Results of the ATLAS solenoid magnetic field map

ATLAS is a general-purpose detector designed to explore a wide range of particle physics topics at the Large Hadron Collider. A crucial component to the success of ATLAS will be a precise knowledge of the magnetic field produced by the ATLAS solenoid. To achieve this, a special field mapping machine was built and deployed to measure the solenoid magnetic field. This paper describes the mapping machine, the field mapping campaign, and the subsequent analysis of the field map data. After a series of small corrections, some taken from surveys and some derived from the data itself, were applied to the recorded data, the corrected data were fitted with a function obeying Maxwell's equations. The resulting field residuals had an rms of less than 0.5 mT, and the systematic error on the measurement of track sagitta due to the field uncetainty was estimated to range fom 2-12 × 10-4, depending on the tack rapidity