 100 Horizontal s * 100 Vertical s * 80 80 60 60 40 40 s * [cm] β [cm] 20 20 0 0 -20 -20 -40 -40 -60 -60 V -20cm H/V -10cm Baseline H +20cm Predicted s * shift [cm]

Experimental results Predicted s ∗ shift v.s. measured β IP . Error bars reflect stan- dard deviation. 85 Horizontal Vertical 80 75 Measured β IP [cm] 70 65 60 55 V -20cm H/V -10cm Baseline H +20cm Predicted s * shift [cm]

Conclusion Turn-by-turn BPM based s ∗ measurement More sensitive than β ∗ measurement, strong coupling in the horizontal plane could be an issue s ∗ knob manipulation exhibits linear/nonlinear response range Manupilation with ∼ 20% beta-beat, studies are in progress Further study Improve machine condition for “cleaner” s ∗ manipulation and measurement Explore other methods