What's new with the CMS hadron calorimeter

The CMS Hadron Calorimeter is designed to measure hadron jets, single hadrons and single mu 's. The central barrel and the two end caps, made of brass and scintillators cover the ¿ eta ¿ range of 0.0 to 3.0. The two forward calorimeters made of iron and quartz fibers extend the ¿ eta ¿ range to 5.0. Scintillators are also placed outside of the magnet coil, within the muon system to measure the energy leakage from the central barrel. The construction of the calorimeter is about 50% complete. Several design changes were made to simplify the calorimeter and reduce the cost. The longitudinal segmentation of the central barrel and end caps was reduced by one unit. The quartz fiber diameter was doubled from 300 to 600 microns. Improvements were made to the hybrid photodetectors (HPD) and various other components. The special purpose ADC (QIE) and other electronics are in prototype stage. (3 refs).