Design and bench test of proportional chambers for the BIS-2 spectrometer

A construction and results of bench tests of proportional chambers (PC) of a BIS-2 spectrometer are described. Dimensions of PC working regions vary from 400x300 to 1000x600 mm. Specific features of the large PC construction having working region dimensions over 820x300 mm and peculiarities of electronics connection to PC are considered. Results of investigations into the determination of charged particle registration efficiency depending on a high voltage, noise properties on a plateau ''region of an ''efficiency-voltage'' curve, dependence of PC characteristics on a gas content, long-time stability, influence of ''supports'' are given. It is concluded that it is expedient to use Ar+13%CO2+3%C2H5OH+0.3%CBrF3 gaseous mixture as a working mixture