The 2D small angle detector project at the FOCUS time-of-flight spectrometer at SINQ

A small-angle detector will complete the performance of the cold time-of-flight spectrometer FOCUS at the Swiss Spallation Source SINQ of the Paul Scherrer Institute, Villigen, Switzerland. It is constructed from position-sensitive 3He tubes located 2.5 m away from the sample, and covers an area of about 95×70 cm2 with a spatial resolution of approximately 1.5 cm. The 2D detector is located within a vacuum chamber, next to the argon chamber of the existing large angle detectors, and covers an angular range from 2 to 22°. Commissioning of the 2D small angle detector will start in spring 2006.