# Tagger Magnetic Field Maps - ca. January, 2013

## Contents

## TOSCA field maps - January, 2013

### Tagger Dipole

The field map linked below was created by Yang Guangliang (Glasgow, UK) on January 15, 2013. The current in the coils has been adjusted to give a central field in the dipole of approximately 15000G. The map grid has been constructed as follows.

- The z axis is defined as parallel to the long axis of the magnet poles, with the origin at the center of the magnet poles.
- The y axis is defined as perpendicular to the bend plane, pointing up, with the origin at the midplane between the poles.
- The x axis is defined as parallel to the short axis of the magnet poles, with the origin at the inner edge of the root of the poles. Here is a drawing that illustrates the coordinate system on which the map grid is based.
- Only the region x>=0, y>=0, z>=0 is represented in the map. The field in the other 4 quadrants characterized by y<0 and z<0 are found by reflection through the planes y=0 and z=0.
- The step size in x is 1 cm from 0 to 100 cm, for a total of 101 grid points.
- The step size in y is 3 mm from 0 to 15 mm, for a total of 6 grid points.
- The step size in z is 1 cm from 0 to 400 cm, for a total of 401 grid points.

The field tables below are readable plain text files with an explanatory header. They also happen to be self-extracting scripts which can be run using the perl interpreter to create compact 3-column files that are suitable to use as inputs to simulation or ray-tracing codes.

- Dipole magnet TOSCA map @ 1.5 T
- Dipole magnet TOSCA field color image @ 1.5 T
- Dipole magnet TOSCA field color image with coils @ 1.5 T

### Tagger Quadrupole

The field map linked below was created by Yang Guangliang (Glasgow, UK) on January 15, 2013. The current in the coils has been adjusted to give a central field gradient that is reasonably close to what is needed to produce a vertical parallel-to-point focus at the focal plane for 3 GeV electrons, for the nominal placement of the quadrupole. In case of a shift in the quadrupole position relative to the dipole, or to obtain a vertical focus at some other point along the focal plane, the map can be simply rescaled under the assumption of approximately linear response. The map grid has been constructed as follows.

- The z axis is defined as parallel to the beam axis.
- The y axis is defined as the vertical direction pointing up.
- The x axis is defined as beam-right.
- The origin in all three coordinates is the center of the magnet.
- The step size in x is 0.1 cm from -2cm to +2cm, for a total of 41 grid points.
- The step size in y is 0.1 cm from -2cm to +2cm, for a total of 41 grid points.
- The step size in z is 1.0 cm from -50cm to +50cm, for a total of 101 points.

The field tables below are readable plain text files with an explanatory header. They also happen to be self-extracting scripts which can be run using the perl interpreter to create compact 3-column files that are suitable to use as inputs to simulation or ray-tracing codes.

### Dipole centre plane at different fields

This is a repeat of the above dipole field calculation for a variety of different central field settings. Only the y=0 plane is sampled, and the range in x has been extended from -25 cm to +100 cm, otherwise the grid is the same.

- Centre plane at 1.7 T (23051.25 ampere-turns)
- Centre plane at 1.6 T (20393.1 ampere-turns)
- Centre plane at 1.5 T (18643.5 ampere-turns)
- Centre plane at 1.4 T (17152.56 ampere-turns)
- Centre plane at 1.2 T (14573.25 ampere-turns)
- Centre plane at 0.9 T (10880.055 ampere-turns)
- Centre plane at 0.6 T (7241.67 ampere-turns)