The detector system for measurement of multiple cosmic muons in the central detector of KASCADE

A detector system for directional and time correlation measurements of mult iple cosmic muons has been set up within the extensive air shower experimen t KASCADE. The system consists of two layers (129 m(2) area each) of positi on-sensitive multiwire proportional chambers (MWPC) triggered by a layer of segmented plastic scintillation counters placed upon an iron/concrete shie lding above the MWPCs. Operation conditions and performance of the MWPCs ha ve been studied by means of a prototype arrangement consisting of a stack o f four detectors and two trigger layers. Results of the detailed prototype studies are presented and discussed. In particular, it has been found that for the present purposes an operation with a commonly used argon-methane ga s mixture instead of previously used argon-isobutane leads to an excellent performance. The chambers are integrated into the KASCADE experiment as des cribed and are in continuous operation since 1996. Some typical measurement s with the full detector assembly are used to illustrate which features of extensive air showers can be studied. (C) 2001 Elsevier Science B.V. All ri ghts reserved.