Field studies for 2 Tesla data

Magnetic field meeting, CERN Oct 19, 2006

V. KarimäkiHelsinki Institute of Physics

Outline

• study of Mapper alignment • simple alignment correction• comparison with Tosca• summary

2

Mapper arms and probes tilt effects

Tilt of arms from the plane normal to B:

• causes Br and Bphi coupling to Bz• since Bz is large ans Br and Bphi are small, even small tilt causes large relative effect to Br/Bphi• the effect is sinusoidial as a function arms rotation

Tilt of probes with respect to the arm:

• causes a constant coupling to Bz (independent of phi)

3

Correction formulas

Br -> Br + [(i +

j sin(-

j)]Bz

Bphi -> Bphi + [(m +

n sin(-

n)]Bz

- is arm turning angle- 's are probe dependent- 's and 's are arm dependent

4

Br vs phi at z=0No alignment correction Mapper alignment correction

5

Bphi vs phi at z=0No alignment correction Mapper alignment correction

6

Bz and Br vs z, r=0.092 m

7

Bz and Br vs z, r=0.500 m

8

Bz and Br vs z, r=0.908 m

9

Bz and Br vs z, r=1.316 m

10

Bz and Br vs z, r=1.724 m

11

Summary

• 2 Tesla field studied• comparison with Tosca• study of Mapper alignment correction in the plane z=0• of the order 1 mrad corrections• fairly good agreement with Tosca• Bz scale difference about 1.0075

• maps with higher current next

12