A Proportional Wire Calorimeter for Magnet Pole Tips

We describe the results of test beam evaluation of a total absorption calorimeter which is designed to have magnetic properties comparable to those of ordinary steel, and thus can be incorporated into the poles of a spectrometer magnet. The test device consists of an iron structure penetrated by a fine-grain pattern of holes, each acting as a gas proportional tube, such that 90% of the volume is occupied by iron. Details of shower development and sampling fluctuations relevant to the design of a large scale device are studied for showers initiated by electrons and hadrons.