Target Resolution Check

1. Target Resolution Check Y.C.Han@k0 Meeting Oct 17, 2007

2. Outline • Method Description • Vertex Position Distribution • Target Resolution w/ Cut • Conclusion

3. Method Description2-tr-vertex Information Opening Angle Vertex Position: p_v = (p1+p2)/2 track1 track2 dist_tr = | p1- p2 | …… Z ( up ) Y Position p1(x1,y1,z1) Position p2 (x2,y2,z2) 0 X (γ beam) (Center of 680) Schematic for 2-tr-vertex Coordinate

4. Method Description3-tr-vertex p_vb p_va Track 1 r_cir B A Track 3 Track 2 r_in C circumcircle incircle p_vc Vertex Position p_v = (p_va+p_vb+p_vc)/3 Schematic for 3-tr-vertex

5. Vertex Position Distribution

6. Vertex Position Distribution

7. Target Resolution-1

8. Target Resolution-2

9. Target Resolution-3

10. Target Resolution-4

11. Conclusion By applying the simple position cut, one can get: • Target resolution using Method of 3-track-vertex can achieve ~ 1.8 mm, comparable with 2-track-vertex result 1.4 mm; • Up beam edge of target has better resolution than down beam edge; • Resolution is sensitive to vertex-distance cut and vertex position along yoke (Y-axis) cut . Z ( up ) Y 0 X (γ beam) (Center of 680) Coordinate

12. That is all.