Author: V. Bocean

Institution: Fermi National Accelerator Laboratory

Co-Author: S. Childress, D. Jensen, R. Ford

The Precise Alignment of the Fermilab KTeV Experiment

Abstract:

The two new kaon experiments currently running at Fermilab, collectively known as KTeV, perform using the same beam and detection system. Using two carefully matched neutral kaon beams, KTeV is currently making very high precision physics measurements addressing the origins of CP violation, as well as sensitive searches for rare and forbidden kaon decays. To achieve a required systematic error contribution well below the sensitivity noise level, precision alignment has a fundamental role in the success of the KTeV physics program. The need for accurate primary beam targeting and neutral beam definition precision have led to stringent alignment tolerances. The primary beam alignment must insure that a 0.25 mm beam hit the 1 mm x 2 mm (30 cm long) target and have a position stability less than 0.1 mm. The resulting neutral beam, precisely defined by the collimators, must be positioned and stable at the 0.2 mm level with respect to the calorimeter and the detector system. This paper gives an overview of the methods, the implementation, and the results of the precise alignment of the KTeV experiment, together with stability issues and the current status of the experiment's alignment monitoring system.